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  1. #11
    He was John S from Nottingham - it has taken me a while to realise it, but I'm sure it is the same John S from Nottingham (HobNob man!) who posts on here, so hopefully he'll chip in soon ! I saw his advert for machining services on the Arc Euro website.
    Did you leave with a handfull of "borrowed tools"? If not then its somone else. :heehee:

    I'm suprised some of the others havent chiped in as they nornally do. Must have bored them to death with the structural and dynamic vibration ramblings in the other threads

  2. #12
    Sorry some Dynamic vibrations put me to sleep.

    Not sure how successful it will be doing ballscrews on a small machine due to rigidity.
    It also depends on how far under you need to go, a 12 mm diameter by 4 mm pitch will just clean up to 10mm but will still be on the hard part.
    A 16mm x 5 will clean up to 12mm but again be hard, down to 10mm and you are into the soft core.

    I rough down using old tips that have been licked on the top to give more rake, all I'm interested in is getting rid of material, surface finish doesn't matter. Once I'm close I change tips to a diamond coated, small cut to clean up and get a size then the ballance is taken off at one cut.

    This is where you need a rigid machine as the tips are 49 each, no misprint and they don't do rubbing or light cuts.

    Another alternative is to stub the screw, I have to do this for one customer as he uses 16mm ball screws but the bearings on the drive end are 20mm. On these I stub with a piece of 25mm turned down to 12mm and pressed into the end with some serious force plus Loctite plus a secret machining operation. The screw is then turned down to whatever diameters and threads to ensure concentricity.
    John S -

  3. #13
    Thanks John.

    So do you think I'm wasting my time then? Im not looking to mass produce them just modify or machine the odd one as I need them, Is the diamond tooling essential or just the best value for you given the amount of work you do?

    I rough down using old tips that have been licked on the top to give more rake, all I'm interested in is getting rid of material, surface finish doesn't matter. Once I'm close I change tips to a diamond coated, small cut to clean up and get a size then the ballance is taken off at one cut.
    Is that TC tooling or normal HSS?, not sure i would have the skill to get the correct finnish diameter in one pass anyway....

    I have a traveling steady so will this help or is it dangeous to use with such hard metals, tool shatter etc....?

    Maybe I wil have to try 2e0poz suggestion with the grinder, sounds messy tho and will have to try and protect the ways.

    As another solution Is it ok to turn a 16mm screw down to say 10mm or to the softer core so its easier to thread and then make a sleeve to bring it back up to the size of the bearing?
    Last edited by Ross77; 20-07-2010 at 01:48 AM. Reason: Missed a bit out

  4. #14
    You need tipped tooling, HSS just won't touch these. You can use normal TC tooling I just use the diamond coated because of the work I do, I machine quite a few screws for other companies, ARC advertise my services others say they do them their selves.

    Never tried a travelling steady, never found one that I can get into the right position. I do centre the ends and support on live centres. Sleeving up to a bearing size is OK but use an over size sleeve and turn to get concentric.
    John S -

  5. #15
    Thanks John

    Care to elaborate on the "licked on the top to give more rake" , not sure I follow. I presume you use the triangular inserts but do you use the side or the radius point?

  6. #16
    z3t4's Avatar
    Lives in Manchester, United Kingdom. Last Activity: 19-10-2017 Has been a member for 7-8 years. Has a total post count of 29.
    Hi Ross

    Did you see the Dick Stephen X3 conversion articles on Arc's site?
    He turned extensions out of mild steel (with all the clever stuff on for the bearings etc) then machined a narrow shaft on these extensions, to insert and loctite into reamed holes in the ballscrews. Avoids the need for angle grinder / special tooling.

    Seems that this is an alternative to

    • machining the screw itself (using proper tooling and skill like John's got)
    • machining the screw itself (using < grinder to de-skin screw)
    • buying pre-machined
    • paying somebody to do it.

    As a complete newb I'd probably get pre-machined, but Dick Stephen's method does at least seem accessible.

    John

  7. #17
    Dick has actually had a couple come loose but I feel that it's more they way he did it.

    Ok I'll share my secret machining technique here, anyone of a gentle disposition needs to shut their eyes at this point.

    You drill and ream the hole in the end of the screw and put a slight countersink on so the new slug fit flush, now get an oversized slug of material and turn down for a nice slip fit into the hole, turn a tad over, allow to cool then polish with emery cloth, again don't get it too hot.

    Then put a light to medium STRAIGHT knurl onto the last half of the spigot, that's the bit up to the shoulder, smear with the shaft fit Loctite and with the end of the ballscrew held between alloy or brass plates in the vise, push the slug in and whack seven shades of sht out of it until it's flush.

    Fit into the lathe and take a light facing cut , centre drill and support.
    Then do all the machining needed and believe me that puppy isn't going to shift until hell freezes over and with Global Warming that's not likely.


    you want 30 to 40mm inside the screw
    John S -

  8. The Following 3 Users Say Thank You to John S For This Useful Post:


  9. #18
    Did you see the Dick Stephen X3 conversion articles on Arc's site?
    Thanks John no I didn't, certainly is an option if my little old lathe isn't up to the challenge.

    Ok I'll share my secret machining technique here
    Ta most appreciated, so your addition is the Knurling! nice.

    I like the way you and Bogs always make everything sound so simple,

    smear with the shaft fit Loctite and with the end of the ballscrew held between alloy or brass plates in the vise, push the slug in and whack seven shades of sht out of it until it's flush.
    thats my favorite bit, got plenty of big hammers

    Dick has actually had a couple come loose but I feel that it's more they way he did it.
    Is that because of the technique or the fact thats not been knurled?

    Sorry to ask so many questions but I was just about to order some TC tooling but it looks like I need decent drills and reamers instead.....

    Thanks again for the help

  10. You are allmissing the thread,, ball screws are case hardend,which means the centre is soft.

    simplydrillout the centre and insert a steel pin of your desired size, lock it in with anarobic glue.

    Works ever time for me,and i have never had one come loose yet

  11. Quote Originally Posted by cncezee View Post
    You are allmissing the thread,, ball screws are case hardend,which means the centre is soft.

    simplydrillout the centre and insert a steel pin of your desired size, lock it in with anarobic glue.

    Works ever time for me,and i have never had one come loose yet
    ummmm but thats exactly what JohnS was doing...

    Quote Originally Posted by John S View Post
    You drill and ream the hole in the end of the screw
    His approach was more about how he does it so the extension stays put...

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