Announcement

Collapse
No announcement yet.

Backplate (pre-drilled and threaded)

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

  • Backplate (pre-drilled and threaded)

    For starters, I’m a novice,

    I want to buy a Bison 4-jaw universal independent plain back chuck for my EMCO Maximat Mentor 10 x 30. I haven’t been able to find (at least on-line like New England Brass & Tool or cataloges) a backplate that is already threaded (1 1/2" x 8) and (notice the AND) the mounting holes also drilled in the backplate. Any reason why they’re not?

    BTW, I understand you need to face the backkplate while on the lathe and how the register must fit correctly. Man, what a super steep learning curve everything seems to be.

    -SD:

  • #2
    My guess is that different chucks have different mounting hole locations.
    What I would suggest is that once you have the back plate machined for the chuck that you mark your holes with a transfer punch and then drill them on a drill press. Give a little clearance around the holes to make sure there will be no binding with the bolts.

    [This message has been edited by Treven Baker (edited 09-08-2004).]

    Comment


    • #3
      I think Bison may sell them, but probably a lot of places don't carry them. You might ask NE Brass & Tool to check for you, or look up Bison on the Internet and go through their online catalog. Unfortunately, it's NOT obvious to find if you search for "Bison" as the website is under another name "(Toolmax or something?) and it's not immediatley obvious that it's Bison. But it is there, if you search enough. If you can find the Bison number (assuming they do in fact sell what you're looking for) you could pass along the part number to NE B&T or whoever and say, "I want one of these."

      ----------
      Try to make a living, not a killing. -- Utah Phillips
      Don't believe everything you know. -- Bumper sticker
      Everybody is ignorant, only on different subjects. -- Will Rogers
      There are lots of people who mistake their imagination for their memory. - Josh Billings
      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
      Don't own anything you have to feed or paint. - Hood River Blackie

      Comment


      • #4
        Smokedaddy,

        This may not be your case but most people who ask me about making a backplate for a lathe think that the bolts are used for alignment of the chuck to the plate. This not the case - the bolts are used for clamping only. Actually machining your own backplate is easy.

        When you get the chuck it will have a recess machined into it. All you need to do is machine a lip on the back plate fit the chuck. If you thread a new backplate on your own or get one already threaded put in on your lathe and machine the lip. This way it will be “perfectâ€‌ for your lathe with the minimum of runout. That’s why they sell the backplate separately and not machined.

        Here’s a link that describes the process:
        http://www.metalwebnews.com/howto/ch.../chuckmnt.html

        Comment


        • #5
          Enco lists 1-1/2"-8 threaded backplates in 4" 5" 6" sizes (Bison brand). As was said above, they wouldn't be drilled as chucks will vary. I fitted one last week to an old 4"3 jaw that had a metric backplate and needed a 1-1/2"-8. I measured the bolt centers and drilled them on the rotary table.The bolt holes in the old backplate were somewhat larger than the bolts, so position is not super critical, as long as it's close. I had never turned cast iron before, what a mess!

          Comment


          • #6
            I thought "John S" idea of how to pick up the taped holes in the back of a chuck was a good tip.

            See here: http://bbs.homeshopmachinist.net//Fo.../006553-5.html

            Haven't figured how you use a transfer punch to get them when the backing plate covers the holes your trying to locate. Maybe Ive missed something?

            Comment


            • #7
              Super easy,all you do is get some allen setscrews,cup point or cone point are the best.
              Thread them into the hole backward with the points sticking out just .015 or so,slip the chuck onto the backplate pilot and pull the two together,once the chuck is bottomed out on the screw points take a brass hammer and give the backplate a good tap with it over each screw.Split the assembly and you should see either little circles or center punch looking marks where the screws dimpled the surface,then just drill as normal.

              They do sell transfer screws,but the setscrews work just as good and don't cost near as much.
              I just need one more tool,just one!

              Comment


              • #8
                As usual, thanks guys for all the tips and advise, it's really appreciated.

                On another note, if in addition to a 4-jaw independent chuck I purchased a Bison 3-jaw and 6-jaw SET-TRU chuck, should I get the largest that will fit on my lathe, like a 10", or go with a smaller 8" chuck?

                -SD:

                Comment


                • #9
                  Check the weight of the 10" vs the eight inch and then decide.
                  Free software for calculating bolt circles and similar: Click Here

                  Comment


                  • #10
                    <font face="Verdana, Arial" size="2">Originally posted by wierdscience:
                    Super easy,all you do is get some allen setscrews,cup point or cone point are the best.
                    Thread them into the hole backward with the points sticking out just .015 or so,slip the chuck onto the backplate pilot and pull the two together,once the chuck is bottomed out on the screw points take a brass hammer and give the backplate a good tap with it over each screw.Split the assembly and you should see either little circles or center punch looking marks where the screws dimpled the surface,then just drill as normal.

                    They do sell transfer screws,but the setscrews work just as good and don't cost near as much.
                    </font>
                    Yes yes Wierd thats exactly what John S's picture discribes. I understand that ok enough. But unless a transfer punch is something different to what I think it is I can't see how they work with a blind hole that you cover with the material you want to transfer to. Doesn't matter maybe I'm just stupid or something. (usually the problem)

                    Comment


                    • #11
                      Ah yes I see now "transfer screws" Ah yes, I'll just creap back under my rock and shut up.

                      Comment


                      • #12
                        I'm not fimiliar with the lathe in question, but I see it's discribed as 10x30 so I guess its 10" swing. You couldn't put a 10" chuck on that. Even an 8" would be pushing it wouldn't it? What about the jaws when they extend beyond the chuck body?

                        Comment


                        • #13
                          I was just going to mention that,great minds do think alike huh

                          Ya,the Bison catalog has diameter at max capacity,at somepoint the jaws will hit the carrage or the ways,question is will they be open to the chucks capacity when they do?

                          I got a Bison catalog at work,I'll bring it home tonight an look for you.
                          I just need one more tool,just one!

                          Comment


                          • #14
                            I was looking in the Toolmex catalog (no 2000, a little out of date) for a ready to use backplate for your 4 jaw Bison chuck and I do not see one for a plain back chuck. They carry one for DIN mount and other mounts, but not for just a plain threaded mount. There are semi-finished threaded adapters and rough adapters, but not a fully finished backplate. There is a threaded steel adapter for a "set-tru" chuck (6.25" chuck with 1.5" x 8 thread, part # 7-876-062). It looks nice and I can only imagine how much it must cost....there are no prices in this catalog, but you can call Rumford at 1-800-592-5912 and ask). Judging from the article in the latest issue of HSM byb Forrest Addy on what a 6 jaw Bison chuck costs you are going to have a real investment in chucks and backplates.

                            For a bit of contrast, I purchased a 3 jaw plain back chuck from JTS for $55 plus shipping (Ebay # 3838759065 )and purchased a piece of 1" x 6.5" round HRS for $10. These inexpensive Chinese made chucks are nicely finished and I can consistently mount it with &lt;.0015" TIR. It is not a Bison, but in more than 2 years of use it has proven itself to be an excellent bargin.

                            Comment


                            • #15
                              Told you I was a novice! &lt;duh&gt; Feel like a real dumb $hit.

                              -SD:

                              Comment

                              Working...
                              X