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Thread: Is this knurling tool any good?

  1. #71
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    Just to show (off) how well the cut knurling works on a small lathe..ehmm equipment I did this knurling to 8mm brass:



    I did it on a POS chinese drill press! like here:



    Its bit chewed-off looking as I didn't have air blast to blow off chips and "drunken" as I just throw everything together without any adjustments.
    Last edited by MattiJ; 11-01-2018 at 02:20 PM.

  2. #72
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    Quote Originally Posted by Zahnrad Kopf View Post
    .................................................. ................

    What I never understand is why so many people never even bother to investigate cut knurling.
    It is ridiculously easy to make tooling for, simple to use, and the results will surpass everything else with ease and aplomb.

    .................................................. .................................................. .................................................. .....
    One of the biggest repeat knurling jobs I had was to diamond knurl aluminum knobs which got black anodized.

    I have an Hardinge cut knurl tool. Worked okay until the parts came back from the anodizer. Cut knurling made a mush of flecks. The flecks get mashed back into the cuts. When the parts are anodized some of those flecks break loose leaving white spots on black parts. The anodizer claimed they'd never seen that before, but talking with an old timer in the business he said it was a common problem with knurled aluminum.

    I switched to a scissor knurl off a B&S screw machine. Running in the CNC lathe we knurled dry with a quick squirt of coolant to lubricate the knurl pins before hitting the work. I programmed the job so the part made as close as possible to a single turn in contact with the knurls, high feedrate on and off the part. Loose flecks were no where near a problem as with cut knurling. We touched up any white spots up with a black marker.

    After that experience I started noticing how few commercial knurled aluminum parts have color anodized finishes. A few high end music systems have aluminum knobs, a bunch of them use straight "knurling" that's extruded that way.

    Anyway, in my experience cut tools are a pain to setup, adjust and get blank diameter correct. In comparison the B&S only needs only a depth setting (distance between knurls) and with floating arms it works first time every time. On the black aluminum knobs it did take a couple tries to get the specified final diameter, most times knurls don't have close tolerance diameters, these did. We got close and took a skim cut pass to bring the diameter to +/-.005".
    Last edited by DR; 11-01-2018 at 03:05 PM.

  3. #73
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    Feb 2014
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    I use the scissor type knurling tool. The picture below is typical of the results I get with it, but sorry for the poor picture quality. The material is titanium grade 5, and the center hole was bored out after knurling.


  4. #74
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    I just received four pair of knurling wheels from AliExpress. They were about $4/pair, and look pretty good:

    https://trade.aliexpress.com/order_d...96528414626638





    They are 19 mm (3/4") diameter, 8 mm (0.31") thick, with a specified 6.00 mm (0.237") bore. One pair had a 6.31 mm (0.248") diameter bore, which fit the 0.250" shoulder bolt (after a little work to get it to 0.244" or 6.23 mm), and I had modified the other bolt to 0.237", so it's a sloppy fit. But the others are 6.11 mm (0.241"), which work well with the 0.237" modified bolt.

    So I have a choice to make the other bolt 0.237" diameter (which will be a sloppy fit for the knurls with the 6.31 mm bore). Or I could bore all the knurls to 0.250" which would be correct for a 1/4" shoulder bolt. But standard shoulder bolts are 1/4"-20 and not 1/4"-28 which is what the knurling tool is tapped for. A 6 mm metric shoulder bolt has 5 mm x 0.8 threads (31.75 TPI).

    The original knurls had a 0.265" bore for the 1/4" shoulder bolt, so they were pretty sloppy. The one I modified with a brass (bronze?) sleeve is now 0.242" bore, pretty close to the 6.00 mm modified bolt. But the other original 0.265" bore is way too sloppy on a 0.237" bolt. I could bore it out to 0.312" diameter and insert a sleeve to make it also 6.11 mm.

    Actually, the pair of new diagonal knurls with the oversize 6.31 mm bores are the same pitch as the original knurls that I modified. I think I will wait until I go to Cabin Fever and maybe buy a scissors type knurling tool and see what size shafts it has.

    I'm also wondering if a knurling tool with two wheels is suitable for the straight knurls? Or maybe replace one wheel with a smooth soft wheel made from aluminum or brass just as a support?

