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Thread: Newbie looking for knurling info

  1. #31
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    Quote Originally Posted by Bented View Post

    90 Rpm spindle speed and .008-.010" feed rate and use lots of coolant, I use one nozzle for each wheel.
    That's about what I do as well, minus the flood coolant which I would use if my lathe was set up for it. To the OP - note that this feed rate is approximately 1/10 of what you used; it doesn't load up the machine or the part as much that way.

    Good consistent looking knurl Bented, and right on about not worrying over the diameter; as long as you take a deep bite at the start it'll come out like your picture.

  2. #32
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    Quote Originally Posted by Yondering View Post
    That's about what I do as well, minus the flood coolant which I would use if my lathe was set up for it. To the OP - note that this feed rate is approximately 1/10 of what you used; it doesn't load up the machine or the part as much that way.

    Good consistent looking knurl Bented, and right on about not worrying over the diameter; as long as you take a deep bite at the start it'll come out like your picture.
    I want to try this on 1018 steel. My only viable options for autofeed are: 256 TPI or 52 TPI (0.019"). I can't get to 0.008" - 0.010" with autofeed.

  3. #33
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    What's wrong with hand feeding? From all the threads about knurling I've read I get roughly the same percentage of success as anyone. Yet I've never used the feed for a knurling job.

    For small parts I just brush on a good dollop of cutting oil to keep things lubricated. For bigger jobs I use a small plastic baby food plate from the dollar store and a squeeze bottle of oil or water based cutting fluid to flush the wheels. The dish catches most of the runoff instead of it running into the chip tray and making an even stickier and gooey mess than it usually is.

  4. #34
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    Quote Originally Posted by devils4ever View Post
    I want to try this on 1018 steel. My only viable options for autofeed are: 256 TPI or 52 TPI (0.019"). I can't get to 0.008" - 0.010" with autofeed.
    You don't have to use power feed if your lathe doesn't have it, just feed by hand. It sounds like your lathe only has a lead screw for threading, without a separate power feed system? If so, you'll need to get good at hand feeding anyway, or figure out the gear combinations to use the lead screw for power feed at appropriate rates. Your 256 tpi is ~.004"/rev, which is good for a fine feed setting. You can certainly use that for knurling as well. The .008"-.010"/rev mentioned above is about 125 tpi - 100 tpi.

  5. #35
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    I tried to use hand feeding with the Aluminum rod and I didn't get good results. So, I used 12 TPI on auto feed and it worked great.

    For steel, I'm think I need the same thing, but slower. Maybe, I can get a feed rate in the 100-125 TPI range by using the gearing in a non-conventional manner.

  6. #36
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    Chances are good then that you used too much pressure on the aluminium. It's easy to do. Any time I've had an ugly knurl it was from too much pressure.

    A couple of us mentioned this earlier in the thread. Aluminium needs a lighter touch on the pressure or it'll do more than just form a nice diamond. It seems to actually swage the metal down to a smaller diameter. And if you pause in the pass it creates a noticeable mark that looks like hell. That's likely what you had that led you to feeling like you must use the feed.

    To get around that use less pressure to where the diamond pattern just closes up to a nice well formed point and no more than that. Then it's nowhere near as prone to forming that stepped looking ring like pattern along the pass. If in doubt try using less pressure than you think it needs. And at the end of the pass check it and if the pattern hasn't closed the tops feed only just a little more pressure in and run it again on the way back. It doesn't need to be done all in one pass. And on aluminium it aids with not overdoing the pressure in the first place knowing you can just add a touch more and run it back out with a second pass.

  7. #37
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    From the looks of his part I don't think he used too much pressure; it's not really even close to a fully formed knurl. Slower feed would help a lot, you really need to use something slower than 12 tpi.

    BTW devils4ever - feed rate is generally measured in travel per revolution (i.e. .008"/rev for example) rather than teeth per inch, since you're not cutting a thread. Typical feed rates are much finer than any normal threads although there is some overlap.

  8. #38
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    I went back and looked at the hammer handle again. And I have to agree with Yondering. The knurl looks well formed on the end farthest from the head but at least in the picture the crests do not appear fully formed towards the head. Now since knurling is sort of like a rotary cold forging process you want the knurls to be in contact for long enough to let them beat the metal fully into shape. And that means a fairly slow traverse. So more towards the finer threading pitches if that's all you have. Like 48 and higher so the traverse is slow enough to let the wheels fully form the pattern.

    It really is a feel sort of thing too. Aside from agreeing with the others that you want to use a slow RPM and fine feed there's no real "numbers" we can really put to how much pressure is needed other than trial and error. At least no information of that sort applicable to the home shop situation. We all had to learn it through trial and error with a bit of advice here and there.

    Given how the butt end of the handle appears to be more fully formed than the head end I'm going to guess that the stock moved away from the wheels a bit. If you didn't use a center to support the long length it would be a nice option. Even the scissors and clamp style tools will try to push the material out and away from the pressure if not supported well.

  9. #39
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    The knurls shown here are perhaps not as fully formed as they could be, but imo they are fine, are often better that way. Below is a shot of a knurl I did in brass - put that on handle and its far less comfortable than those shown above

    .

  10. #40
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    When I've found that the knurls feel like holding a cheeze grater I've just given them a bit of a rub with fine emery cloth or silicon carbide paper. And yeah, it happens more than we'd expect. But they still look nice. I find the crumbly looking peaks of less fully formed knurls doesn't look as nice.

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