#18 Definitions of some Unfamiliar Terms

Defining some terms may make these posts easier to understand. I have chosen some words when a traditional term was not known to me. The terms are in italics; accompanying text and photos are intended to define and explain their meaning.

~frame sides: The two longer parts of the mould frame parallel to the laid wires. Ribs are set perpendicular to the sides, both ends being fixed in holes drilled there.

~frame ends: The two shorter parts of the mould frame parallel to the ribs.

(above) The underside of a wove mould. This photo identifies the frame sides and frame ends along with a few other parts of a paper mould.

~chain wire / chain wires: These words are especially confusing to use. I will use the singular “chain wire” in these posts to mean a single pair of wires that spiral around each other, binding laid wires side by side to make a facing. Visually it appears as a single line of wire, resembling a miniature chain, crossing the laid wires at a right angle. I will use the plural “chain wires” to refer to more than one of these structures. Examples of the two uses might include: “Each rib has a chain wire positioned above it.” And “All of the ribs have chain wires positioned above them.” (It is awkward to write many times about “chain wire pairs”. And what is the plural of “chain wire pairs”?)

(above) An excerpt from a drawing showing the process of making a laid facing in a loom. It provides a simplified view of the structure of a laid facing including a few laid wires, a chain wire and a twist.

~laid facing: The uppermost wires of a laid mould. The porous wire surface on which macerated cellulose fibers are collected when forming sheets of paper.

(above) This photo shows a laid facing being fitted to make a ‘single faced laid’ mould. This is the simplest and oldest type of European style paper mould. Another type of mould, ‘double faced laid’, uses this same type of facing supported upon an additional layer of wires, called ‘backing’.

~wove facing: The uppermost wires of a wove mould. These are in the form of a fine screen of woven wire that collects fibers to make a sheet of wove paper.

(above) A wove facing is being trimmed and fitted to its mould. A wove mould always has two layers of wire and is sewn in two stages.

~backing: A layer of wires that lies beneath a laid or wove facing to support it from below. Backing is prepared on a loom like a laid facing but with wires spaced much further apart.

(above) Backing being fitted to what will become a double faced laid mould.

(below) The very bottom of a large backing that is finished and ready to cut off of the loom. Three half-twists in the chain wires keep the laid wires widely spaced. The last four laid wires are more closely spaced with two half-twists in the chain wires. Including a few narrow spaces along one edge makes it easier to fit the backing to the mould frame.

~facing laid wires: The long, straight wires that make up a laid facing. There are hundreds of laid wires lying close together in a typical laid facing. They are fastened together by a dozen or so widely spaced chain wires.

~backing laid wires: The long, straight wires that make up a backing; these wires are the same as facing laid wires but spaced further apart with extra twists between them.

(above) Facing laid wires and backing laid wires are shown in this extreme close-up. The red arrows show where two backing laid wires are hidden under laid wires of the facing.

~loose chain wires vs. sewn chain wires: With the exception of one chain wire at each end all of the chain wires of a mould are fastened in place, each being sewn to a rib. The two ‘loose’ chain wires at the ends can’t be sewn to a rib. To secure them they are ‘trapped’, either in a groove in the wooden frame (single faced laid and wove) or between two bridge wires (double faced laid).

(above) The chain wire running across the top of this double faced laid mould is ‘loose’ (not sewn), but it is trapped between bridge wires to keep it from ‘wandering’. The chain wire seen along the bottom of the photo is sewn to its rib.

~bridge wires: Bridge wires are physically the same as laid wires but have a different purpose and are used only in double faced laid moulds. They are straight, stiff wires that bridge the widely spaced backing laid wires to provide a smooth, firm support for the laid facing. Over each rib, a single bridge wire runs alongside and between the two chain wires (one facing, one backing) and is sewn in place as part of a ‘bundle’ of wires. Bridge wires are also used at both ends of a double faced laid mould to provide extra support for the ends of the facing laid wires. They provide a firm base for the laid wires which keeps them from distorting badly when copper edge strips are tacked in place.

(above) Above each rib a single bridge wire is inserted alongside chain wires and between the laid wires of the facing and backing. It crosses the widely spaced laid wires of the backing, providing a smooth, solid support for the upper facing to prevent it from being cinched down unevenly by the stitches that bind it to the rib.

(below). You can see both uses for bridge wires here; at “A” as one piece of the ‘bundle’ of wires sewn to a rib, and at “B” lined up in a group to support the ends of laid wires where they lap over the frame end.

twists: These are extensions of the chain wires that lap over the frame sides.

(above) Extra laid wires have been pulled out to fit a laid facing to its mould leaving this twist a bit loose.

(below) The same twist has been tightened and will be trimmed to fit in the notch. After the mould is sewn all of the twists will be covered by copper edge strips to protect them.

single faced laid: The most basic type of paper mould having a single layer of laid wires sewn directly to the ribs. Until the mid 18th century it was the only type of European style mould. Paper made on this type of mould is distinctive for having ‘shadow zones’ along the chain wires. This is a result of the rate of drainage along the ribs differing from the rate of drainage between the ribs.

