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#53 Mould Maker’s Loom Part 6, More on The Wire Twisting Mechanism

This is a self contained mechanism that is fastened to the front of the traveling beam of the loom. The spindle rack is the base of the twisting mechanism; all the other parts are attached to it. It is made from a single piece of wood, as long as the longest laid wire. It has 5/8″ holes bored through it at regular intervals to hold the spindles. A cord reel passes from end to end. It is attached by end plates to the spindle rack. A crank is affixed to the right-hand end. The crank’s back and forth rotation is limited to about 180 degrees, between the fixed stop and the adjustable stop. This hand powered crank supplies the effort to turn as many spindles as are required to make any size facing or backing. A drive weight and cord are hooked up for each spindle used. The back end of each cord is fixed in the cord reel and the front is tied to a 2.2 oz. lead weight. Each cord wraps three times around a spindle to turn it by friction. When the crank is rotated back and up it ‘reels in’ the cords causing all of the weighted spindles to turn clock-wise simultaneously. This allows all of the chain wires to be twisted at the same time. This simple cord/spindle mechanism has a couple of important qualities that I will attempt to describe in the following text, photos and videos.

Spindles are normally placed in the center of the spindle rack when a wire facing is being made. For these photos a single spindle has been hooked up near the crank so most of the working parts can be shown together. The wire trough has been removed to reveal the spindle, weight and cord.

Some of the parts are identified here.

The left hand end of the mechanism showing the plywood end plate, and a washer, cap and machine screw that hold this end of the cord reel in place.

A spindle is rigged by wrapping a cord three times around it. The 1/8″ brass rod at the front of the spindle rack holds the front of the cord up to keep the loops from crossing over each other.

Understanding How it Works

The crank is limited to turn (back and forth) about 180 degrees. The reel is a larger diameter than the spindles so the spindles end up turning a little MORE than 180 degrees. This is important and will be explained later. As you can see above when the spindles have no load on them they will simply turn back and forth with the crank.

A repeat of the first video showing an unloaded spindle turning back and forth.

I am placing gentle pressure on the side of the spindle with my finger. Under load the spindles turn clock-wise and do not ‘back up’. This is the first ‘beauty’ of this simple mechanism; a simple back-and forth motion of a crank can be converted to a ‘one way’ rotation of the spindles. This allows wires to be twisted in one direction to form chain wires. But if you look closely you can see that the spindles gain a few degrees with each rotation of the crank.

These extra few degrees of rotation are intentional and the stops of the crank are set to provide it. This video attempts to show the constant ‘re-calibration’ of all of the spindles (the second beautiful thing about this simple string and weight arrangement) that happens when a facing is being made on the loom. I am using my finger to simulate the stopping action usually provided by the pairs of (as yet untwisted) chain wires being raised (by the treadle and lifting mechanism) to engage the slots in the wire trough. (If the trough were in place you wouldn’t be able to see anything. ) My finger is allowing the holes in the spindle to re-align each time the crank is released, clumsily simulating the regulating action that is normally provided by the lift mechanism.

Repeating Cycle of Twisting Mechanism Only (other actions of the loom not included here)

(1) At Rest

The crank is ‘parked’ against the lower stop and the weight has dropped as far as the cord will allow; the resting position for the entire mechanism. The pair of spindle holes are oriented front and back with hole “a” in back.

(2) Crank Reels In

The crank has been rotated up to the fixed stop (and held there), reeling in the cord and causing the spindle to rotate a little more than 1/2 turn. Hole “a” has moved around to the front. The holes are not aligned directly front to back, having rotated past the center line. I’ve added imaginary chain wire here (red) and an imaginary wire trough slot whose sides are described with the parallel black lines.

(3) Chain Wire Lifted into Slot

The crank is still being held against the upper stop so the rotation of the spindles continues to be ‘frozen’. However the loom treadle has been stepped on, lifting the upside down “Y” up, engaging the splayed wires in the ‘slot’. The wires are bent sideways a little by the edges of the slot because the holes aren’t directly below. The blue line shows how far ahead the spindle has turned compared to the green line which is drawn straight across.

(4) Crank Returned to Lower Stop, Spindles Re-Calibrated

The operator’s foot remains on the treadle holding the wires up so they are still engaged in the slot. The crank is on its way back down to the lower stop thus unreeling the weighted cord. This causes the spindle to reverse by a limited amount. At a certain point the engaged wires prevent the spindle from turning further and the cord begins to slip. By the time the crank has been released completely to rest against the lower stop the spindle has re-calibrated (a tiny bit behind the center line which is OK). Each time this cycle is repeated all of the many spindles in use will automatically re-align. That way spindles don’t get behind or ahead and all are always ready for the next twist.

Two laid wires are being added here. One is already in place. If you watch the white wire spacers behind the weights you can see them reverse a little just as the weights drop down. This shows the spindles re-aligning.

#52 Mould Maker’s Loom Part 5, The Wire Twisting Mechanism

Assembly of the Mechanism

Examining the parts as they are put together may be one way to understand its workings.

I don’t usually assemble the parts on the loom as I will do for this post. Normally the various spindle racks (a different one is needed for every chain spacing) are pre-assembled except for certain parts that they all share. For instance there is only one cord reel and crank needed for this loom. There are enough spindles and drive weights to make the largest possible facing. When a facing or backing is made only the number of these actually needed are attached.

