How to mount a chuck to the same diameter rotary table.

[pontiac428]

The most important thing to consider when setting up a rotary table is preserving center. Most rotary tables have holes in them, and, at least found on decent tables, that hole will have a precision taper. My funky-cool Kamakura RT has a weird/proprietary metric taper center , but who cares about proprietary, I own a lathe. I turned a few center taper "blanks" out of aluminum bar. When I need a threaded hold-down on center, I just whip one up a taper plug with the thread I need on center. When I need to mount a threaded chuck, I'll grab a blank and thread it, then plunk the chuck on top of the table, centered on the taper- piece of cake. I have a library of RT centers forming now, so some setups are off-the-shelf, literally. Every rotary table setup needs at minimum a hole or a dimple at center, but the humble taper is the most versatile. You can ream your own Morse taper and use morse tool/work holders, including an ER collet holder, which is a very nice thing to have on a rotary table! With a taper interface, you don't need to re-center the chuck or setup like you do with t-slot bolts every time you swap fixtures. The taper is always centered, wasting no time. You change tools in your tailstock without blinking about alignment routinely, so outfitting your RT to work the same way just makes sense.

 

[Spajo]

How about something like this? You would lose some Z height though.

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I was headed down this road and stopped. I have a 4-jaw and a 3-jaw chuck. One has 4 holes and one 3. I have a nice piece of an aluminum alloy that was used in a wax mold already cut to size. I'm not sure I can get all the holes set up. However, I could just make two, one for each chuck. Thanks for the input.

 

[Spajo]

With careful placement I managed to sneak 4 holes through an 8 inch Chinese 3 jaw to mount on my 8 inch rotary table.
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Greg

Greg,

Yow. After a few beers I might get up the nerve to drill holes in my chucks. But then, after a few beers is probably not a good time to drill holes in my chucks. You were confident in you skills for sure. No doubt this works and is theoretically straight forward.

Spajo

 

[Spajo]

The most important thing to consider when setting up a rotary table is preserving center. Most rotary tables have holes in them, and, at least found on decent tables, that hole will have a precision taper. My funky-cool Kamakura RT has a weird/proprietary metric taper center , but who cares about proprietary, I own a lathe. I turned a few center taper "blanks" out of aluminum bar. When I need a threaded hold-down on center, I just whip one up a taper plug with the thread I need on center. When I need to mount a threaded chuck, I'll grab a blank and thread it, then plunk the chuck on top of the table, centered on the taper- piece of cake. I have a library of RT centers forming now, so some setups are off-the-shelf, literally. Every rotary table setup needs at minimum a hole or a dimple at center, but the humble taper is the most versatile. You can ream your own Morse taper and use morse tool/work holders, including an ER collet holder, which is a very nice thing to have on a rotary table! With a taper interface, you don't need to re-center the chuck or setup like you do with t-slot bolts every time you swap fixtures. The taper is always centered, wasting no time. You change tools in your tailstock without blinking about alignment routinely, so outfitting your RT to work the same way just makes sense.

 

[Spajo]

Pontiac 428:

No my little RT doesn't have a tapered hole, but I think it is going to get one. I have what I think is a MT3 (maybe MT2) reamer that a friend gave me. Since I'm planning on buying a set of ER40 collets and chucks soon the idea of a MT for setup and holes is really a good idea.

Seriously, I see the wisdom in your thinking.

Spajo