Full Chisel Blog

January 28, 2012

The Moxon Vise

This post is inspired by a recent completion of a tool I made a while back, see here.  I needed to add a cleat and after finding some of the yellow poplar that I used to build the tenon clamp, I cut a 6″ long piece.  In the side of the clamp I cut a full mortise ¾” deep and glued it in place with Fish Glue, I will peg it later.  Now when I use the holdfast to secure the clamp, the hold fast is out of the way.  I then either had an epiphany or thought the whole thing up.

Looking at the cleat as a method of securing this clamp and other planing and sawing appliances, I considered that perhaps this is how the Moxon Vise was also secured to the bench.  The holdfast might get in the way with this interpretation.  Then I also noticed the similarities between the movement of this clamp and the garter to the original engraving from Moxon’s work.

 

 

 

 

 

I first illustrated the Moxon Vise here.  I drew two illustrations as to how the vise was used.  However there was one mistake, I failed to draw one more hole on the workbench top.  This hole can be important as I will explain later*.

From the very beginning I have had inquiries as to how the vise was attached to the bench.  Up until now I did not know but I think I may have come up with a possible solution.  The screws need garters as mentioned by Henry Mercer in Ancient Carpenter’s Tools, so extra screw sticks out front and does not complicate things on the back of the vise.  The cleat allows the vise to be mounted on the underside of the bench by inverting the holdfast*.

This looks like a much better method of holding the vise chops.

Stephen

January 26, 2012

Cutting Wooden Threads

Spiral threads have been cut in wood for centuries.  I discussed making thread by hand earlier.  During the nineteenth century the tools had been perfected but still retained their original design.  There are two components to threading; there is the screw and the nut.  The screw has external threads and is referred to as the male element and the nut has internal threads and is referred to as the female.  While these can be meticulously cut by hand, it is much easier to accomplish this by using some simple tools.   There are two tools used to make the threads by hand and they are the tap and the die or die box or screw box.  Wooden threads can also be cut on specialized lathes from a design first proposed by Leonardo da Vinci.  This discussion will be about using the two hand tools to make the threaded screw and nut.

There is nothing quite like creating wooden threads.  The process is a unique experience and the results can be rewarding.  You are capable of making your own wooden screw clamps, veneer presses, vices and adjustable items such as music stools, embroidery frames and candle stands.  Threading wood is something unique, a wooden nut and bolt is unusual, something that few others have.  The projects, tools, furniture and fun things you can make with a set of these tools are endless.  Wooden threads have always intrigued me; there is just something fascinating about them.

Wooden Thread Cutting Tools

There are two ways to go, the first is to buy a set of wooden thread cutting tools or you can make your own.  The new wood threading tools are of good quality and generally follow traditional designs.  If you choose to make your own you will need to have made a tap of the proper size that you are interested in making.  This should have sharp edges to make clean cuts; a machinist or good blacksmith can fabricate a tap to your particular dimensions.  These taps are similar to modern metal cutting taps except they are larger and have fewer teeth per inch.

Eight teeth per inch is about the minimum for a ½” tap and larger should have 6 teeth per inch and on very large screws for presses 4 TPI to withstand the pressure.  To make a tap the threads can be cut in the metal for the tap and then the four sides flattened to produce 4 cutting edges at each thread.  Regular taps have a tapered end to make it easy to start the tool into the wood.  Bottoming taps are not tapered but will cut to the end or the bottom of a blind hole.  Do not use a bottoming tap for initial threading as it can easily cut off centered internal threads.

There is another old design that has the threads machined on the outside and a hole drilled in the center of the end of the tap.  On the end of the tap, the threads are machined down to form the taper and at the first thread a small hole is drilled at an angle into the large center hole.  This forms a very sharp tooth that cuts and the chips go through the small hole and out the larger hole in the end of the tap.  This type of tap does produce a very smooth cut, but the traditional 4-sided tap, if it is sharp and used properly will also produce clean cuts.  The wooden handle should be strong and long enough to give leverage for the sometimes difficult process of cutting internal threads.  The handle should be rounded and shaped to fit the hand as the hand is touching the handle a lot during tapping.