(above) It is easy to see that there is only one layer of laid wires in this single faced laid mould. A laid facing is in the process of being sewn to the ribs.

double faced laid: A type of laid mould developed around the middle of the 18th century having two layers of wire. Adding the extra layer (backing) improves drainage and eliminates the uneven formation typical with single faced laid.

(above) Two layers of wire are visible here, identifying this as a double faced laid mould.

wove: Wove moulds were also devised around the middle of the 18th century. Paper made on these moulds lacks the distinctive laid pattern because the facing is a nearly featureless fine woven mesh. Wove moulds require a backing; the wires of the backing keep the relatively soft wire mesh from sagging between ribs.

(above) A wove mould with deckle in place. The support grid of the backing can be seen through the fine wire mesh of the wove facing.

wove backing: The layer of wires devised to support the facing of a wove mould. It resembles a laid facing but with laid wires spaced much further apart.

grid wires: A grid is created on top of the backing to support the wove facing evenly. The grid is made of a single wire strung back and forth between small brass or copper nails. Two rows of stitching between each pair of ribs will secure the facing to the backing.

(above) The wove backing has been completely sewn to the ribs and a grid has been created to provide an even support to which the wove facing will be stitched.

ledge: A shelf or lower level created to support laid wires where they overlap each end of the mould frame. The cut ends of the wires must be protected by a copper strip. It is difficult to keep this strip from distorting the wires when it is tacked down. This can be minimized with careful attention; aiming to support the laid wires at the same level as they are supported by the ribs.

(above) One end of a double faced laid mould with two ledges. The deeper one supports the ends of the backing laid wires. The shallow ledge supports the ends of the facing laid wires.

trap groove: A groove cut along the inner edge of a ledge to ‘trap’ the ‘loose’, unsewn chain wire so it can’t move.

copper edge strip: The narrow strip that is affixed to the top edges of the frame to protect the vulnerable ends of laid wires and twists. Along the ends it also functions to bind the laid wire ends to the mould; holding them in place to align them evenly with the rest of the facing.

(above) A copper strip has been tacked to both ends of this mould. It protects the ‘ragged’ ends of the laid wires while holding the ‘loose’ chain wires (facing and backing) and bridge wires in place. The strips along the sides do less; serving only to protect the twists. If not covered the ends of wire are vulnerable and likely to be snagged and bent. In moulds receiving hard use chain wire twists sometimes ‘escape’ from their covering and will be bent, first one way, then another. They eventually fatigue and break, most likely right at the first laid wire. The chain wire will the loosen near the break and laid wires may come loose, too. The copper strips at the ends sometimes work loose, allowing laid wires to protrude and become damaged.

#16 Leveling the Ribs

The wooden structure of the mould is complete; now the tops of the ribs are scraped level in preparation for sewing down the wire facing.

I like to pre-load the mould with weights before leveling the ribs. This gives the mould a very subtle camber; an extremely shallow arch in all directions. The forces of forming sheets and couching push against the ribs. By its nature a mould is weaker and less well supported in the middle. Leveling a mould under weights gives this part a little lift to compensate. It is surely better for the top of a mould to be slightly domed than either flat or hollow.

The photos above and below show one way to support the long sides of the mould while allowing weights to be hung on the single brace rod that supports the ribs.

I cobbled together this structure by clamping some planks to my table saw. I will likely try to come up with something more convenient in the future.

This method of hanging the weights is fairly new to me; earlier on two brace rods and deeper ribs allowed the 12″ x 3/8″ diameter steel weights to be simply laid in place between the ribs. As shown below, a mould could be placed on any flat surface while leveling the ribs. The smaller mould shown above uses 5/8″ ribs and there isn’t enough space above the brace rod for the weights (even if there were two brace rods). The weights must be hung from the single brace rod to pull down on the ribs.

This larger mould had 3/4″ deep ribs and two brace rods passing through the ribs. Two rods allowed the weights to lie horizontally between the ribs and below the surfaces to be scraped.

The weights are hung in pairs from the single brace rod. These are leftovers from an unrelated project. Some have set screws which make it easy to attach the wires. A simple hole or even tape would also work.

Here’s what they look like from below. The two weights on the left have been attached to the wire with strapping tape.

The blade for this scraper plane is a narrow strip hacksawed from a woodworker’s card scraper, sometimes called a cabinet scraper. The arrow shows the direction that the plane is pushed. It may seem backwards when looking at the angle of the blade. This is because a sharp, forward facing burr has been formed on the backwards facing blade.

A cross-section drawing of the scraper plane and enlarged views of the blade. The burr at ‘b’ is much exaggerated and the blade shown wedged in the plane would normally be set a little lower.

