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Project: Building the MLA-18 Filing Machine

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  • I would flip it and grip it by the OD with the base bumped up against the jaws. Bore out both bores and press in bushings.
    21" Royersford Excelsior CamelBack Drillpress Restoration
    1943 Sidney 16x54 Lathe Restoration

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    • Wow, thanks for all the ideas, guys!
      I think I figured out how to go, but if it doesn't work I'll have to revisit some of these.
      My main limitation is lack of larger drills and boring ability.
      Especially for longer/deeper holes.

      But at a more fundamental level, I simply screwed up a setup somewhere along the way.
      Most likely I made a bad assumption somewhere.
      It's getting fixed shortly.
      25 miles north of Buffalo NY, USA

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      • This is the reamer that covers 5/8'. The left end is the pilot.



        The sliding cone and adjustable (19/32 to 21/32) cutter section

        2730

        Keep eye on ball.
        Hashim Khan

        Everything not impossible is compulsory

        Comment


        • OK I know how this is gonna sound, but...
          I want to try my idea first.
          If that fails, then I'll be calling on you guys for sure.

          I am working on the lower tool-holder bearing, which was way off location spec.

          The hole through the bearing stock needs to be ~0,500 plus ,001.
          They need to line up close enough for the nicely finished drill rod that I made the tool holder off....
          Bearing stock is (eye-watering) C932/SAE660 hollow bronze.
          Messr's. Brown & Sharpe say the bearing bore "cleaned up" around 1,020 (25.908mm).
          All readings average to that, no variation greater than ,001.
          Brown & Sharpe say I have the OD of the bronze at 1,019 (25.881mm)
          Its a bit looser than i would like, but the instructions call for a "loctite fit"
          It cannot be pushed all the way in with fingers,
          A good tight fit, such that the Loctite is more of a safety rather than a requirement.
          it requires some knocking it in half way with a brass bar and ball peen.
          I imagine that the bore in the casting was slightly tapered due to the boring bar flex;
          no matter, the bearing is in there rather permanently with a hammered plus loctite fit.

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          The plans state to bore the bearing bore in situ. The raw hole is about 7/16 dia (0,437 or 11mm)
          Recall how I had the casting mounted on a very close-fitting test bar, and zero run-out.
          I will re-mount it again in the same way, since the test bar is still in the casting.
          Then proceed to bore and ream the bearing,
          This will give the lower bearing the same axis as the test bar in the upper bearing.
          In the following photo you can see the beginning of that setup;
          notice the bronze bearing tube visible in the bottom of the machine.

          Click image for larger version  Name:	mla18-80.jpg Views:	0 Size:	790.5 KB ID:	1949007
          Last edited by nickel-city-fab; 06-28-2021, 05:23 PM. Reason: arrangement, small-screen readability
          25 miles north of Buffalo NY, USA

          Comment


          • OK, here's a close-up of the proposed setup and method:

            Click image for larger version  Name:	mla18-81.jpg Views:	0 Size:	758.8 KB ID:	1949077

            The large bar sticking thru into the cavity is the close-fitting test bar.
            The casting is glued onto it with super glue, it had no play before.
            The bar is zero in the chuck, the indicator needle doesn't move.
            Therefore the axis of this bore should be "zero".
            The end of my small (10mm) boring bar has a good CCGT2151 insert.
            The ID is currently at 0,430 (say 11mm) it needs to be 0,500 plus a thou (say 12mm)

            That's a 70 thou difference, or 35 on the radius.
            Both of my dials read radius, I prefer it that way.
            So I'll take a total of 60 out by taking two cuts
            015 on the dial both times.
            Finish with a long chucking reamer, it should leave me .006 for the reamer.

            The bearing is 1-3/8" (say 35mm) long, in a bore that is 2" (say 50mm) deep.
            I plan to use the very slowest feeds and speeds and take spring passes if need be
            Because of the stick-out on the boring bar.
            Last edited by nickel-city-fab; 06-28-2021, 09:00 PM. Reason: typo, hopefully no thinko
            25 miles north of Buffalo NY, USA

            Comment


            • Well, that worked out beautifully.
              The lower bearing is bored and reamed.
              I tried the tool holder shaft in it, dry -- feels just like I wanted it.
              Visually seems to be centered well, too.

