Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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Knifemaker / Craftsman / Service Provider
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- Aug 20, 2004
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I had a recent email request to help a new maker with his handle assembly. I did this tutorial, and though I would post it here for the many others who are struggling to get handle pins and rivets right.
Before any handle fitting, the blade needs to be shaped, heat treated, and sanded/buffed/etched to its final finish. All that should be left to do is sharpen it. Tape the blade up with blue painters tape to within 1/2 Inch of where the scales will be. This prevents the curse words you will say when you scratch a finished blade while sanding the handle.
To do riveted ( peened) pins properly, there are a few tricks. I'll use a 3/16" pin as my example. The term pin and rivet are sort of interchangeable. The difference is that when you peen a pin, it becomes a rivet. The slightly flared end of the rivet will help it hold tighter. The epoxy does a lot of the work, but peening makes it even stronger. There is nothing wrong with just gluing in the pins when gluing up the handle and sanding them flush in shaping the handle. The bulk of knives are done this way. However, if you want a professional and stronger construction, learning to peen pins is the way to go.
First thing to know about almost all handle assembly is that the tang hole is always larger than the pin diameter. I usually use the rule of 25-50% larger. For a 3/16" pin, use a 1/4" drill bit to drill the tang. This allows for misalignment and prevents binding as you assemble the handle on the knife. Also, in peening, the pin will expand in diameter slightly. If the tang hole is a snug fit, the pin will expand on each side of it and raise the scale ( or bolster) up off the tang. There is no amount of hammering that will push it back down.
Second, the hole through the handle material should be a slip fit. That is a hole that allows the pin to go through without having to force it, but is not loose or sloppy. Usually you want the hole a couple thousandths larger than the pin. Generally, that is one drill bit size larger than the pin stock. For a 3/16" pin, use a #12 bit. You need to test it out on some scrap wood first, as all round stock isn't exact. This is where a cheap pair of digital calipers from Harbor Freight is very handy.
Now for the biggest tip: Don't rivet in the pins until the handle is shaped and 95% finished, or you will end up grinding/sanding away the flared ends, and they will be just pins again.
There are two good ways of doing this.
One is to use temporary wooden pins (dowels) and temporarily assemble the handle for shaping. After the handle is shaped, the wooden pins are removed or drilled out and the metal pins are installed and riveted. This works well for take down handles. I'll post a tutorial on this at another time.
The other, and simplest way when riveting, is to assemble the handle with metal pins, but don't put any epoxy in the pin holes. When the epoxy gets to the gel stage, break the epoxy bond to the pins, and let the handle cure. Remove the pins when the epoxy is cured, install new pins, and rivet.
The full procedure for the simple way:
Finish and tape up the blade, with the tang holes already drilled.
Drill pilot holes in the scales first, roughly about half the pin size, so use a 1/8" bit to drill the pilot holes for a 3/16" pin.
Mark the holes positions on one scale with the tang on it, remove and drill the pilot holes through it. Place the other scale on it and tape them together (or use a couple small dots of CA glue). Drill through the second scale using the holes in the first one as a guide. Do one hole, and stick a drill bit or 1/8" pin through it to assure the scales don't move. Drill the second hole and put another drill bit/pin through it. Drill the last hole (if there is a third hole). This will assure the holes all line up during assembly.
Cut the 3/16" pins about 1" longer than the handle thickness, and chamfer the ends. Re-drill the holes for the pin stock using the drill bit you selected (for 3/16", a #12 bit). Drill through the front hole, place the scales on the tang, and stick one of your chamfered pins through the hole ( use some tape to keep it in place if it wants to slide out). Drill the other holes out and stick pins through them as you do. If one pin is sticky, run the drill in and out a few times to smooth the hole a bit. You now have a perfectly aligned scale, tang, and pins.
