Mounting A Chuck on a Rotary table?

[Blogwitch]

In reality Wm, you are stuck with mounting a 3 jaw chuck. I prefer the 4 jaw self centering and because I own an old Vertex 6" with four slots, it was dead easy.

You need to buy a front bolting chuck, this is where the bolts go in from the front rather than the normal back mounting ones.

A 100mm chuck will be just fine, but you will most probably have to make yourself 3 T-nuts to match the slots in the table and to fit the screws that usually come with the chuck. Once you have all the bits, it is only a 30 minute job to put it all together.

First off, centre up the RT to the spindle using the MT hole in the middle using a dial gauge. Once done, lock up your table in the X&Y then recheck to make sure it hasn't moved.

Mount the chuck on top of the table, but leave it 'tapping' tight so that you can move it with soft taps from a soft hammer.

Put a precision mandrel in the chuck (I use the shank of a milling cutter), and turn the rotation wheel of the RT and using your dial gauge, see how much runout you have when measuring the mandrel. Gently tap the chuck until you get no movement on the clock when doing a full rotation. When you find the sweet spot, gently tighten the chuck holding bolts until tight. Recheck with you gauge to make sure nothing has moved, if it has, redo the tapping bit.

Job done, chuck perfectly in line with your RT and spindle, it is now ready to use.

John