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Knurling Straight Wheel?

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  • #16
    Originally posted by Bented View Post
    I suspect that the customers engineers had a good laugh, they gave me a finished knurled diameter that may be dusted off .005" after knurling, a knurl pitch of 12 and no start diameter, the parts have an 8"+ long surface, it took a few trial and error tests to get the starting diameter correct. These are recurring parts, the stock for every order comes from a different heat making consistency nearly impossible........
    Right on Bented..great work !.....and as you point out, they did not give you the start diameter ( probably didn't know ! )
    Those look like feed rollers for a paper product by the way...

    Now sometimes you need a finer knurl than the tool you have on hand ..say a 10 pitch and you need one 5 times finer..not to worry
    You purposely want it out of time. In the pictures here, you see what a standard Aloris 10 pitch can do when it is out of time.
    Normally you want the knurl tooth to engage the exact impingement it made at the start of it's first revolution so it is "In Time" with the knurl pattern.
    What if you want the knurl point to be every ten degrees in a circle , so that is 36 points at 10 degrees apart- right ?
    Well what if the Knurl Tool points hit every 50 degrees because they are too big Pitch wise.. You get knurls every 50 degrees and when it comes to
    the first complete hits at 350 ( 7 turns or the "knurler" ) and misses the 360 mark, and the next hit is at 40 ( 350 + 50= 400 - 360) and so it misses the mark
    all the way around and it takes 5 turns ( 360 x 5 = 1800 which is divisible by 50 ) to return to the very first impingement .
    Now depth settings are extremely important ( ! ) in order to achieve the desired result

    In the pictures below, the knurled cap is about .180" in diameter ( the copper tube is .062 for scale) and the "course" knurl tool used is shown on the left next to the work piece
    The impingement was about .002" in order to get the results seen. I believe the tool made 5 or 6 revolutions before returning to the initial point
    So many things are possible with Knurlers if you push the envelope or study the effects .
    Hope this helps

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    Green Bay, WI


    • #17
      I recently needed to produce a straight knurl on 303 stainless. The part was a hose insert and needed to resist rotation, so the coarser the better and appearance was not important. Using the standard issue bump knurling tool I could not get sufficient pressure without the toolpost rotating. I made a holder that allowed me to put the knurling roll on center with the toolpost mounting stud.

      Click image for larger version

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      It took a lot of pressure, but it worked. The insert will not spin inside the hose. Now I just have to stop it from leaking. You solve one problem only to create another.
      It's all mind over matter.
      If you don't mind, it don't matter.


      • #18
        You need an annular ridge or two for the circumferential seal.

        I like your fix for dealing with the high pressure needed to form the knurl you needed.

        This issue of torque for knurling tools, especially on the single wheel coining or straight tool is why I made a special holder for bump knurling tools that puts the tool very close to in line with the bolt. This has worked well for me for many years now. At the time I didn't have a QCTP so making the small dedicated post shown here was a good option. And for the small time needed to just swap posts I'll continue to use this dedicated post for knurling.

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        Chilliwack BC, Canada