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Thread: Newbie looking for knurling info

  1. #1
    Join Date
    May 2019
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    17

    Default Newbie looking for knurling info

    You guys helped a lot with getting my MicroMark 7X16 lathe running great.

    Now, I need some knurling info. Is the LMS Large Capacity Knurling tool (#1911) good quality? Will it work well on my lathe or is there another one that I should buy?

    I understand how the diameter affects the finish, but isn't the feed rate also a factor? Don't I have to change the feed rate based on diameter as well?

    I want to knurl a 3" or 4" section of 1/2" aluminum rod.

    Thanks!

  2. #2
    Join Date
    Mar 2010
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    1,112

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    If you digest the info on these pages, you will have a successful knurling experience: https://www.cgtk.co.uk/metalwork/reference/knurl http://conradhoffman.com/knurling.htm

    It all comes down to starting with the correct dia. workpiece for the knurl pitch you have. You also need to flood the cut with cutting oil or compressed air to remove the chips.

    RWO

  3. #3
    Join Date
    Oct 2013
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    USA MD 21030
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    Here are some threads that have a lot of information on knurling:

    http://bbs.homeshopmachinist.net/thr...ighlight=knurl

    http://bbs.homeshopmachinist.net/thr...light=knurling

    http://bbs.homeshopmachinist.net/thr...ighlight=knurl

    This is the large capacity knurling tool I found from LMS, but it is #3770:

    https://littlemachineshop.com/produc...ProductID=3770


    And here is the #1911:
    https://littlemachineshop.com/produc...ProductID=1911


    They seem to be identical. I have the knurling tool that came with my set of QCTP holders:

    https://littlemachineshop.com/produc...2285&category=


    The scissors, or clamp, type is much better. I found one of the knurls was not bored concentrically, and thus caused the entire lathe to twist and wobble as the pressure changed with each rotation. I was able to fix the knurling wheel, but it took a good deal of effort. I bought more knurls from Aliexpress, but they also had similar problems.



    Some video clips of my experiences with knurling, as well as making a low cost clamp type knurling tool:

    http://enginuitysystems.com/pix/tools/Knurling_4762.AVI (Shows wobbling and flexing with bad knurl wheel)

    http://enginuitysystems.com/pix/tool...verse_4763.AVI (After fix, knurling aluminum)

    http://enginuitysystems.com/pix/tool...4937.AVI(Using my shop-made tool)
    http://enginuitysystems.com/pix/tool...minum_4938.AVI
    http://enginuitysystems.com/pix/tool...minum_4939.AVI

  4. #4
    Join Date
    Jan 2003
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    3,981

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    Quote Originally Posted by devils4ever View Post
    You guys helped a lot with getting my MicroMark 7X16 lathe running great.

    Now, I need some knurling info. Is the LMS Large Capacity Knurling tool (#1911) good quality? Will it work well on my lathe or is there another one that I should buy?

    I understand how the diameter affects the finish, but isn't the feed rate also a factor? Don't I have to change the feed rate based on diameter as well?

    I want to knurl a 3" or 4" section of 1/2" aluminum rod.

    Thanks!
    If possible support the outboard end of your 1/2" material with a center. 1/2" aluminum can flex easily when the knurls hit.

    I've knurled thousands of production parts with the scissor or clamp type tool (actually that's about your only option on a small, light lathe).

    Diameter has never been an issue, except when the knurl needs to be a bit deeper increase diameter, or adjust knurl wheels closer together. Don't listen to any nonsense about calculating work diameter based on knurl pitch, etc, it's just never been an issue with scissor knurlers.

    Aluminum, surprisingly, can be nasty to knurl. Flecks of the material can be beaten back into the knurl pattern so you should use a very fast feedrate, get on and off the work as fast as possible. You only need a revolution or two of the work to create the knurl. The loose flecks can be a really big problem if you send the work out to be color anodized, the flecks break loose in the process and you end up with a speckled knurl.

