Knurling Question

[HighWall]

I was fortunate to inherit a nice old lathe and a bunch of tooling. Included was an Aloris AXA19 knurling tool holder, which is lovely. My benefactor seldom did any knurling as he never really liked it, but I am interested in it. The AXA19l I have has straight cutting wheels installed and does not cut a diamond, but rather longitudinal grooves in the workpiece. I am not sure why one would want to do this, but I can't find any of the diamond cutting wheels, so I need to get some. I'm not sure which ones to buy, but I've seen there is a wide range in pricing and sizes. Any advice on which ones to get me started? MSC has a good selection but I am not sure I need to spend $60/wheel...

 

[hman]

Not your main question, but I can give at least a partial response to "I am not sure why one would want to do this". Longitudinal grooves are usually applied to a shaft or bar to make a section of it "larger," for pressing into a bore. Think of the crossbar on your lathe chuck key.

 

[mikey]

I have an AXA-19. It takes any knurling wheel with the following dimensions: 3/4" OD, 3/8" wide, 1/4" center hole for the pin. You are looking for a RH/LH pair of knurls and ebay is your best shot. Do your homework to determine which kind of tooth pattern and pattern density you want. Unless you are going to knurl only nominal stock, I recommend you buy Circular Pitch knurls instead of Diametral Pitch knurls. Most knurling companies will have tech articles on this stuff: http://www.formrolldie.com/knurling_tips.htm

For axial running (a long knurl that you make as you feed down the work piece with the tool), knurls with a convex radius work best. Accu-trak is the best known supplier. An alternate to the convex shape is a knurl with a bevel ground on the edges. Form Roll knurl will grind the bevels for you if you call the factory.

 

[Bob Korves]

Longitudinal grooves are also used for knurling on high end surface gages and other metrology equipment on the O.D.'s of the adjustment knobs. They are of a simply beautiful modern style, and also feel better to the fingers, in my opinion. Some eclectic examples:

Don't throw those straight knurling tools away!

 

[MalR]

I agree with Bob about the feel of straight/longitudinal knurls, they’re great for thumbscrews. The coarseness of the knurl depends on the diameter and use: generally use coarser pitch on larger diameters. Be careful with coarse knurls though: too deep and they become sharp and can shred your hands. As well as reducing this risk it can also look quite cool to take a finishing cut with a regular lathe tool after you’ve knurled - the little flat produced seems to emphasise the diamond shape of the knurl. I remember Joe Pieczynski did a good YouTube video on knurling - his stuff is well worth checking.


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[HighWall]

Thanks for the information. I found a set on eBay which is on its way even as I type this.