Small rotary table fix.

Small Rotary table upgrade.

4” rotary table fix.

I bought a 4” rotary table from India a while back, it turned out to be below par, the table rocking back and forward due to the worm and gear not meshing close enough, and that made milling hopeless. There is an adjustment screw on the side of the unit, but that pushes the worm gear housing over to one side making turning the table handle very tight.

To fix the problem, I elongated the four mounting holes on the worm gear housing so I could move the worm gear in closer to the gear under the table, and that fixed the problem. The holes only need to be elongated by around 0.5mm.

Another problem cropped up regarding the graduated bush on the worm gear shaft. It is held in place by a grub screw, when the grub screw is tightened it skews the graduated bush, making the bush rub against the worm gear house at different points as it is rotated. To fix that problem I turned a recess on the graduation bush deeper enough to take a three piece thrust bearing, and that fixed the problem.

Obviously a thrust bearing either side of the worm gear housing would be better, maybe I'll tend to that another time. For now the rotary table works great: the table doesn't rock back and forward and there is virtually no back lash on the handwheel.