The long wooden body of the plane rides on top of the long sides of the mould frame. The blade is advanced by small increments for as many passes as it takes to completely level all of the ribs.

The scraper blade needs to stick out quite a lot to reach the ribs that are recessed below the top of the mould frame.

The scraper is ground and honed at about 45 degrees. Then a ‘burr’ or ‘hook’ is turned on the sharp edge with a burnisher. You can see the burr in this photo. This allows a scraping action which is safer than the cutting action of a normal plane.

The iron or blade of a woodworking plane protrudes from a narrow mouth in the sole, the flat bottom surface of the tool. The sole normally rests on the wood right next to the blade and keeps slivers of wood from rising up when caught by the sharp edge, particularly when the grain runs the wrong way. Since ribs must be recessed below the sides of a mould it is not possible for the sole of the plane to serve this function. A cabinet scraper is slower and less efficient but a safer cutting device. I have found that a narrow piece of one mounted in a wooden plane body makes a workable tool for leveling mould ribs. The sharp burr on the scraper blade turns and breaks the shavings as it cuts so fibers can’t rise up and splinter off.

The total amount of wood that is scraped off the tops of the ribs is very small; about .010″-.015″ (.25mm-.4mm) around the edges and less toward the middle of the mould.

A block of graphite has been rubbed on the top edges of the ribs to make the leveling process more visible in the photos.

Working from the center outward, one rib at a time is scraped with a couple strokes of the plane. After finishing the ribs on one side (each rib having been be scraped for half of its length) one must walk around to scrape them from the other side. Then the cutter is advanced with a light tap and the process repeated. This is done a number of times until the tops of all the ribs have been reached by the blade and scraped to the same level. When the proper level is reached the ribs are given a few extra strokes each (without changing the blade setting) to leave them extra smooth and level.

The shavings left at the ends of the ribs look like this.

The first areas that the blade reaches are along the ends and edges; the brighter parts show where the graphite has been scraped away. The weights cause the middle to sag so it will be the last part to be reached by the blade.

A smaller unleveled area remains here.

The last unleveled bits are circled.

When no unscraped areas remain the ribs are checked to see if they are low enough. The top layer of laid wires should end up with at least 2/3 of their diameter sunk into the frame so that they can be trapped against a ledge at each end to prevent them from working out at the ends of the mould. The depth that the ribs need to be recessed depends on the type of mould; wove, single-faced laid, or double-faced laid each being a little different.

After the ribs have been scraped clean and level the weights are removed and the mould structure will relax and lift, creating a slight camber.

This drawing illustrates the relationship between the top of the ribs and the upper surface of the mould frame. The ribs are recessed by the combined dimensions of the wires that will rest on them. This topic will be covered more fully in the next post.

Adjusting the scraper plane

The wedge is given a tap now and then with a drill rod to keep the blade tight. This mould is not actually being leveled; these photos just show the method of adjusting the cutter.

The cutter is advanced by small taps with the same drill rod.

If you press a fingertip into the place where wood and steel come together while tapping you can feel the cutter’s advance even though it may be by only one or two thousandths of an inch.

#15 Pinning Ribs, Corners and Brace Rods

Metal pins are used to improve the connection between the parts of the mould. Holes are drilled and pins are driven down through the frame and rib pegs. These are made of 1/16″ unfluxed brazing rod that I bought from a welding supply house. Ribs are not glued and the pins make certain that the sides of the mould don’t spread.

A piece of rod is pointed on a grinding belt and pieces trimmed off to length with these flush cutters. I grind the other ends flat to make them drive better when they are hammered in.

Slightly undersized holes are drilled so the pins fit tightly.

I twist the ends on a block of beeswax before driving them in.

Every third rib is fastened this way. The other side will match so each of these five ribs will be secured at both ends.

A hole is drilled off-center through the brace rod end. This way the pin will pass through the plastic part while missing the brass rod.

These corner pins are started near the inside of the corner and slanted outward. This will leave room for hammering in the nails that will be used later to fasten the copper edge strips at the corners.

#14 Fitting Corner Braces

For these moulds both the braces and rub strips are made from polycarbonate sheet.

To make rub strips narrow pieces are sawed and cut to length. Like the braces they are made slightly oversized and trimmed off later.

Rub strips are attached with brass escutcheon pins. They are drilled in the same way that the braces were in the last post. First with a #00 center drill…

…then with a small number drill.

The strips are nailed on with 1/2″ long #18 escutcheon pins.

After they are attached the strips are rounded off with a router. This machines off the overhanging material so the ends can be accurately trimmed to fit the braces.

This is how the ends of the rub strips are trimmed square. Once again, the hollow ground planer blade is used.

Now the braces can be nailed in place. The heads of the brass pins are driven down into the recesses with a carpenter’s nail set.

This white plastic guide fits into the countersunk holes to guide the drill so the pilot holes for the screws are centered.