Spindle Rack

This spindle rack started out as a long piece of yellow birch with a simple rectangular cross-section (3″ wide by 1-1/8″ thick). These pieces should be the same length as the frame cross-pieces and the traveling beam, 42″ in this case. After the large spindle holes were bored two cuts were made on the table-saw to create the shape shown here. The thick back side provides support when screwed to the traveling beam; the front side is narrowed to 1/2″. This is the amount that the (7/8″ tall) spindles are set down into the rack.

A strip of polycarbonate screwed to the bottom prevents the spindles from dropping through the holes and provides a slippery surface for them to turn on. These holes were bored with a 5/8″ forstner bit and the spindles had to be turned down a bit on a lathe to turn freely. A simpler method is described at the end of the post.

The strip overlaps the hole just enough to support the spindles without blocking the small holes through which the chain wire will pass.

The partially completed spindle rack can now be fastened to the loom; specifically to the traveling beam of the indexing mechanism. The dark colored spot is one of five acetal ‘plugs’ sunk into holes. They are cross-drilled and tapped to receive the threads of the machine screws. Two of the five machine screws are visible here.

The rack has been attached at the center only.

All five of the machine screws have been tightened to firmly attach the spindle rack to the traveling beam. Wood screws could also be used but would be difficult to drive from behind.

A view from beneath.

End Plates

These blocks are screwed in place; one at each end.

They provide a way to fasten the end plates in place.

The end plates are mirrors of each other.

The right-hand end plate has a few extra holes for attaching the two stops.

These limit the motion of the crank to about 180 degrees (back and forth only). The top one is fixed and the bottom one is adjustable.

Cord Reel and Crank

The cord reel is made of 3/4″ diameter acetal rod. A line of holes has been drilled into it for nearly its full length. The spacing of the holes isn’t too important. (about 1/4″ is good).

At one end a crank is attached by a machine screw in a threaded hole. The square shank and mortise allow the crank to be re-positioned. This makes it possible to correct the orientation of the reel after attaching the cords and drive weights.

Two pairs of metal posts (located at thirds) keep the reel from being pulled forward when drive weights are attached. The reel needs to be elevated above the top of the rack to provide room for the cords. Plastic shims placed over the posts elevate the reel in the middle. The ends of the reel are already held up by the holes through the end plates.

The cord reel is ready to insert through the big hole in the end plate. A large washer keeps the crank from rubbing against the end plate.

The reel passes through the left-hand end plate in the same way.

It is held loosely in place by another washer, a plastic cap and a small machine screw.

Wire Trough

This is the wire trough which covers the row of spindles. The V shape makes it easy to slide laid wires in (one at a time). The cross-wise slots allow the pairs of chain wire to remain spread out (when lifted) so laid wires can pass between them. The slots also engage the lifted chain wires to prevent the spindles from turning backwards as the crank and reel are reversed.

This design is more complicated than it needs to be and I will show a simpler version at the end of the post. These were made this way to solve a problem; it was possible for the loops of cord that are wound around each spindle to slip up off the top. This happened when a drive weight was accidentally bumped from below. Two changes were made. First, the spindles were lengthened from 3/4″ to 7/8″ so they would stick up farther above the cord loops. Second, the wire trough was shaped to enclose the tops of the spindles and prevent the cord from slipping up that high. Both work very well to prevent these occasional accidents but simply lengthening the spindles may have been enough.

The trough lying on its side. The very narrow saw cuts were made with a Japanese style backsaw held in a cross-cut jig.

The wire trough is laid upside down to show how the top of the spindle is enclosed to prevent the cord from slipping off the top.

The holes in the cord reel receive these tiny cotter pins to connect the weighted cords to the reel. The cotter pins start out too long and have to be snipped off a bit. The knots at both ends of the cord are fixed with ‘Crazy Glue’. As mentioned the spacing of the holes is not critical, the location of each cord attachment just needs to be fairly close.

The cords are fitted with the holes in the reel pointing straight up. (Just to make it easy to put the cotter pins in). After all of the spindles are hooked up the crank can be loosened and slipped out of its square mortise so that the weights can be reeled in the right amount. (If they hang down too low they get in the way.) After the adjustment is made the socket of the crank is firmly tightened over the square shank of the reel.

The ends of the cotter pins should start at the back and end up in the front when the weights are cranked up fully. This way the pins and knots stay on top as the reel is turned back and forth. The purpose of the 1/8″ brass rod fastened along the front is to elevate the cords at the front of the spindles. This prevents the cord loops from lapping over each other.

This photo provides a good illustration of the problem mentioned a few photos back. If a weight is bumped from below the loops of cord might loosen and slip off the top of the spindle. This was even more likely with the original spindles which stuck up only 2/3 as far as these do. The more elaborate wire trough I now use prevents this from happening.

Chain wire is added with the wire trough elevated. This process is covered more fully in other posts.

When the wire trough is lowered over the spindles and screwed down the assembly is complete. For this post only three chain wires have been used. Normally there would be many more chain wires, spindles and weights.

Older, Simpler Parts

When it came to time to make a second loom I tried to refine the design using everything I had learned over the years. But some of the original features were very functional and easier to make.

An example of the original wire trough made of pine from a lumberyard.

Pairs of screws work as little ‘jacks’ which are adjusted to hold the bottom of the trough just above the spindles. If longer spindles were used (7/8″ or even 1″) longer screws could easily be adjusted to fit. This might solve the ‘cord over the top’ problem mentioned earlier in this post.

The wire racks were also a little crude but worked well for as long as this loom was in service.