Once the tap is made it is possible to make the die box and all that is required is a V-shaped cutter that is secured in the box and cuts the external threads.  Unlike the tap, which will cut with four cutters on each thread, the die has only one cutter that cuts all of the threads.  A proper sized hole is drilled for the tap into a piece of hardwood such as beech or maple, see list below.  This hole must be square to the body of the die box.  The holes are then chamfered or countersunk to prevent the tap from splitting out the wood as it enters and exits the hole.

The tap should be lubricated with linseed oil to make the threading easier.  The tap is then inserted carefully into the hole and started squarely to insure a straight threaded hole.  It is very important that the tap is started perpendicular to the surface and square to the hole.  If the tap binds up gently back a ½ turn then start again, if it becomes too difficult, remove the tap, lubricate and try again.  Make sure the exit hole is countersunk to insure that the tap doesn’t break out any wood when it exits.

Now that you have the die box drilled and threaded, the next step is to cut a mortise for the V-shaped cutter that is on the front leading edge of the die box.  The cutter is positioned right over the first complete thread peak at an angle of 30ºand the leading edge of the cutter should engage the wood at the widest part of the cutter first to score the wood being removed.  The end of the cutter is ground at an angle of 15º with the top of the V leaning forward, with the bottom of the V trailing.

The cutter needs to be sharp and set to cut just slightly deeper than the threads that were cut by the tap.  This insures that the newly cut external threads will not bind up in internal threads of the die box.  The die box can also be equipped with a removable plate that will center round pieces as they are fed into the screw box.  The plate needs to be thick enough to line up the piece to be threaded and removable so the external threads can be cut all the way up to the shoulder of a turned piece if necessary.  The internal threads of the screw box should be well lubricated to make the cutting of the screw shaft easier.

Nut – The Nut is the part with the internal threads that are cut with the Tap.  The nut is prepared by drilling the hole using the following starting holes sizes.

Starting holes:

½” threads use a 3/8” drill

¾” threads us a 5/8” drill

1” threads use a 7/8” drill

1 ¼” threads use a 1 1/8” drill

1 ½” threads use a 1 3/8” drill

1 ¾” threads use a 1 5/8” drill

2” threads use a 1 7/8” drill

2 ¼” threads use a 2 1/8” drill

2 ½” threads use a 2 3/8” drill

 

It is important that the hole is drilled square and perpendicular the flat surface of the nut.  The wood for the nut should be a wood that is capable of taking the threads.  While most hardwoods will hold the threads some are better than others.  Beech, maple, hickory and oak can be used for nuts and will take threads, as can alder, elm and poplar.  Some brittle woods such as cherry are difficult to thread, but it can be done.  The thicker the piece of wood that is threaded, the stronger the threads will be.

On thin pieces for the nut, the threads can easily be cut at an angle, so make sure the hole is straight and the threading is done properly.  When threading in an angled hole, the grain orientation is important as is beginning the cutting with the tap.  The tap needs to go straight down the hole; if you get off at an improper angle the threads will be too deep on one side and too shallow on the other.  While the internal threads on the nut are not as critical in terms of strength, the screw needs to be constructed of specific woods.

After the proper sized hole is drilled, the edges need to be chamfered or countersunk to prevent split out during the entry and exit of the tap.  This must be done on both sides, as the tap will chip out the wood.  The tap is lubricated with linseed oil or beeswax and it is inserted in the starting hole.

It is very important to make sure that the tap is perfectly square and lined up with the hole.  The tap is twisted and forced into the wood, taking care to make sure that it is perpendicular to the surface of the nut. Enough downward pressure is exerted to engage the tap into the hole, after the cutting begins, the tap is self-feeding.  If the tap binds in the hole, gently and carefully back it off a half a turn and start again.  If it still binds, back the tap out of the hole, lubricate it again and carefully start the tap back into the cut threads.

Be careful when doing this so you don’t cross thread the screw and ruin your work.  Every once in a while, back the tap out a half a turn and continue until cutting becomes more difficult, then repeat and go at it again.  It is better to take your time and make sure that the work is done properly.  Continue until the tap comes out the exit hole, clean out the shavings and back the tap out of the hole.

