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  • Quick-change tool post problems--help me please.

    My Grizzly 12x24 lathe came equipped with a quick-change tool post.

    For the first time ever, I tried to remove it. I unscrewed the big top
    nut, slid the tool holder up and off, and then, I tried to remove the
    threaded rod--the one with a round flange that fits into the t-slot on the compound.

    The rod will not slide out of the tee-slot in the compound. It moves
    (and pivots slightly) about 1/4 inch. It seems to be held by a
    vertical pin on one side--a pin that goes through the t-slot lip. The
    parts diagram calls it a pin and spring, so I'm assuming that I should
    be able to press it and release the bolt.

    But it won't budge. It appears to be wedged in at an angle. I've
    tapped on it, pried on it, hammered on it, and finally decided I'll
    have to drill it out.

    Questions:
    • What's the purpose of this pin?
    • Why does the bolt (with its t-slot flange) need to be locked into the slot?
    • If I drill out the pin so that I can remove the bolt, have I destroyed anything important?
    Thanks.
    James

  • #2
    HHHMMMMMMM
    That's strange.
    I wouldn't worry about damaging anything important by drilling out the pin.
    If need-be, just replace it with a new one.
    I don't see the purpose of the pin in the first place.
    Maybe it's there to prevent the toolpost from Slipping/Twisting ???
    I had to make a "T-NUT" for my compound, when I bought my toolpost...and It holds just fine. No pin necessary.
    I'd drill it out.

    Comment


    • #3
      seatlanta, would it be worth giving Grizzly or one of the dealers a call? May also be a Yahoo group for that lathe.

      Rgds
      Michael

      Australia

      Comment


      • #4
        Does the main bolt go all the way through? Perhaps it turned into a set screw, Grab ahold of it with a Vise Grip and try to turn it to the left(CCW), If you put tooth marks in it they will buff out.

        Comment


        • #5
          I'd be guessing that positively locating the QTCP bolt is done to make it foolproof for the guy or gal that installs the QTCP further down the assembly line.

          Comment


          • #6
            I'd put away the hammer and drill and pick up the phone tomorrow

            You don't want to start chipping away at the valuable T-slot casting and possibly create a damaged area that can crack easily under stress.

            Perhaps it is a goofy arrangement I've seen before where if you compress the spring (with some sort of thin blade), the bolt head will pivot out on the pin diameter alone but is restrained when the spring is released ?

            Comment


            • #7
              Hi James,

              Just a thought, but on my machine there are 2 small setscrews that enter the tee slot from the back of the compound to lock the tee nut in place. The original tee nut on mine was for a turret type tool post and it had a button that popped up on a spring - was supposed to index the turret, but all it did was jam things up! Not sure if this is where your pin is - this could be it's purpose.

              Anyway, you might look for a locking device on the tee nut, the post bolt may have a head on it, countersunk into the tee nut.

              Hope this helps
              uute

              Comment


              • #8
                Originally posted by seatlanta
                My Grizzly 12x24 lathe came equipped with a quick-change tool post.

                For the first time ever, I tried to remove it. I unscrewed the big top
                nut, slid the tool holder up and off, and then, I tried to remove the
                threaded rod--the one with a round flange that fits into the t-slot on the compound.

                The rod will not slide out of the tee-slot in the compound. It moves
                (and pivots slightly) about 1/4 inch. It seems to be held by a
                vertical pin on one side--a pin that goes through the t-slot lip. The
                parts diagram calls it a pin and spring, so I'm assuming that I should
                be able to press it and release the bolt.

                But it won't budge. It appears to be wedged in at an angle. I've
                tapped on it, pried on it, hammered on it, and finally decided I'll
                have to drill it out.

                Questions:
                • What's the purpose of this pin?
                • Why does the bolt (with its t-slot flange) need to be locked into the slot?
                • If I drill out the pin so that I can remove the bolt, have I destroyed anything important?
                Thanks.
                James
                Hi, on the 12x24 with the normal four way tool post the circular T nut has either a semi-circular cutout or a clearance hole and the indexing pin of the four way goes through the T slot and locates in this cutout/hole. Sometimes it is a spring loaded pin sometimes just a plain pin. It merely stops the T nut sliding out of the slot when the centre post is loose. On the standard post one just pulls the plunger (and spring if fitted) out which releases the circular T nut to slide from the slot. Most people when fitting a QCTP don't use this method of location and either leave the T nut floating or fit a couple of grub screws through the T nut and below the top surface to force it up against the T slot and provide enough friction to stop it sliding out inadvertantly.

                The locking pin is normally a fairly loose fit in the T slot hole and pulls out easily. It sounds as if yours is bent and has jammed in the hole. As far as I am aware from the few I've seen drilling it out shouldn't cause a problem if you can't pull it. The pin, if they have used the original will have an angle cut at the top so that it can be forced down against the spring in one direction allowing the post to index round.

                On my own 12x24 none of this is fitted and the T nut is locked by two set screws which go through from the front of the topslide. As far as I can see it only stops the T nut sliding out when the post is loose. When I fitted a QCTP to mine I didn't bother to re-fit the screws so that I can just loosten the centre nut and slide the whole assembly off if I need to. I didn't use the circular T nut either.

                Take care as these machines can differ slightly in the detail.

                Best regards

                Keith

                Comment


                • #9
                  I have a 12x36 lathe which is set up the same way, don't ask me why, but if you get a small magnet ,it will pull the pin out and also the spring underneath, then you will be able to slide the tool holder out.

                  Comment


                  • #10
                    [QUOTE=seatlanta]
                    The parts diagram calls it a pin and spring, so I'm assuming that I should
                    be able to press it and release the bolt.

                    Sorry I missed this comment on my first post, pushing down on the pin against the spring won't release the T-nut in fact it will hold it tighter. The pin and the spring have to be pulled right out. As has been suggested a magnet will possiblky move it. The angled top means that it is difficult to get a grip on it other than at right angles to the slope.

                    Regards

                    Keith

                    Comment


                    • #11
                      Answer from Grizzly

                      Thanks for all the suggestions.

                      I called Grizzly today (now that they're open again) and spoke with someone in technical support.

                      According to the tech-support guy, the pin should lift out to release the flanged bolt. On my lathe, the pin won't budge. I think it's a bad fit or has been installed incorrectly. For whatever reason, it's binding.

                      In any event, he said it's OK to drill it out, so that's what I'll do--I hope.

                      Thanks again.
                      James

                      Comment

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