These were also made of pine which has some advantages. The original spindles were cut from 5/8″ diameter acetal rod and filed smooth on the ends. (I didn’t have a lathe). This material is manufactured slightly oversize so the 5/8″ holes drilled in the wood fit too tight. The holes were easy to enlarge with a strip of coarse sandpaper and dowel chucked into an electric drill. As you can see above the spindles can be quite loose.

#51 Mould Maker’s Loom Part 4, The Lift Mechanism

The purpose of the lift mechanism is to repeatedly lift the wire facing so that laid wires can be added at the bottom. A treadle and lift lever (not pictured, at the bottom of the loom) pull down on the middle of a “V” of rope. (The top ends of the V are visible here.) The ends of the rope pass up and over a pair of large wooden pulleys. The wooden pulleys reverse the rope’s direction to lift two smaller steel pulleys attached to the short upper lift beam. This raises the entire lifting beam assembly one half inch. Attached to the bottom of the long lower lifting beam is the steel lifting rod. Weighted wires will hang over this rod to form chain wires when making a laid facing (or backing) on this loom. When pressure on the treadle is released the rope relaxes and the lifting beam drops back to its lower position.

Large Wooden Pulley Assembly

Two large pulleys are made from layers of birch plywood. Each one is a sandwich of one smaller disc and two larger ones. Steel washers and nuts are added to both sides of each pulley to bind all of the parts tightly together. Both pulleys turn together as a unit and only rotate (back and forth) a few degrees, about an inch at their perimeters.

Loosely placed at the sides of the cross-piece above are two wooden blocks which attach the pulleys to the frame. Each is fitted with a nylon bushing for the threaded rod/axle. It might seem sub-standard to use threaded rod as an axle and nylon bushings as bearings. But it is a simple solution that has proved to work very well. The original pine loom had no bearings at all and worked for decades without any problem. Nylon bushings are more durable than pine and have the advantage of being easily replaced.

The wooden pulley assembly in the process of being slid into place over the four carriage bolts that secure it to the frame.

3″ Offset from Front of Loom Uprights

The plywood pulleys are sized and placed so that the rope passing over the back is centered over the treadle lever at the bottom of the loom. More importantly, the rope coming down off the front of the pulleys should be exactly centered over the lifting beam. A wire facing being made on the loom will take the form of a vertical plane hanging directly below the lift beam. This loom is designed for that plane to be located exactly 3″ in front of the faces of the loom frame uprights. The lifting beam and all its moving parts must be centered in this plane as shown above. The red line indicates the front face of one of the uprights. The green line shows the centerline of the upper lifting beam (and other attached parts below). The purple arrows indicate that the rope is also centered in this plane.

Later when the twisting mechanism is attached the spindles (that fit in these holes) will also be centered 3″ in front of the loom uprights.

Lifting Beam Assembly

Here the lifting beam is off the loom and partly assembled.

The protruding ends of the bolts fit into holes drilled into the lower part of the beam.

The small steel pulleys are bolted to the upper lift beam with nuts recessed at the bottom.

Directly below each steel pulley a steel bushing is flanked by a pair of washers. When the 5/16″ carriage bolt passing through them is tightened (to connect the lower lift beam to the upper one) the three separate steel parts (washers and bushing) are squeezed tightly together to act as a unit. The bushings are 5/8″ long with a 5/16″ bore. The washers are more precise than average washers, all having the same thickness and snug fitting holes.

This shows the purpose of the washer and bushing ‘units’ after the lift beam assembly has been installed on the loom. The bushings slide smoothly up and down (through holes drilled in the steel angle) to guide the lift beam. The washers at the top and bottom limit this motion to one half inch. The beam was set to be neither up nor down just for the photo; normally (with the treadle released) the upper washer rests on top of the steel angle. When the treadle lifts the beam the lower washer is pulled up against the underside of the angle.

Transferring Motion from Treadle to Lift Beam

When the treadle is pushed down with the right foot the lever pulls both halves of the rope down the same amount. This is about 1-1/2″ (the rope stretches a bit when pulled tight). The large steel weight serves only to lift the lever and attached treadle when foot pressure is released.

The upper ends of the rope pass over the wooden pulleys from the back. The motion of the rope is reversed by these pulleys to lift the beam assembly at the front. The lower steel pulleys give some mechanical advantage since they only lift the beam 1/2″ for the full inch that the rope travels under them. This makes it easier to raise the facing and attached wire weights which can weigh as much as 45 lbs. if the facing is very large. The ends of the rope are fixed to the top two carriage bolts where they are clamped between washers and extra nuts. These bolts are extra long for this purpose. This is where the rope is adjusted for length to work properly.

The loom frame equipped with the complete lifting mechanism.

#50 Mould Maker’s Loom Part 3, The Indexing Mechanism

The purpose of the Indexing Mechanism is simply to control the downward motion of the Traveling Beam (above). This beam is supported at both ends by square nuts; each fits into a notch created for it. These in turn are supported by a pair of Lead Screws, which are just full length pieces (3′ long) of 1/2″-13 threaded rod, available at hardware stores.

The lead screws are attached to 1/2″ x 4″ Machine Screws with connecting nuts. These machine screws have been inserted down through the Chain Sprockets and fastened to them by set screws. The sprockets are supported by the Chain Race and Upper Cross-Piece. The lead screws (and traveling beam) essentially hang from these two sprockets. A Timing Chain made of a loop of roller chain connects the sprockets so they always turn together and at the same rate. The Top Crank, on the right, is turned by the operator’s hand to create the motion. Each complete turn of this crank (counter-clockwise) lowers the traveling beam 1/13th of an inch. The Counting Wheel Assembly at the top left regulates the incremental downward movement of the traveling beam so that a variety of laid facings and backings can be made.