A larger hole is drilled a little way into the wood to accommodate the unthreaded part of the screws.

This tool is just a ‘stop’ to keep the hole from being drilled too deep.

I use these oval head brass screws because I think they look nice though flat head ones would also be fine.

Now the bottoms of the braces are rounded to match the rub strips.

Corner braces strengthen the mould and protect it from shocks. Both rub strips and braces reduce wear on the bottom edges.

#13 Making Corner Braces

The bottom edges of paper moulds are often protected by the addition of corner braces and rub strips. Here is an ‘old style’ brace made of brass. You can see that this one was made by soldering two pieces together.

The moulds I’m working on for this series of posts have braces and rub strips made of polycarbonate. This is a very tough material. It is used for glazing storm doors and such, shields on machine tools and, lately, for covid shields in stores and supermarkets. Narrow off-cuts (scrap) are usually big enough for making the parts needed for moulds. This plastic can be machined with ordinary woodworking tools. It tends to be very flat and fairly stiff, both good qualities for making moulds.

A strip is cut to a suitable width and the center line is marked to show where to stop the cuts when sawing out the L shaped pieces.

The pieces are sawn slightly oversize so their edges will hang off the sides of the mould frame a little. The rough edges will be removed when the bottom of the mould is rounded.

I make enough for several moulds at the same time. The burrs left from sawing need to be filed off before the next step.

Using the hollow ground planer blade to saw the ends square. These brackets measure two inches on a side.

A couple of special tools make things easier. The drill on the top makes a countersunk hole for a standard #6 screw. The #00 center drill on the bottom starts a tiny hole for the #18 escutcheon pins that will be used to tack the brace to the bottom of the mould. The wider part leaves recesses for the head of the escutcheon pins to fit into. Center drills are used by machinists to prepare material to be held between centers on a lathe.

A fence is clamped to the drill press table to keep the holes centered. A stop is set to drill the first hole in all of the parts and then moved to determine the locations of succeeding holes.

These burrs must be removed before moving to the next hole. This can be done by hand using this countersink.

Drilling the last of the four holes. Larger moulds sometimes have larger braces with six holes and screws.

I start drilling for escutcheon pins using the center drill. The pins make it easy to install the braces and, in theory at least, add a bit of grip between the braces and the mould.

The center drill doesn’t reach all the way through. To drill the rest of the way I choose a number drill that leaves a tight fitting hole to drive the pins through. The tight hole keeps the pins from working out. (Number drills are a series of 60 small drills that range in size from .040″ (#60) to .228″ (#1). )

All the braces needed for the five moulds being made.

Many years ago I was inclined to copy traditional moulds more closely. I made patterns and had bronze braces cast for this reason. I believe that many braces on old moulds were castings but I now know that some were made of soldered pieces of half round brass.

In the back are cast bronze braces including one set that are finished and ready for a mould. Making braces this way is a lot of work. The white ones are made of acetal. These are much easier to make, lighter weight and very tough. They were made in the same way as the polycarbonate ones described in this post.

Here is some half round brass that I have recently purchased. At some point I’ll try mitering and soldering this material to make some corner braces.

#12 Gluing Moulds

This mould has had epoxy applied to the corner joints and is secured with spring clamps while the glue cures. The dents left by the clamps poking into the wood will be covered by brass sheathing.

Using clamping cauls eliminates the dents for moulds without sheathing. This mould is ready to glue and clamp. At the ready are spring clamps, the clamp spreader and a puddle of epoxy ready to be mixed and applied.

I buy Devcon 2 Ton epoxy at my local hardware store. I mix and apply it with a short piece of 1/16″ brass rod with ends sanded and buffed smooth.

Glue is applied to both parts for every joint.

The socket for the brace rod end.

The cauls are made of thin polycarbonate plastic with pieces of sanding belt attached with contact cement. A groove has been cut along each end to engage the points of the spring clamps.

The clamps hold the parts tightly together while the glue cures.

The mould stays in clamps until the next day.

There is always glue squeeze-out to clean up.

Excess epoxy inside a corner.

Epoxy can be pared away with a sharp chisel.

The job is finished with a file.

Squeeze out around the brace rod end is easy to clean off with a chisel.

Applying a little paste wax with a toothbrush after dry-fitting the parts but before gluing helps the excess epoxy come off a little easier.

#11 Fitting Waterbars and Brace Rods

Before the corner joints of a mould are glued a brace rod must be fitted. It will pass through all the ribs and be anchored in the frame at both ends. Waterbars also need to be fitted along the ends of each mould.

The waterbars are really just little ribs and have the function of helping to draw water away to help form a good deckle edge. They are made in much the same way as the regular ribs. I straighten them and cut them to size in only one sequence of steps, unlike the ribs which have been reduced and shaped in two sequences. This might make more sense after reviewing the post on making ribs.