              Next step is to get the bearing into the top of the machine.
              Made in the same way, but with a 7/8 (22mm) OD.
              A made a stub arbor to go in the bottom bearing
              The other end goes in a ER23 collet.
              That is how I will center it to bore the top bearing.

              PS that 932/660 bronze is beautiful stuff -- I love it!
              25 miles north of Buffalo NY, USA

              Comment


              • OK, working on the top bearing, where the tool holder shaft will stick out.
                Same process as before: turn to OD, part off, and knock it into the bore with some loctite:

                Click image for larger version

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                Then I turned up a stub of 1/2" material, threaded a bit of 1/2-13 on one end.
                Super glue that into the just-completed lower bearing.
                Put the ER32 chuck on the spindle, grip the rod with that.
                Then tighten the nut against both the super glue and the face of the ER32.
                Now the top bearing can be bored on the same center as the lower bearing.

                Click image for larger version

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                Notice the bronze sleeve bearing in this last pic.
                That bore has to be concentric with the lower one, that is being held in the ER32.
                I'm pretty confident in this setup, having pushed a piece of drill rod thru the part already.


                Click image for larger version

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                25 miles north of Buffalo NY, USA

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                • Glad it worked out NCF.
                  21" Royersford Excelsior CamelBack Drillpress Restoration
                  1943 Sidney 16x54 Lathe Restoration

                  Comment


                  • Originally posted by The Metal Butcher View Post
                    Glad it worked out NCF.
                    Thanks, I was *really* sweating over it. Those bronze pieces cost enough to go party on the wrong side of town.
                    25 miles north of Buffalo NY, USA

                    Comment


                    • very cool. It's been a lot of fun seeing the creative solutions to the various problems as they come up. Always something new to learn!

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                      • SUCCESS !!

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                        The o-1 drill rod goes thru both bearings with zero perceptible radial play.
                        It feels almost "hydraulic" in its axial motion.
                        This project is getting very close to being finished.
                        Probably another half-dozen posts.
                        25 miles north of Buffalo NY, USA

                        Comment


                        • Even MORE success !!

                          I got the input shaft bearing made up. Installed with loctite and rubber mallet.
                          All the moving parts were assembled into the housing for the first time.
                          Everything feels nice and smooth, moving.
                          There are some minor things I have to deal with yet.
                          First will be putting some clearance on the corners of the scotch yoke block.
                          They are hitting on the inside corners of the casting.
                          I'll just centner it up in the chuck and make a very interrupted cut to knock the corners off.
                          25 miles north of Buffalo NY, USA

                          Comment


                          • Here's a couple pictures showing what's going on:

                            Click image for larger version  Name:	mla18-86.jpg Views:	0 Size:	666.7 KB ID:	1949387
                            Notice the marker lines on the corners of the scotch yoke block,
                            with reference to the corners inside the housing.
                            That is what needs to be cleared out.
                            I also chucked the block up in the 4-jaw
                            and turned to the same thickness (5/16 or 8mm) on either side of the slot.
                            This just gives around 1/16 (.060 or 1,5mm) clearance on the top and bottom of the stroke.

                            Here's a general view of the inner parts, hopefully this clarifies the operation:

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                            Will be back later, have to go spend some quality time with the angle grinder outside.
                            .
                            Last edited by nickel-city-fab; 06-30-2021, 02:53 PM. Reason: typos
                            25 miles north of Buffalo NY, USA

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                            • Looks like you have done some creative setups to deal with having no mill. Looking good!
                              2730

                              Keep eye on ball.
                              Hashim Khan

                              Everything not impossible is compulsory

                              Comment


                              • Originally posted by J Tiers View Post
                                Looks like you have done some creative setups to deal with having no mill. Looking good!
                                Thanks! Believe me, a mill is on the wish list.... right next to winning the lotto and marrying Dolly Parton
                                25 miles north of Buffalo NY, USA

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