As the lead screws are turned square nuts move down, carrying the traveling beam and attached twisting mechanism with them.

Chain Race

The chain race is simply a piece of 1/4″ plywood with holes in the right places for the lead screws and for screws to fasten it in place. It provides a wider surface to support the loop of chain. The circular oil stain was left by a steel washer, one of a pair at each end on which the sprockets turn. The washers lift the sprockets up to mesh smoothly with the chain, reduce friction and bear the weight of the traveling beam and the twisting mechanism.

Chain Sprockets and Modified Machine Screws

The chain sprockets have 14 teeth and a 3/8″ pitch. The number of teeth doesn’t matter much as long as both sprockets are the same. They were purchased with a 1/2″ finished bore and each have two set screws. High grade 1/2″ diameter x 4″ long machine screws were chosen because their true 1/2″ shank diameter closely fits the sprocket bore to ‘run true’ (unlike standard hardware store bolts which tend to be under-sized). Flats were filed for the set screws and the heads were drilled and tapped for 1/4-20 threads.

Top Crank Attachment

Two washers elevate each sprocket so the teeth will line up with the roller chain. A hexagonal recess chiseled in the top crank provides a positive connection to the crank.

The right hand sprocket assembly in its place. It will be linked to the other sprocket with a loop of roller chain.

Counting Wheel Attachment

A circle of birch plywood with a hexagonal hole provides a firm base to attach counting wheels using a 1/4-20 machine screw like the one used for the crank.

Timing Chain

The timing chain is intentionally a little loose and is kept within bounds by the plastic post and a small strip of wood nailed to the front. The roller chain doesn’t need much lubrication and will run freer if the grease is cleaned off.

In use the front side of the loop runs straight since the right hand crank is turned counter-clockwise. The crank can be turned the other way (clock-wise) to return the traveling beam to the top of the loom.

Counting Wheel Assembly

This is a device that makes noise (clicks) that can be counted to lower the traveling beam a very specific amount, the distance of one laid wire plus one space. Depending on the diameters of laid wire and chain wire used this can vary a lot.

A rubber band is wound around and around so the pawl will click as it passes steel pins on the counting wheel. In this photo the pawl is disengaged.

I made a complete set of these counting wheels having from 3 pins to 27 pins so I can experiment with different sizes of wire and different spacings. Most of these wheels won’t get used. This makes it possible to make any even number facing (17 wires per inch, 18 wires per inch, 19 wires per inch, etc.) all the way up to 27 wires per inch. Even number backing is also possible with three half-twists between wires. (5, 6, 7, 8, and 9 wires per inch more than covers this need). Many in-between sizes are also possible. It’s just a matter of doing the arithmetic, calculating the number of pins to use and how many clicks to turn the crank (and pairing this with the right wire sizes).

A counting wheel with 10 pins is given 7 clicks to lower the traveling beam the distance of one laid wire and one space. If a facing was actually being made this would make a laid wire spacing of 18.57 wires per inch. This video only demonstrates the counting wheel action and the the other mechanisms are not being used.

The upper part of the indexing mechanism completed.

Connecting the Lead Screws

The lower end of each machine screw is connected to this extra long nut with a 3/32″ roll pin. As you can see these pins are also used to attach the upper end of the lead screws to the connecting nuts. It’s a bit tricky to drill these small holes through the layered steel parts without breaking a drill. It helps to snug the parts up with added hex nuts (maybe pack the lead screw in teflon tape?), to clamp things securely on the drill press and to use cutting oil. (The cutting edges of the twist drill tend to catch when exiting the inside threaded surfaces.) After assembly these parts should be a little loose; the lead screw and machine screw ends shouldn’t quite touch. The amount of force put on these parts is minimal and having some play helps them run smoothly.

A piece of plywood holds the traveling beam level while the lead screws are hooked up.

The bottom ends of the lead screws are held in place by the bushings in the bottom cross-piece. Only about an inch hangs down into the hole.

Calibrating the Lead Screws and Beam

After the lead screws are attached the notches in the beam can be lowered down over the square nuts, ‘trapping’ them so they can’t turn. The beam can be leveled (calibrated) simply by lifting one end of the beam and turning the square nut one way or the other. Each quarter turn raises or lowers that side 1/52″ (.019″) so the beam can easily be leveled to the frame within that tolerance (which is close enough for all practical purposes).

If you want to get closer the connecting link can be removed to shift the chain slightly on one of the sprockets. This lowers or raises that side between .005″ and .006″ per tooth.

Traveling Beam Backing Iron

The traveling beam slides along the front of the two loom uprights. It has a tendency to sag forward at the top so this piece of steel angle is bolted on to limit this. This metal rule is used to gauge a small space which must be left as the steel angle is cinched tight between two nuts (the back nut is hidden behind the steel angle). The rule is .020″ thick (.5mm) which works well. The traveling beam is made of a heavier wood (Oak) to help it move down the loom smoothly.

#49 Mould Maker’s Loom Part 2, The Frame

Designing and building a functional loom requires working out details of how all of the mechanical parts interrelate before starting construction. This post is limited to decisions and dimensions that must be incorporated into the parts of the frame. Many of the dimensions used are somewhat arbitrary but I will emphasize those that directly affect the capabilities of the finished loom.

