How to: Center a rotary table

[A_Pmech]

While setting up my cross-slide rotary table a few days ago it occurred to me that many may not know this "trick".

Most of the time you can center a rotary table by indicating the Morse Taper socket in the center of the table. A cross-slide rotary table has no taper socket to indicate and it wouldn't be a reliable indication anyway, as the center of the table top can move relative to the center of rotation of the table.

The answer is to disengage the worm and indicate to the OD of the quill rather than indicating the ID of the table taper:

Where this trick shines is when you have a part clamped to the rotary table and lose your position. Re-indicating the rotary table concentric with the spindle using the taper socket becomes mighty difficult when it is covered by the part! With this method, simply install the indicator anywhere on the table, or the part for that matter, swing it until the quill OD is indicated in and you're good to go again.

 

[cnc-me]

Must be nice, having a mill table thats big enough to have
a vise and a rotary on at the same time.
How do you get that monster rotary on the mill table, forklift I presume?
I thought my 10" chi-com jobbie was heavy until I seen yours.

 

[justanengineer]

Always appreciate a tip. Thanks.

 

[gorilla]

That's a nice rotary table, I have a lot of not so pleasant memories of milling half dovetail oblong O ring grooves in 304 SST with one of those. Is that series two Bridgeport not CNC?

 

[A_Pmech]

Must be nice, having a mill table thats big enough to have
a vise and a rotary on at the same time.
How do you get that monster rotary on the mill table, forklift I presume?
I thought my 10" chi-com jobbie was heavy until I seen yours.

It is nice. The table is 11" x 58"

The vise is an 8" Kurt, around a 275lb appliance with the optional swivel base. The rotary table is a tad more, I'd say around 350-375 lbs if I was to guess. You can be sure cranking the knee with 600lbs of appliances on the table gets old in a hurry! I'm working on solving that though.

Vise and rotary changing involves the use of an engine crane.

Always appreciate a tip. Thanks.

You're welcome!

That's a nice rotary table, I have a lot of not so pleasant memories of milling half dovetail oblong O ring grooves in 304 SST with one of those. Is that series two Bridgeport not CNC?

I was actually putting it on the machine to do some 304. Dovetail grooves in 304 sound fun! NOT!

It's a Series II standard with the 4HP 4J head. No CNC here.

 

[mike13u]

Great stuff as always. Thanks for shareing.