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  • 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
    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

    Comment


    • #3
      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
      http://pauleschoen.com/pix/PM08_P76_P54.png
      Paul , P S Technology, Inc. and MrTibbs
      USA Maryland 21030

      Comment


      • #4
        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.

        Comment


        • #5
          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.

          Comment


          • #6
            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, 08:57 PM.

            Comment


            • #7
              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 ;-)

              Comment


              • #8
                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.

                Comment


                • #9
                  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.

                  Comment


                  • #10
                    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.
                    Chilliwack BC, Canada

                    Comment


                    • #11
                      Originally posted by Yondering View Post
                      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.

                      OK, but LMS calls it a Scissors Knurling Tool. So what's the difference between the two?

                      Comment


                      • #12
                        Originally posted by devils4ever View Post
                        OK, but LMS calls it a Scissors Knurling Tool. So what's the difference between the two?
                        Both crap and limited in use, why have to constantly set the things for the job in hand when can go straight in with a normal knurling tool.
                        Also never ever seen a decent knurl done by either, even the best would end up my scrap bin

                        Comment


                        • #13
                          So, assuming I get the tool set properly, do I use the power feed or do I manually turn the cranks to do the knurling?

                          It seems I would have to greatly increase the feed rate it I wanted to use the power feed.

                          Comment


                          • #14
                            Originally posted by devils4ever View Post
                            OK, but LMS calls it a Scissors Knurling Tool. So what's the difference between the two?
                            Below is a scissor-type knurling tool; the hinge is between the knurls and the clamping screw. This allows more force to be applied to the knurls, at the cost of more force taken by the hinge. If the hinge is midway between the knurl and clamp screw, the knurls see the same force exerted by the clamp screw but the hinge is subjected to twice that force.



                            Below is a clamp-type knurling tool; the clamping screw is between the knurls and the hinge. Not as much force is applied to the knurls as in the scissor type, but the hinge also takes less force. If the clamping screw is midway between the knurl and the hinge, both the knurls and the hinge see half the force applied by the clamping screw.

                            Comment


                            • #15
                              Originally posted by devils4ever View Post
                              So, assuming I get the tool set properly, do I use the power feed or do I manually turn the cranks to do the knurling?

                              It seems I would have to greatly increase the feed rate it I wanted to use the power feed.
                              Hand feed is just fine. The knurls turn so they follow any speed you use.

                              For steel you will want to apply pressure (a fair amount) that makes it move and hold that pressure. As the knurls do their work the carriage will move in response to your pressure against the knurls pounding away room to move ahead. For aluminium and brass I can't really feel that same "clearing" so I just move the handwheel smoothly and at a rate of roughly 4 turns of the work for each width of the knurl for travel.... might be more like 5 or 6 turns for each width of travel.... Needless to say this means low spindle speeds.

                              At least that's how I've done it and generally I get some nice clean knurls and coinings.

                              As for the styles DrMike pointed it out well.

                              I only recently "graduated" to my own scissors style tool. Up to now I'd used the straight push tools. Likely still will for coining. Something to keep in mind is that a good way to use both the clamp and scissors tools isn't to set them right over the center and screw down the nut. Instead set the tool so they won't go over the top of the part you're making by the depth of the knurl and a bit more. Basically in most cases set up the wheels so they contact the part at 7 and 11 o'clock. Then you push the cross slide onto the part and the knurl you start is complete and ready to be fed on by the time the knurl wheels are at roughly 6:30 and 11:30.

                              The wedging action this produces puts some but very light bending loads on the part. But it makes it far, far easier to engage and disengage the tool at the ends of the knurling operation. You simply move the cross slide in and out like with a push tool. But with only about a tenth or less of the force needed due to the wedging action. Play with it on some scrap and see what I mean. Also doing it this way means you are not trying to use some manner of tool or get your fingers in close to the spinning chuck. So far safer all around.
                              Chilliwack BC, Canada

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