PM 8" 4 jaw chuck
Close
Login to Your Account
Results 1 to 16 of 16
  1. #1
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default PM 8" 4 jaw chuck

    Greetings, I'm new here and just as new to machining. First off I'd like to say thanks to all contributors on this site. The amount of information I've learned here is priceless.

    Now as for my most recent issue. About a month ago I purchased my very first lathe Pm1228. The lathe and all the tooling I've recieved have been great so far aside from a few blemishes and what not I've been totally happy with the machines performance. Been learning a lot and was working exclusively with the 3 jaw that comes with the lathe until a couple days ago I decided to try out the 4 jaw I purchased from PM in addition to the lathe.

    Right away I noticed the threads for the scrolls are a lot more stiff then the 3 jaw I recieved from them. Odd as everyone raves about the quality of Taiwanese products compared to Chinese products. Anyways after fiddling around with the studs I noticed that one of the cams would engage at a different spot then the other two when mounting it to spindle. When I ran the lathe It looked like something was wobbling and I was experiencing slightly more vibration. Being a newbie I didnt check the run out of the OD of the chuck or the back. I guess i just trusted PM wouldn't put out a weak product(not saying the verdict it out). Anyway I took a face cut of .032" and it was beautiful. Then i went to turn the diamater with a .060" doc and bang instant chatter. As bad if not worse than when I part and dont feed fast enough. I flipped the power feed off quickly but Figured it was rubbing and reduced doc to .050". It was better but still not even close to what I was getting with 3 jaw. Decided to check run out of OD of chuck and sure enough it was out about .002". I removed and reinstalled then camlocks tightening the in a more incremental fashion and reduced the run out to about .0015" but ran out of time last night to try and zero it in. Honestly one of the camlock studs was all nasty and had a little rust while still in the packaging and it threw me off. Like why is this company with a phenomenal reputation sending me stuff from tawain which also has a good all around reputation that has rust on it while its still in original packaging. While i was installing the camlocks doing the whole if it falls between 6 and 9 or 1 t to 3 thing I noticed the indicator ring(for lack if a better term) on one of the camlock studs is at a different height along the stud vs the other two. For instance when the studs are bottomed out in the threads the indicator ring sits higher then the other two. So obviously when it its position to lock it's at a different height. I have a feeling one of my locking studs is just off.

    After doing this I checked the nose onnmy spindle to see if I possibly damaged the surface running a chuck off center but it was like hardly registering any movement on my .001" indicator so probably less than .0002". Is there anywhere else I should check for damage? It looked like it was good but I'd just like to make sure. Very frustrating to pay extra for something and it doesnt even work right out of the box. The chuck manual says less than .00098"of runout. This is frustrating

    I'm going to run home for lunch and mess around with it but I feel like it shouldn't be so questionable. A quick google brings up a youtube video of someone last year having exact same issue. Also other mentions of people having issues with the scroll threads being all out of whack. LoL after all typing I guess I'm just venting cause all i can really do is screw around with the camlock stud positioning which I already have quite a bit as well as tighten it more incrementally. To me its wonky that the damn thing is that sensitive if that's the case. I've already been pretty careful not to tighten the cams unevenly.

    Guess I'm just looking for people who have had good or bad experiences with the PM 8" 4 jaw chuck. LmK thanks

  2. #2
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    31,232
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    9807

    Default

    Quote Originally Posted by nighthawkFmobil View Post
    Greetings, I'm new here and just as new to machining. First off I'd like to say thanks to all contributors on this site. The amount of information I've learned here is priceless.

    Now as for my most recent issue. About a month ago I purchased my very first lathe Pm1228. The lathe and all the tooling I've recieved have been great so far aside from a few blemishes and what not I've been totally happy with the machines performance. Been learning a lot and was working exclusively with the 3 jaw that comes with the lathe until a couple days ago I decided to try out the 4 jaw I purchased from PM in addition to the lathe.

    Right away I noticed the threads for the scrolls are a lot more stiff then the 3 jaw I recieved from them. Odd as everyone raves about the quality of Taiwanese products compared to Chinese products. Anyways after fiddling around with the studs I noticed that one of the cams would engage at a different spot then the other two when mounting it to spindle. When I ran the lathe It looked like something was wobbling and I was experiencing slightly more vibration. Being a newbie I didnt check the run out of the OD of the chuck or the back. I guess i just trusted PM wouldn't put out a weak product(not saying the verdict it out). Anyway I took a face cut of .032" and it was beautiful. Then i went to turn the diamater with a .060" doc and bang instant chatter. As bad if not worse than when I part and dont feed fast enough. I flipped the power feed off quickly but Figured it was rubbing and reduced doc to .050". It was better but still not even close to what I was getting with 3 jaw. Decided to check run out of OD of chuck and sure enough it was out about .002". I removed and reinstalled then camlocks tightening the in a more incremental fashion and reduced the run out to about .0015" but ran out of time last night to try and zero it in. Honestly one of the camlock studs was all nasty and had a little rust while still in the packaging and it threw me off. Like why is this company with a phenomenal reputation sending me stuff from tawain which also has a good all around reputation that has rust on it while its still in original packaging. While i was installing the camlocks doing the whole if it falls between 6 and 9 or 1 t to 3 thing I noticed the indicator ring(for lack if a better term) on one of the camlock studs is at a different height along the stud vs the other two. For instance when the studs are bottomed out in the threads the indicator ring sits higher then the other two. So obviously when it its position to lock it's at a different height. I have a feeling one of my locking studs is just off.

