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Thread: A thread for random quick questions

  1. #151
    Senior Member Wolfcreek-Steve's Avatar
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    I learned in a 1 semester tech school course. All they taught in that amount of time was 6011, 6013, and 7018 in all 5 positions. I could have gone to Alaska and welded on the pipeline after that course, but I chose to go on for 2 years of machine tool school. All of it has been a blessing, I've made my living with that combination of skills, plus lots of my hobby stuff is based at least partially on the same knowledge.
    I have a Lincoln 225A tombstone and it certainly won't run on a 30A circuit. A lot of the Primary Amperage requirements depend on arc voltage, it is a variable that the cheepos won't talk about, and one of the reasons they won't weld worth a crap.
    What is that squeaking noise?

  2. #152
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    Quote Originally Posted by Zapins View Post
    I was thinking, put the bearings in, then insert the rails through both sets of bearings on both plates to preserve the alignment, then use a corner welding vice to hold them at 90 degrees..
    That may help them not get way out of whack but they still move enough to side load the bearings and cause premature wear if not binding. Nothing that requires precision should be done on a piece that will be welded before the weld has been completed. That said, "precision" is a loaded word and can vary from from +/-.0001" to 1/4"
    FLAME ON...!!!!

  3. #153
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    The self aligning type of bearing have gotten me out of several jams because I didn't follow J. Viberts rule above.
    https://www.mcmaster.com/#standard-f...rings/=183v6bj

    Pete

  4. #154
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    Hey Zap, Always take your bushings to the machinist who is going to make the hole, just like you always take your pistons to the guy who is going to bore your cylinder walls.

    If it's a high speed shaft you are setting up, you should weld it first and then have a machine shop line bore the holes so that they are perfectly aligned.

    Richard
    When I die, Heaven can wait—I want to go to McMaster-Carr.

  5. #155
    Senior Member Zapins's Avatar
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    Quote Originally Posted by J. Vibert View Post
    That may help them not get way out of whack but they still move enough to side load the bearings and cause premature wear if not binding. Nothing that requires precision should be done on a piece that will be welded before the weld has been completed. That said, "precision" is a loaded word and can vary from from +/-.0001" to 1/4"
    I'm not sure that I could get it more accurately made if I welded it up then drilled. I think I'd have more error welding first.

    I think for the welds I shouldn't do an entire edge. I should just do the edge in 1" strips of weld. Not a continuous weld all the way along. That should help reduce warping while still keeping the vice together.

    I asked a machine shop how much to drill the 4 holes. He said he didn't have a large enough drill bit so it would have to be drilled, reamed or bored. At $60 per hour he would need probably 3-4 hours to do that. So basically that is out of my price range.

    I suppose I could have just asked them to CNC plasma cut the damn holes in if I had thought about it. But then again that might have been pretty off as well.

    Maybe I can find someone in CT. Will have to see and let you know how I make out.

    Alternatively I've seen some large drill bits on ebay for 40-60 dollars in the size range I need, so that is another possibility, though I think they are too fat for my drill chuck to hold, so I'd still need to find someone to drill the holes for me.

    - - - Updated - - -

    Quote Originally Posted by Petee716 View Post
    The self aligning type of bearing have gotten me out of several jams because I didn't follow J. Viberts rule above.
    https://www.mcmaster.com/#standard-f...rings/=183v6bj

    Pete
    I will have to take a good look at those and see which one will work best, I think they look like what I need instead of the press fit linear bearings. I could just chop out a section and then bolt them in place. Much easier I think. Again, another instance I wish I knew the correct words to describe the parts I need. Hopefully the prices won't be crazy high.

    Thank you!

    Speaking of alignment. I did a deflection calculation for a 400 lb load shared on 2 rails. I got a max deflection of 2.4 mm using a 1.5" thick drill rod. I am unsure if this will cause binding of the blade in the rock as it travels down the length of the vice. I think probably not because the vice would simply be pushed down and remain parallel with the blade, but then again, mistakes were made when I designed the hood to weigh 210 pounds instead of lowering the gauge like all the commercial saws have...

    - - - Updated - - -

    Oh wait. I need these to slide along the rail, not allow the rail to twist in circles.

    So close!

    Unless something exists like that?

  6. #156
    Senior Member Wolfcreek-Steve's Avatar
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    Zap, I hate to say this, because you are "trying" and that is what it is all about, but I think you are going way outside of your fabricating abilities here. If you are trying to weld steel plates that are much heavier than your welder is speced for, after drilling holes for bushings that must line up perfectly, you have about the same chances of success as a snowball surviving Hell. If you can post some drawings of what exactly you are trying to do, so I can help formulate a plan, maybe we can pull it off.
    What is that squeaking noise?

  7. #157

  8. #158
    Ok,
    I think everyone is over thinking this a bit. Tack the two side plate together (like back to back) drill the hole through both at the same time. Now get a bit of pipe the same diam as the holes tack it into the holes. Weld the plates in place. Let everything cool (like over night). Remove the tacks on the pipe, and the pipe. If everything went well it should all stay lined up.
    The other option is to make the holes undersized. go through the steps above. Then build a simple line boring setup to bore the two holes to final size. (or pay the local machine shop to do the line bore). Any shop that does engine work should have a suitable line bore setup. diy-line-boring-setup



    To give you someplace to start.
    CBB
    Last edited by CrazyBillyBob; 06-20-2017 at 05:39 PM.

  9. #159
    Senior Member Wolfcreek-Steve's Avatar
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    OK, Now I see what you are doing. I would weld it up, drill the bushing holes as accurate as possible and try to assemble. If the slider won't slide, determine which hole(s) are causing the bind, relieve the offending hole(s) until the binding is gone, then "pot" the bushing(s) into the relieved hole(s) with epoxy. This is the way it is often done in the machine tool world on die sets, where .0005 is a sloppy fit between pins and bushings.
    What is that squeaking noise?

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