The frame of this loom is fairly simple. The four main parts are made of Tulip Poplar; final dimensions of these were largely determined by the the larger planks they were cut from. Upper and lower cross-pieces, 1-7/8″ x 1-7/8″ x 42″ are bolted to two uprights, 1-3/4″ x 3″ x 71″ tall. These are spaced 22-1/4″ on center. Two 1/4″ thick plywood panels are screwed to the back to brace the structure. The loom is lag bolted and screwed to the wall. As mentioned many of these dimensions are not critical but in order for the loom to work well there are some important things to consider.

Size of the Largest Wire Facing?

The length of the two horizontal members of this frame, the cross-pieces, determines the longest laid wire that can be used and thus the length of the largest facing. For this loom I chose 42″. These cross-pieces could be made shorter (or longer) depending on the sizes of mould you intend to make.

The distance between the upper and lower cross-pieces limits the width of the largest facing. From its starting position (shown here by the upper red line) the bottom of the 4″ wide traveling beam can be lowered 29-3/4″ before it bumps the top of the lower cross-piece. This allows a wire facing width of about 29″ (after accounting for starting and finishing twists). Another important dimension that is built into this loom frame is shown by the green arrow (22-1/2″ long here) indicating an additional space that is sized to provide enough height for the weighted wires should the loom be used to its maximum 29″ width.

Sufficient Wire Length and Enough Space for It to Hang

When preparing to make a laid facing lengths of soft wire are hung over the lift rod and attached to weights at the bottom. These chain wires get twisted around the laid wires as these are added, one by one, and as the upper parts of the chain wires get more and more ‘squiggly’ the unused, straight parts below will seem to shrink, pulling the wire slides and attached weights gradually upward. This ‘mock-up’ (pictured in the next few photos) of the largest possible facing tries to show why it is important to take both the wire length and ‘shrinkage’ into account. The mock-up is limited to only two wires, one full length and the other shorter. This second, shorter wire is included just to show how much the first would have moved up had a 29″ facing actually been made here.

Based on experience I’ve found a standard calculation that works to figure raw chain wire length: width of facing times 2.5 plus 16″. This provides enough length without creating too much waste. The calculation for this (fictional) 29″ wide facing went like this: 29″ x 2.5 = 72.5″. 72.5″ + 16″ = 88.5″. After a piece of wire was cut to this length it was draped over the lift rod. The two ends were passed through the twisting mechanism and twisted together at the bottom of a wooden wire slide. With a weight attached it looks like the one ON THE LEFT above. You can see that the wire can’t be longer since the weight needs to swing free above the floor. This is how this weighted wire would look at the beginning BEFORE the addition of laid wires.

The shorter weighted wire ON THE RIGHT shows how the first one would look AFTER it had been ‘used up’ by twisting in enough laid wires to make a 29″ wide laid facing. The bottom would have risen a little over 7″ from its starting position.

Now the twisting mechanism has been cranked all the way down (as it would have been to finish this fictional super-wide facing). Even though the weight and wire slide have ‘risen’ about 7 inches there is still room beneath the spindles for the remaining wire to swing free as the last twists are added. (The weights, wire and wire slides all need to turn freely as twists are added.) This is important; you don’t ever want the bottom of the twisting mechanism to interfere with the top of the wire slide.

Another view of the waste wire that would be left in the wire slide. This is a good amount.

Locating Holes for the Lead Screw Bushings

The traveling beam is exactly 1″ thick and the lead screws should pass right up through its center…

…so the holes for the lead screws should be set exactly 1/2″ in front of the uprights. ‘A’ shows the plane established by the front surfaces of the two uprights. ‘B’ shows the center line of the lead screws (and the traveling beam). The upper part of each hole is drilled large enough to accept standard nylon bushings.

The lateral distance between these holes is figured out in a different way. Upper and lower crosspieces are virtually identical with holes spaced exactly the same.

To find this spacing a loop of roller chain is cut to get the twin chain sprockets very close to the preferred spacing. This would put them near the ends of the frame cross-pieces. (Unlike in the photo the linked sprockets and chain would simply be set out on any flat surface in order to do this. I may replace this photo when I have a better one.) The actual center-to-center distance is measured from the sprockets to determine how widely to space the holes drilled down through the cross-pieces. All four holes should be the same distance (left or right) from the center line of the loom. The chain should be a little loose. The two lead screws on this loom ended up just shy of 38-1/4″ on center.

A Place for the Lift Lever

Slots are cut in the frame to accommodate the lift lever. The exact placement isn’t too critical; it needs to be high enough for a weight to be attached to the far end as shown here. The weight serves to return the lever to its starting position when the treadle is released. The bottoms of these uprights are shaped and drilled so that a base can be attached if the loom needs to be free standing. This makes the loom somewhat portable, and able to be set up almost anywhere if needed.

#48 Mould Maker’s Loom Part 1

This series of posts should allow for a better understanding of how this loom works. This first post is an overview of the four basic parts of the loom; the frame, the wire lifting mechanism, the indexing mechanism and the chain wire twisting mechanism. Later posts will give more detail on each of these in turn.

Above, the loom complete, with all its mechanical parts attached. Other essential parts are added when the time comes to make a laid facing or backing. These include wire weights, wire spacers and wire slides.

The Frame

Here is the loom frame stripped of all of the moving parts which are normally attached to it. Two mechanical assemblies will be fastened directly to this frame; the lift mechanism and the laid wire indexing mechanism. The third mechanism, the one that twists the chain wires, is not attached directly to the frame. The loom is fastened to the wall in the photo. This takes up much less space than the free-standing option.

