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Project: Building the MLA-18 Filing Machine

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  • #91
    My holes came out within .030 of each other (0,75mm) which is not great but not bad either considering they are tapped for 3/8-16. I think the difference is going to get lost in the noise floor when it comes time to assemble the finished machine. Especially if I go a hair oversize on the mounting leg holes.

    BTW, Metamucil (psylium husk) is your friend. No photos though, sorry.
    25 miles north of Buffalo NY, USA

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    • #92
      Back at it again, I have to face off the same pair of mounting bosses on the body casting. This is another area where having the MLA-7 boring head would make things easier, or certainly a mill would be much easier. Since I have neither at the moment, I have to get creative with the little South Bend 9. These bosses measure ~4.9 and change, they need to be 4" (100mm) exactly between them with the file holder centered between them. I finally decided on the following setup, as a "poor man's fly cutter". This is because I don't yet have a large face mill or shell mill that will fit in the spindle. First step is to square everything up with reference to the base:

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      Once again the body casting is mounted up on blocks with a threaded rod going into the cross slide.
      I decided to use a large RH DCMT tool in the chuck as a cutter.
      Note that I tightened all the jaws down till I couldn't move the wrench any more.
      Obviously the job will be with the spindle in reverse.

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      And an overall shot of the setup just to give an idea.
      These bosses are only maybe an inch round,
      but the length needs to be exact to match the bosses on the work table.

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      Last edited by nickel-city-fab; 06-17-2021, 11:01 AM.
      25 miles north of Buffalo NY, USA

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      • #93
        Well, that was short-lived. Gonna have to invent a different setup.
        Chuck tried to unscrew.
        Maybe there's a way I can mount a grinding/cutting wheel in the spindle and feed it with the cross slide.
        Or mount the part in the chuck and use the die grinder in the tool post.
        Will explore those options and get back.
        25 miles north of Buffalo NY, USA

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        • #94
          It looks like your setup would work fine with a proper fly cutter
          Location: Northern WI

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          • #95
            Originally posted by Galaxie View Post
            It looks like your setup would work fine with a proper fly cutter
            Yeah, it's on the "to-do" list, you know how those lists are...
            25 miles north of Buffalo NY, USA

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            • #96
              OK, here's the new idea: using a cutoff disc in the lathe to face off those bosses.
              Turned up an arbor out of 1" MS, with a 7/8 dia step, .040 thick
              to clamp on the cutoff discs with an ordinary grinder nut, 5/8-11.
              The disc is an el cheapo 1/16 thk.

              I'll fix the part in place as before on the cross slide and feed into the wheel that way.
              Should produce a great finish, and I bet it gets closer to the spec than one would think.

              Click image for larger version  Name:	mla18-68.jpg Views:	0 Size:	677.7 KB ID:	1947421
              25 miles north of Buffalo NY, USA

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              • #97
                You just need a right handed tool is all.
                21" Royersford Excelsior CamelBack Drillpress Restoration
                1943 Sidney 16x54 Lathe Restoration

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                • #98
                  Originally posted by The Metal Butcher View Post
                  You just need a right handed tool is all.
                  Yep, it's on my shopping list. Or maybe just grind up some HSS, goodness knows I have enough of it around here. I've got some *nice* new chunks of T-15.....
                  Last edited by nickel-city-fab; 06-17-2021, 09:14 PM.
                  25 miles north of Buffalo NY, USA

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                  • #99
                    left handed I think?

                    Either way, this project is definitely keeping your grey matter well exercised!

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                    • Originally posted by mattthemuppet View Post
                      left handed I think?

                      Either way, this project is definitely keeping your grey matter well exercised!
                      Doh! Damn if only I had two handed objects with me at all times to keep them straight!
                      21" Royersford Excelsior CamelBack Drillpress Restoration
                      1943 Sidney 16x54 Lathe Restoration

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                      • I finally have a setup that will work. It's slow going but very controllable. I'm taking my measurements from the tool holder shaft, stuck in the bore with a bushing, and holding a parallel against the machined surface of the boss. I can then use the calipers or an adjustable parallel to get that distance, and add 1/4" (0,250 or 6mm) to get the actual center line of the bore. These bosses need to be 4" (100mm) distant, so the idea is to get 2" (50mm) from the face of the boss, to the center line of the tool holder bore.