Remove the scales from the blade and put the pins back in the holes, taping or clamping the scales tightly together. Go to the grinder and sand the front of the scales to shape. Round them up onto the sides. Sand to at least 400 or 800 grit and buff (or sand to 1000 grit if you don't have a buffer). The front of the scales must be shaped and smoothed before assembly, as that area can not be shaped or sanded once assembled to the blade without damaging the already finished blade. If you are applying a finish, do that to the front now, too.
Use 1 hour epoxy at the minimum, but the 24 hour type is much better for gluing up the handle. DON'T use 5 minute epoxy (unless you are on Forged in Fire and don't have the time to do it right). Wear rubber gloves when doing epoxy work. The solvent for uncured epoxy is denatured alcohol ( the cheap stuff from Home Depot). Have lots of paper towels already pulled into sheets, and don't be afraid to change gloves if they get covered with epoxy. The cheap gloves from HF are perfect for epoxy work.
To do glue up, place the pins through the holes in one scale - no glue in the holes or pins. Put a reasonable amount of epoxy on both sides of the tang and place it on the scale with the pins sticking through the tang holes. Try not to get epoxy on the pins, and wipe off any if it gets on them. Put the other scale on the pins. Press the assembly together by hand and check that everything seats properly. Wipe off the excess epoxy run-out, clamp lightly with two low tension spring clamps, and set down for a bit. The temptation to clamp together hard with screw clamps or powerful spring clamps must be avoided. This will create a glue starved joint by squeezing out all the glue between the tang and handle. That would make a much weaker handle.
Monitor the left over glue pot and when it gels, take a pair of pliers and twist the pins around to break any glue bond. Re-twist every five minutes or so until the resin in the pot is hardened. Don't pull out the pins yet. Set aside to cure overnight. Once cured, pull or tap out the pins. If for some reason one is stuck, heat the end with a torch and it will come out easily. Run the #12 bit through the holes carefully to remove any epoxy, and put in new pins to check that all is good.
Set the pins aside and shape the handle. When it is 95% done and at 400 grit, you are ready to re-install the pins.
Put epoxy in the holes and rub on the pin sides. Slide the pins in the holes with a twist to distribute the resin. When the new resin starts to gel, cut the pins off about 1/8" above the handle surface (hacksaw or metal bandsaw. For smaller pins, just clip off with diagonal cutters.) File the ends flat so they are about one half the pin diameter above the surface. As a general rule, 1/16" to 1/8" is right. One reason to use 24 hour epoxy is that there is no rush at this point. You have an leisurely hour or more between the gel stage and any firm hardening to peen the rivets.
Using the round end of a small ball peen hammer, lightly tap the pins while the other side is sitting on a hard solid surface. A cutler's anvil is great, but a piece of granite, block of steel, etc. will work fine. The HF small anvils will work here. Tap around each pin, switch sides and do the other ends, repeat and reverse until the pin ends have rounded out and lowered down onto the surface. Adjust the force of the blows as needed to move the metal, but don't wail away at the pins unless you want to damage the handle. What you want is a little rounded end to the pins that is larger than the pin was before peening. Set aside overnight to cure.
Tape up the blade the rest of the way up to the handle. Now, you can file the pins flush, do a little finish sanding and it is done. On things like stag, leaving the small rounded knob of metal proud of the handle is popular. Either carefully peen the pin so it looks good, or use a head spinner ( a type of cup burr).
NOTES:
If your rivet stock is half-hard or hard ( as much pin stock is) you can anneal it by heating in the HT oven to 700F for an hour, then dunking in water. A hand torch will work, too. Heat to dull red and quench in water. You don't have to clean off any discoloration, just use as it is. It will be much softer after annealing.
Check the diameter of pins/rivets with a caliper before drilling holes. Pick a drill bit accordingly. Test on a hardwood block (or Micarta) to assure the proper fit.
Grind/file the ends of the pins at a chamfer. Square ends don't want to slide through holes.
It is a good idea to roughed up the pins on 100 grit paper, but if you do, be sure to measure the pins after the sanding to get the right size drill bit for the hole.