The Lift Mechanism

In the photo above only the lift mechanism is installed on the loom. In use it has a simple function; to lift the entire web of wire a short distance (1/2″) to make room for laid wires to be slid in at the bottom, one at a time. When the lifting mechanism is released the wire facing drops back down. The chain wires are then given a half twist to incorporate the new laid wire into the facing. This cycle is repeated hundreds of times to make a facing.

Above are shown the two positions of the lift mechanism, up and down. When the foot treadle is depressed (a brick supplies the force here just to demonstrate) the lifting beam at the top is raised by means of rope and pulleys. The middle of a length of rope passes under a lever which is attached to the treadle on the right. This creates a V shape with two upper ends. Each of these (rope) ends passes up and over the top of a wooden pulley, then down and through a metal pulley and back up to the very top of the loom where it is firmly attached. The inch or so that the rope is pulled down by depressing the treadle lifts the beam and all the wire and weights attached to it a half inch. The lift beam returns to the lower position when the treadle is released.

In both photos above the upper line (red) passes through the (fixed) axle of the wooden pulleys and the lower line passes through the axles of both steel pulleys (movable). Hopefully this makes it easier to see that the metal pulleys (and the beam they are attached to) move up and down when the treadle is depressed and released.

The motion may be easier to see in these two photos. Notice the smaller beam being lifted up from the angle iron which supports it. There’s only 1/2″ of movement and it’s hard to see in the photos so I’ve added arrows to show the gap.

The Indexing Mechanism

In this photo only the laid wire indexing mechanism is installed on the frame. The purpose of this assembly is to lower the chain wire twisting mechanism a precise distance for every laid wire added. The twisting mechanism will be bolted to the top edge of the horizontal ‘traveling beam’ by means of the five holes along the beam’s edge. Identical vertical lead screws are linked with sprockets and roller chain. When the crank at the top right is turned (CCW) the two screws will turn together and lower both ends of the beam the same amount. As laid wires are added the beam gradually ‘travels’ down, ending up near the bottom if a large facing is being made. A counting wheel attached to the top of the left hand lead screw makes it possible to precisely control how far the crank is turned each time. This is done by counting audible clicks as the pins of the counting wheel pass a pawl; the same number of clicks are counted out each time to produce uniformly spaced laid wires. There are many of these wheels, each with a different number of pins, so that a counting wheel can be selected to create a specific spacing.

The Wire Twisting Mechanism

In this photo the loom (with both previously discussed assemblies attached) is ready to receive the twisting mechanism which will be bolted to the traveling beam. The twisting mechanism is self contained and activated by a hand crank at its right hand end. The whole thing moves gradually down the frame of the loom as the wire facing grows larger.

The twisting mechanism is composed of many parts. Above are shown five ‘spindle racks’; a separate one must be made for each different chain wire spacing. Each of these provides the main structure for the mechanism. All of the moving parts are interchangeable and are only installed to complete the spindle rack that is currently in place on the loom. After it is bolted to the traveling beam of the loom and completed the mechanism functions to add twists to the chain wires. The crank twists all chain wires simultaneously. The twisting mechanism is the most complicated part of the loom and will have its own post; probably the last.

The Complete Loom

Once again, the complete loom, with all of the mechanical assemblies attached.

#47 Making a 24″ x 36″ Laid Facing

The largest laid facing I’ve made measured 30″ x 40″ but that was more than twenty years ago. Until now I hadn’t hadn’t made a very large facing on my new loom. There was no reason to think that it wouldn’t work but I was pleased to get a positive result.

This mould maker’s loom is designed to make laid facings as large as 29-1/2″ x 40″ (approx. .75 meter by 1 meter). The completed facing above measures 24″ x 36″.

The facing required about 530 laid wires, each 36″ long. Pulling the wires off the spool and through the straightener took about 2 hours.

I ended up using only the first set of rollers. I wasn’t able to get significantly better results by adding the second set. I think this was because the ‘helix’ of this wire was so slight. This was the first time I had straightened this size wire.

A complete circle cut from the spool shows a ‘cast’ of 8″ diameter. This ring of wire lies flat by its own weight; the ‘helix’ is minimal. It would be impossible to use this tightly curved wire for laid wires but just below it you can see a usable wire (from the same stock) which has been pulled through the straightener. This wire is .020″ diameter phosphor bronze with a 3/4 hard temper. It will be used along with annealed .011″ diameter wire (as chain wire) to make a facing with 22 laid wires per inch.

The diameter of the loop is the cast; this photo shows the helix. If it was possible to remove the cast alone a slight curve would still remain from the helix. This is what was done (sort of) with the single bank of rollers that were used. But the wire cannot be controlled precisely enough when passing through the rollers to completely isolate the cast from the helix so the resulting wires vary in their straightness.

This is the completed batch of laid wires. When bundled together they appear to have the same curvature but if examined separately all are different. Many of these wires lie nearly straight, a few are truly wild and the rest fall somewhere between.

Putting the Wires Together

This loom is very dependable. I’ve made improvements over the years to reduce the chance of error while making up facings, but a certain level of concentration must be maintained and it’s still possible to goof up. Large facings are a little stressful since making a mistake often means starting completely over. Set-up took for this facing took 3-1/2 hours. This involved swapping out the twisting mechanism already on the loom for another of the correct spacing, adding the spindles and hooking up drive weights, measuring out, stringing up and weighting chain wires, and putting all the foam board spacers in place. (Many of these steps are illustrated in other posts). This facing was completed without incident but the actual ‘weaving’ took 4-1/2 more hours.

