Sherline lathe 10mm collet adaptor.

Discussion in 'Clock Repair' started by Altashot, Mar 26, 2020.

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  1. Altashot

    Altashot Registered User

    Oct 12, 2017
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    I recently purchased a 4500 Sherline lathe with a bunch of accessories including the threading attachment.
    I already owned an American Watchtool Co. lathe with many collets. I was often pushing this lathe to its limits (sometimes even beyond) so I decided to upgrade my 12” watchmakers lathe to a 15” Sherline.
    I had planned on using my current collets with the Sherline but found out that it will only accept 8mm collets. Mine are 10mm. I was a bit disappointed. The 3 jaw chuck is fine but as we know, as with all 3 jaw scroll chucks, not very accurate.
    At least not for what we do.

    I didn’t want to dish out the money to purchase Sherline collets, I already dished out a lot for the lathe.

    I had to find a solution, and this is what I came up with.
    8F33AFB3-72EE-4A37-AE70-F62A5BCEBC59.jpeg
    I turned this with a taper inside matching my collets and threaded it with my threading attachment. CC9C7398-B3A9-4F67-B18F-D1BFD114E01F.jpeg
    I can slip my 10mm collets in it then screw in the nut. I also made the nut and a tool bit to thread the inside.
    0DEFCB8A-7A6E-41C4-A2D2-8A70926985B6.jpeg
    Once tightened, it holds the part very well.
    I know some of you will say: “But these collets are supposed to be pulled in by the threaded tail”. Yes, I agree, that’s how they’re supposed to work but here, I don’t think I had a choice. They are indeed pushed by the nut into the taper. It works.
    CB6C77BA-3DBB-4931-80DB-F2CB44531940.png
    To assure repeatability, I marked the adapter to always remount it the same way. A little notch marked “A” to line up with jaw A. It spins within 1/2 a thousandth of an inch.

    And as for the colour, well, I tried to heat blue it, but I failed miserably. It was uneven and spotty. I did it in brass shavings but I don’t think it was very clean. It smoked pretty bad upon heating and a lot of it stuck to the parts.

    Something I’ll try again later. This time I’m going to get brass shavings from a Locksmith’s key cutting machine. It’ll be clean and even in chip size.

    M.
     
    Bruce Alexander likes this.
  2. Old Rivers

    Old Rivers Registered User
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    Oct 4, 2016
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    Altashot,

    Very cool, I like it.
    Did you consider internally threading your collet holder so it would screw directly onto the Sherline's headstock spindle threads?

    Bill
     
    Bruce Alexander likes this.
  3. glenhead

    glenhead Registered User
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    Nov 15, 2009
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    That's a danged nice solution! With half-a-thou repeatability I'd say it was an Epic Score. How the collets close isn't particularly relevant as long as the closing pressure is applied correctly by the taper, and from your description it sounds like you nailed it. The 8mm tailstock collet adapter from Sherline works exactly that way.

    Good on ya!

    Glen
     
  4. Altashot

    Altashot Registered User

    Oct 12, 2017
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    Old Rivers, no, I didn’t consider that. Damn! That’s a good idea! I might have to try. I still have some of the 1” round bar I used here. I was astonished that the Sherline spun that thing effortlessly without bogging down.
    I did however consider making an adapter that would slide right into the Morse taper and screw the nut onto the spindle 3/4-16 but the walls of said adapter would be soooo thin...
    I can try your idea but I’ll have to make a better internal threading bit to cut a 3/4-16 thread. This is the one I made, held in a custom holder also made by me. It’s the shank of a1/8 drill bit.

    C8306292-63F3-4EC7-909D-D184C9860CB5.jpeg
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    image.jpg
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    Glenhead, thank you for the nice comment. I thought that Sherline’s adapter and collets used a draw bar?

    M.
     
  5. glenhead

    glenhead Registered User
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    The headstock adapter uses a drawbar, but not the tailstock adapter. The tailstock adapter is like yours, and mounts into the Adjustable Tailstock Custom Tool Holder and locks in place with a set screw. The adjustable tool holder allows for precise center alignment. The holder is mounted on a #0 Morse backplate to mount in the quill.

    Adapter
    parts.jpg


    With collet installed
    complete.jpg

    Tailstock adjustable holder
    holder.jpg

    All together
    together.jpg

    Glen

    IMG_8356.JPG
     
  6. MARK A. BUTTERWORTH

    MARK A. BUTTERWORTH Registered User
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    Jul 4, 2009
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    Nicely done. For anyone that does not have collets we have the Sherline lathe adapter for the ER-16 collets as well as the metric sized collet set from 1mm-10mm. Much less expensive than the WW or Sherline collets. The adaptor screws directly to the headstock.
     
  7. Jerry Kieffer

    Jerry Kieffer Registered User
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    May 31, 2005
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    Altashot
    If your adaptor works for your needs, thats all that counts.

    Some years ago, I machined a 10mm collet pocket in the existing Sherline spindle nose and then drilled/reamed open the rest of the spindle for a drawbar. This was done for someone with the same situation as you have while retaining the threaded spindle for the chucks and other threaded accessories. It was dead accurate and provided the wide open clearance at the nose of the collet for setup versatility and maximum stability. While you would loose the spindle taper, it is really only used for a center in the lathe that is easily replaced with a 10mm collet with a center. If you wished to return the lathe to original, simply replace the spindle with a new spindle since they are inexpensive. An unexpected plus to this modification was the enlarged spindle bore that came in handy on a regular basis. Unfortunately I did not take photos.

    Jerry Kieffer
     
  8. Altashot

    Altashot Registered User

    Oct 12, 2017
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    Thank you Glen for clarifying this for me. I see now.

    Mark, it all seems very interesting, could you provide a link please? I couldn’t find it on your website.

    Thank you.

    M.
     
  9. shutterbug

    shutterbug Moderator
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    Please go to PM for that discussion guys.
     
  10. MARK A. BUTTERWORTH

    MARK A. BUTTERWORTH Registered User
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    I should know this but how do I do that.?
     
  11. shutterbug

    shutterbug Moderator
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    Just click on the avatar of the person you want to talk privately to, and then look for the "start a conversation" button there. You can also invite other people into the conversation if you want to ;)
     
  12. Altashot

    Altashot Registered User

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    Well, as per Old Rivers suggestion and now knowing that there are accessories that screws right on the spindle, I made a new one.

    Better than the last with about 1/8 of a thousandth run out, I don’t have to worry about indexing it properly, and I can use my 10mm collets reliably.

    I attempted to heat blue it again, with yet, another poor result. Believe me, as bad as the bluing is, it’s much better than the last.

    I made an internal thread cutting bit and a long boring bar for this project. They both worked well.
    F39FF9B5-8D18-447D-8C8C-C9FCA1C0CAB2.jpeg

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    It took quite a while to grind those tools, I spent a good 40 minutes in the cold garage on the bench grinder, another 40 in the shop with a dremel and finally about an hour polishing them on the Arkansas stone. My lack of experience likely plays a role here. With the bluing as well.

    I’m going to keep trying until I get it right.

    M.
     
    Old Rivers likes this.
  13. Old Rivers

    Old Rivers Registered User
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    Nicely done. I like it!

    Re. boring, I've found the MICRO 100 solid carbide miniature boring bars are terrific. They're pricey from the manufacturer but I've bought a few new ones on eBay for decent prices. They seem to last a long time, too.

    Bill
     

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