Reamers for slipjoints

H

Hubert S.

Joined
Dec 14, 2019
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I am getting ready to attempt a slipjoint knife and have been reading a bunch of tutorials, and while I think I have a good idea of the process, I am a bit unclear about what reamers to get. For reaming the pivot hole for 3/32" pins, what size reamer should I use? I have seen recommendations ranging from 3/32" (seems too tight) to 0.097" (seems too loose). I have some 3/32" stainless (416) pin stock from Trugrit. It seems to be pretty true to size, maybe a tenth or two over if my micrometer can be trusted.

Also, I am not really sure what kind of tapered reamer I should get to ream the scales before peening. McMaster has some tapered pin reamers, but they're close to $50, so I thought I'd ask before getting the wrong thing. Any recommendation would be much appreciated.
 
I use a 3/32" reamer when using a pivot bushing and a .097" when not using a bushing. I got the .097" because that was recommended in Luke Swenson's video. I have not had any problem with either.

On the advice of Jason Ritchie, I have been using a dremel 125 bit in a hand pin vise for chamfering holes prior to peening.
 
Sean Yaw said:
I use a 3/32" reamer when using a pivot bushing and a .097" when not using a bushing. I got the .097" because that was recommended in Luke Swenson's video. I have not had any problem with either.

On the advice of Jason Ritchie, I have been using a dremel 125 bit in a hand pin vise for chamfering holes prior to peening.
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Do you mean 3/16" for the bushing? Also, do you ream the pivot hole in the blade before or after heat treating, or both?

How deep do you ream with the Dremel bit?
 
Yes, with a bushing, I ream the pivot hole in the blade with a 3/16" reamer. I also ream the bushing hole with a 3/32", but I am not sure that matters. The bushing should not swell, so, reaming the blade pivot hole to exact size makes sense. Since the bushing is stationary in operation, it does not matter if the pin swells in it, so not oversizing the hole makes sense too. I ream after heat treat.

I just build up a very slight chamfer with the dremel bit. I've been doing less as less as time goes on. Bill Ruple has a video where he says he does not chamfer the pivot hole at all in bolsters.
 
Sean Yaw said:
Yes, with a bushing, I ream the pivot hole in the blade with a 3/16" reamer. I also ream the bushing hole with a 3/32", but I am not sure that matters. The bushing should not swell, so, reaming the blade pivot hole to exact size makes sense. Since the bushing is stationary in operation, it does not matter if the pin swells in it, so not oversizing the hole makes sense too. I ream after heat treat.

I just build up a very slight chamfer with the dremel bit. I've been doing less as less as time goes on. Bill Ruple has a video where he says he does not chamfer the pivot hole at all in bolsters.
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Thanks, Sean.
 
I use a .097 reamer for the pivot (I like the #41 idea better though) and a 4/0 tapered reamer for the scales. I suggest getting a carbide one for the pivot so you can ream the pivot after HT. For the scales, the 4/0 is much less aggressive than the dremel model and I think works much better. It does not take much to ream the scales - so don’t over do it.
 
bjansen said:
I use a .097 reamer for the pivot (I like the #41 idea better though) and a 4/0 tapered reamer for the scales. I suggest getting a carbide one for the pivot so you can ream the pivot after HT. For the scales, the 4/0 is much less aggressive than the dremel model and I think works much better. It does not take much to ream the scales - so don’t over do it.
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Thank you. Do you taper by hand or in a drill press? Do you have a preference between straight or spiral flute reamers?
 
I ream the pivot using a drill press and the scales by hand. All of mine are straight fluted.
 
Coming into this kind of new, humor me with some clarification. Is this what this means?

The pin that one wants to put into the pivot hole of the bolster and blade is 3/32". (~.0920-0940) Or possibly someone is making pin material that is 0.09375
In theory, the intent is to redrill the hole in the blade and the bolsters as well with some # drill and then follow up with a reamer of the discussed size #41 (0.0960) which, for all intents and purposes is larger than these described pins.

I can understand over sizing the hole by one or two thou, but the question I am missing is what size drill are you wanting to use first? Would you use an actual 3/32 (0.0938) or a #42 (0.0935) or does it even matter?

Is it worthwhile to get the solid carbide? or is HSS sufficient, or even Cobalt? I am assuming this is a chucked reamer? This sounds like a drill press operation. Does a reamer have some aspect that would draw it into an existing hole, or does one count on the accuracy of a drill press, or is a mill implied at this point?
 
BradleySmall said:
Coming into this kind of new, humor me with some clarification. Is this what this means?

The pin that one wants to put into the pivot hole of the bolster and blade is 3/32". (~.0920-0940) Or possibly someone is making pin material that is 0.09375
In theory, the intent is to redrill the hole in the blade and the bolsters as well with some # drill and then follow up with a reamer of the discussed size #41 (0.0960) which, for all intents and purposes is larger than these described pins.