A note on the hammer ball - It should be smooth to at least 400 grit. Most folks polish it on the buffer. The smoother it is, the better it pushed the metal around. If doing decorative peening on a blade surface or exposed rivets, the smooth surface is very important.
Before any handle fitting, the blade needs to be shaped, heat treated, and sanded/buffed/etched to its final finish. All that should be left to do is sharpen it. Tape the blade up with blue painters tape to within 1/2 Inch of where the scales will be. This prevents the curse words you will say when you scratch a finished blade while sanding the handle.
To do riveted ( peened) pins properly, there are a few tricks. I'll use a 3/16" pin as my example. The term pin and rivet are sort of interchangeable. The difference is that when you peen a pin, it becomes a rivet. The slightly flared end of the rivet will help it hold tighter. The epoxy does a lot of the work, but peening makes it even stronger. There is nothing wrong with just gluing in the pins when gluing up the handle and sanding them flush in shaping the handle. The bulk of knives are done this way. However, if you want a professional and stronger construction, learning to peen pins is the way to go.
First thing to know about almost all handle assembly is that the tang hole is always larger than the pin diameter. I usually use the rule of 25-50% larger. For a 3/16" pin, use a 1/4" drill bit to drill the tang. This allows for misalignment and prevents binding as you assemble the handle on the knife. Also, in peening, the pin will expand in diameter slightly. If the tang hole is a snug fit, the pin will expand on each side of it and raise the scale ( or bolster) up off the tang. There is no amount of hammering that will push it back down.
Second, the hole through the handle material should be a slip fit. That is a hole that allows the pin to go through without having to force it, but is not loose or sloppy. Usually you want the hole a couple thousandths larger than the pin. Generally, that is one drill bit size larger than the pin stock. For a 3/16" pin, use a #12 bit. You need to test it out on some scrap wood first, as all round stock isn't exact. This is where a cheap pair of digital calipers from Harbor Freight is very handy.
Now for the biggest tip: Don't rivet in the pins until the handle is shaped and 95% finished, or you will end up grinding/sanding away the flared ends, and they will be just pins again.
There are two good ways of doing this.
One is to use temporary wooden pins (dowels) and temporarily assemble the handle for shaping. After the handle is shaped, the wooden pins are removed or drilled out and the metal pins are installed and riveted. This works well for take down handles. I'll post a tutorial on this at another time.
The other, and simplest way when riveting, is to assemble the handle with metal pins, but don't put any epoxy in the pin holes. When the epoxy gets to the gel stage, break the epoxy bond to the pins, and let the handle cure. Remove the pins when the epoxy is cured, install new pins, and rivet.
The full procedure for the simple way:
Finish and tape up the blade, with the tang holes already drilled.
Drill pilot holes in the scales first, roughly about half the pin size, so use a 1/8" bit to drill the pilot holes for a 3/16" pin.
Mark the holes positions on one scale with the tang on it, remove and drill the pilot holes through it. Place the other scale on it and tape them together (or use a couple small dots of CA glue). Drill through the second scale using the holes in the first one as a guide. Do one hole, and stick a drill bit or 1/8" pin through it to assure the scales don't move. Drill the second hole and put another drill bit/pin through it. Drill the last hole (if there is a third hole). This will assure the holes all line up during assembly.
Cut the 3/16" pins about 1" longer than the handle thickness, and chamfer the ends. Re-drill the holes for the pin stock using the drill bit you selected (for 3/16", a #12 bit). Drill through the front hole, place the scales on the tang, and stick one of your chamfered pins through the hole ( use some tape to keep it in place if it wants to slide out). Drill the other holes out and stick pins through them as you do. If one pin is sticky, run the drill in and out a few times to smooth the hole a bit. You now have a perfectly aligned scale, tang, and pins.
Remove the scales from the blade and put the pins back in the holes, taping or clamping the scales tightly together. Go to the grinder and sand the front of the scales to shape. Round them up onto the sides. Sand to at least 400 or 800 grit and buff (or sand to 1000 grit if you don't have a buffer). The front of the scales must be shaped and smoothed before assembly, as that area can not be shaped or sanded once assembled to the blade without damaging the already finished blade. If you are applying a finish, do that to the front now, too.
