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  • Who has a Benchmaster? Question or two..

    Bought a Benchmaster horizontal today at an estate sale, for an asking price that was low enough that even my wife said "buy it". Dunno just why, I have a mill, and if I was adding, I'd want a vertical...... but maybe I can swap with someone who wants the horizontal spindle... or sell this when I clean it up. Jury is out, but the mill not having back-gears is pushing towards the 'sell it quick" area, if I don't find a vertical head.

    Anyway...

    The thing I have in pieces, being cleaned of years of crud, and a little rust on some bits. I had to disassemble to get it out of the shop it was in.

    Aside from a lot of dirt, the way surfaces appear to be barely worn, I don't think they were scraped much if at all, they still have some machining marks, but too much material left for that to have been a later re-machine job.

    I WANT to pull out the leadscrews, but they don't want me to do it. They are full of dirt and crud, and I want to clean the bearings out.

    I would also like to adjust them, as they have about 40+ thou of slop, just about ALL of it in the collar adjustment.... the screws and nuts are GOOD.

    The collars appear to be intended to unscrew, although there is barely a quarter thread visible, if that. Just the hint of a thread on the shaft. They each have a setscrew, those are out. The setscrew in each case was squashing a brass plug against the threads that should allow adjusting the nut, or removing it.

    Can anyone confirm the "unscrew" theory?

    I think the brass is squashed and extruded into the threads and maybe the space between collar and shaft.....

    How the &^%$! does one get a brass plug out from inside the threaded hole in a steel collar, when none of the parts have much you can grab without damage?

    So, here is the table one, exploded as far as it will come apart......



    Close up of collar. You can see plug, with setscrew in background.



    Crossfeed screw collar and end.



    Closeup of crossfeed collar, you can see the &^%* plug on this one also. And a decent view of the swarf and dirt in it.




    They didn't waste money on these.... the dials are zamak, held on the screw with a taper pin that does double duty as the handle clutch. Everything else is taper pins also.... and not so easy to tell which is the big and which the small..... I have inadvertently been a "big-endian" a couple times.

    I do like the table locks, they work fine. I intend to copy them for the other mill.
    Last edited by J Tiers; 06-26-2010, 11:45 PM.
    1601

    Keep eye on ball.
    Hashim Khan

  • #2
    I suspect those collars are just pushed on. I can't see evidence of threads, just rust. But just to be sure, why not clamp the leadscrew in a vice sandwiched between blocks of some softwood, then attempt to unscrew the collars. At the least you will be able to get them loose, then if they are threaded you know what the adjustment method is. Once they are apart you can decide if you want to add thrust bearings of some sort.

    To avoid marking up the outer surface with the vice grips, put a strip of aluminum around the collar first, then clamp down over that.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

    Comment


    • #3
      No rust, just dirt, old oil, maybe trick of the light, even though I used flash. Rust in other places, NOT on the screws.

      As for the thread, maybe I get a better picture and you will see the tail off of the thread.....

      Why not put in a vise? Well because in one case, the screw is down inside a casting where there is no room for a vise. I already tried a gear puller, no go.

      But, no sense working as if there is a screw if in fact no screw is there... hence asking Benchmaster owners if they can confirm it.

      Also very little reason to have the brass plug if no screw threads......

      here is a picture that shows the thread end..... sorry for bad focus, this camera gives little choice, I tried to get it to focus on the scriber, but no luck.

      1601

      Keep eye on ball.
      Hashim Khan

      Comment


      • #4
        Just a random thought, could you use a pin-spanner on it without mucking the threads in the hole???

        fred

        Comment


        • #5
          Originally posted by J Tiers
          How the &^%$! does one get a brass plug out from inside the threaded hole in a steel collar, when none of the parts have much you can grab without damage?
          I think I would try washing the brass plug in the hole with some brake cleaner to remove any grease/solidified oil and maybe help loosen up their grip on the plug, then I would stick an appropriate sized air hose nozzle into the hole and give it a blast of tank pressure air. It might not do anything but then again, there is a chance it'll work. What have you got to lose?
          Location: Saskatoon, Saskatchewan, Canada

          Comment


          • #6
            Probably the pin spanner would squash the threads.