A by-product of roughing the deckle parts to an “L” shape are small strips of wood just right to make waterbars from. The straightest of these scraps were saved to make these waterbars. The lighter colored ones are for the experimental wove mould that is being made completely of Larch.

The bottom edges are rounded just like the ribs were.

These are ready to be cut to length and fitted into notches in the mould frames. They have tapered sides and rounded bottoms like ribs but do not need pegs formed on the ends.

Instead the ends are slimmed down with a block plane to fit into shallow mortises previously routed in the frames. Here a waterbar has been fitted into place and a brad point drill is being used to mark the location of a hole that needs to be drilled for a brace rod.

The brad point drill is turned with the fingers until the wings score the wood.

The sides of the waterbars are tapered so the table of this drill press is tilted to drill the hole at an angle. Using the same brad point drill to mark and then to drill is a good idea.

Fitting a Brace Rod

1/8″ diameter brass rods are used to brace the ribs. They are threaded on both ends so larger diameter acetal plastic ends can be screwed on.

Here, a 6-32NC threading die has been embedded in a block of wood with a 1/8″ diameter guide hole drilled through to the other side. The rod is held in the lathe chuck as the die is turned by hand. The power to the lathe is disconnected.

About 1/4″ of the ends are threaded.

In old moulds these rods are often hammered flat and inserted into slots chiseled into the ends of the mould frame. A small pin at each end anchors them in place. Until recently I glued the ends into same-size holes and then drilled for a 1/16″ diameter pin after the glue was set. This works but is tricky; it’s not easy to ‘hit the target’ and the brass shavings enlarge the hole in the wood as they are carried away by the flutes of the twist drill. And it is easy to break a drill this small. Now I prefer the method described in this post.

A brad point drill is backed into the holes in the ribs and waterbar in order to mark the place where a hole needs to be drilled into the frame.

In these moulds the brace rods pass through the waterbars. This is a recent innovation of mine to accommodate the narrow ribs in these small moulds. In larger moulds with deeper ribs (and all other moulds I’ve seen) they are not drilled this way. Usually the waterbars are added after the mould frame is complete. They rest on top of the brace rod(s) and are bound to them with wraps of wire.

The end of the frame is removed to be drilled after the point of the drill has marked it. The inked circle makes the mark easier to see in the photo.

A 3/8″ diameter hole is drilled to fit the acetal plastic cylinders that will be threaded on to the ends of the brace rod. To start the drill I lift the wood up and feel that the point of the drill is in the small hole. (This with the drill press turned off.) Next I move the drill down with the feed handle to push the wood gently down onto the table. Then the motor is switched on to drill the hole.

A forstner bit drills a clean, flat bottomed hole; good for this purpose.

The hole is drilled about 3/4 of the way through.

The brace rod is inserted through holes previously drilled in the ribs.

A piece of plastic rod is threaded onto the end of the rod as a sort of wrench. It is used to twist the brace to even it up at the ends.

Fittings for the brace rod ends are prepared. Pieces of acetal plastic rod have been cut and surfaced at both ends to about 3/8″ length. Smooth 1/8″ diameter holes have been drilled 1/8″ deep and smaller (#36) holes have been drilled all of the way through and threaded with a 6-32 NC tap. Here the outside diameter is being reduced to fit into the 3/8″ hole drilled into the wooden frame. (The acetal rod is manufactured slightly oversized to allow for machining.) For this operation the fittings are threaded onto a scrap piece of threaded brace rod that has been chucked into the lathe.

The inner end of each is beveled. The waterbar will rest against this end. The length of the fitting and the depth of the hole in the frame are calculated so the waterbar will end up being held at the right distance from the frame.

A fitting is threaded onto the brace rod at both ends.

The plastic fitting has a couple of advantages. It strongly secures the brace rod to the frame and holds the waterbar away from the inside of the frame. Waterbars can slide along the brace rods and often shift out of place.

The ends can be adjusted by screwing or unscrewing them a little to make the overall length exactly right so the ends of the frame won’t be bowed in or out.

The frame joints and the brace rod ends are ready to be glued with epoxy. After the epoxy has set a 1/16″ diameter hole will be drilled down through the wood and plastic (slightly to one side to just miss the brass rod). A brass pin is then tapped into the hole to make the connection even more secure.

#10 Assembling the Mould Frame and Ribs

The first step in putting a mould together involves only the ribs and the four pieces of the frame. Other parts; a brass brace rod and extra ribs called waterbars will follow.

You may recall that one edge of each frame piece was intentionally left rough. This bottom edge is now smoothed by a single pass over the jointer.

Compressing the pegs by twisting them into a sized hole smooths out the facets left from the twelve sided rib peg tool. This also makes the ribs easier to fit into the holes in the sides of the mould.

Ribs are lightly sanded mainly to remove the little bits of wood that are left from drilling all the sewing holes.

The inside surfaces of the frame are also lightly sanded.