Above are shown some steps in creating the facing. At the beginning the loom has been strung up with 30 chain wire sets, each formed of a single soft phosphor bronze wire draped over the steel rod at the top, threaded through spindles and weighted at the bottom. Wire spacers made of foam board (300 in all!) are important to keep the wire from twisting up at the bottom as the spindles add twists at the top. As the facing grows larger and the twisting head descends, these wire spacers are removed, a row at a time. The last photo shows the completed facing. At first it is best to work standing but later when the wires must be inserted lower it becomes easier to sit (thus the stool).

When finished most facings can be cut off of the loom by simply holding the free edge in one hand while snipping off the attached edge with the other. But larger facings are harder to hold onto and more likely to be damaged while being cut away from the loom. To help support this large facing I added a strip of stiff cardboard at the bottom. But it still seemed risky and I tried something new. After the weights were removed and the bottom edge of the facing cut free I cranked the twisting mechanism back up to its starting position. As shown above it passed behind the completed wire facing as it moved up.

I found this piece of honeycombed cardboard among my packing supplies. It is rigid and light weight; perfect for this purpose. After it was inserted vertically behind the facing the fully raised twisting mechanism provided a ledge to support the back of the cardboard as it was raised, carrying the facing with it. The front end was propped to hold the whole thing horizontal and the back was lightly clamped so it wouldn’t slip off.

The chain wire twists could now be safely snipped off. The facing weighs about two pounds. If it’s not well supported as the chain wires are cut the weight of the wire could stretch some of the chain wires and damage the facing.

When not in use the weights are returned to this wooden crate. The box with a complete set of weights weighs 48 lbs.

The wire slides and remaining wire spacers are separated.

This box stores enough spacers to make the largest possible facing.

The scrap wire will be added to the scrap box for recycling and the slides are returned to their bag.

About this Facing

This facing has 22 laid wires per inch. It took me quite a while (years in fact) to realize that this loom can easily make laid facings with an even number of wires per inch. At first I used a limited number of counting wheels and the spacings were all odd fractions (except for 26 wires per inch, easily made by giving the crank 1/2 turn).

My most used laid facing had 18.57 wires per inch (10 pins x 7 clicks). Others included 20.8 (8 pins x 5 clicks), 21.67 (5 pins x 3 clicks), 7.8 which I use for wove backing (3 pins x 5 clicks), and 5.77 (4 pins x 9 clicks) for laid backing.

When provided with a large set of counting wheels the loom is capable of a vast number of intervals, most of which will never be used. Of course there’s no reason that the spacing of laid wires SHOULD come out even but it was interesting to be able to compare my facings to standard Amies facings. As near as I can tell the loom that was used there since 1889 (now used by Serge Pirard) was designed to make ‘even-inch’ facings.

All that is needed for the wires to come out even is a counting wheel with the same number of pins as the desired number of laid wires per inch. Since the twin lead screws have 13 threads per inch simply counting 13 ‘clicks’ will lower the twisting head the precise amount to make the that ‘even number’ spacing. This must be done over and over; once before each laid wire is inserted in the wire trough. But it’s easy to count to thirteen (almost without thinking) if you break the number into smaller units. Very soon you get used to hearing the pattern of clicks even if it’s fairly rapid:

“onetwothreefourfive”….”onetwothreefourfive”…”onetwothree”. Or:

! ! ! ! ! ……… ! ! ! ! ! ……… ! ! !

Together these three easily recognizable audible patterns add up to 13. It would take much more concentration (and more time, with a greater chance of error) to count the clicks one at a time.

Above, the 22 pin counting wheel in place on the loom. As the disc rotates the pawl slips off of the pins creating audible clicks that can be counted to produce a desired laid wire spacing.

See Post #20 “Making Laid Facings” and Post #21 “Making a Laid Backing on the Loom” for more details.

#46 Investigating an Amies Wove Mould

In which some interesting variations (and a couple of mysteries) are discovered.

This pair of wove moulds was given to Cathleen Baker by the late Larry Lou Foster of Tuscaloosa, Alabama who acquired them in 1968 while traveling in England. Cathy loaned me this pair and another laid pair to examine.

The moulds are small, 11″ x 12″, and of fairly standard construction but with a few puzzling features. The bottoms are fitted with boxwood rub strips and these curious, roughly shaped ‘minimal’ cast brass corners. These moulds, being so small, are naturally very stout. In this case at least, brass corners must have been added to take wear rather than to brace the structure; that there are only two screws each and that the corners are so small supports this idea.

The moulds have been altered and/or re-conditioned. They seem to have started out (as many small moulds do) plain, without rub strips and brass corners. This is indicated by the remains of a miter partly hidden beneath each of the eight brass corners. A miter (combined with the regular joint) is a traditional way to neatly finish the bottom corner of a plain, unbraced mould. Corner braces and rub strips were added later, possibly because the mould was wearing badly on its bottom edges. The narrow copper strips that protect the edges of the wire facing were originally folded down over the ends and nailed. The current edge strips stop just shy of the corners. You can see the two holes left when the nails were removed and also an area which was carved out of the wood to accept the thickness of the original strips. The joints seem to be nailed and countersunk; filled holes appear on both faces of each corner. Also interesting is this variation of the double dovetail joint in which the top ‘pin’ (this refers to the part that overlaps the ‘tails’ in dovetail joints) is offset by about 3/32″. My guess is that this was intended to add strength to the end of the frame. Gripping the mould to the deckle during formation might tend to pull the bottom edge out, thus torquing the top edge inward; in this case the inward thrust would be stopped by the narrow ‘ledge’ cut into the adjoining (long) side of the frame. (This is illustrated more clearly at the bottom of this post).

