Cut Knurling tool in March/April issue

[rkepler]

The cut knurling tool in the HSM March/April issue looks interesting, but why is it shown with a form knurl? Am I missing something or is this just using the center of a form knurl to perform axial knurling?

[gr8life]

Really too bad you are not getting any action on this. If you had to guess how large a dia. would that thing knurl?
ed

[KINGWELD]

It looks to me to use the center of the knurl but not completely sure. The pics aren't real clear. What is clear is I want one and the next edition of the magazine can't get here fast enough. Jim

[TGTool]

The wheel really is cutting rather than just impressing the pattern. If you picture the contact area between the wheel and the workpiece as the workpiece is rotating, because of the tilted axes the contact point is moving sideways through its contact arc so the leading edge is pushing a small chip.

It's a really nice write up and I'm anxious for the next installment too. I already went out to the shop to look for those little bearings I'm sure I have somewhere.

[rkepler]

I don't know what diameter it's designed for, but with cut knurls you can cut much larger then you'd expect with regular knurls. Comparing with what I see online I'm sure this one is good for at least 6".

As to the original question: perhaps there's less difference in the knurls than I thought, and a form knurling tool will work as a cut tool if presented in the right way.

[Mcgyver]

hey Russ....I'll own up to this one

I'm not sure what you mean by 'shown with a form knurl'?? there's a pic of a form knurling tool; it's just there for comparison/context. the tool is a cut knurling tool, does a complete fully formed knurl in one pass....i think there's a pic of it doing so in 5/16 stock (demonstrating how little force is involved)

It'll cut almost any size dia, theoretically infinite. The two round arms carrying the spindles are adjustable; they need to be in different positions based on the diameter of the work. They rotate in opposite directions and are geared together, you turn a knob and they move, one clockwise, the other counter...the lever on top locks them in place via a double split cotter (if there is such a thing!)

[Frank Ford]

That looks like a great project.

Cut-type knurls are cool. I bought a dandy one off eBay - a Hardinge - they go for about $75 or so. This one is a bit beat looking:

http://cgi.ebay.com/Hardinge-L20-Knurling-Holder-lathe-tooling-w-extras_W0QQitemZ380145060333QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item58826949ed

Unlike the expensive rigs, the Hardinge has simple independently adjustable knurls, so they are somewhat harder to set up, I suppose.

[gwilson]

Is it necessary for the 2 knurls to be geared together? If they were just independent,wouldn't each knurl make its own cutting track?

[Mcgyver]

Is it necessary for the 2 knurls to be geared together? If they were just independent,wouldn't each knurl make its own cutting track?

the knurls aren't geared together, the the round arms in which are knurl spindles are mounted are geared together. They don't make a complete rotation, just go from closed (two knurls touching) to wide open (one knurl fully at the top, one at the bottom)

[lynnl]

The article makes no mention of special knurls, i.e. different from normal pressure or displacement knurls.
What's the true story? Are special "cutting" knurls required?

[rkepler]

I'm not sure what you mean by 'shown with a form knurl'?? there's a pic of a form knurling tool; it's just there for comparison/context. the tool is a cut knurling tool, does a complete fully formed knurl in one pass....i think there's a pic of it doing so in 5/16 stock (demonstrating how little force is involved)

The "purchased parts" list shows the knurl wheel as "5/8 OD, 1/4 ID 40TPI" (paraphrasing) and I don't know of a source of inch pattern cut knurl wheels. Not saying that there's isn't one, just saying that I've never run into one. Picture 32 also shows a couple of form knurls (Form Rol GK are forming tools, or so I understand) mounted on the tool. Perhaps cut knurls work pretty much like cut knurls, at least for the HSM?

I have a couple of cut knurl tools from Vogel Pieterlen, nicely made from Switzerland but I think the company is defunct. The cut knurls are fairly difficult to find being 25-5-11 form and only one maker I know of any more. The tool being described in HSM is nicer. The Vogel uses a much simpler mount for the tool - there's a bushing through the center of the knurl wheel fron the back and a screw from the front into the tool body. It seems to work pretty well, you can tighten up the screw and push the bushing against the body but the tool remains easy on the bushing. The downside is that it requires a pretty big opening in the knurl.

It'll cut almost any size dia, theoretically infinite. The two round arms carrying the spindles are adjustable; they need to be in different positions based on the diameter of the work. They rotate in opposite directions and are geared together, you turn a knob and they move, one clockwise, the other counter...the lever on top locks them in place via a double split cotter (if there is such a thing!)

I'm looking forward to the rest of the article. Did you thread the "double split cotter" with right and left handed threads?

[Mcgyver]

The "purchased parts" list shows the knurl wheel as "5/8 OD, 1/4 ID 40TPI" (paraphrasing) and I don't know of a source of inch pattern cut knurl wheels.

thanks...they came from kbc.....doesn't matter which you use, just seemed about the right pitch to me, and cheap...you could make them as well. Without the chamfer and presented at the right angle, the roll knurls become cut knurls

lynnl, they are regular knurl wheels but the style with out the chamfer....patience, there's more content coming

[Carld]

The way I understood the article he said the knurls are cut by the edge of the wheel, not in the grooves. He said the knurls are CUT not rolled as with the standard knurling tool.

The finished knurl is the same diameter of the work it was cut on because it does not raise the metal.

[randyjaco]

The knurling tool is a masterful piece of work and amazingly complex. But seriously, someone would need need to have to do a hell of a lot of knurling to justify the time and effort expended to build that tool. It is way over the top for me. I'll just stick with my old scissors tool.

Randy

[MuellerNick]

As to the original question: perhaps there's less difference in the knurls than I thought, and a form knurling tool will work as a cut tool if presented in the right way.

Clearly wrong!
A forming wheel will have rounded sides, a cutting one needs sharp edges to be able to cut. You can't use a cutting knurling wheel in a forming action and vice versa.


Nick