One end of each rib is inserted into a hole.

The penciled numbers are used to keep the ribs in the proper order.

Four ribs to go.

After all of the ribs are fitted in one side the whole assembly is carefully turned around so the free ends can be started into holes on the second side. One at a time, ribs are gently twisted back and forth while pushing them down. All will end up about halfway into the holes at each end. In this photo only the first and last rib (not visible here) have been moved down.

This just shows how the ribs move down as they are re-positioned. Three ribs have been moved down partway into the holes of the opposite frame piece.

When this step is completed the mould looks like this. The rib pegs are all about halfway into their holes.

Now the frame must be pushed in from both sides. This is done gradually as the sides are gently tapped together in small steps. Care is taken to tap evenly across the length of the frame, keeping the sides parallel. I turn the mould around each time so the sides get tapped from both sides equally.

After each stage of tapping all of the ribs are turned a bit in their holes. This is easy but important. Here the top five ribs have been ‘flipped’ down a little by my thumbs running down the sides. If the mould is assembled without doing this the ribs can become locked in; turned at odd angles. It can become difficult to straighten them and there is even a chance of breaking a rib.

When the pegs are all the way in their ends will be flush with the outside of the mould. Now they are aligned with the scribed marks on top. Both ends are rotated at the same time to make a rib stand nearly straight up; then each end can be individually nudged into position.

The narrow top surfaces should be centered on the scribed lines.

Now the ribs are completely inserted and aligned.

The holes drilled to receive the brass brace rod now line up perfectly.

The ends of the mould can be fitted in place.

The mould frame should be square, or very nearly so. This is the cumulative result of the care taken to make all of the pieces, ribs and frame, as straight as possible, with ends cut perfectly square; and of being certain to drill the rib peg holes into the frame at exactly 90 degrees.

This batch turned out very well!

Five assembled moulds, ready to be fitted with brace rods and waterbars.

#9 Finishing the Ribs

The ribs have been shaped, cut to length and have had pegs formed on their ends. Now each must be drilled for a brace rod and then for sewing holes. The brace rod keeps the ribs lined up and helps them work together for added strength. A row of very small evenly spaced sewing holes are made along the thin upper edge of each rib. These sewing holes must be drilled ahead before a mould is assembled. Later, a single sewing wire will follow a spiral path through all the holes in each rib. Between each pair of sewing holes it will pass up and over the chain wires to attach the wire facing to the mould.

The ribs are all marked on one end. While they are being drilled and later assembled in the mould they must be kept in this orientation with (in this case) the mark always being on the right.

Skipping ahead a few steps shows why this is important. Using care to orient the ribs and holding them against fixed stops while drilling insures that the brace holes line up. In this photo the holes are already there; the drill is the best way I’ve found to insert the brass brace rod.

This base has slanted faces so the ribs will stand up straight in the mould after assembly. At the top of the slanted surface is an edge that the ribs are pushed up against; a ‘fence’ that spaces the hole a precise distance from the top edge of the rib.

A stop is fixed at the left to push the ribs against while an 1/8″ brace hole is drilled in the middle of each. Larger moulds often have two brace rods.

Each rib is held in place on the slanted surface of the base and against the stop while a clean hole is made with a brad point drill.

Another view of the drilling set-up.

Ribs for a mould. A few still need to be drilled for the brace rod.

Sewing holes are drilled next.

A #60 twist drill is used. The largest wire that I use for sewing is .013″ diameter (for sewing down wove backing) and these .040″ diameter (1mm) holes have proved to be plenty large.

The ribs are given an identical cluster of three holes at both ends. Stitches at the ends of the ribs will be closely spaced; a stitch every other space followed by one each for the last three spaces.

Holes drilled in the ribs of this laid mould have regulated the spacing of the stitches. Along a rib stitches fall between every pair of sewing holes, crossing over a pair of chain wires and between a pair of laid wires. From rib to rib the stitches are staggered so they won’t line up along the laid wires. Both features are pre-determined by the way the holes were drilled in the ribs before assembly. If you look closely you can see where the sewing wires pass through the holes in the ribs, about halfway between stitches.

I space the sewing holes for laid moulds at a stitch for every six laid wires. A serrated ‘rack’ is made for each configuration of laid facing. Above, preparing to cut teeth on a strip of inexpensive, easy to work Sintra plastic. To get the proper spacing a completed laid facing is laid on top and marks are drawn by pushing the pen point down between the wires, every sixth space.

Notches are cut on the tablesaw with the hollow ground blade.

One side of each notch is chiseled away to make teeth, like saw teeth. Once it is finished a strip can be used to make any number of laid moulds that share the same wire spacing.

The serrated strip is clamped on top of the base block. A little block (a ‘pawl’) fits over the rib peg to engage the strip. The pawl has a slanted face that clicks in and out of the spaces between the teeth. The rib can be rapidly re-positioned, moving from left to right as sewing holes are drilled at the proper spacing. Holes should be close to the top edge of the ribs so the sewing wire won’t need to be excessively long.