One of the moulds has a decided twist, though the mahogany sides are all very straight (as is the grain of the wood). Both moulds are slightly concave; the metal screen sags by about 1/16″ in the middle. This may be a result of the long term stresses of couching. The photo shows the back side of the mould where the pegs of the ribs are visible. These moulds have ‘through holes’ and the pegs formed on the rib ends pass all the way through the frame. The entire front of each mould is sheathed. The sheathing ends right at the two front corners and is not folded around the sides. You can see this in the previous photo.

Mystery #1: Why are all of the holes that the rib pegs rest in uniformly ‘lemon shaped’? And why are they oriented the same way? I can imagine that a file or a sort of broach must have been used to shape the holes. If anyone has any insights please share!

This is truly weird for me to see. The holes have little points at 10 o’clock and 4 o’clock. This uniform orientation seems to argue that a jig or mechanical device was used to make the holes.

The brace rods are hammered flat at the ends and set into oblong mortises. The ribs are made of wood with a very uniform grain; not resembling any coniferous wood that I have worked with. They may be made of a species called Parana Pine. I have a couple of samples given me by Serge Pirard and I fancy there is a resemblance. (I will at some point make a mould using this wood for ribs.) The wire structure that supports the wove facing is a variation that I haven’t seen before. There are two ‘grid’ wires between each pair of ribs; this is not unusual but what IS unusual is that only one of them is stitched in place. (See post #26) The other ‘floats’, giving support to the facing but not held in place by stitching. ‘Floating’ grid wires are pretty standard but usually they are flanked by a two sewn grid wires, one on each side.

In each space between ribs you can see the two grid wires; in the usual repeating pattern a sewing wire passes under three (backing) laid wires and passes up and over two wires of the mesh and back down, taking a spiral path and binding the layers together. But this is true only for the grid wires on the right in this photo; the ones on the left are not sewn at all.

I was gratified to see that the stitches are carefully placed to ‘lie low’ by crossing the mesh wires at the low points as they spiral around the backing wires. (Gratified because I sometimes wonder if I imagined this detail; it seems such a fine point and may or may not be a common feature). The sewing wire is unusually small at .006″ diameter and the mesh wire is relatively coarse at .011″ diameter. The mesh is fairly coarse at 36 wires per inch by 40 wires per inch. The 4 stitches visible in this close-up are indicated by blue arrows. The path of a floating grid wire is shown by the yellow arrows. Ideally this grid wire is held in a sort of ‘trough’ formed by a pair of zig-zagging mesh wires; here you can see that this wire wanders off to the right a bit.

When I first studied moulds in the early 1980s I noticed an inward slant on their sides but with time came to doubt my first impression. This feature would make it easier to place and remove the deckle. I started out making moulds this way but soon switched to making them with no slant at all. These moulds show an inward slant (actually more of a slight curve) that was probably shaped with a plane after the mould frame was assembled. This slant is on the short end of the mould, parallel to the ribs.

This shows the slant on the long side, at right angles to the ribs.

Mystery #2: Is it possible that grooves were actually carved out for the backing laid wires to rest in? It sure looks like that here, along with a transverse groove to hold the chain wire. Usually there is what I call a ‘ledge’ here but there’s no sign of that on this mould. It seems unlikely that the laid wires could have been pressed into the wood. When wet the wood would tend to return to its original shape, pushing the wires back up. The copper nails in old paper moulds are often remarkably loose; I was able to pull these out with my fingernail so I could peek under the facing. I would have loved to examine this more thoroughly but couldn’t ‘dig any deeper’ without damaging the mould.

These deckle joints were made in the fashion that I prefer with joints fitting together in a rotating ‘pinwheel’ pattern. This eliminates the necessity of cutting opposite forms of the complicated joint. Notice the single inset wear plate of brass at lower right.

The left front corner of the deckle has a brass plate inset into the vertical inner edge. It is bent at a right angle and nailed into a shallow mortise. There was also an “L” shaped flat brass plate that was set down into the groove behind the deckle rim. Now it is missing. Both front corners also have bent brass plates along the very narrow vertical face of the rim. These ‘wear plates’ are standard features on most British moulds I’ve seen.

The left front corner viewed from a different angle. The extra reinforcement (I believe) reduces wear on the part of the deckle that first hits the edge of the mould as the deckle is quickly placed on it (over and over and over…).

This is a pretty deckle. It is very ‘curvy’ and the relatively thin sheathing (.008″) is nicely fitted.

The front and back edges are shaped to a very narrow edge; less than 1/8″.

I have not carefully examined a lot of moulds and deckles. I thought I should get organized to make it easier to note features and variations. The survey that I devised ended up describing about 75 features that I am interested in recording for comparison. I first print blank versions with only the questions to complete by hand. Then I enter the information for a digital record. Pictured is a completed survey of this pair of moulds.

More about the offset in the corner joint

I’ve altered and annotated the above photo to show how the offset part of the joint adds an extra strengthening feature to the completed joint.

The red lines show what the edges would look like if the facing and edge strips were removed. The yellow arrow shows the offset and the black arrows point to the extra joining surface that is created on the right hand part of the mould frame. This little ledge would keep the mould frame (on the left) from being pushed in at the top. That’s the theory I’ve come up with to explain the function of the extra feature. There must be some reason to do it this way since it makes cutting the joints a little more difficult.