Pin & Hole Sizing - What method do you use?

MTBob

Well-Known Member
I'm still on a vertical learning curve with knife making, having done a couple dozen at this point. A reoccurring issue is how to get a tight (but not too tight) a fit when installing pins in a knife scale. For instance: when drilling for a 1/8" G10 pin that measures .125 I'll try a 1/8" drilled hole and the pin is often too tight. Or, conversely, if I drill a #30 hole the pin may be too loose. It seems the pin material can vary a couple thousandths (often +/-.0015). I've used all kinds of pin and handle material and the pin fit seems to vary enough to make it frustrating (G10, brass, SS, Micarta, etc). I'm attempting to be very precise so that there is absolutely no visible gap between the pin and scale. Recently I've adopted a "safe" method of sanding each pin to a snug fit (using drill press, lathe or hand drill). But, I don't see a lot of knife makers doing that, so I must be missing something.
So, here are my questions:
1) do you only drill holes and hope for the best fit? or,
2) do you drill an undersized whole and then sand the pin so there is a snug fit?
Then also,
3) do you oversize the pin holes in the knife tang (say a 1/64 larger) to make sure there is no sizing issue with the pins interferring with the tang holes?
And,
4) do you want a fit that A) you have to "pound" in, B) push in hard by hand, or C) will move smoothly through the whole and actually fall out?
5) if you've screwed up and made holes too big for the selected pin size is there a way to fix the gap...other than starting over?
Thanks in advance
Bob
 

Randy Lucius

KNIFE MAKER
I may be just getting lucky. For 1/8 I use a #30 drill bit and I don’t have fitment issues. I use nickel silver, brass, carbon fiber, and natural micarta pins. They all fit fine. 1/4 pins I use a letter F drill bit. I’ve gotten away from using 1/4 pins except for the occasional mosaic pins. No fitment issues with those either. Those drill bits with those size pins will leave a couple of thousandths clearance that you will need for the epoxy. When the epoxy cures you won’t see a gap. What’s the runout on your drill press? Is it wobbling around? What epoxy are you using?
 
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Oze

Well-Known Member
Gudday mate. I am no expert but this is what works for me. I only us 1/4 and 1/8 inch pins. So you only need two size drill bis and remers of same size. Drill your holes and ream. The reamer gives a more precise sized hole. Measure your pins with a digital calipper. Check they are correct size. When gluing and fitting up, put the pins in a cordless drill. They screw in easily. Put glue into the scale holes as well as on the scale.
 

tmr

Active Member
I have used #30 for 1/8.......#10 for 3/16.......and letter F for 1/4 for many years and like randy says no fit issues what so ever.......on some of the exotic woods the pins are still a little tight.......i would check out your drill press cause you shouldn't be having fit issues......also use the best quality drill bits and keep them sharp
 

EdCaffreyMS

"The Montana Bladesmith"
I posted this on my KnifeMakerTraining FB page last week....hopefully it helps:
1599135321348.png

All of those will give you the room necessary for a pin or thong hole liner to fit without having to "force it". Sometimes I find that the "F" bit for thong hole tubing is just a tab bigger than I'd like, but otherwise the bits I keep loaded in my burgmaster drill press follow this chart.

I think I answered all the other questions with the above...

4) do you want a fit that A) you have to "pound" in, B) push in hard by hand, or C) will move smoothly through the whole and actually fall out?
5) if you've screwed up and made holes too big for the selected pin size is there a way to fix the gap...other than starting over?
#4= Smooth through the hole, with just enough room for either expansion (if you peen...which is a whole other subject), or room for glue.

#5= I always use either 1/16" or 3/32" pins....that way is if do goof it up.... I can move up to the next pin size.... if you start big, you have nowhere to go, and have to start over. ;)
 
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MTBob

Well-Known Member
Thanks everyone, great comments!
As Randy mentioned, I'll check my drill press spindle run out again. I'm using a old Walker Turner drill press on which I've installed a KBAC VFD. It's a great machine, particularly for power taping.
1599144185540.png
Here's my typical setup for drilling pins using machinists clamps, and a machinist vice for support. The knife/scale assembly is not clamped down, but held firmly by hand (and a slow'ish drill speed). If I'm using "shop" cut scales from bulk stock, I first size them in the mill to make sure the mating surfaces are parallel.
1599144525339.png
I'll also carefully check the new pack of #30 jobber drills I got from Amazon the other day. I'm suspicious that they may not be straight.
Again, thanks for all the comments, much appreciated.
Bob
 

John Wilson

Well-Known Member
#4 above is where I struggled as a new maker. ROOM FOR GLUE. When you have to persuade pins to go into the hole it can cause problems. You’d think that the tightest fit possible would be a good thing but that’s often the cause of pins getting loose over time because there’s no glue.

I then struggled with “mooning” where you get a ring around the pins. I thought my holes were too big. Now I was in a pickle because an exact fit was too tight, and one size up to allow for glue seemed too big. I was wrong. The mooning was from too much heat when shaping the handle. I was burning the glue. Using fresh(er) belts on the handle shaping doesn’t get the pins screaming hot.
 

EdCaffreyMS

"The Montana Bladesmith"
The mooning was from too much heat when shaping the handle. I was burning the glue. Using fresh(er) belts on the handle shaping doesn’t get the pins screaming hot.
That... everyone... is GOLDEN!! Paste that on your grinder! :) I can't tell you how frustrating it is to try to explain that to someone who's having the issue, and just can't get it through their cranium to SLOW DOWN. :)
 

MTBob

Well-Known Member
Wow, that's gotta be part of my problem. I've been using old belts to hog off handle material... and, ya, my handles get hot in the process.
That, gentlemen, is indeed a bit of golden wisdom. Thank you!
 

MTBob

Well-Known Member
Good information, I've tried making mosaic pins, what a PITA! So, based on the above expert advice, I'm likely not to use them again.
... because I certainly don't want my "internals" coming apart:D
 

MTBob

Well-Known Member
Ed: Your sizing table is now prominently displayed next to my drill press - thanks!
Bob
 
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