The holes must not be made in the same position on all of the ribs. If stitches pass between the same two laid wires on adjacent ribs it can create a depressed channel in the wires that may show in the paper. This drawing shows a system that helps the stitches skip around without creating an obvious pattern. This random-seeming pattern repeats and every fourth rib is drilled the same.

This laid mould has 14 ribs. I have separated them into four piles and numbered them #1,#2,#3 and #4. All ribs in each pile are drilled the same according to the pattern.

To do this, I drill a test rib (using the pawl and serrated fence) and label it #1. Lines are drawn to divide the spaces between holes into sixths. Each of the #1 ribs is now drilled using this first set-up, creating a row of evenly spaced holes along its entire length . (I’m making four moulds with the same laid wire spacing so all of the #1 ribs for all of these moulds are drilled at the same time, in this case about 16 ribs). Before drilling the #2 ribs the serrated strip is shifted slightly. Using this test rib as a gauge the drill will be set at the mark indicated by the #2 arrow, two increments to the left of the #1 hole. Then all the #2 ribs are drilled, each along its full length between the three-hole cluster at each end. Still following the pattern shown in the drawing the serrated strip is shifted three spaces to the right before drilling all of the #3 ribs. Finally, the strip is shifted two more spaces to the right before drilling the #4 ribs. I don’t know if mould makers would have done this in the past. Perhaps they would just drill (or pierce) the sewing holes by eye to an approximate spacing.

Many old moulds show evidence that the sewing holes were pierced rather than drilled. This may have been done with a device which was squeezed by hand to push a steel pin with a wedge shaped end through the wood. The oblong slots are made across the grain of the wood, presumably so as not to split it. These ribs are from old (probably early 20th century) British moulds. I have not tried this.

The slanted teeth allow the pawl to climb out and away from one tooth and ‘click’ back against the next tooth as the rib is pushed along. After each incremental re-positioning with the left hand the right hand advances the feed lever of the drill press to make one hole. Each cycle takes about one second. The drill press is set to spin the drill at a high speed so the chuck and drill can be jammed down quickly after each advance of the rib.

One of each ( #1 through #4) ribs showing the variation in hole spacing. The ribs are placed in the mould in order; 1,2,3,4,1,2,3,4,…

Sewing Holes for Wove Moulds

The sewing holes for my wove moulds follow a simple 1,2,3 diagonal pattern and are spaced to put a stitch between each third pair of laid backing wires. This can be seen in the photo where a wove backing is in the process of being stitched to the ribs. The backing wires will provide a support for the fine wire cloth that will be sewn down in another step. I use the same spacing of laid backing wires for all wove moulds, so one serrated rack is sufficient for all.

#8 Drilling Holes in the Frame to Support the Ribs

First Step: Dial In the Drill Press Table

This drill press has a table that can be tilted and is prone to getting out of alignment. A dial indicator mounted in the chuck can be rotated by hand to check this. Small taps from a dead blow hammer are usually enough to correct misalignment. If the spindle is not true to the table (90 degrees in all directions) the holes drilled for rib pegs will tend to push the ribs out at odd angles. This introduces tensions into the structure that may throw the mould out-of-flat and/or out-of-square.

Setting the Drill Press Fence

The center of the rib peg hole, having been calculated, is scribed onto a test block, usually an off-cut or extra piece from the batch of moulds being made.

The hole to be drilled here (in this test piece) has been calculated to make the narrow top edge of the rib end up high by about .010″. This bit of extra wood will allow the ribs to be leveled after the mould has been assembled. Different types of mould will require the ribs to be set at different levels. This is to account for the differing arrangements of laid, bridge and chain wires that will rest on and be sewn down to the ribs. Drawings at the bottom of this post may make this more clear.

A fence is adjusted by eye to drill to the center of the mark. It is clamped to the table with two C-clamps and a test hole is drilled with a brad point drill.

A rib is inserted…

…and the depth of the recess is checked. The drill press fence is then re-adjusted as required before drilling the holes in the actual frame pieces.

Drill the Rib Holes

Try to put the point of the drill exactly in the middle of each mark. I sit on a chair so my eyes are nearly at the level of the table and use magnification to see better.

The top edge of the mould frame piece rests against the fence. The hole is drilled from the inside of the mould where the marks have been made. The depth stop of the drill press is set so that only the sharp point of the drill pokes through the other side.

The frame piece has been flipped over to show the tiny hole created by the point of the drill. Using the fence, the piece can be positioned so that the drill point will ‘seek’ the hole to finish drilling from the other side. This way the hole can be finished neatly without tear out.

