Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Results 1 to 10 of 10
  1. #1
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,537

    Default Proxxon Chuck on a Toyo ML-1

    Finally got the Proxxon three jaw chuck for my Toyo ML-1. Chuck register on spindle measures 21.99mm. Chuck itself is more like 21.98mm. It does not slip straight on and not game to use any force at all. If I freeze the spindle it may go on but then I may never get it off again. These chucks mount to spindle with three M4 bolts through the chuck face. After suggestions on what to do to make it fit without affecting the accuracy.
    Nev.

  2. #2
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,537

    Default

    For those who want more details on this chuck and the Toyo take a look here -

    https://metalworkforums.com/f65/t192...hlight=proxxon
    Nev.

  3. #3
    Join Date
    Jul 2016
    Location
    Melbourne
    Age
    35
    Posts
    1,523

    Default

    Have you got any other workholding for the lathe like a 4 jaw chuck or collets? Id turn a piece of stock in whatever you have, clamp the new chuck on that and just skim the new chuck ID.

    Sent from my SM-G973F using Tapatalk

  4. #4
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,537

    Default

    Toyo is still in pieces. No other chuck for it yet. The Optimum is still in trailer. Great idea though. I think I need less than half a though to make it fit. Very expensive little chuck so don't want to stuff it.
    Nev.

  5. #5
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,135

    Default

    Quote Originally Posted by SurfinNev View Post
    I think I need less than half a though to make it fit. Very expensive little chuck so don't want to stuff it.
    So a DOC of about .0002", I think that I would hold the chuck in a lathe and polish that out with some wet n' dry wrapped around a short length of rod.

  6. #6
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,545

    Default

    Hi, Guys,

    Silly idea and you would need to be very careful.

    Will the chuck grab a piece of bar with a few thou skimmed off to ensure that it is true to the spindle, and then polish off a couple of tenths with a round stone, say 600 or finer grit held in the tool post, just using the front edge of the stone. Lots of diesel fuel to stop the stone clogging.

    I've only done this once on a hardened steel shaft to make a bearing push fit rather than a very tight push on.
    Best Regards:
    Baron J.

  7. #7
    Join Date
    Aug 2010
    Location
    Toorloo Arm, VIC
    Age
    39
    Posts
    1,313

    Default

    Quote Originally Posted by BaronJ View Post
    Will the chuck grab a piece of bar with a few thou skimmed off to ensure that it is true to the spindle, and then polish off a couple of tenths with a round stone, say 600 or finer grit held in the tool post, just using the front edge of the stone. Lots of diesel fuel to stop the stone clogging.
    The problem with this approach is that 3 jaw scroll chucks inherently have some radial runout, no matter how good they are. While you could hold the bar in a 4 jaw, and then adjust the 4 jaw to get the register running true, or try shimming a jaw of the 3 jaw to get there, probably just as easy to set it up in the 4 jaw directly (time to get the Optimum out of the trailer?).

    I found a chuck for a Proxxon PD250 listed online, which specifies 0.04mm concentricity. If that is the runout spec, even if it chucks up at half that, you're still going to be taking the 0.01mm on diameter just from one side. From memory this runout 'moves' around the chuck depending on workpiece diameter etc, so it won't get canceled out by cutting the register to match it, and in some situations it will be additive.

    The 'good' news is that if I understand the style of mounting correctly, overshooting the target diameter is probably not going to be the end of the world and a ruined chuck, it just means the chuck just becomes a 'poor mans set tru'.... May not be the fit you wanted, but in some ways a better solution, and certainly easier.

    If you ended up at say 22.1mm, with a chuck runout spec of 0.04mm, that would mean you should be able to bump the chuck 100% true for any workpiece clamped in it, even after a little bit of wear....

  8. #8
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,545

    Default

    Hi J&H, Guys,

    I 100% agree with you !

    In my case I held the bar in soft jaws, so runout wasn't an issue and that is why I said taking a skim off the bit of bar that you were going to use as a mandrel. But you are right half a thou runout at worst is two and a half times greater than the amount of material that is wanted removing.
    Best Regards:
    Baron J.

  9. #9
    Join Date
    Aug 2010
    Location
    Toorloo Arm, VIC
    Age
    39
    Posts
    1,313

    Default

    Quote Originally Posted by BaronJ View Post
    In my case I held the bar in soft jaws, so runout wasn't an issue and that is why I said taking a skim off the bit of bar that you were going to use as a mandrel.
    That doesn't solve the issue of the runout in the new chuck that needs modifying though, which is where the potential problem arises. The approach you mentioned can be a valid solution for the right circumstances (like facing off the flat mating face for example), but clamping the new 3 jaw onto that machined stub will only get the register on the back that needs modifying running as concentric as the new chuck happens to run for that diameter. Axially it should run perfect if it's a good quality chuck and the machined bar has no taper, but radially it's going to have some amount of runout.

    Probably not that clear from my previous post, but that is what I was getting at, for best results if you're using a tool rigidly fixed to the toolpost you need some way of dialing out whatever runout the new 3 jaw has (hence my comments about holding the bar in a 4 jaw, or shimming the jaws of the new (added for clarity) 3 jaw chuck with paper to get the register running dead nuts. Of course that assumes that the central point of the chucks runout is concentric to the register to begin with. You would certainly hope so on any decent chuck, but....

    Polishing it with a hand held tool in theory mostly removes this consideration. Creates some slightly different ones to do with how consistent you are with angles and pressures, but that's a bit beside the point...

    Or ignore it all, and deliberately bore a touch oversize for a poor mans set true, if the mounting style allows it as I suspect it does. A decision for the OP.

  10. #10
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
    Posts
    1,537

    Default

    Thanks to everyone for the replies. A bit to think about and not going to rush it. The chuck was just over $300. Was lucky to get one, as they are now very hard to find. The original Toyo impossible to get. Considering the four jaw proxxon as well, but having trouble finding them anywhere as well now.
    Nev.

Similar Threads

  1. 4 jaw chuck
    By outoftown in forum THE HERCUS AREA
    Replies: 1
    Last Post: 12th Aug 2020, 11:40 PM
  2. collets : to chuck or not to chuck
    By steamingbill in forum METALWORK GENERAL
    Replies: 4
    Last Post: 26th Jul 2014, 10:17 PM
  3. which proxxon?
    By jack620 in forum METALWORK GENERAL
    Replies: 17
    Last Post: 30th Dec 2011, 09:49 PM
  4. New 3 jaw chuck
    By Tiger in forum METALWORK GENERAL
    Replies: 5
    Last Post: 24th Sep 2008, 10:17 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •