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Help with stuck Y travel on Sherline mill

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  • Help with stuck Y travel on Sherline mill

    I admit to being new to metalworking, but this has me stumped. I was milling a 1/8" piece of aluminum and the Y-travel got tougher and tougher. So I stopped and removed some screws and the Y-dial to slide the saddle off. It was extremely difficult, but I got it off. The screw moves freely and there was nothing on the ways that I could see. Adjusting the gib, moving it forward toward me, seemed to make it a little easier to slide the saddle back on, but not enough. The forward travel of the gib was limited by the length of the wire holding it in. So now I am stuck with a saddle that I can barely force back on and no ideas. I would appreciate any advice you can offer.

    John

  • #2
    Something may have gotten between the gib and the saddle. Did you take the gib completely off?
    Any products mentioned in my posts have been endorsed by their manufacturer.

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    • #3
      Yes I took the gib off. It is only held in by an L shaped wire (which goes into a hole in the gib) and a small set screw. I could not see or feel anything where the gib seats. I also made sure the adjusting screw was completely loose.

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      • #4
        Got a surface plate? Odds are something warped. I had one of these and it warped in use. No idea why.
        This product has been determined by the state of California to cause permanent irreversible death. This statement may or may not be recognized as valid by all states.
        Heirs of an old war/that's what we've become Inheriting troubles I'm mentally numb
        Plastic Operators Dot Com

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        • #5
          "Got a surface plate? Odds are something warped. I had one of these and it warped in use. No idea why."

          clamping things down tightly into T slots can warp things iv found.
          Might be the stress of clamping to the table slightly warped the table and it did not return to shape.

          My old toolpost in my lathe, when tightened really hard, would bind the compound slightly.

          My new '-0.01" undersize 0.001" tollerance' T Nut for my new quick change toolpost seems completely unable to bind my compound reguardless how tight, fits WAYYY better then the origional nut, and hence spreads the stress out better. (origional T nut was WAY undersize)
          Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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          • #6
            T Nut

            Black Moons-
            Check to make sure the top of your new T Nut is below the top of the compound slide.

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            • #7
              Not sure what "Y" is on the Sherline but if that's an axis with one of the plastic gibs, perhaps the gib is stuck on one wide causing it to wedge tightly. Den

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              • #8
                I was working along milling some plastic boxes. More or less I had fixture and I'd crank in and back out and that was the entire operation.

                Over the course of 1,500 parts I found it harder and harder to turn the wheels... I took it apart expecting to find buildup or something broken... what I found was warpage of several parts.

                I'll go into more detail tomorrow I am quite tired.
                This product has been determined by the state of California to cause permanent irreversible death. This statement may or may not be recognized as valid by all states.
                Heirs of an old war/that's what we've become Inheriting troubles I'm mentally numb
                Plastic Operators Dot Com

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                • #9
                  1. I notice when I tighten the t-nuts that it causes the slide to tighten up.
                  2. Also check your brass saddle nut lock? That can wear, and might need adjusting.

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                  • #10
                    Originally posted by Toolguy
                    Black Moons-
                    Check to make sure the top of your new T Nut is below the top of the compound slide.
                    Yea it is, I think I left 0.01" there too Read that post about the guy with the nut too tall some months back.

                    I think too small (skinny) of a T nut actualy adds 'leverage' in the T slots trying to split them apart, deforming the table around it.
                    a full sized T nut just places shear stress on the very inside of the T slot.

                    I wonder if those 'half twist' fast insert T nuts are problematic for that reason.

                    And of course, whatever shape your vise/work/etc is may try and deform the table.
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      The sherline uses tapered gibs. If the set screw holding the L shaped wire gib retainer in place is loose, the gib could wedge tight in one direction. The backlash nut on the lead screw slipping can also cause binding. The lead screw may initially seem to move freely until it engages both nuts. The lead screw can also get bent or the bushing at the end misaligned which will cause binding when you are close to one end of the travel.

                      If you drive a bolt too far into one of the t-nuts, you will damage the table but that will generally affect the top rather than the bottom and probably shouldn't affect sliding unless you really overdid it. The end bolt should never be allowed go all the way through the t-nut and dig into the bottom of the t-slot. If you flip the t-nut upside down on an anvil, put a ball bearing on top, and wack it with a hammer, you can damage the bottom threads making it difficult to drive the bolt in too far. I also use threaded rod or a long bolt and a nut instead of the plain bolts - that way you don't end up with a bolt which is too long for the particular clamping job which when tightened messes up your t-slots. If you see the top edges of the t-slot dimpled upward or score marks on the bottom of your t-slots, you have been driving the bolts in too far.

                      If you vigorously clamp a part with a convex bottom surface to the table, you could bend the table. Or if you have chips under a part or vice when you clamp it.

                      There is a little cylinder shaped lock on the front of the saddle.

                      If chips got behind the tapered gib, you might not be able to loosen the gib enough. Disassemble and clean thourougly.

                      Physical abuse of the machine when moving it can bend parts.

                      If necessary, you can get replacement tables from sherline or a2zcnc.com (larger than the original).

                      The gibs have to be custom cut for the amount of slop in each machine. You can buy replacement gibs from sherline but you have to cut them to length and drill the hole for the retainer. If you replace the table, order a new gib blank, as well - they don't cost much. In some cases, you may be able to replace the L shaped wire retainer with a longer home made one to loosen the gib or drill a new hole to use the existing wire.

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                      • #12
                        Also be sure to check the brass "star" nut that the feed screw goes into. If it's loose it can tighten up while cranking the feed.

                        http://www.sherline.com/backlash.htm

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                        • #13
                          Some success

                          After two replies mentioned warping due to clamping I went back downstairs and removed the vise I had perfectly aligned and clamped tightly into place with four T-nuts. Checked this evening and it seems much improved!!! Not perfect, so maybe some warp remains. Thanks for all of the insightful suggestions.

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                          • #14
                            I find the Sherline t-nuts are too small, and cause the table to deform when tightened. The t-nuts below are Sherline's.



                            I machined some new ones similar to the ones below, and any binding of the Y axis is now gone. The increased size of the T spreads the force out more evenly.

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