            Brake cleaner already used.

            more later.
            1601

            Keep eye on ball.
            Hashim Khan

            Comment


            • #7
              JT, don't worry about bunging up the threads, you're an HSM

              Seriously, on a lot of old machines, a home made replacement part can frequently be of better materials, finish, etc.

              I've learned about soft metal plugs the hard way recently. I foolishly used a lead plug on one part of a project to protect a thread. When I had to rework it, the thing was a #^$&# to get apart. Next time, the plug is longer and harder, or maybe plastic than can be softened or dissolved.

              Den

              Comment


              • #8
                A slightly longer set screw or small stud would let you get some purchase on the outside with a hook spanner or equivalent. Back off the screw just enough that you know the brass has room to back out a little
                .
                "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

                Comment


                • #9
                  Ha... I don't need ANY better purchase on the OUTSIDE, what I need is to grab the acme thread better...... at least for the moment.

                  I would suggest in future using aluminum plug. Yes it may distort etc, but you can always dunk it in lye.......
                  1601

                  Keep eye on ball.
                  Hashim Khan

                  Comment


                  • #10
                    Something similar to a pin spanner- just a hole the size of the collar in a piece of bar. Drill a second hole thru the side into the larger hole, and use a bolt with the same threads as the setscrew to act as the pin. Maybe cut off the threads on the bolt leaving just enough to thread into the collar. The tool will then be pushing on the shank part of the bolt and should keep it from tilting sideways.

                    If you can't clamp on the leadscrew threads, then clamp on the handle side, again using some wood blocks as protection. As those collars are threaded on, the brass plug should be just resting on top of the threads. You wouldn't screw the pin bolt in far enough to compress the plug against the threads, so it should just float loose once the collar starts moving.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                    Comment


                    • #11
                      Originally posted by nheng
                      I foolishly used a lead plug on one part of a project to protect a thread. When I had to rework it, the thing was a #^$&# to get apart.
                      Could you have melted it out with a blowtorch?

                      Comment


                      • #12
                        Originally posted by J Tiers
                        Ha... I don't need ANY better purchase on the OUTSIDE, what I need is to grab the acme thread better...... at least for the moment.

                        I would suggest in future using aluminum plug. Yes it may distort etc, but you can always dunk it in lye.......
                        So did you find a way to hold the leadscrew sufficiently so that you can actually make twisting tests?
                        John M...your (un)usual basement dweller

                        Comment


                        • #13
                          Originally posted by Deja Vu
                          So did you find a way to hold the leadscrew sufficiently so that you can actually make twisting tests?
                          Lacking any input, the problem resolved itself with PBlaster, time, and a decision to sieze the two parts with pump pliers and give them a mighty twist.

                          Both screw assemblies unscrewed.

                          So the one remaining problem is a pin that will not drive out. It has been solved by a policy of masterly neglect, cleaning the rest of teh knee assembly, and NOT cleaning the knee crank shaft.

                          The collar still in place in pic is probably also screwed on, but I have no reason to remove it.

                          In the pic, of the crossfeed, the little brass piece is the slug. it is much bigger in diameter than it is wide. And,, it did not seen to be bearing on the threads in any significant way, not even a small indent on either side.

                          Last edited by J Tiers; 06-28-2010, 12:29 AM.
                          1601

                          Keep eye on ball.
                          Hashim Khan

                          Comment


                          • #14
                            Your last post with the parts dissemble will be priceless to other Benchmaster owners. I was going to suggest drilling a small hole through the brass pad and forcing it out with a blast of compressed air.

                            Comment


                            • #15
                              J Tiers,

                              You should post all this info on the Yahoo Benchmaster Group site as it will help other Benchmaster owners with similar problems.

                              Comment

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