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Need Milling Hold-Down Ideas

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  • Need Milling Hold-Down Ideas

    I have a cast iron table with a brass center plug from a band saw I would like to face off. It's about 14" square so needless to say, it overhangs the 9" BP mill table. I'd like to sweep the entire top for aesthetics instead of multiple passes. The Suburban fly cutter will handle the 14". I'm not sure the mill will.

    The table is the typical rib-cast (about 1/4" thick) with a skirt. It's about 1 1/4" high. The slot for the blade has a 5/16" threaded hole at the outer edge and accessible from the underside. The threads are shared with both halves of the table slot so I suspect this was used to tie the edges of the slot together during manufacture. I plan to do the same.

    There's two holes on two opposing sides but they fall outside of the mill table. I was thinking about drilling two more holes on the two opposing sides that will line up with the T-Slots. I could use those and probably a plate/flat mounted to table tilt holes to hold the center down. The table will be set above the table using thick parallels. While I have it mounted, I'll sweep the sides with an end mill to clean them up. The sides look like they were flame cut. What do you think?

    I can probably post pictures tomorrow, if I have time. My dividing head came in this evening so I may be cleaning that up and taking a test drive.

  • #2
    Ken,

    I'd also go for the method of drilling a pair of extra holes on each side. Insert long rods through these, and place a bar across them on each side. Bolt through these bars. The holes should then be a bit further apart than your outer tee slots.

    Having a couple of blocks of steel snugged up against the edges of the work and bolted to the table wouldn't hurt either; you don't want anything to shift half way through fly cutting.

    Ian
    All of the gear, no idea...

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    • #3
      What about turning it on your lathe? It would solve the issue of that large a sweep perhaps being too much for the R8. It doesn't make your holding issue any less bothersome but at least the lathe would be OK with the interrupted cuts and diameter.

      As for holding it down I think I'd be inclined to clamp it down and face off the edges one at a time. At this point I'd also introduce a few holes in the outer surround or maybe a small step that could be used for low profile wedging holders to clamp the table down from the sides for the facing. That way you don't need to drill extra holes in the upper surface.

      Chances are good that the underside stiffener ribbing is in no way parallel to the top. So when you have the table clamped face down on some parallels to space it up off the mill table I'd also dress at least a few spots around the edge to use with parallels to set the upper surface flat when clamping it to mill the top face. Doing so would very likely ensure the table stays warp free as well. Stiffeners or not I'll bet the clamping forces would warp it if the force isn't directed down into proper supports like the parallel shims.
      Last edited by BCRider; 03-28-2018, 02:50 AM.
      Chilliwack BC, Canada

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      • #4
        Can you first mill the bottom of the table? The bottom as cast will not be the same distance from the top. If the bottom has different height surfaces can you mill 3 or 4 different places to the same height and use spacers when you turn it over to mill the top? If you aren't careful the table will warp from clamping and you will end up with high and low spots.

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        • #5
          The bottom of the table looks machined. The skirt, mounting bosses and a tick-tack-toe pattern ribbing all appear to be machined. I ran a flat file over them and they seem to be at the same level. There's some additional ribbing that falls below that but would be of no concern. Through rods are not possible because of the ribbing. I have some L-style hold down clamps I could pin for use in the side holes. I just have to find them all. Those were in an auction lot I bought years ago. They're shop made out of 41xx series I think.

          The lathe is out. I'd be about 2.5+" short on the swing.

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          • #6
            Oh, so the holes you mentioned are through the perimeter skirt? A couple more and some cheap scrap hold downs to work through them would likely do a great job of holding the table to the table...

            I guess that my other question at this point is to ask what you'll be cutting on this bandsaw table? If it's wood then your new flycut face will look great for years and perhaps even many owners to come. And well worth the effort in that case. But if it's for cutting metal then I have to ask why you're bothering? The mill scale on steel and the steel "sawdust" being dragged around by the parts is going to scuff it all to blazes in a short time anyway. So just some hand sanding to clean it up is probably all it really needs.
            Chilliwack BC, Canada

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            • #7
              IS a part you would prefer to send to a tool and die shop with a large surface grinder for $200? Or is solving the problem on your own for fun one of the project requirements?
              If the women don't find ya handsome, they should at least find ya handy

              https://www.facebook.com/WDHSTechClub

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              • #8
                Would you spend that much on a 1980s Craftsman 12" band saw? I thought it would be good practice for some engine heads I'll do later. And no, that car is not worth much either.

                I'll use the band saw to cut wood and aluminum. I don't have the room for a real metal saw yet. The more I think about it the more I'm leaning to just taking a body grinder and 7" sanding disk to it. Then finish up with a DA sander and carnauba car wax. It's been in a shed a few years and apparently, the roof leaked and turned the table into a chunk of rust. Not only that, I had it covered with a large trash bag and the bag crumbled to flakes. Oh, but some of the bag has adhered permanently to the painted surfaces. The sander is looking better every minute.

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                • #9
                  Hmm.... what's the rest of the saw look like for condition? Is it up to snuff well enough to justify the time for the flycut table? Or are you looking at more like a sander sort of rest of the machine?...

                  And yeah, the grinding job would be more than the saw was worth even after the grinding job.
                  Chilliwack BC, Canada

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                  • #10
                    I'd start with EvapORust first (because I have a gallon of it).

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                    • #11
                      Originally posted by CCWKen View Post
                      Would you spend that much on a 1980s Craftsman 12" band saw?
                      Probably not, but I don't know that I would value several hours of my time at less than $200 either. Depends on whether I am doing it for the challenge, or doing it because I am trying to be cheap.

                      I think a lathe with appropriate swing would be my approach.
                      If the women don't find ya handsome, they should at least find ya handy

                      https://www.facebook.com/WDHSTechClub

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                      • #12
                        It's a woodworking machine table, I'd use a single edge razor blade and push the bulk of the rust off, then proceed with a belt sander. If I wanted it flatter, I'd find a guy with a medium sized metal shaper or planer.

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