Knurling tool

[ljchipmaker]

I am making a modified version of Guy Lautard's knurling tool. After reading several archived post on these style of tools it was recommended to case harden the ears of the arms that the knurling wheels ride between. After machining the slots to .001" undersize I am planning on hand fitting the wheel slots to the wheels; and my wheel axle holes are reamed to .250". I have several questions regarding this, and here are my available options: Oxy/Acetelene torch, propane torch, LP Stove/Oven, Kasenite, oil drench, water drench.

Which combination of the above listed options would be best?? and please include the steps.

The pins, could be made out of Drill Rod or Cold Rolled. After turning up the pins for these holes should I also harden them (don't know if its oil or water hardened, but am sure its not air hardened Drill Rod)?

How much, if any, should I allow for expansion of these parts so I don't have to do a lot of unplanned lapping-in to get these parts to fit?? I am willing to do some, but would like to keep it to a minimum.

Thats all I want to know, I will stay away from the scientific debate of how to use the tool correctly and continue with the technique I have used with all the knurling I have done up to this point, plain dumb luck.

Thanks for any help, LJ

[sandiapaul]

Have you started yet? I started one of these a long time ago and never finished it. I made some changes, like I weldedd the shank on instead of screwing it...it's just been sitting around for years. Its yours for postage.

Paul

<font face="Verdana, Arial" size="2">Originally posted by ljchipmaker:
I am making a modified version of Guy Lautard's knurling tool. After reading several archived post on these style of tools it was recommended to case harden the ears of the arms that the knurling wheels ride between. After machining the slots to .001" undersize I am planning on hand fitting the wheel slots to the wheels; and my wheel axle holes are reamed to .250". I have several questions regarding this, and here are my available options: Oxy/Acetelene torch, propane torch, LP Stove/Oven, Kasenite, oil drench, water drench.

Which combination of the above listed options would be best?? and please include the steps.

The pins, could be made out of Drill Rod or Cold Rolled. After turning up the pins for these holes should I also harden them (don't know if its oil or water hardened, but am sure its not air hardened Drill Rod)?

How much, if any, should I allow for expansion of these parts so I don't have to do a lot of unplanned lapping-in to get these parts to fit?? I am willing to do some, but would like to keep it to a minimum.

Thats all I want to know, I will stay away from the scientific debate of how to use the tool correctly and continue with the technique I have used with all the knurling I have done up to this point, plain dumb luck.

Thanks for any help, LJ</font>

[lynnl]

I made one, and just used dowel pins for the wheel axles. Dowel pins are already pretty hard.

[ljchipmaker]

Yes I have started it. Everything has been completed except the hand fitting of the wheels and the machining of the pins. It is because these locations and axles may/or may not be affected by the heat treating that I ask for the advise.

LJ

[SGW]

Since you talk of case hardening, I assume the arms are made of mild steel of some kind.

In that case, I don't think you'll need to allow for any expansion when heat treating. High-carbon steel (O-1 or whatever) expands a little when hardened, but I don't think case hardening mild steel will make enough difference to worry about.

Read the directions on the Kasenite for proper use. You might get away with a big propane torch, but you'll need to get the parts you're case hardening up to about 1750 degrees or whatever before quenching. A propane torch may have a hard time doing that because of the size of the pieces. Oxyacetylene will do it for sure--the danger there is overheating, though. You don't want to burn up the parts.
See what the Kasenite directions say about a quenching medium (oil or water).

I think I'd follow the lead of lynnl and use dowel pins for the axles.

[jim_geib]

I also made one about a year ago and used dowl pins on the wheels and it has been just fine. Now this is just in a hobby use maybe 3-4 times a year.

[SGW]

Personally, I don't think I'd go to all the trouble of case hardening. The sides of the arms aren't really wear surfaces, and I can't imagine, in a home shop, you're ever going to use the thing enough for it to matter.

[BobWarfield]

Seems like a lot of older articles (Lautard's stuff seems drawn from those) like to harden things, while in recent times home machinist's have gotten away from it so much. In many cases I think this probably just reflects what people are saying here which is that the tools don't have to stand up to hard duty in hobby applications. I think it also reflects that with carbide inserts and chinese tools so common, the need to hand craft every cutter is less as well.

BTW, Lautard himself will tell you how to do the hardening in one of the books. There is also a ton of information on hardening from the knife making community out on the net.

I would personally use an oxy-fuel rig and do all of this outside!

Best,

BW

[sandiapaul]

Hi guys,

My start on Lautard's knurling tool has been spoken for.

Happy Knurling Days!