If you are threading a blind hole, your starting tap will hit bottom, then back out the tap, remove the dross and carefully place the bottoming tap into the threads and run it down until it cuts the internal threads on a blind hole.  If the wood is fuzzy on the inside of the threads, I wet the piece with water and raise the grain.  I allow it to dry completely and run the tap down the hole again to remove the raised grain and fuzz.  Sometimes running the tap in from the opposite direction will remove the fuzz and clean up the internal threads.

Screw – The Screw is the part with external threads and is cut by the Screw Box or Die.  The selection of the material for the screw is important as certain woods make excellent threads while others are more difficult.  Softwoods are difficult without an extremely sharp cutter in the screw box.  Hardwoods are preferable and woods such as beech, maple and hickory are the best for wooden bolts or screws, those with external threads.  Strong, tough woods such as elm are better than brittle woods like cherry.  Walnut also accepts threads as well.  With care any wood can be threaded.

It is also important that the grain be as straight as possible.  This is for strength and for a more uniform cut.  The piece to be threaded should be turned to the size of the thread box.  Therefore if the threads are for a 1 ½” screw then the dowel or piece should be turned to just under 1 ½”.  All it takes is just a 32nd under to make the piece just the right size.  It may take a slightly smaller say 16th under to get a proper fit, it may take some experimenting.  But I guarantee if it is too large the threads will crumble as it is forced through the screw box.  If it is too large it will not fit into the screw box and if it is too small it will not properly thread through the screw box.  A slightly smaller screw works much better than one that is too tight.  I like nice crisp threads, so I always turn the pieces just under the required size.

For some applications where you don’t necessarily need sharp peaks, such as heavy duty tools, the screw blank or dowel can be slightly undersized producing flat topped threads instead of sharp peaks.  Small fine threads such as 8 threads per inch can be difficult and these fine external threads can easily break off.  Denser woods work better for these fine threads.  If the dowel is undersized, it is important to make sure that the screw box travels over the dowel in a uniform manner to insure proper threading.  If flat-topped threads are required, I usually turn the dowel to the proper size, thread the piece, then re-chuck it in the lathe and turn off the peaks.

When you turn the screw or dowel on the lathe, just use your gouges and chisels, do not use sandpaper.  The sandpaper can leave residue in the wood fibers that can dull the cutter in the screw box.  Also you will want to chamfer the edge of the dowel or screw blank to make it easier to start the screw box.

I always dip the end of the screw blank or dowel in linseed oil to provide lubrication for the cutting process.  I usually clamp the screw blank in a vice to hold it during the threading process.  It is important to make sure that the screw box engages the screw blank or dowel perfectly square to insure accurate threading.  I always look down the waste hole in the screw box where the chips come out to see how the cutter engages the threads.  I try and exert enough pressure to engage the wood on flat grain first rather than the side grain.  It just seems to start better if the cutter enters the wood on the flat grain.

Once the cutter has began to make threads they engage and pull the screw blank into the screw box, so the pressure can be reduced.  After cutting begins, simply turning the screw box is sufficient.   When the cutter has made the first part of the threads, they will engage the internal threads of the screw box and advance the screw into the tool creating a perfectly cut spiral thread.  The first ½” or so is usually not perfect and I always allow for an extra half inch or so to cut off after the threads have been cut.

Once the cutting has started, the tool should ‘sing’ through the work.  If the stuff is tight in the tool, the cutter may be set too shallow or the dowel is too large.  Most screw boxes have a removable plate that guides the screw blank into the screw box.  This is removed if the threads are to be cut up to a shoulder.  The plate should be used to cut well into the screw blank and can be removed to thread just the last inch or so.  A properly positioned and very sharp cutter will make the cutting much easier.

It is important that you keep your tools sharp and well maintained.  The teeth on the tap need to be clean and sharp at their cutting edges.  The new made tap and die sets require sharpening.  The screw box has a V cutter that needs to be honed mirror shiny on the outside and perfectly flat on the inside. The V-shaped cutter in the screw box should be ground at the proper angle of 15º and should be very sharp and properly positioned.  The bevel is ground on the outside of the cutter.  Both edges must be honed for a good clean cut.

