Kevin, I can tell you bone, antler are easy to chip out. The advice from Steve is spot on!
bladegrinder:
The hardest thing about using stag or jigged bone for scales is tha no matter where you put a pin or screw.....it won't be in a flat spot, it's always on top or in the wall of a raised ridge. I always go REAL SLOW and use some Kentucky windage by hand on the drill press.
Kentucky windage (plural Kentucky windages) (US, slang) An adjustment made by a shooter to correct for wind (or motion of the target) by aiming at a point horizontal to the target's position in the sight rather than by adjusting the sight to compensate.
What Steve is trying to say is when drilling you have to use some eyeballing. The antler or bone is not always the same thickness at both ends. I have accomplished the drill for pins in this manner. I drill where I want the pins in my knife blank! Now is where you have to use some Kentucky windage.
I am going to try and work thru this step by step. this may not be how other do it but this is my process.
I figure out where I want the bone/antler is to be placed on the handle of the knife blank.
I will take a pinch clamp on it being careful to not slide the piece. (this is where you want to look at the bone/antler well) Do you like the positioning, is there anything you do not like about it.
I mark the edge of the bone/antler with a marker on the backside around the blank, That way I can reposition it exactly like I had it when I looked at it I mark the shape of the blank on the backside of the bone.
I will determine where I want to stop the front end of the handle material. Mark it on both edges. Use some of the blue painters tape and go around the antler/bone from mark to mark! Cut it on your band saw!
Take it back to the knife blank and by lining up the marks on the back side, and once again look at it do you like everything about it! If you do then you have to proceed to the next step.
I take my piece of antler/bone in between to flat pieces of metal and using a digital calipers I check to thickness from end to end. Lets say one end is an 1/8" thicker than the other. I mark that end with a piece of tape. I take it to the grinder and using some two sided tape. Like this, it can be bought at Walmart in the paint section.
I buy the stuff on the roll made by Scotch. Buy the good stuff.
I have a wooden handle made up. Think 1x6 drill a hole at each end and cut between the holes, this is for your hand, round over the corners on the hand side, sand the bottom edge smooth, and clean all dust off of it. Stick a piece of the double sided tape bottom edge of and push it down on the bone/antler.
Now on my platen I can apply flat to platen but, the handle allows me to apply more pressure to the bone/antler. Keep it flat to the platen and you have to learn to move it around the platen as much as possible or you can burn it. The idea here is to make that piece as closet to the thousand as possible, the same at both ends. Write that number down or remember it! You now have a flat ground piece to place against the knife blank! If is doesn't look right you have let it rock while sanding, and you may be able to fix that or you may have to chunk that bone/antler and start all over again. The backside of the bone/antler has to lay flat at this point or it never will! If you have to re-grind remember the new thickness number!
Place the bone on the knife blank and re-draw the lines for positioning the bone/antler. Using one drop of superglue . Let the glue dry and place bone/antler side down on a foam backing at the drill press. I use the foam like they use for yoga mats. This is where the
Kentucky Windage that Steve mentioned comes into play! You have to eyeball the knife blank to keep it level to the foam, so you holes go straight thru.
Using the holes you have already drilled into the blank, drill thru the bone/antler using the least pressure you can get away with! When you are about to break thru use almost no pressure. The foam backer and the light pressure will minimize chip out!!
Now repeat the steps in positioning and matching thickness of the first side, and cutting the front edge of the bone to match the existing side. For the second side.
One drop of superglue and place the other side on the blank and laying it on the foam backer drill like the first side. The first side and the holes in the blank will make the line up easier! Once drilled slide a longer pin thru and look at the line up. If the pin appears coked as it goes thru the handle, (then it is and you may have to start over). Holding the knife up and looking down the spine do the pins appear off, if not you are good to go.
Take the bone/antler off by either letting a little acetone get under the pieces if bone/antler or since it is just one drop a bump from a dead blow will break the bond!
Now here is where you have to make the decision
do I want to peen my pins of not. If you haven't had a chip out you need to cover. I say NO. If you still want to peen your pins. Countersink the holes. This can sometimes cause a chip out. Remember one slip of a hammer or a spinner if you decide to go the peening route and it is "all she wrote"!
Most folks after having one get this far and having a catastrophe happen they will opt not to peen the pins.
Make sure the blank is completely finished, make sure the front of the bone/antler is completely finished before doing glue up! I often drill extra holes thru the blank and countersink some holes in the back side of the bone/antler. This allows for the epoxy to travel thru the handle and into voids in the bone/antler and when dry,
you have a bond almost impossible to break!
The pins are there for shock value. they stop sideways movement! If you are in this school of belief then you do not have to peen the pins at all.
Just rough up the center of the pin material to allow the epoxy to bond to the pin!! Once you allow for drying time. Cut the pins as close to the bone/antler as possible and grind them flush, very carefully!! Also
do not let them heat up. Remember the pin is small and heat builds quickly so dunk to cool often!!
Now sand down the outer profile of the handle, (top bottom and end) and polish these areas to the grit you want to finish it at!!
Kevin , I hope this helps! My PC is having a stroke I think and this thing has been like running a marathon to type out! It is experiencing freezes every few seconds and when I go back and try to insert something in the allready type text it start eating the text I already had typed! So if something is misspelled or doesn't make sense feel free to ask. Maybe by that time I will have either figured out what is going on with my PC or I have made it a date with the forge!
Others may do this process and entirely different way!
Along those lines here is a youtube video about that very subject!!