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  • Cut knurling tools

    This is a follow on from my previous post called CNC knurling as all the tools and setups can be applied to manual machines with just as much sucess as with CNC, perhaps more so, more later.

    Warning, could be long, go make a coffee and for Christ's sake will someone dig Alistair in the ribs and wake him up.

    Ready ?

    Well I bought that tool off ebay that I wrote about in the earlier post, fitted some side knurling wheels from J&L and tried it out with very good results on steel,aluminium and even on soft magnesium.
    Here's a shot of the tool with the new knurls and an example of the pattern in steel and alloy [ large piece ]

    This next shot really shows how little effort is needed to operate these knurls.

    This is an actual shot, not staged and is a piece of 1.5" diameter exhaust pipe 16 gauge thick extending from the chuck by about 2"
    No support and only lightly gripped it still cuts a decent knurl.

    This tool and the picture I saw on the Dorian site of a single wheel straight knurl cutting tool gave me the idea to see how easy one of these would be to make and how effective.

    ALISTAIR - Stop scratching yourself and pay attention !!

    I took a piece of 1" square steel bar and turned a length down to 3/4" so it would fit into a boring bar holder I had.
    Some of the 1" square left was thinned down and tapped to take a left hand side cutting knurl running on a hardened bush.

    Nothing in the design of the knurl holder is critical. The only two critical measurements are the centre hight which is adjusted like any normal tool, either on the quick change or just by packings, and the angle of the knurl which is adjustable by rotating it in the holder.

    The operation of this is just the same as the cross knurl tool, touch onto the work, wind clear, feed in then go for it.
    Around 300 rpm and a fast feed seems to be about right.
    I have tried it at low speed but the quality suffers, I haven't gone higher than 300 rpm.

    Shows this tool cutting the opposite end of that thin walled tube.
    Cutting forces as compared to normal crush knurling have got to be reduced to a minimum or this tube would have either been spun or ripped out the chuck.

    One problem with this tool is getting a parallel knurl. This is achieved by tilting the tool so the wheel pattern lies horizontal but it's hard to adjust slightly the way I have got it set up at the moment.
    What is needed is a vertical pin in the tool that's able to be pushed both ways to move very slightly. This will be the MKII mod.

    Are some examples of straight knurl.
    These are in fact far better than the picture shows, for some reason they look rough and bitty but they aren't.
    The large top one is in alloy and has no indication of bits crushed in, something common to soft materials.

    The small shaft at the bottom was the first example I did, the centre portion has a slight uphill slope to the knurl.
    I then adjusted it and got the left portion going down hill and then I managed to get the right portion going straight but without some form of fine adjustment it's a hard call.

    John S.
    Nottingham, England

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.

  • #2
    Good results John must be very sophisticated I still don't know how it told you I was scratching myself still thats C.N.C for you out of my league.
    Seriously though what a nice finish.
    Despite what Darin said though I still agree with you though fifty one smackeroonies is a lot but what a beautiful job I hope Gert never finds out you spent that much Alistair
    Please excuse my typing as I have a form of parkinsons disease


    • #3
      I have had another look and I must say it again what a great job seriously well done question, when are you making me one? actually it doesn't look too hard the way you describe it I think when I am up and running I will try one of these myself top marks. Alistair
      Please excuse my typing as I have a form of parkinsons disease


      • #4

        It looks a magic tool.

        My home made scissor type knurling tool takes standard knurls and your style needs a knurl without a shoulder.

        Do you think it would be feasible to knurl a piece of silver steel first and then harden it to make my own knurl.



        • #5
          I take it that this works somewhat similarly to "crossed axis gear shaving", without the cutting edges.

          So if I have this right, angle knurling is done with straight knurls. And straight knurling is done with angled knurls, since there has to be some crosswise movement along the knurling.

          Now, that first tool is interesting. I am not 100% sure I see how it is set up.

          Can teh simple version do the angled knurls, even though it will have to be in two steps? Or is there an additional angle on the axle of the first tool? It looks that way, and it would seem there might have to be due to the locations of the contact points. I don't think I have the geometry quite in view.

          Oh, and what is the knob on #1 for?


          Keep eye on ball.
          Hashim Khan


          • #6
            Fifty one quid was an absolute bargain, I paid for it using Gerts paypal.

            The straight knurl is simple, it's just a knurl wheel on the end of a shank.
            The wheel came from J&L but I had to surface grind the face to remove the chamfer to make it side cut.
            Total cost was a bit of metal for a shank, a bit of drill rod or silver steel for a bush and 12 quid for the knurl wheel.
            Total time was about one hour to make and test this.