I can understand over sizing the hole by one or two thou, but the question I am missing is what size drill are you wanting to use first? Would you use an actual 3/32 (0.0938) or a #42 (0.0935) or does it even matter?

Is it worthwhile to get the solid carbide? or is HSS sufficient, or even Cobalt? I am assuming this is a chucked reamer? This sounds like a drill press operation. Does a reamer have some aspect that would draw it into an existing hole, or does one count on the accuracy of a drill press, or is a mill implied at this point?
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The reamer size charts I've seen show drill sizes for either 2% or 3% under final size. If you ream after heat treating, you need carbide. HSS/Cobalt will just dull (unlike carbide, which just snaps!).
 
I drill all my holes with a 3/32 bit (blade, spring, and scales). After heat treat (and really like one of the last steps prior to putting the knife together) I will ream the pivot hole in the tang (just the blade tang…not the in the bolster or scales) a bit larger (say #41 for example purposes) with a carbide reamer chucked in a drill press with oil.

The scales are then hand reamed ever so slightly with a tapered reamer prior to peening.
 
Absolute best thing to do to get into slipjoints is get one of the Crawford videos. Either Craig’s or Luke’s single blade Slipjoint videos are great. It will pay for itself immediately in time saved and cut down on the learning curve significantly.
 
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Slipjoint pivot holes Don't need to be precise-far from it. They can be significantly oversize.
 
Bill DeShivs said:
Slipjoint pivot holes Don't need to be precise-far from it. They can be significantly oversize.
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Really? Is this a serious statement, or facetious to mess with the n00b? How would one get away with "significantly oversized" pivot hole? This sounds counter-intuitive to me, but I am willing to hear it out.
 
BradleySmall said:
Really? Is this a serious statement, or facetious to mess with the n00b? How would one get away with "significantly oversized" pivot hole? This sounds counter-intuitive to me, but I am willing to hear it out.
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I actually use a drill bit .002" larger for 3/32 pins

I mean you beat the the damn thing together with a hammer
 
Pocket knives are simple little machines. This is a very serious statement.
The backspring holds the blade in place, open or closed. The pivot keeps the blade in the knife.
You really don't have to ream anything-just drill holes and use pin stock that fits the holes.
Pocket knives have been made this way for 150 years. Only recently has the need for reaming and great precision measurements become "necessary."
 
AVigil said:
I actually use a drill bit .002" larger for 3/32 pins

I mean you beat the the damn thing together with a hammer
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I guess, I don't consider 2 thou to be "significantly larger". That's like using a #41 in a 3/32. I would think that would be "slip fit" for a dowel pin. Significantly larger, suggests that it could rattle around, front to back, side to side. Perhaps it is just my idea of "significantly larger".
 
Bill DeShivs said:
Pocket knives are simple little machines. This is a very serious statement.
The backspring holds the blade in place, open or closed. The pivot keeps the blade in the knife.
You really don't have to ream anything-just drill holes and use pin stock that fits the holes.
Pocket knives have been made this way for 150 years. Only recently has the need for reaming and great precision measurements become "necessary."
Click to expand...
When you say significantly larger are you talking tapping difference? 7/64 or 1/8 for a 3/32 pin?
Kind of sounds like the recipes from my grandmother. "Put in just enough so that it has the right consistency. But not too much or too little."
So last night, I shattered a 1/16" drill bit because my vice slipped. (and it wasn't even a carbide bit). By the time I fished out all the little pieces, I then ruined a cobalt bit trying to drill it from the other side. Sharpened it as best I could by eye, and finished the hole. Interestingly enough, I had to still spin down my brass 1/16 stock which mics at 0.062 (I meant to get a final measurement but didn't because it was late) to get it through that hole. Obviously, the Dewalt TiN drill bit does not make an 0.0625 hole. Not that I am expecting precision from the bits sold in a plastic index from a big box store. I ordered some replacements in solid carbide and M35 cobalt to see if I can get close to 1/16. In a different piece I tried the 5/64 bit figuring if the 1/16 was that tight then perhaps the 5/64 would be tight too and it would better match the stock. Of course, that makes a hole that I can simply drop the stock right through it. Granted, that might be cutting as much larger than 5/64 as the other one was cutting smaller than 1/16... precision be damned :)
Now, this is just my adventures with 1/16 which I am really only going to be using for scales, and initial spotting of the holes merely for fitup before final drilling for pivots and springs depending on whether it is to be 3/32 or whatever the Corby or Loveless requires. But, if I put a 3/32 pin in a 7/64 hole won't I have a blade that will want to close off to one side or the other, or otherwise not snap open or closed like one might expect? I am not arguing that this is the case, but sincerely asking why this wouldn't be the case. Not trying to start a fight, just wanting to learn something. :)
 
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