                        I'm just using a 3/8" (10mm) HSS blank held at an angle in the chuck, running forwards on the spindle at around 250 RPM and sweeping a ~2" (50mm) dia circle of cut.... a poor mans fly cutter. I lock the carriage and cross-feed very slowly by hand. There is quite some ways to go, so I may change to power feed. So far it can handle a DOC up to ,030 (0,75mm).

                        Click image for larger version

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                        Once again, the top slide is removed and a dovetail plug inserted in it's place, with a random length of 1/2" threaded rod holding everything down onto a pair of 1-2-3 blocks on the cross slide. It is very important to tighten everything down as much as possible and double check all your clearances when doing cuts like this. It's gonna be a long day....
                        25 miles north of Buffalo NY, USA

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                        • Onto the other side today, this photo shows better, what I have to do:

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                          Distance from the center line of the tool holder bore (yellow arrow) to the face of the boss (red arrow) needs to be 2" (50mm) and the faces of the bosses need to be parallel. The body of the machine is just under 4" (100mm) diameter, and the bosses will have 4" between them when finished. The center line (yellow arrow) needs to be exactly centered between the bosses, or as close as I can get it. That means I have to take 0,353" off the boss in the photo, the one on the right side is already done. Slow going at ,030 (0,75mm) DOC but the finish is beautiful with the power cross feed. Bosses are about 1 inch dia.
                          25 miles north of Buffalo NY, USA

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                          • Yet another update.
                            All of the major machining is done, just a few minor tasks, then assembly.
                            I had another gift today: lining up the drill holes on those bosses.
                            Turns out that I had left the base of the machine, just thick enough, to put the drill holes at the center height of the lathe itself
                            By setting the base of the machine directly on the ways, basically puts the drill right where it needs to be,
                            These holes will be tapped 3/8-16 (say 10mm) to hold the legs, that support the work table finished previously.
                            The brass rod in the tail stock chuck simply holds the part square and provides feed into the drill chuck in the spindle.
                            I love it when a plan comes together

                            Click image for larger version

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                            25 miles north of Buffalo NY, USA

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                            • OK, doing the work table supporting legs. These bars will be bolted in between the body of the machine, and the work table, via all those bosses I just faced, drilled, and tapped. These bars are 1/2" x 1" (say 12mmx25mm) and they get a 3/8 (10mm) hole thru each end, 3 inches (75mm) apart. Each hole gets a counter bore 9/16 (let's call it 14mm) about half way thru the thickness. This will be kinda fussy to set up but worth it, I think:

                              Click image for larger version

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                              When all that is done (total 4 holes) the ends get rounded over in a nice 1/2" (12mm) radius. Will probably just use the angle grinder and some files for that, and work to a marked line. It is possible to use the machine itself to do the final shaping once it's all together. After these bars are done, there is only one thing left: turning, boring, and reaming the bronze bearings. Then assemble it.
                              25 miles north of Buffalo NY, USA

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                              • *sigh* back at it again. It's been one of those days, so getting some shop time is therapeutic.
                                I'm still making the support legs for the work table.
                                The nominal center-to-center distance for the bolt holes is supposed to be 3 inches (75mm)
                                HOWEVER it is far more important that the dimensions are all the same, than whatever the dimension turns out to be.
                                In my case, I had a fairly good drilling layout from the surface plate and height gauge...
                                But the holes are still visible "off".
                                I completed 3 holes with the counter bores for the cap screws.
                                Now on the 4th hole, I bolt the parts together and use the completed part to guide the remaining hole.
                                Now all 4 holes will agree even if the distance is off a bit.
                                This will allow the tool to adjust freely, without binding when in use.

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                                Notice the "micro" solid carbide boring bar doing the work, these things are excellent for this sort of thing.
                                I pray that I do not have to buy another one any time soon -- they are not especially cheap.
                                Also, the part is gripped by two jaws out of the four. Tightening the other two will push the part off center.

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                                Last edited by nickel-city-fab; 06-22-2021, 10:13 PM. Reason: emph.
                                25 miles north of Buffalo NY, USA

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