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R/Table chuck mount ???

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  • R/Table chuck mount ???

    Hey you all! I finally got a chuck for my R/T. Paid way too much for a Buck 5" on Ebay (lol...bidding fever..."You ain't beatin me sucker!!!") Nice chuck though..seen very little use. I've had it sitting on my 6" table all afternoon, oogling it and trying to figure how to mount it. Was going to mill horizontal slots in it directly above the T-slots and use bolts/clamps to hold it down with. Now I think I may just turn a plate, bolt it to the back of the chuck then bolt this into T-nuts in the table..probably a stiffer setup than the slots milled into the side of the chuck. All seems simple enough. Now I have a new brainwave...I've searched and can't find out if this would work. Why can't I turn a MT #2 plug that would fit into the center hole of the table that has a straight section that sticks up through the chuck jaws. To center the chuck to the table I could just tighten up the chuck jaws on the straight part of the plug and it should center it's self. If the plug was seated firmly and indicated to zero then the chuck should center to whatever accuracy it was capable of anyway..right? Then just tighten down the bolts holding the new backer plate down. Any thoughts? Thanks!
    I have tools I don't even know I own...

  • #2
    Russ if it was mine I would use the backing plate, but you may want to check the back of the chuck and see how parallel it is to the jaws. Yes it is easy to get that bidding fever.
    Don\'t ask me to do a dam thing, I\'m retired.


    • #3
      Charlie...good point! I never thought of that. If I chuck up a 1 1/4" or so rod in my 4 jaw...indicate to zero, then tighten the 3 jaw onto that in the lathe and indicate the back...would that be an acceptable way to check right angle of the jaws to the backing plate? I don't have a surface plate.
      I have tools I don't even know I own...


      • #4
        <font face="Verdana, Arial" size="2">Originally posted by torker:
        . Why can't I turn a MT #2 plug that would fit into the center hole of the table that has a straight section that sticks up through the chuck jaws. Russ</font>
        I duno why you can't..

        I would make a backing plate with a 2 morse taper on it and use that to attach the chuck to the table.

        Precision takes time.


        • #5
          I put the chuck on my rt, with a plate. I drilled the center out and since the rt has a through hole I can pass a car axle throught it. It is next to my cnc machine on the floor waiting on it's next motor drive.
          I have mounted two motors onto it now. Not having much luck, I guess I should've stayed with the geckodrive and first stepper.

          The real small one I bought I built a mount for it to carry a toolpost on the lathe, you can rock it back and forth and it cuts a neat lil arc or ball, or indention according to the raduis it is set back on. I built it to cut wheels for my english wheel. So far the finish is not that great.
          I saw something neater than that thou, a conversion for a regular compound slide that bolts to the factory one and rotates it. Does not affect regular lathe operation. The play in the HF rotary table makes for some chatter and ruins the finish.

          I adgree, if the Morse taper runs out true it would stop the "half" hour of setup my big table requires.. I tap it this way with the brass hammer, then tap it that a way.. yeah?


          • #6
            Ringer...I need to have the through hole for a lot that I want to do. That's why I want to remove the plug after the setup.
            David..I hear you about the brass hammer. That's how I've been lining things up on this table that are held down with clamps etc. Pretty frustrating sometimes!
            I have tools I don't even know I own...


            • #7

              I mounted my 3.5" Bison onto a backplate attached to a MT#2 shank - don't you dare mangle that Buck chuck up! (worth too much, man) - turn a backplate for it you lazy bum! Even 1" aluminum plate is better than nothing and will work just fine. If you are stuck I have a chunk laying about somewhere you can pick up (along with that power supply) - might cost you a cheezeburger though...


              • #8
                Hahahahaha...Thanks Dave !!! I was sorta thinking it might be sacriligious to mill slots in the side! A backplate it is then! Hmmm maybe a use for one of the 6" X 1 1/2" alu discs I got from Sandman! I finally got the motor mounts made for the quill feed, just have to mount the shaft/ bearings for the secondary shaft and it's ready to try. Then I can see what kind of amps it'll draw.
                I have tools I don't even know I own...


                • #9
                  Hi Russ

                  Things will be a little tight fitting a 5" chuck to a 6" rotary table, but I would suggest a 6" cast iron backplate with machined register to locate the chuck, countersink the chuck mounting bolts on the underside of the plate. Turn a spigot on the underside to match your tables centre bore to provide a repeatable concentric mounting & drill the plate for the T nut bolts.