New set of ¾” taps and V-cutter, factory ground, NOT sharp.  Note improper ground V-cutter, burr protruding from the bottom of the V.

New set Sharpened.  Threads and slots have been dressed and V-cutter sharpened and honed.

The tap needs attention as well.  The V-teeth need to be dressed to remove the grinding burr left during manufacture.  Make sure to get both sides of the slot and both places where the slot and the V groove meet, especially on the leading (cutting) edge.  Use a triangular file to dress the teeth.  Use a thin flat mill file to dress the gullets so the cutting edge is sharp.  Then go back and re-dress the V-grooves with the triangular file to remove the last of the burrs.

The sharper your tools the easier the work.  I use a bit of sandpaper over the files to hone the edges to a mirror gloss.  Your holes need to be clean, straight and countersunk and your turnings need to be of the proper size and chamfered to produce the desired results.  Use linseed oil or beeswax to lubricate the parts being cut, it just makes the job easier.  Make sure the tool engages the work squarely to produce quality work.

Clean out any shavings that can interfere with the cutting operation.  Work slowly and carefully.  This is not like cutting metal threads; it is a continuous operation, only backing out when the cutters jams or the cutting is complete.  After you are finished using the tool make sure to clean off all excess linseed oil before it dries!

There is no end to the possibilities for using wooden threaded devices and the results are delightful.  Wooden screws are capable of exerting incredible pressure when used for clamping applications and can provide for ease of assembly and disassembly for transportable furniture.  There are endless applications and uses of wooden threads and they are fun to make.

Stephen

January 24, 2012

International Shipping of Books

Filed under: For Sale or Trade,Publications,Uncategorized — Stephen Shepherd @ 9:59 am

I had to add an additional $10.00 to cover the cost of international shipping.  I have received several orders and the rate I have posted is for domestic shipping.  Instead of adding an additional button to each order, I have just added this new button.

So if you are placing an order and you live outside of the United States please add the additional international shipping charge.  Full Chisel Store.

Thank You

Stephen

January 19, 2012

Back in Business

Filed under: Of Interest,Uncategorized — Stephen Shepherd @ 3:17 pm

My blog and website have been off line for a couple of days due to changing host server.  I can now get back to work.

Stephen

January 12, 2012

Preparing for the 18th Century

Filed under: Finishing,Furniture,Historical Material,Of Interest,Publications,Uncategorized — Stephen Shepherd @ 11:35 am

One hundred years before my general interest in woodworking technology [being the 19th century see Shepherds’ Compleat Early Nineteenth Century Woodworker], I do have some understanding of the earlier tools, materials, and techniques of the 1700’s.

I have a couple of projects ahead that requires 18th century material.  So in order to prepare for this I thought I would start at the ground floor and work up.

I traded for these ‘straights’ [the common name for shoes that are neither left nor right footed] from Sir George and they came with some awful* reproduction buckles.  I traded a pair of Fry lanchet shoes for these Fugawee shoes, but kept my buckles I got from the Sutler at Mount Misery back in 1976, those on the left.

*The forks on the large military shoe buckles are too long, as you can see in the before picture.  I nipped them off and filed them to a point, trimmed the lanchets and made new holes.  The buckles work just fine now.

I will break the shoes in by wearing them for a day then switching shoes the next day, I am however open to hiring someone to break them in for me.

Now, I guess I need a pair of knee breeches and maybe a Moxon wig.