    After doing this I checked the nose onnmy spindle to see if I possibly damaged the surface running a chuck off center but it was like hardly registering any movement on my .001" indicator so probably less than .0002". Is there anywhere else I should check for damage? It looked like it was good but I'd just like to make sure. Very frustrating to pay extra for something and it doesnt even work right out of the box. The chuck manual says less than .00098"of runout. This is frustrating

    I'm going to run home for lunch and mess around with it but I feel like it shouldn't be so questionable. A quick google brings up a youtube video of someone last year having exact same issue. Also other mentions of people having issues with the scroll threads being all out of whack. LoL after all typing I guess I'm just venting cause all i can really do is screw around with the camlock stud positioning which I already have quite a bit as well as tighten it more incrementally. To me its wonky that the damn thing is that sensitive if that's the case. I've already been pretty careful not to tighten the cams unevenly.

    Guess I'm just looking for people who have had good or bad experiences with the PM 8" 4 jaw chuck. LmK thanks
    Wise to delete all mention of "Piss-is-on-yah, Matthew!", LSO (Lathe Shaped OBJECT).

    See site rules on discussion of hobby-grade scrap-metal.

    Feel free, OTOH, to research D1 camlock philosophy, fit, and adjustment - of which there is plenty of info here, much of it in the Monarch forum.

    Chucks as well. Some are better than others. And there really ARE "bad ones", too.

    Whether you "got what you paid for" or not, you will now be "paying for what you got", going forward.

    Take it as a learning experience. All part of life's bitch travesty.


  3. #3
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    My apologies if my post was out of line. Thanks for the reply.

  4. #4
    Join Date
    Jan 2005
    Location
    Houston
    Posts
    6,243
    Post Thanks / Like
    Likes (Given)
    787
    Likes (Received)
    3005

    Default

    lathe shaped object, lol!

  5. #5
    Join Date
    Aug 2004
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    2,467
    Post Thanks / Like
    Likes (Given)
    179
    Likes (Received)
    980

    Default

    That's the main reason why I prefer an independent four jaw over one with a scroll. If everything else is set up properly, you should be able to dial in an independent chuck dead nuts on. Anything wonky in the scroll, in my humble opinion, negates the value of a four jaw.

  6. #6
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    Quote Originally Posted by crossthread View Post
    That's the main reason why I prefer an independent four jaw over one with a scroll. If everything else is set up properly, you should be able to dial in an independent chuck dead nuts on. Anything wonky in the scroll, in my humble opinion, negates the value of a four jaw.
    Yessir, this one is an independent 4 jaw forgot to add that. I've tried putting the studs at all spots along the threads that I possibly could at all the positions on the clock and I'm gettin better results but still out on the back side of chuck like .0045". The wobble is way less and almost not noticeable but its annoying. I'm afraid to take a cut and fuck something up. Something tells me the taper surface on the chuck is the wrong size. I dont feel I should have to sand it down to open it up.

  7. #7
    Join Date
    Oct 2009
    Location
    Louisville, KY, USA
    Posts
    996
    Post Thanks / Like
    Likes (Given)
    214
    Likes (Received)
    219

    Default

    the OD of the chuck is not important (unless it's so far out it creates balance issues) what's important is whether the work is centered. Since it sounds like you have a four jaw scroll chuck I'd check the runout of different sized rounds. (Usually for jaw implies an independent chuck where each jaw has its own screw) If the runout is in the same place for multiple sizes the error is in the chuck mounting, if it moves around it's in the scroll.

    Traditional wisdom holds that anything less than.003" is pretty good for a scroll chuck.

  8. #8
    Join Date
    Jul 2004
    Location
    Houston, TX USA
    Posts
    30,857
    Post Thanks / Like

    Default

    this one is an independent 4 jaw forgot to add that
    Then it has no "scrolls"

    It does have jaw screws

    Since you refer to cams, etc., I'll suppose it has a D1 type spindle nose. These were made at least from D1-2" to D1-11", and there are dimensions and tolerances published for such things in such as ASA/ASME B5.9 Spindle Noses.