            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


            • #7
              Do you ever Knurl shafts or housings to "fix" bearing Knurl the shaft or bell housing to "keep the bearing tight".
              Your reasons for/against
              please visit my webpage:


              • #8
                John...looking at the last three pics...where is the ebay bought knurler missing..
                the one youve substituted looks easy enough to make .... .
                just buy the wheels off j&l and the rest looks strait forward enough ...or am i missing something... is there more too it than i can see.
                ps would it not be a good idea to put the traveling steady the other side and mount say a heavy ball bearing roller onto it.pressing on the oppsing side of the bar that you are stop straining the head bearings.
                all the best....mark

                [This message has been edited by Mark Jones (edited 08-18-2004).]


                • #9
                  Only one thing with cut knurls. If you want them above the surface you have to leave the knurled suface oversize. Actually I think these work better on small lathes than even the scissors type as they put very little load on the machine at all.
                  Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.


                  • #10
                    Bunch of replies:-

                    No I don't knurl shafts and housings up as the customers won't allow it. They expect then to be rebuilt or sleeved.

                    The Ebay tool is the complex looking one that does cross knurls in the first pics.
                    The later pics are of the simple one that does straight knurling and no you aren't missing anything - they are that simple.
                    No need for a steady because as Spin has said they produce low pressure in their actions and a boon for small machines.

                    J Tiers,
                    You have it right, straight knurls produce crossed and helical produce straight.
                    It has to do with the angle they sit at.

                    The one I bought off ebay is qute complex in it's design.
                    There is a centralising mechanism that allows you get get both knurls onto the work exactly equal, this is simple but that knob rotates the knurls thru an arc and is calibrated in diameter.
                    The idea is that at a given diameter the straight knurl wheel lays on the circumference of the work to allow it to track thu.

                    If you set it to 1" and offer it up to a 1" bar it will cut fine as the front edge just leads and the rest follows thru.
                    If you offer it up to a 2" bar it will also cut but only on the leading edge and because the wheels don't lie on the bar they don't follow thru and clean up but it does still work althogh as the wheels are at the wrong angle to the bar you get a knurl with a shallower angle.

                    If you set the tool to 2" and offer it onto a 1" bar it won't cut as the wheels are touching at the rear and the front cutting edge isn't making contact.

                    That to calibrated knob rotates the two axles the wheels are on via a worm and wheel setup on each.
                    If you wanted to make on it could be simplified by having these axles free to turn but lockable and calibrate the diameters on the ends of the axles.
                    In use you would release the axles, turn each axle to the diameter needed and relock.

                    Spin Doctor,
                    The cross knurl off Ebay does cut undersize but for some reason the one I made although it cuts and you can see slivers coming off it still pushes up and it finishes oversize.

                    Whether this is an error in the design I don't know but it suits me as most of the straight knuring I do is on motor shafts that need to be pressed into a rotor

                    Now I've prooved that it works I'm scrapping the one I built and going for the MKII with micro adjustment on the wheel angle to get straight knurls.

                    John S.
                    Nottingham, England

                    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


                    • #11
                      I have one of the hand knurling tools that looks like a pipe or tubing cutter. It has knurls and rollers that oppose them. You put it over the shaft and tighten it and then you turn it like a pipe cutter. Some of the CRS shafts that I knurled looked rough. Are these tools any good or am I not using it right?


                      • #12
                        John, put a flat on the shank with setscrews (grub screws) at opposite sides of the flat to adjust the angle, assuming that only a small angular adjustment is needed.


                        Of course, you probably have a better solution, but this is used on some of the toolholders we use in New Britain screw machines.
                        North Central Arkansas


                        • #13
                          Very nice work! I'm gonna make one today!
                          Thank you

                          I did a search and found the Dorian has cut knurls without the shoulder, also the 100-2 cuts diamond and it seems to me should cut straight with the right knurls.
                          Of course it's 600 bucks!
                          I thought the replacement cut knurls might be a good source of knurls for those that don't have a grinder to take off the shoulder of a standard knurl.

                          [This message has been edited by me (edited 08-19-2004).]


                          • #14
                            Thanks for that about the flat on the shaft.
                            Started the MKII tonight but got dragged off screaming and kicking by Gert.
                            Gert collects old scales, all sorts of scales.

                            Local scrappie rang up and he's rescued a set of coal scales that they weighed one hundredweight [ 112# ] bags of coal and potatoes out with on railway platforms back at the turn of the century [ last ]
                            Too good to miss so had to rush out with the Donald and collect these.

                            Didn't manage to get a lot done on the MKII.
                            I was using my boring bar holder on the MKI so I decided to make a dedicated holder just for this and also incorporate the twin screw idea put forward by Ulav8r.

                            I have got to drill and tap two holes in the flat on the knurl holder at each side for the two push screws so they bear on the step of the holder. This give give micro adjustment so I can get a straight knurl.
                            The hole in the top is to take a split cotter arangemant similar to a tailstock quill lock to hold the holder without damaging it and I need a hight adjustment screw and stop for the quick change holder.

                            I'll see if I can get this finished first thing tomorrow.

                            John S.
                            Nottingham, England

                            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.


                            • #15
                              Very nice work!!
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