Use 1 hour epoxy at the minimum, but the 24 hour type is much better for gluing up the handle. DON'T use 5 minute epoxy (unless you are on Forged in Fire and don't have the time to do it right). Wear rubber gloves when doing epoxy work. The solvent for uncured epoxy is denatured alcohol ( the cheap stuff from Home Depot). Have lots of paper towels already pulled into sheets, and don't be afraid to change gloves if they get covered with epoxy. The cheap gloves from HF are perfect for epoxy work.
To do glue up, place the pins through the holes in one scale - no glue in the holes or pins. Put a reasonable amount of epoxy on both sides of the tang and place it on the scale with the pins sticking through the tang holes. Try not to get epoxy on the pins, and wipe off any if it gets on them. Put the other scale on the pins. Press the assembly together by hand and check that everything seats properly. Wipe off the excess epoxy run-out, clamp lightly with two low tension spring clamps, and set down for a bit. The temptation to clamp together hard with screw clamps or powerful spring clamps must be avoided. This will create a glue starved joint by squeezing out all the glue between the tang and handle. That would make a much weaker handle.
Monitor the left over glue pot and when it gels, take a pair of pliers and twist the pins around to break any glue bond. Re-twist every five minutes or so until the resin in the pot is hardened. Don't pull out the pins yet. Set aside to cure overnight. Once cured, pull or tap out the pins. If for some reason one is stuck, heat the end with a torch and it will come out easily. Run the #12 bit through the holes carefully to remove any epoxy, and put in new pins to check that all is good.
Set the pins aside and shape the handle. When it is 95% done and at 400 grit, you are ready to re-install the pins.
Put epoxy in the holes and rub on the pin sides. Slide the pins in the holes with a twist to distribute the resin. When the new resin starts to gel, cut the pins off about 1/8" above the handle surface (hacksaw or metal bandsaw. For smaller pins, just clip off with diagonal cutters.) File the ends flat so they are about one half the pin diameter above the surface. As a general rule, 1/16" to 1/8" is right. One reason to use 24 hour epoxy is that there is no rush at this point. You have an leisurely hour or more between the gel stage and any firm hardening to peen the rivets.
Using the round end of a small ball peen hammer, lightly tap the pins while the other side is sitting on a hard solid surface. A cutler's anvil is great, but a piece of granite, block of steel, etc. will work fine. The HF small anvils will work here. Tap around each pin, switch sides and do the other ends, repeat and reverse until the pin ends have rounded out and lowered down onto the surface. Adjust the force of the blows as needed to move the metal, but don't wail away at the pins unless you want to damage the handle. What you want is a little rounded end to the pins that is larger than the pin was before peening. Set aside overnight to cure.
Tape up the blade the rest of the way up to the handle. Now, you can file the pins flush, do a little finish sanding and it is done. On things like stag, leaving the small rounded knob of metal proud of the handle is popular. Either carefully peen the pin so it looks good, or use a head spinner ( a type of cup burr).
NOTES:
If your rivet stock is half-hard or hard ( as much pin stock is) you can anneal it by heating in the HT oven to 700F for an hour, then dunking in water. A hand torch will work, too. Heat to dull red and quench in water. You don't have to clean off any discoloration, just use as it is. It will be much softer after annealing.
Check the diameter of pins/rivets with a caliper before drilling holes. Pick a drill bit accordingly. Test on a hardwood block (or Micarta) to assure the proper fit.
Grind/file the ends of the pins at a chamfer. Square ends don't want to slide through holes.
It is a good idea to roughed up the pins on 100 grit paper, but if you do, be sure to measure the pins after the sanding to get the right size drill bit for the hole.
A note on the hammer ball - It should be smooth to at least 400 grit. Most folks polish it on the buffer. The smoother it is, the better it pushed the metal around. If doing decorative peening on a blade surface or exposed rivets, the smooth surface is very important.