    If you have already been cutting on your fourjaw in these areas that does not sound hopeful at all

    You can identify the SIZE of your D1 by the cam pin diameter screwed into the chuck. For instance on a D1-3", the cam pin O.D. will be .563"

  9. Likes eKretz liked this post
  10. #9
    Join Date
    Mar 2005
    Country
    UNITED STATES
    State/Province
    Indiana
    Posts
    4,753
    Post Thanks / Like
    Likes (Given)
    1254
    Likes (Received)
    1185

    Default

    Sounds like it's not seating correctly. As John alluded, you'll need to investigate the mating surfaces to find out why not. Could be a ding with a raised bit of metal preventing proper seating or could be that some dimension is incorrect. Check it. Tightening the cam locks slightly unevenly should not affect runout much. Check that the flat part of the chuck is seating against the flat part of the spindle nose all the way. If not, you have a problem in the taper of the chuck or the spindle nose. The chuck should seat on the taper first then draw up flush on the flat when the cam locks are tight.

  11. #10
    Join Date
    Sep 2009
    Location
    Phoenix,AZ
    Posts
    1,861
    Post Thanks / Like
    Likes (Given)
    2866
    Likes (Received)
    483

    Default

    You DID clean and lube the jaws/screws ? Second call up the seller of the lathe and talk to them. Even the best quality machines will sometimes get outside vendor supplied parts that have issues.

  12. #11
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    Yes, I made the mistake of referring to them as scrolls. Thanks for pointing that out so I dont do it again.

  13. #12
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    It's has to be the taper of the chuck. My 3 jaw sits perfectly fine but if I put sharpie on my spindle the depth of sharpie that makes it onto the chuck isnt deep enough for the flats to he mating correctly.

    I think I'd rather get a refund and buy something more ready to go even If i have to spend more. Unless the company wants to let me take Emory paper to it without risk. The jaw screws are kind of rough to turn as well.

  14. #13
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    I cleaned and lubed the jaw screws. Still quite a bit tougher to turn vs the 3 jaw I got.

  15. #14
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    7
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    0

    Default

    It's a d1-4 camlock

  16. #15
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    31,232
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    9807

    Default

    Quote Originally Posted by nighthawkFmobil View Post
    Yessir, this one is an independent 4 jaw forgot to add that. I've tried putting the studs at all spots along the threads that I possibly could at all the positions on the clock and I'm gettin better results but still out on the back side of chuck like .0045". The wobble is way less and almost not noticeable but its annoying. I'm afraid to take a cut and fuck something up. Something tells me the taper surface on the chuck is the wrong size. I dont feel I should have to sand it down to open it up.
    D1 (and its twin, A-series) use a VERY precise combination of "American Standard SHORT taper" and a flat. The taper is meant to be an interference fit.

    EG: As the camlock studs (D1) OR the face bolts (A series) draw the backlate taper up the spindle taper it grows seriously TIGHT, meant to hit its target AS it approaches the flat, but only just BARELY touch it. If it hits the flat before "wedging" tight and true, the fit is WRONG.

    On any NEW lathe, even an "economy model", that is more often on a cheaper, mass-produced, backplate than on the spindle itself.

    ANY "wobble" and you do not have a proper fit.

    D1 camlocks draw-in from 12 o'clock toward 6 o'clock, then LOOSEN AGAIN from 6 o'clock back to 12 o'clock.

    Your goal as to adjusting each stud is that it does its work in the second quadrant. That it starts to take-up by 3 o'clock, and will be locked before it reaches 6 o'clock. Take 4:30 as a goal. Get as close as you can.

    You will have metric threads on your camlock studs, just a skosh less strength than coarser US ones, but also a skosh finer adjustment.

    This is all well-covered, and more than once, over in the Monarch forum on PM. You do not have to own a Monarch to be allowed to read it.

    First, get a good understanding of how it is MEANT to work. THEN you can better assess what, if anything, is WRONG.

    Or perhaps solve your problem cheaply and rapidly with nothing more than a bit closer attention to "timing" your camlock studs?

    IF.. you have been going at EITHER the spindle nose OR the backplate with abrasives? NOW you have a problem.

    New backplates are often under a hundred bucks.

    Repairing a damaged D1 spindle is harder. Tedious, finicky, precise, and wanting of extreme patience and care in measurement and action. But not mysterious.

    That, too, is covered, Monarch forum, 'coz our lathes tend to have a LOT of age and wear.

  17. #16
    Join Date
    Oct 2003
    Location
    East Peoria, IL, USA
    Posts
    5,414
    Post Thanks / Like
    Likes (Given)
    354
    Likes (Received)
    810

    Default

    the OD, back of chuck mounting plate etc... none of those are important in the least and .004 is quite good.

    learning how to personally adjust your chucks cam pins to get them to lock up at the correct spot is important, and EXPECTED. Who knows what chuck you may mount to what lathe and everything has tolerances. Make sure your tightening the cam-locks in the correct direction also. That is easy for a new guy to mess up, -and dangerous.


Tags for this Thread

Bookmarks

Posting Permissions

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