                  Here is my 10" table showing the underside of the chuck adapter plate which takes a 6-1/4" chuck.


                  Here is a view of the plate mounted on the table


                  However, it occurs to me that if your table only has the MT2 centre bore it would be better to provide a register for the back plate to your tables O/D, then you could bore the centre hole of the back plate to the same size as the chuck bore, this obviously assumes that the O/D of your table is concentric with the MT2 centre bore. This would require a finished back plate diameter of 6-1/2" or just enough to clear the table locking clamps.

                  Having made a few of these over the years I would suggest the following procedure gives the best results assuming a lathe & a vertical mill are available.

                  1/ Even if the backplate blank is rough cast mount it on the lathe in a 4 jaw chuck with outside jaws, face off, then bore to size the desired centre hole. Then turn up a piece of bar to a diameter about half a thou larger than finished centre hole, make this to a length equal to the thickness of the plate plus twice the depth of the chuck jaws, centre drill both ends of the bar taking care to get both exactly concentric. Leave the bar somewhere cool & place the backplate on top of a radiator for a couple hours, then press the bar in to the back plate with an equal amount protruding each side.

                  2/ Mount the back plate in the 4 jaw gripping the bar with the faced side of the plate towards the chuck, finish turn the O/D, then face off incorporating the outer locating shoulder to exact size, you can cut into the bar a little to get a full face, better to be a tad tight than slack on the locating diameter.

                  3/ Having checked that the vertical mill head is trammed spot on mount the rotary table in the preffered orientation & centre exactly with the quill. Fit the back plate to the rotary table & drill for the T nut bolts making sure the PCD is slightly larger than the chuck O/D plus a bolt head diameter to give clearance for installing the bolts when the chuck is mounted to the back plate. Bolt the back plate down ready for machining the chuck register & mounting face.

                  4/ Using a suitable sized square edged milling cutter face the plate incorporating the chuck register shoulder, to a snug fit, using rotary table & the X axis of table travel leaving the Y axis securely locked.

                  5/ Before removing the plate mark it to coincide with a suitable division on the rotary table, then offer up the chuck & decide the most suitable orientation for chuck key clearance etc, mark the position then remove & drill the chuck mounting holes & conterbore.

                  This gives a nice quick & repeatable set up using a mandrel made to fit the quill & either the centre bore of the table or the backplate bore for centering although I'm sure there are several other popular methods.



                  [This message has been edited by pistonskirt (edited 01-12-2005).]


                  • #10
                    The back plate is essentially just an adapter, not a necessity. You can use the three through holes that would be used to mount it to a back plate. This will keep the setup short (more rigid) and simple. Cutting a groove in the table to center the chuck may be a little too barbaric, but three tapped holes should be civilized enough.


                    If ya wannit done your way ya gotta do it yourself.


                    • #11
                      I seem to remember an article in HSM using such an adapter to align a chuck on a rotary table. It included tapping the table for mounting as well.

                      But, at risk of being called pedantic, I would recommend spending some time in practice in the use of indicators for centering on the milling machine. It really only takes a minute or two to accomplish using much the same methods as you would use to center work in a four jaw chuck.

                      The easiest method is to invest in a Blake Co Axial indicator, but other indicators can be used.

                      I have mounted a chuck on a square of aluminum, and use the R/T Tee slots to bolt down. I center the table to the mill spindle using the center hole, loosely bolt the chuck in place and tap into center, indicating a ground shaft or dowel pin held in the chuck jaws.
                      Jim H.


                      • #12
                        A 5" chuck on a 6" table is only going to leave you 1/2" to bolt down to your table. That makes me think you will only be able to use 1/4" shcs.
                        4 jaw chucks can be drilled and countersunk from the face of the chuck for mounting onto a R/T. But being a three jaw chuck it may not be possible. Might be worth investigating though.
                        Just my .02 cents.

                        Paul G.
                        Paul G.


                        • #13
                          Geezus H. Murphey there is a great big jesus hole in the middle to pass a bolt through the back and a countersunk allen screw and washer assembly will do just fine. Then all you neeed is a dog on the back plate to engage one slot to prevent turning and it won't go anywhere. There are other ways too. Front mounting a 4- jaw would be my FIRST CHOICE - if I had a spare...

                          Ah crap - time for my Lou Dobbs daily rant...


                          • #14
                            What you suggest in my opinon would work or maybe lay the chuck on the RT and place a dial indicator on the face of the chuck and see what happens as you rotate the table.
                            Don\'t ask me to do a dam thing, I\'m retired.