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  • darryl
    replied
    Yup, I've used mine like that too.

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  • Paul Alciatore
    replied
    My "tool post grinder" is the head of my Unimat lathe. I made a block that mounts on the compound to hold the Unimat's vertical column and the head mounts to that. It gives me speeds from a few hundred up to 7500 RPM. I have used it for grinding, drilling, and even milling in the lathe.

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  • J Tiers
    replied
    Originally posted by Mcgyver View Post

    what would you do with the grinder if you couldn't move it MUCH?

    .......
    There, I fixed it for you.

    While you COULD move it the length of the bed with one of the barrel pulleys, most setups would have used what Tom S showed in post 16. PUT it anywhere you like, and move it just a bit to finish whatever you needed to work on.

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  • darryl
    replied
    That's a good 'trick' that everyone should know about at least. In this case I seldom use the compound anymore because it just adds to the play and flex. I fabricated a more solid mount for my tool post, which can be set anywhere within range of the T-slots. This has proven to be very handy, and I've never looked back. I can turn within a half thou easily (that's a quarter spacing between the marks on my dial- easy enough to see and dial in). I did some closer work recently with the pivot points for my drawing machine.

    One thing that has come up for me several times when grinding on a shaft is ringing. Most of the time what I'm grinding on is a small diameter- usually 1/4 inch or smaller. The unwanted reduction in diameter on the workpiece can be quite dramatic when this happens, not to mention the out-of-round that it probably creates. I'll apply some damping, which could be some kind of gummy material like window seal, silly putty, some wraps of solder, or just some touching with the eraser end of a pencil.

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  • Tundra Twin Track
    replied
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    Originally posted by darryl View Post
    Spindle balance- looking at die grinders one day at Princess Auto, I test ruan a few of them and picked the smoothest one. There was a difference for sure. The Ridgid router I have is pretty smooth- I actually have two of those and they are both good. I did not have to rout through more than those two to make sure they were smooth.

    I bought a second Power Fist die grinder, and again I went through three boxes to get the best of the bunch. And it turned out to not be as good as the first one I bought. So much nicer to use one that's balanced.
    I used a 2-1/4 hp Bosch Router for my Overarm Diegrinder,old motor housing was bored out and Router slid in with tight fit,KN filter keeps filing out of brushes.It runs smooth 8000-25000 rpm,not a Machine that's uesed daily but handy for a lot of wonky jobs that free handing a Diegrinder doesn't work.

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  • Tom S
    replied
    There is also this style, which I believe a number of bench lathe manufacturers had a version of. Spindle can traverse through a pair of bushings, knob on the end spins freely and you feed by hand. Gives a couple inches of travel, might be good for internal grinding of small parts but you're not going to be OD grinding shafts with it.

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  • Mcgyver
    replied
    Originally posted by J Tiers View Post

    I think they were not really to actually move the TPG much under power, but to allow it to easily be at any point along the bed. They might have worked to move it while working also, don't know.
    what would you do with the grinder if you couldn't move it?

    The reason those lathes (ones with slide rests vs a saddle on bed ways) are a lot less than idea for grinding is the traverse is painfully slow - you are cranking on a little feed screw instead a handwheel and rack. Schaublin has a super cool grinding attachment that is lever operated, but its still too small a lathe for the projects I have in the que. I've also got an air spindle off a jig borer I haven't tried yet....maybe I should rig that up, not sure of the air consumption though
    Last edited by Mcgyver; 05-27-2020, 04:23 PM.

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  • Randy
    replied
    You mention the T-slots on the cross slide. I'd suggest you mount your TPG on the compound. You're usually grinding just the last few thou to a tight tolerance. By setting the compound to slightly less than 6° from the main spindle axis you get a 10X fine infeed. E.g. advancing the compound .005" gives you .0005" radial infeed, or .001" diametral. You can work in tenths that way. I can hit a target of .0002 or .0003, and a really nice lathe might do better.

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  • J Tiers
    replied
    Originally posted by Mcgyver View Post

    I've got a few including the Schaublin Tom posted and Levin. problem is 1) the lathes are too small for a lot of work, and 2) neither have a saddle moving on bed ways.

    It wouldn't be hard to try, taking the motor off the lathe, but before that I'm trying to improve the balance of the motor/pulley assembly
    I think they were not really to actually move the TPG much under power, but to allow it to easily be at any point along the bed. They might have worked to move it while working also, don't know.

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  • old mart
    replied
    I have a little 12V angle grinder that uses 75mm X 1mm X 10mm bore discs. They are rated for 20100 rpm. The discs I have are metal cutting fibre reinforced and metal discs with brazed on carbide grit for multi use. The equivalent in the USA would be 3" X 1/24" X 3/8" bore. I recon an adaptor made of decent steel with a 1/4" shank would be ok to hold them in a router.

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  • Mcgyver
    replied
    Originally posted by J Tiers View Post

    Don't any of your smaller bench lathes have the "drum" pulley up above so the belt on a TPG can move the length of the bed? Quite a few older jeweler's clockmaker's and modelmaker's lathes were set up like that. I think early Rivett 608 were.
    I've got a few including the Schaublin Tom posted and Levin. problem is 1) the lathes are too small for a lot of work, and 2) neither have a saddle moving on bed ways.

    It wouldn't be hard to try, taking the motor off the lathe, but before that I'm trying to improve the balance of the motor/pulley assembly

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  • Tom S
    replied
    Or one of these nice little units from Schaublin

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  • J Tiers
    replied
    Originally posted by Mcgyver View Post
    It'd be lots of belt flying around, but I've thought about taking the TPG motor off the tool post and mounting it on a bench to get its vibration off the lathe.
    Don't any of your smaller bench lathes have the "drum" pulley up above so the belt on a TPG can move the length of the bed? Quite a few older jeweler's clockmaker's and modelmaker's lathes were set up like that. I think early Rivett 608 were.

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  • darryl
    replied
    Well, that's a fundamental alternative- putting the motor off the lathe entirely. That's what I've done with the lathe motor. Belt drive to a jackshaft, second belt to the spindle pulley. It's the smoothest this lathe has ever been. No reason why it can't work for a TPG. Two of mine have the motor on the mount, but belt drive to the separate spindle. I had at one point my Dremel handle mounted on the cross slide, and the flex shaft gently flexing upwards to the motor, which was hanging by a wire. That worked ok, but it's still a pretty small spindle. I really like being able to use 1/4 inch shank cutters.

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  • Mcgyver
    replied
    It'd be lots of belt flying around, but I've thought about taking the TPG motor off the tool post and mounting it on a bench to get its vibration off the lathe.
    Last edited by Mcgyver; 05-26-2020, 06:04 AM.

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