knurling stainless steel

i have some repeat work that we have been doing for years and both jobs get the od's knurled on them. they are both out of 303 stainless steel, and one is a straight knurl on a .750 dia. and the other is a diamond knurl on a 1.500 diameter. both knurls are not real critical,(they just call for a medium knurl). i am looking at replacing my current knurling tools. i did a little looking online and i wanted to get opinions on form knurling vs. cut knurling. tool life. speed. quality of knurl(cosmetics). etc. i do about 4000 pcs. per year of the straight knurled part and about 1000 of the diamond knurl. (i do other knurling besides, but these two jobs are by far the most knurling we do) any thoughts, opinions, past experiences would be helpful, otherwise i am going to order about the same tool as what i have now. just a run of the mill, 1 inch square shank, bump knurler with form wheels.

also, in stainless, would i be better off with a cobalt wheel or not?

thanks a bunch.

Aaron;

I think you'd have better results with a scissor or straddle type knurl holder.

http://www.accu-trak.com/holders_straddle.html

Give them a call, they are VERY helpful!

http://www.accu-trak.com/index.html

+1 for the straddle knurl.... I knurl THOUSANDS of 303 parts a week with a straddle knurl, ours is a Lester-detterbeck model, it works quitle well.

though we DO use Accu-trak knurls in it.

If you are doing any longitudinal knurling (feeding in the Z axis) make sure to get the convex profile knurls... they make parts PRETTY!! Also, at the quantities you are making, one set of knurls should last you a year or 2.

If you need any more suggestions let me know!

Sorry to thread jack, but does anyone know of a knurling tool designed for a mill? I just for a quote for a bunch of aluminum parts that are round, but have all sorts of pockets in them, so I know I could get them done quicker on the mill rather than the mill and lathe. So, is there a tool I can use to knurl in a mill?

Definately sounds like you need to put the bump holder down and back away slowly.

Scissors and convex from Acu-trax all the way!


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Street:

Look for a knurl holder for a B&S or other similar made from the likes of B&S, Boyer Shultz, others?

These would have a hollow shank with opposed holders on them. They are generally used as a static toy - but I don't think it would know if you used it live. Not like your gunna be going fast eh?

Just rummaged through my B&S book here real quick and see that tool #185 comes in shanks from 5/8 to 1-3/4 with capacity to 2-1/16 x 2" deep and 1-11/16 x 3-1/2" deep on their biggest.

Page #86 in my 15 yr old B&S book from ***AMSCO*** - 1-800-83-AMSCO. (Haven't seen Wendal in a few yrs now - enyone know how he's dooin'?)


Found and blew the dust off the old Boyer Shultz book as well. Looks like thjeirs only goes to 1"D and has three rolls. ??? Called a "Burnishing and Knulring Tool".

Knurling with three rolls sounds kinda tricky to me? (Diamond enyway...)



One groovy feature of the two roll on a VMC with Spindle Orient would be that you could feed on, stop, orient, and then slide off the side and not hafta backtrack!


Sorry - Googl didn't come up with a good link to a pic of this style and I don't have one to take a pic of. If needed I guess I could take a pic of the catalogue, but you may as well just call the good lookin' Honeys @ AMSCO.


Actually - There is a good chance that a chumm has some of these F/S! (He'd be cheaper'n Wendal.) I'll try to remember to call him in the morning... Putz is a first shifter. LOL! (Top this to remind me eh?)



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Think Snow Eh!
Ox

Straddle knurls are the best to work with if you can use them. Sometimes you can't get them in places you need to knurl though. If this is the case and you have to bump knurl, you should use the convex knurl on the straight knurled part. You can't get a convex knurl in diamond pattern if using a single bump knurl tool, but you will have easier penetration if you use a male knurl versus female. If you can get a narrower knurl that will help too. Just feed in and then move over in Z.

You mentioned that you were knurling about .75 diameter. I would knurl something like that at about 300 to 400 rpm.

Form versus cutting? Can't say anything about cut knurling, never tried it. I did research it at one time and decided against it but I don't remember why....??

Cobalt versus HSS. I think either one would work but like anything else, you will want to spend a little more to get some good quality knurls.
Good luck!!

Street - I checked and my chumm does have a few diff sizes in that style holder. If you git the job - git with me.


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Think Snow Eh!
Ox

hdrider63 said:

You mentioned that you were knurling about .75 diameter. I would knurl something like that at about 300 to 400 rpm.

Click to expand...

I would say triple that RPM... though i'm cutting with the convex TiN coated knurls (.800 Diameter at 1400 RPM), so maybe just double it. Though I'm not the one known around the shop for being conservative... in anything

also, a good trick I picked up from the Brownie guys is to once a day or so take a stiff bristle brush and scrub the teeth of the knurls out. Especially in 303, little flakes like to get packed in there and lead to a crappy looking knurl and poor tool life.

Let us know how it goes!!