Announcement

Collapse
No announcement yet.

Need 4 jaw recommendation...

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Need 4 jaw recommendation...

    Used my 4 jaw for the first time recently, and this thing pretty much defines Chinese crap :-). Add in that it looks and feels like it's been hammered, literally, and I need to think about a replacement, and I could use some guidance.

    What I have is an 8" with independent jaws. My lathe is a 12x24, would I be foolish to go to a 10"? Much as I'd like them, I don't really need 2 pc. jaws or a Set Tru type setup, just a well machined chuck that doesn't require a 4' cheater bar to adjust the jaws. My spindle is threaded 2 1/4"-8, I doubt I'll find one with a threaded mount, so plain back is probably my only option. In 8" chucks, I see prices ranging from just over $100 to over $1000. Needless to say, I want to stay toward the bottom of that range. Thanks in advance, guys.

    Dave

  • #2
    Generally speaking.....

    Price is directly related to accuracy. With a 4 jaw because you set it true you don't normally have a "set true" option. Where on a three jaw chuck the accuracy of it's centering is a big consideration with the 4 jaw it's about the jaws holding the material in lateral alignment. That is when you get out to the far end of your material is it still spinning on a true axis through the center of the material.

    The other thing you'll be paying for is the quality of the materials used in the
    product. In production this is a serious consideration I would expect as a home user this will be less of an issue. My understanding is that some of the products out of east europe are pretty good (i.e. poland, romaina etc)
    but I'd be open to an update on that.

    In my opinion...better a good used chuck than a new poor quality chuck.

    The reality is how much accuracy do you need in the work you're doing.

    Just a thought...do you know your chuck is bad or is it just ugly...they're not always the same thing. The other thing is that if it's not moving smoothly you can take it apart, clean it and relubricate it for better function. You can also do a minor regring on the jaws if they need truing up.

    If you want more info drop a line.
    Allans Rule: Anything worth doing is going to be a pain in the butt.

    Comment


    • #3
      My spindle is threaded 2 1/4"-8
      IIRC that is not that "rare" so good condition used may not be out of the question...I THINK that is the size of large bore South Bends (Heavy 10?) and if so, it becomes more accessible if a bit pricey.

      Comment


      • #4
        It would have to be a pretty sad 4 jaw not to be usable. Accuracy in the chuck itself doesn't really matter too much. You can do as accurate work in a worn out 4 jaw as a new but the work will go quicker in the new chuck.

        The mistake many make in using a 4 jaw is "swallowing" the work setting it far back in the jaws seeking greater rigidity. Jaws are never uniform in "splay" that is the knurled grip for each jaw is a differing a bit out of parallel with the spindle axis. Thus it always grips at the heel and the uneven splay causes the work to seek the average of the splay and it nutates.

        I wrote an article on the use of a 4 jaw chuck and the points I make here are illustrated therein. I'll send it as a .doc file to any who send me an email addy to [email protected] and title it: Attn 4 jaw. I'll throw in the 3 jaw article too.
        Last edited by Forrest Addy; 04-17-2012, 09:47 PM.

        Comment


        • #5
          I've a 10" on my SBL, and it's about all I can handle, and I'm a pretty big dude. The older I get the more I wish I had bought an 8". Those couple extra inches are a BUNCH of extra pounds.
          I'm here hoping to advancify my smartitude.

          Comment


          • #6
            Weight goes up with the cube of the size increase. 7 ft 250 lb b-ball players look SKINNY.

            A 10" 4 jaw should be double the weight of an 8" chuck other things being equal
            Last edited by Forrest Addy; 04-18-2012, 09:27 AM.

            Comment


            • #7
              There are light and heavy pattern chucks too.

              Comment


              • #8
                Originally posted by Bryan B
                There are light and heavy pattern chucks too.
                Which is why I qualified with "other things being equal." But I should have addressed however briefly light and heavy pattern chucks.
                Last edited by Forrest Addy; 04-17-2012, 11:44 PM.

                Comment


                • #9
                  I generally default to Bison brand chucks. i.e. Made in Poland---careful, the Toolmex labeled ones aren't. Bisons aren't as affordable as they used to be, but they are still a very solid price/quality ratio from my perspective. In general, I think people tend to go too big with their chuck size to swing ratio. I would highly discourage a 10" chuck for a 12" lathe.

                  Comment


                  • #10
                    Thanks, guys...

                    I really appreciate the responses. I especially appreciate the reality check for the 10" vs. 8", I'll be staying with an 8". And yes, I would certainly be open to a good used chuck if someone has one that needs a new home.

                    I'm still very much a newb when it comes to this stuff, but this chuck is definitely beyond simply ugly. I believe it's been dropped more than once over the years, and has sustained damage that makes it very difficult to use. I've made some "repairs" that have made it useable, but I'm sure what I've done hasn't extended it's useful life any :-). Of course, now that I've finally used a 4 jaw, it's opened up a whole 'nother world of projects that can only be done with a 4 jaw, so I need one that will help me work, instead of make more work for me. Thanks again.

                    Dave

                    Comment


                    • #11
                      If you buy a 10" chuck for a 12" lathe you may find the jaws hit the ways before you can open them enough to grip anything over 2" diameter or so.
                      Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                      Comment


                      • #12
                        Originally posted by Black_Moons
                        If you buy a 10" chuck for a 12" lathe you may find the jaws hit the ways before you can open them enough to grip anything over 2" diameter or so.
                        I bought a 10" Pratt Burnerd 4-jaw for my Harrison L5 by mistake. Fortunately the description was wrong and it was actually 9". The jaws were identical to my 8" Pratt Burnerd, so the work holding capacity without fouling the ways was identical. They were of course better supported by the larger body.

                        Why was I buying a new chuck to replace another good chuck? The original chuck used a backplate, whilst the new one had an integral L00 mount.
                        Paul Compton
                        www.morini-mania.co.uk
                        http://www.youtube.com/user/EVguru

                        Comment


                        • #13
                          There is someone selling Vertex brand 4 jaws on E Bay at the moment. They are (?) made in Taiwan and I would expect good build quality based on my 6" R/T. The price is reasonable, too.

                          Geoff

                          Comment


                          • #14
                            Originally posted by Forrest Addy
                            Which is why I qualified with "other things being equal." But I should have addressed however briefly light and heavy pattern chucks.
                            I didn't mean to be pedantic. I meant to suggest that a light pattern 10" might be a compromise for those worried about weight. I find mine quite manageable, and I'm old enough to dislike heavy lifting.
                            Last edited by Bryan B; 04-19-2012, 06:51 AM.

                            Comment


                            • #15
                              I know what you mean, Bryan. Who would think my Buck 12" 4 Jaw could doubled its weight in the last few years. When I was 30 it was just a medium fift from floor to spindle. Now I have to lift it in stages. Looks like I gotta build a chuck crane. Hm. Maybe one that stores all my chucks -3 jaw, 4 jaw, little 4 jaw, collet - so when I have to swap I just swing them in and out of position. Lessee.... (Blank stare out the window; meanwhile, a dozen basic concepts flash before my mind's eye.)
                              Last edited by Forrest Addy; 04-19-2012, 09:43 AM.

                              Comment

                              Working...
                              X