what undersize drill bit to use before 1/8" reamer for 1/8" scale pins...

V

Vulcanite

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I want my bolsters to be real secure and tight especially since they'll be securing guards and grips on hidden tangs. I'll be using 1/8" peened brass pin, many of them. Was gonna use an undersized drill bit, then use a reamer to get it exact like.

I think a #31 is the next below 1/8", I think it is .1200". Is that the one to use or should I use a 30? US knife maker has little short length machinist bits for <$1, was gonna get a bonch of #31s....

Let me know. Thx
 
Well, to answer your question- the 'ol stand-by is to drill 1/64 under for small holes. So you'd be looking at a 7/64 bit.

BUT--- I'm not really following your desired process. Why do you say you'll be using many pins? IMHO a bolster needs 3 pins at most. A guard doesn't need a pin. And a bunch of 1/8 pins in a handle is going to look gawdy. So just what exactly do you have in mind here?
 
If you're going to be peening the brass, I don't know why you'd want a perfect fit to begin with anyway. They need a little room to expand or you're likely to lift the bolster/scale right off the tang when you peen them.
 
if your going to ream to full size you can use a no.40 a pack of 10 should only cost a few bucks and the make good fit up pins when they go blunt
 
DamienC said:
if your going to ream to full size you can use a no.40 a pack of 10 should only cost a few bucks and the make good fit up pins when they go blunt
Click to expand...

#40 is .0980". 1/8, of course is .1250. Why so small? Isn't that a lot to ream? Is 1/8 brass pins undersized? 7/64, for what is it worth is .1094"
 
I would use an 1/8" bit to drill the holes, and use a tapered reamer to make the outer part of that hole slightly larger than 1/8". That way the 1/8" pin will expand and lock the bolster in place.

While a good fit in the tapered hole through the bolster is important for a good tight assembly, It is important that the pin is NOT tight in the tang hole. If it is, the pin will bulge slightly at that point and lift the bolster off the tang. No amount of hammering will get it flush again. Make the tang hole about 5% larger than the pin.
 
I was planning on using a tapered pin reamer to flair the holes (in the bolster or handle scales).

I will be shoving the guard up against the radiused shoulders under the ricasso and then securing securing w/ a bolster. I guess I am afraid that if the holes are a little large there will be play in the bolsters the guard will wiggle.

But you are telling me that if I have perfectly tight holes in the tang and bolsters the pin will bulge and lift the scale. This means that the pin will fatten up a little bit along all its length, not just where the flares are and that it is therefore good to have a slightly oversized hole from using a regular drill bit.

Well, that makes things simpler. I like that. Please advise if I have any misunderstanding.

I wasnt to use a lot of pins to secure the guard, at least b/c on the pikal style knives, b/c the guards will also act as a rest for the blade of the hand.
 
Also, are there any other details to peening?

If you over do it w/ the hammer do you run he risk of lifting up your scales even w/ slightly over sized holes?

The devil is always in the details isn't he.

Thx
 
Well, maybe just different strokes for different folks----- but I don't agree with the notion of drilling oversized holes. An oversized hole will allow whatever you're trying to pin down, to shift around WHILE you're peening the pins.

I drill and ream so the pin has a tight fit and use a tapered reamer, just like you were thinking off.

I have never had this result in lifting the bolster up/off. I have had it happen with an oversized hole though.

BTW- You really need to measure all your pin stock, because some "1/8 in. pin stock" is 0.130 and some is 0.120 and everything in-between. ;) :)

As far as peening. I gently round and polish the end of the pin. I also polish the peen on the hammer.

IMO, the biggest risk in over doing it, is smashing the top or bottom edge of the bolster... like getting a big bulge on the top edge of the bolster! :eek: :grumpy: Then it's time to grind it off and start over.
 
I know where you are coming from, Nick, and am sure that someone of your skills will never have a problem peening bolsters.

Dead flat mating surfaces, proper drilling technique, careful measurements, chamfering the holes in the tang and bottom of the bolsters, firm clamping ,and solid peening will assure that the bolsters are seamless to the tang. I just add a little wiggle room to prevent anything from lifting the bolster before the heads get fully flared and seated into the tapered pin holes.

The amount of oversize I recommend is very small. If the pins are .125", then a 5% oversize hole would be .131". That would allow for no more movement than the thickness of a sheet of printer paper. The first taps in peening the pins will make that snug anyway. Since the bolsters and scales are going to be fitted to the tang after they are peened in place, any microscopic drift left or right is negligible.
 
I guess I shoudl start another thread about how to go about securing a guard w/ a bolster. I am imagining doing it and and probklems developing...

Maybe I champher, which i guess is a very slight countersink, on the tang holes and the undersides of the scale holes so if the brass does expand a little bit there it won't push the scale up off the tang...
 
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