  5. #5
    Join Date
    May 2015
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    Somerset UK
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    As already noted, with a small lathe, the clamp type is better as the push type puts far too much strain on the cross slide screw.
    I would try to wash away the swarf with a stream of soluble oil/water as the knurling progresses. A shallow catch tray under the bed can control the mess if you don't already have a coolant pump for the lathe. Having chamfers at either end of the knurl can help.

  6. #6
    Join Date
    Apr 2012
    Location
    Medford Oregon USA
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    Default

    A few years ago I was in your situation. I had an 8x14. There is a set of plans that I purchased from Hemingway kits in the UK for their sensitive knurling tool. I still have them. Its a mini me copy of the Marlco knurling tool. I never used the plans, I upgraded to a slightly larger lathe and found a deal on the real Marlco knurler on eBay UK. It works very well for a hobby lathe, but not sure it would fit on a 7x12 ect. Since the Hemingway is a scaled down version, I cant see how it would be any less satisfactory. It has a pressure handle that works great! You can crank down or lighten up a little to adjust the depth very easy. Any of the hemingway versions would be much more stout than what is pictured above. The important thing if you build one is to source a common wheel size. Cruddy wheels will not produce good results so like inserts, a common size gives you more choices. http://www.hemingwaykits.com/cgi-bin...y=0&PR=-1&TB=A

    Next I want to explore a cut knurling tool. Those are smaller, especially the single wheel version. Since it cuts I do think you may have a chance of using that too on a mini lathe without stressing it too badly.
    Last edited by donf; 05-20-2019 at 08:57 PM.

  7. #7
    Join Date
    Jun 2004
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    1,048

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    For formed knurling some chump will tell you OD matters, experienced engineers will tell you it doesn't -

    https://www.youtube.com/watch?v=9Zwi0ZAUCUc

    It's more about the way you present the tool to the work, and the John Stevenson also debunked this OD calculationamateur myth by knurling a tapered bar ;-)

    Cut Knurling does work more consistently with a calculated OD but my experience has shown that it will also work 9 times out of 10 with whatever diameter you tee it up for.
    If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

  8. #8
    Join Date
    May 2019
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    17

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    I have the push type and it was instantly clear it wasn't going to work on this small lathe.

    I just ordered the scissor type 1911 from LMS. Stay tuned...

    All these calculations make sense on paper. I'll see how it works in practice. I may need to speed up the feed rate based on DR.

  9. #9
    Join Date
    Feb 2014
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    956

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    Quote Originally Posted by devils4ever View Post
    I have the push type and it was instantly clear it wasn't going to work on this small lathe.

    I just ordered the scissor type 1911 from LMS. Stay tuned...

    All these calculations make sense on paper. I'll see how it works in practice. I may need to speed up the feed rate based on DR.

    FYI, that is a clamp type, not a scissors type tool. They are different things, although some here continue to use the names interchangeably. The scissors type is more robust and applies more clamping force easier.

  10. #10
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    Dec 2015
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    Chilliwack, BC, Canada
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    Quote Originally Posted by DR View Post
    ......Aluminum, surprisingly, can be nasty to knurl. Flecks of the material can be beaten back into the knurl pattern so you should use a very fast feedrate, get on and off the work as fast as possible. You only need a revolution or two of the work to create the knurl. The loose flecks can be a really big problem if you send the work out to be color anodized, the flecks break loose in the process and you end up with a speckled knurl.
    I've had that and it leaves a dull ugly mess even without any other processing.

    It seemed to occur too when I put on too much squeeze in my attempt to obtain nice crisp well formed knurl peaks and the metal broke down from the pressure.

    I found it was better to go a touch lighter in my guess and run a second pass with just another few thou. And while a single pass seemed to be best a second pass is a cleaner/better option than too heavy a single pass. Does this match what some of the rest of you have found?

    If you want to buy this "one time" I'd say go for the 3770 package that includes both the 1911 tool with diagonal knurls as well as the additional straight knurls.

    I really like the straight knurls for a lot of the small thumbwheels. It gives a cleaner look and better grip to have the narrower edges of such things "coined" instead of a lot of partial pyramids along the edges.

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