Stephen

January 1, 2012

Carving Chisels and Gouges

 

Carving chisels and gouges differ from cabinet chisels and other gouges in that they are usually somewhat thinner and are sharpened with a finer angle on the cutting edge.  Some are intended for handwork only while others can be struck with a mallet and of course are never struck a metal hammer.  They have thinner blades and handles that are easy to control, are comfortable and don’t tend to roll on the bench.  I have replaced every round handle on my carving tools with a tapered octagon handle.  This eliminates any rolling of the tool, when I place it down on the bench it stays there.  If I am using a series of chisels and gouges for a particular job I have a mat, a piece of carpet that I use to lay the tools down on to protect their cutting edges.  I also point the sharp ends away from me on the mat to protect me from the very sharp cutting edges.  Most carving jobs are done with two or three tools; sometimes a couple of more but each carving job can require different tools to accomplish the task at hand.  Therefore if you intend to do a lot of carving you will want to equip yourself with the necessary tools.  While both chisels and gouges come in different sizes and with gouges different sweeps you can invest a substantial amount of money to have all of the various sizes of chisels and different sizes and sweeps of gouges.  There also Palm Chisels and Gouges that are smaller versions usually with mushroom or knob type handles for ‘better’ control of these tools.  I have several of these small ‘palm’ tools but like my other chisels I have replaced all of their handles with long tapered octagon wooden handles, I just find them easier to use and they all match.   Large heavy duty carving tools can have socket handles but the most common have tangs to secure them to the handles.

Back Bent Chisel is a regular flat chisel with the blade bent backwards to a curved chisel.  The advantage of this tool is that it brings the cutting angle down very low to produce a finer cut.  The bevel is ground just the opposite a regular chisel with the bevel on top.  Useful for rounding over and shaping convex and protruding detail work.

Curved Chisel is a flat chisel with a blade curved opposite the bevel and is used to get down into areas that need to be flattened.  The curve of the blade will allow for the cutting angle to engage the wood fibers at a low angle.

Double Bevel Chisel is a special carving tool that has a bevel ground on both sides of the blade.  This tool, usually with a straight blade is used for cleanup work; the double bevel is not good for layout work as the blade pushes in both directions when it is plunged into the cut.  Single bevel tools are used for striking the work into the groundwork.  This tool is also available is a skew, which is handy because you can easily reverse it to get into tight areas.

Fishtail Chisel is like a regular chisel but of lighter weight and the blade tapers from wide at the cutting edge to narrower at the tang.  One great advantage to this tool is that it can get into tighter areas; the angle of the taper allows the cutting edge to work up against a shoulder or other interior detail.  These chisels are usually more flexible than regular chisels.

Flat Chisel is very similar to a bench chisel in that it has a flat blade and the cutting edge is at 90º to the blade.  The blades are usually manufactured with a tang and are thinner than a cabinet chisel and may or may not have bevels up the sides of the blade.  Because of the thin nature they are more commonly like a firmer with no side bevels.  One of the more useful carving tools a surprising amount of work can be done with a flat carving chisel.  Most are ground at a fine 15º angle on one side of the chisel.  Some are ground with a double bevel. The single bevel is used to layout and strike work into the groundwork.  Also called a firmer or carving chisel.

Skew Chisel is like the flat chisel but the cutting edge is ground at an angle to the blade.  The skew angle can be either left or right and ground on one or both sides.  When ground on both sides the skew is reversible, if it is ground on one side then a pair may be required.  These chisels cut smooth because of the skew angle and can get into tight corners for easy clean up.

V-Chisel is also called a veiner and is used to add V-shaped details in wood.  This tool and the U-Chisel are used only for shallow work; if deeper V-cuts are needed straight chisels are used to cut down both sides of the v-groove.  Like the U-chisel curved cuts can present grain direction problems.  I make my first v-cut shallow on the side of the curve that is with the direction of the grain.  I then reverse and make my second v-cut to final depth with the grain of the wood.  Tipping the tool up when engaging the wood will start the cut on the top edge of the wood first preventing chipping out.  Some of these chisels are sharpened with the outside edges projecting further than the center part of the V.  This allows the tool to score or cut the wood ahead of the V to prevent tear out.  This tool can also have a bent blade such as a long bend or short or spoon bend to just the end, allowing v-cut detail work in deep excavations.

Dog Leg Chisels are also used for carving work and are referred to as entering or cornering chisels.  These tools are particularly handy, the offset or dogleg is usually in the shank just at where the blade starts to widen out.  This offset allows the back of the blade to be flat keeping the cutting angle low for a smoother and easier cut.  In a set of three there is a straight blade, left skew and right skew to handle any application.

