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Anyone know of a 3 jaw chuck for rotary table

Like so.

3800-5810-B_2__06482.jpg


Or drill and tap a 3 hole pattern in the rotory table.
 
Firstram said:
You need the t slots to center the stock in the chuck on the RT, tapped holes would limit that.
Click to expand...
Make a centering spud. Put pattern in centered. Not seeing a problem here. The spud I made for mine comes in about a thou out of round if you just slap it on when vertical. A few hammer taps with the bolts snug and it's good to go.
 
bdkw1 said:
Make a centering spud. Put pattern in centered. Not seeing a problem here. The spud I made for mine comes in about a thou out of round if you just slap it on when vertical. A few hammer taps with the bolts snug and it's good to go.
Click to expand...
The chuck I use on my RT is pretty beat, it needs a fair amount of movement depending on the diameter being clamped. A 3/4" centering spud doesn't do much for me.
 
We have quite a few "milling chucks" at the shop, extremely valuable for rotary tables as well as just doing production work flat on the table.
They are far superior to lathe chuck for milling, they are lower profile have built in flange for bolting down in four places and the chuck key location is mounted at an angle for easier access. you can get soft jaws as well so you can cut exact sizes or shapes in them for quick fixturing.

tlas-workholding-8-3-jaw-low-profile-chuck-nbk8-39.png



3 jaw milling chuck
 
CNCJerry said:
We have quite a few "milling chucks" at the shop, extremely valuable for rotary tables as well as just doing production work flat on the table.
They are far superior to lathe chuck for milling, they are lower profile have built in flange for bolting down in four places and the chuck key location is mounted at an angle for easier access. you can get soft jaws as well so you can cut exact sizes or shapes in them for quick fixturing.

tlas-workholding-8-3-jaw-low-profile-chuck-nbk8-39.png



3 jaw milling chuck
Click to expand...

I need one of those, but not for $1500. Waiting to score one at an auction at some point.


Pretty cool though. Didn't know anything was still being sold under the Atlas badge. Apparently Pratt Burnerd owns them now...or at least the workholding portion. :smokin:
 
Lbhsbz said:
Then clamp a 3 jaw in the 4 jaw and leave it there until you need a 4 jaw for something.
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Or center the rotab under the spindle and get a long indicator holder and rotate it around the part rather than crank the rotab…then tap the chuck around using the slop in the mounting bolts or clamps to get your work concentric. My biggest complaint with 3 jaws is they‘re not great at actually centering anything which is why the adjustable 3jaws became a thing , once you’ve been in a shop for a little bit of time you can run a 4 jaw pretty fast.
 
Bullitt1 said:
Or center the rotab under the spindle and get a long indicator holder and rotate it around the part rather than crank the rotab…then tap the chuck around using the slop in the mounting bolts or clamps to get your work concentric. My biggest complaint with 3 jaws is they‘re not great at actually centering anything which is why the adjustable 3jaws became a thing , once you’ve been in a shop for a little bit of time you can run a 4 jaw pretty fast.
Click to expand...

A 4 jaw on a lathe is 100x faster to center than a 4 jaw on a rotary.
 
bgaidan said:
A 4 jaw on a lathe is 100x faster to center than a 4 jaw on a rotary.
Click to expand...
I do it pretty regularly and it doesn’t take me much more time than in a lathe, I start by having the adjustment points at 45° so they’re easy to reach from the front then it’s just spinning the indicator holder and make the changes.
 
Bullitt1 said:
I do it pretty regularly and it doesn’t take me much more time than in a lathe, I start by having the adjustment points at 45° so they’re easy to reach from the front then it’s just spinning the indicator holder and make the changes.
Click to expand...

I don't think i've ever been in a shop that didn't have a set up like that.
Only time a 4 jaw eats my lunch if its thin wall tube and I was too lazy to slug it.
 
Bullitt1 said:
My biggest complaint with 3 jaws is they‘re not great at actually centering anything which is why the adjustable 3jaws became a thing
Click to expand...

This. They're close enough for oversize bar stock you're gonna turn down and part off.

They have no business on a mill.
 
bgaidan said:
A 4 jaw on a lathe is 100x faster to center than a 4 jaw on a rotary.
Click to expand...

You're only saying that because you don't have a 24" chuck with a ~6 TPI thread on the jaws. :laughing:

Fuck setting shit up on that. A fraction of a turn and you're .050 out.

Also gravity holds the part on the mill which helps a lot.
 
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