Cold Rolled Steel

J

jroma1

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Most of the steel that I work with is cold rolled steel or 1018. The reason for that is the supplier I buy from is in the Philadelphis Pa area, is within driving distance and is cheap.

I have used 12L14 and have found it to be better to work with and usually yields a better finish than 1018. It also seems to knurl better than 1018.

I originally tried to knurl 1018 with the knurler that came with my QCTP and always with poor results. Somewhere along the line I get the idea of making my own knurling tool. Only this time I thought of trying a scissor type and purchased a pair of knurling wheels (Medium & course) at $10.00 a pair. I made one tool using the $10.00 wheels both medium and coarse and I get what resembles a decent knurl the first 2 or 3 uses. I made a second tool tighting up on some of the tolerances which didn't seem to be any different.

I have noticed wear on the wheels in fact the screws that they ride on are scored. Either these wheels are to soft or i am applying too much pressure or doing something wrong? Is 1018 noted for this problem or am I missing something?

In a previous post one of our members mentioned the possibilty of buying a better set of wheels,that is my next move. In the mean time I would appreciate any comments or suggestions

Thank You.

John Romano
 
If you are using threaded screws as the axles, that may be the problem. My scissor knurl uses smooth, polished shafts with e-clips on the ends, they have a fairly close fit to the holes in the knurl wheels so there is no play (wobble) to cause scoring....
 
The pins of a knurl holder need to be plenty hard and strong. The surfaces need to be hard as any particles that get in there will quickly start to degrade the surface. Also, strength is needed because a lot of force applied to that part. Screws or bolts with threads don't stand a chance. If I had to guess (and a guess it truly is) 1045 or 4140 with a good, deep case hardening would be adequate.

The wheel must fit tight with minimized slop or wiggle. Knurling is a machining operation and just like anything else, attention must be paid to all details. Things that flex and wiggle under pressure will screw-up a knurl.

Really high end knurl tools cost 2, 3... 5 hundred bucks or more. You don't need to spend that much but conversely, most of those $29 cutters with junk wheels will likely get you nowhere in the way of decent knurling. Can they knurl? Yes (well, mostly yes). On my project list is to make a decent one but for now, I get by with one Franken-Knurl-Tool that I pieced together out of 4-5 junky ones and got pieces to fit tight enough to work half-decent. Next one I get/make will be a scissor type.


Also, here's some information about "cold rolled"... Please see post #2 of this thread. The second paragraph talks about CR and HR steel.
http://www.hobby-machinist.com/show...tes-using-carbide-cutters?p=101224#post101224

Ray
 
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