Rotary Table Fix

[cfellows]

Several folks who saw my cam making video on youtube have commented about my wobbly rotary table, so I've been shamed into fixing it... :embarassed:

Here is a picture of the top of the old bushing on the right and the new bushing on the left. This is the part that the chuck back plate rests on.

And here is the bottom side, old on the right and new on the left. The new bushing has a large, flat surface that the worm gear will ride against.

Here is the worm gear. It's a 72 tooth, 24 pitch.

And here is bushing as it will be relative to the gear once assembled.

Chuck

 

[cfellows]

So, here we go with the reassembly. First picture shows the new bushing from the top. From this side, it's the same size as the old one, 2" in diameter. Can't go any bigger or it would interfere with the studs and nuts that hold the chuck to the back plate...

And here's the new bushing from the bottom. This part is 2.5" diameter where the old one was less than 1". The full face of the gear will bear against this part of the bushing and will give it a lot more rigidity and strength.

Here's the chuck and back plate.

And partially reassembled...

And fully assembled with the worm gear installed. This is a 72 tooth, 24 pitch worm gear.

Here I'm re-centering the chuck. There are 4 set screws around the ring at the bottom of the chuck which let me center it to within .001".

The rotary table was originally designed for drilling circular bolt patterns. I never really intended to use it for milling, but we all know how that goes! The assembled table now seems very rigid and I think it work fine for light duty milling.

Chuck

 

[gus]

Hi Chuck,

Winter is about over and here comes the RT season which should nice and warm.
Very simple and very rugged. How come,I did not think of using Channel Steel.:hDe:

 

[cfellows]

Hi Chuck,

Winter is about over and here comes the RT season which should nice and warm.
Very simple and very rugged. How come,I did not think of using Channel Steel.:hDe:

Thanks, Gus, I'm always trying to use square steel tubing and channel iron whenever I can. It's kind of nasty to machine, but it's cheap and largely already in a shape I need. Also easy to weld if I need to!

Chuck