A gouge is any chisel with a curved cutting edge; this includes even very low sweeps or curves.  If it is curved it is a gouge.  Some heavy-duty carving gouges are quite similar to a bench gouge, but most are smaller, thinner walls and lighter duty and they are sharpened to a finer edge.

Back Bent Gouge is a handy tool for finishing off curved convex surfaces.  The bevel is on the top and this tool can perform functions that no other single tool can accomplish.  While you can do the same with a flat chisel, the back bent gouge can do the same job in one or two strokes.  The back bend can be on full-length gouges as well as the spoon gouge shape.

Curved Gouge is a gouge with a curve to the shaft allowing the tool to work on deep inside curves.  The curve along the length of the shaft gives a lower angle of attack to the cutting edge.

Fishtail Gouge is a lightweight gouge that has a wider cutting edge and the shaft tapers back to the tang.  The fishtail gouge like the fishtail chisel in that it is flexible and the taper allows the sides to be moved up next to a corner or edge without the shaft interfering with the cutting action.  The fishtail also makes the gouge lighter weight, as there is less metal in the blade.

Flat Gouge is the standard classic carving gouge.  With thinner walls and lighter construction than a Cabinet gouge, this tool comes in many sizes and sweeps to the curve.  The shaft is straight and attaches to the handle usually with a tang in some rare instances a socket.  The bevel is ground on the outside or convex side of the gouge.  When used for laying out and working the background this chisel is used to follow the sweeps of the curves in the carvings.  The appropriate sweep is chosen to match the pattern for the carving.  You can see why you might need several sizes and sweeps of this tool to match all curves that might be encountered.  A special grinding (on the inside) to this tool produces an ‘in cannel’ gouge and the outside of the tool can be used to do the lay out and initial chopping.

Fluting Gouge is similar to the flat gouge but usually have a greater sweep with high thin walls.  More of a U-shape these tools are great for deep flutes and other deep detail.  When using a gouge it is important that sometimes when you are cutting you are cutting with the direction of the grain on one side and against the grain on the other side.  Always be aware of the direction of the grain and cut first on one side and finish up the other direction on the other side of the flute.

Spoon Gouge has a shaft that becomes a spoon shape near the cutting edge.  With more curve along the length of the shaft than a curved gouge these tools are ideal to get down in the bottom of bowls, spoons and other steeply sided excavations in the wood.  The curved shape to the spoon also gives added leverage to the cutting process.

U-Chisel should actually be classified as a gouge as it has a curved cutting edge.  This very fine U-shaped edge is used for adding details and fine u-shaped cuts into the wood.  When using this tool always keep in mind that on curves one side is with the grain and the other side is against the grain.  I do the initial cut a little shallower in the correct direction for that cut.  I then I do the second cut in the other direction to keep me working with the grain of the wood.  This tool can also have a bent blade such as a long bend or short or spoon bend to just the end, allowing detail work in deep excavations.

Individual wood carvers have their own preferences for how the tools are sharpened.  Most agree on a fine angle of 15º for the bevel on the cutting edge.  Many sharpen a secondary bevel on the cutting edge, but I prefer a single 15º bevel that is flat and not hollow ground.  The problem with hollow grinding is that it is impossible to polish the entire bevel, which I believe makes for a smoother and easier cut.

As for storage of carving tools, the tool roll of canvas or leather is popular as is hanging the tools up on the wall to both display and keep the cutting edges from getting dull by banging into each other.  This can happen if they are kept in a drawer.  A drawer will work if it has dividers that separate each tool.  I have used tool rolls and they are handy if you have to take them out of the shop but for storage and accessibility I prefer to hang them up and show them off.  After I use my carving tools, I always wipe the blade down with turpentine to remove any pitch or sap that might be on the blade.  I also keep my entire tool bright and free from rust.  A tool that has a bright finish will not tend to rust as one with just a ground surface.  I also check the sharpness and touch up the blades if necessary so they are always sharp and ready to go.

Stephen

 

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