As mentioned in a previous post some moulds have ‘blind’ holes that don’t pass completely through the frame. In my way of thinking a through hole is better. I have repaired old moulds where the shorter ‘blind’ rib ends weren’t adequately pinned to the frame, allowing the frame sides to spread apart. I also think that a mould with full length rib pegs might dry out a little more quickly after use, possibly helping to prevent decay. There are no concealed pockets to trap moisture (after any amount of use all parts of a mould will be thoroughly soaked) and the exposed end grain of the ribs may actually help wick away the moisture that has accumulated. Moisture enters and exits wood more readily through end grain than it does across the grain.

The sides of the frame are lightly sanded to catch and remove any ragged fibers around the edges of the holes.

Finished rib holes.

A rib seated in its hole in the frame.

The same rib from the other side.

When inserted the ribs should be held square to the frame. Individual ribs will usually curve slightly one way or the other. Turning a rib 180 degrees and checking it twice from the same side will reveal this. If the variation from square is the same both ways the hole is drilled perpendicular to the frame. If not the hole may be slanted.

Waterbar notches

A waterbar is a small extra rib that lies closely along the short ends of a mould. The wires of the mould aren’t sewn to it, it just touches the bottoms of the wires that cross it. Notches are routed into the frame to hold the ends of a waterbar. In Britain what I call “ribs” are called “bars”. So “waterbar” might translate to “water rib”. This could be a shortening of the awkward-to-say “de-watering bar”. These little ribs are intended to improve drainage along the short ends of a mould just under the edge of the deckle. Ribs provide pathways for water to flow down and away from the paper being formed on top of the porous wire facing. Including theses small de-watering ribs makes sense for single-faced moulds. These moulds suffer from poor drainage in the areas between ribs so the fibers are deposited on the wires there in a thinner layer. Thicker areas, known as ‘shadow zones’ form along the ribs where drainage is improved by the presence of those ribs. It follows that an extra rib positioned right under the edge of the deckle might improve drainage and help to form a substantial deckle edge there, too. But I’m inclined to think that waterbars are not needed for double-faced laid or wove moulds. In these moulds a layer of backing wires provides more pathways for water to flow along. This more complicated wire structure improves drainage and makes formation very even over the entire top layer of wires and eliminates the shadow zones. I would argue that no extra help from waterbars is needed for these moulds that include an extra layer of wires. Many people make their own wove moulds which must have backing wire of some sort to function well. Most, if not all of these moulds do not have waterbars and don’t seem to need them.

(Though I have long suspected that most waterbars are ‘vestigial’ and unnecessary I do not follow my own advice. Waterbars are still found on all of my moulds.)

This drawing shows the waterbar and how it relates to the inner margin of the deckle.

Mould sides drilled and ready for assembly.

Drilling Sequence

Because the drill leaves a little bump where its point exits the other side of the mould frame I drill only every 5th hole in a pass. This way the bump will hang over the edge of my drill press table and can’t affect the alignment of the next hole as it is drilled. Here I’m on the third ’round’ having just drilled the 3rd and 8th holes. (The gap visible between the work and the fence is not normal. My hands are holding the camera and the piece has shifted on the table.)

I don’t like the idea of the bump preventing the frame piece from resting completely flat on the drill press table (having already gone to the trouble of aligning it with the dial indicator). When a side is 1/5 finished I pare off the bumps on the back. Then the piece is returned to the drill press to repeat the process with the next several holes, again every fifth hole (depending on the size of the drill press table). This process isn’t difficult and doesn’t take significantly longer. This is just one more detail that’s intended to improve the outcome.

Making Fine Adjustments

When setting up the drill press the first hole drilled into a test block inevitably needs to be moved a little closer or farther from the top edge of the frame. Here is a simple way to accurately re-position the fence. In the photo I’ve clamped a scrap block of wood with a true flat end tight against the fence. After loosening the two clamps that secure the fence an appropriate shim can be inserted. Then the fence is pushed up tight against the shimmed block and the C-clamps re-tightened, re-positioning the fence BACK by exactly the thickness of the shim. Block and shim are then removed. If the shim is placed FIRST (before clamping the block in place) the fence can be moved FORWARD after the shim is removed.

Waterbar Notches

After waterbar notches have been made in one end of all of the mould frame pieces the stop (shown here clamped to the tablesaw fence) has to be moved to the other side of the router bit.

This is because the notches must be cut from the opposite direction on the other end(s).

Placement of Ribs for Three Types of Mould

A single faced laid mould will have the ribs set very close to the top of the mould frame. After the tops of the ribs are leveled they should be lower by a little more than the diameter of the laid wires. The level described by the top edges of the ribs is indicated here and in the two drawings below by the lower line and arrow. The upper line shows the top edge of the frame.

For a double faced laid mould the tops of the ribs should be set considerably lower as shown above.

The edges of the wire cloth wove surface generally rest on top of the mould frame. The ribs of a wove mould need to be set at a level to accommodate the diameters of the backing and bridge wires that support the wove facing.