  5. #75
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    Anyone made one of these? Since I will hopefully have a functional milling machine in the future I was thinking of making a tool in this vein

    http://tomstechniques.com/clamp-knurling-tool/

  6. #76
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    Quote Originally Posted by DennisCA View Post
    Anyone made one of these? Since I will hopefully have a functional milling machine in the future I was thinking of making a tool in this vein

    http://tomstechniques.com/clamp-knurling-tool/
    There's one complication to that style. Nothing on it "floats" so the two wheels need to be adjusted for pressure independently. If they two slides are not set up for the same amount of pressure using the screws then some of the pressure will be transferred to the tool post and lead screw anyway. And again because the frame is fixed to the tool post if you are knurling multiple items you would need to ensure you go back to the exact cross slide position each time you put the knurling tool back in or you have to adjust the screws again.

    I do like the idea that it acts a bit like a threading die head in that the screws are set once and you just run it on and off. But it seems to me that it would be really nice if the whole frame had some even slight side to side float so the knurls and frame could find its own center so the knurls automatically cut into the material in a balanced manner. Clearly the idea works. But it seems like it's adding some setup steps and the need for extra care to use it between other cutting operations.

    Now contrast that to the double arm styles as seen with the scissors style and the simpler double arm style. The arms do float on these tools so setting the pressure is just a case of one control. And when you swap tools you still want to go back to some same index mark. But it's not anywhere near as critical as it would be with the fixed frame style from Tom's plans.

    So far I've only used the "jam it in" style. But I'd like to do something along the lines of the Riley style twin arm tool as seen in this Hemingway Kit's Riley style tool. But I'll design my own to fit the knurls I've got on hand already that will come from the tools I've got.

    I like this Riley style over some other floating arms style for a couple of reasons. First is that the side plates easily ensure that the arms stay in plane with each other to a quite fine degree. Second is that the arms are long enough that the pressure setting screw can be closer to the knurls than to the pivot pins. That means more of the force from the screw is on the knurls than on the pivots. And that's not the case with some of the twin arm style knurling tools. Those have more slotting to be done and the fits of the slots to the tenons needs to be done with care to avoid the side to side play in the tool.

    So all in all I'll be using that Riley design as my guide but making the actual dimensions to suit my own needs.

    Part of that is that I can see where changing the knurl wheels will be a bit annoying too. So I'm thinking of a way that would allow me to swap arms with knurls easily by simply removing the tension screw and the arms fall away and out and are replaced with the new ones that slip in and the tension screw goes back into place. Or maybe given that this style of tool would not need a whole lot of fancy bits or machine operations perhaps simply make a bunch of them. Three for diagonal knurl pitches and two for coining and call it a day. A lot of the fancy stuff, such as it is, would be in the arms anyway. So with just a bit more work I could avoid swapping the knurls or arms altogether.

  7. #77
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    Feb 2014
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    Quote Originally Posted by DennisCA View Post
    Anyone made one of these? Since I will hopefully have a functional milling machine in the future I was thinking of making a tool in this vein

    http://tomstechniques.com/clamp-knurling-tool/
    I have not. It appears to be needlessly complex compared to a simple knurling tool, both in design and use. I think you'd be a lot better off to make a scissors type or a cut knurler if you're wanting to make something.

  8. #78
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    I have one of them. It works fine.
    The one that you found looks expensive. See link
    https://rover.ebay.com/rover/0/0/0?m...2F173668425239

  9. #79
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    Quote Originally Posted by DennisCA View Post
    Anyone made one of these? Since I will hopefully have a functional milling machine in the future I was thinking of making a tool in this vein

    http://tomstechniques.com/clamp-knurling-tool/
    I think BCR and Yondering have it correct.... Why would anyone design it like that? It's complex, it's not very flexible in use, and it sure is not flexible as to any "float".

    Looks like it would possibly be fine for someone setting up production knurling a large number of identical pieces, where they could fiddle with it for 20 minutes to get it set up. But for "off-hand" use, "slap it in and go", it looks like a disaster. I'd stay far away from that design for general use.
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  10. #80
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    Quote Originally Posted by ahidley View Post
    I have one of them. It works fine.
    The one that you found looks expensive. See link
    https://rover.ebay.com/rover/0/0/0?m...2F173668425239
    Thats hilarious! From India with rust already applied. JR

    My old yahoo group. Bridgeport Mill Group

    https://groups.yahoo.com/neo/groups/...port_mill/info

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