Drilling the 4" lathe chuck

[Alberto-sp]

Hello. (Sorry my english if I make mistakes)

I bought a rotary table. 110mm diameter, and I have my minilathe 3 jaw chuck 100mm.



The problem is that there is no way I can fix the chuck to the rotary table directly. I can make and adaptor, but I would loos space and is more weight. I have thought about drilling the threaded holes all way trought, counterbore the other side to alocate the head of the new internal hex screws and that is all.



This is the lathe spindle




After that, I could use the same chuck in the lathe, using the same nuts that I have using until now, but now I´ll need a hex key too. And also in rotary table using T nuts.



As you can see, there, he is happy because is versatile.

In my head the idea looks great, but I prefer to ask you, the experts before ruin my beloved chuck.

Thank you

 

[francist]

Your English is fine, Alberto.

As for the chuck, I drilled through mine to mount it to my small rotary table and it works fine but it's a 4-jaw independent so work can be centered by the chuck. With your 3-jaw though I think I might be tempted to make an adapter plate. Yes it adds more length and more weight, but it would give you better reliability for the chuck being centered again if you switch back and forth with the lathe. If you only rely on the threaded bolts they may not keep things centered well enough so you'd need to spend time dialing it in every time you remounted it to the rotary table. With a close-fitting adapter it should mount back in center every time.

Just something to think about. Let's see what others have to say...

-frank

 

[Alberto-sp]

Your English is fine, Alberto.

As for the chuck, I drilled through mine to mount it to my small rotary table and it works fine but it's a 4-jaw independent so work can be centered by the chuck. With your 3-jaw though I think I might be tempted to make an adapter plate. Yes it adds more length and more weight, but it would give you better reliability for the chuck being centered again if you switch back and forth with the lathe. If you only rely on the threaded bolts they may not keep things centered well enough so you'd need to spend time dialing it in every time you remounted it to the rotary table. With a close-fitting adapter it should mount back in center every time.

Just something to think about. Let's see what others have to say...

-frank

Thanks for your answer. As always, I get illumination on this forum. If I make an adapter, since I don't move, every time I put the chuck in the rotary table, the chick will be aligned. And of course I'll make that adapter compatible with the 3 and 4 jaw chuck.

 

[Manual Mac]

Alberto, that’s pretty much what I did to mount my 5” 4jaw to my 6” RT.
Drilled through the rear mounting holes on the 4jaw, it so can mount from front to T nuts in RT, or to the back plate so I can use it on my SB9 Lathe.
Of course this was for 4jaw mounting to a 4 slot RT. like francist mentioned.
It should be the same mounting a 3 jaw to a 3 slot RT.
Then use alignment dowels (or some such) to center RT on mill table, then alignment dowels (or some such) to align the chuck to RT, then bolt it down.
This (for me) is plenty accurate enough for small steam engine parts.
above all, have fun.

 

[Alberto-sp]

Thank you!

 

[tq60]

Another thought.

If the studs on the chuck can be unscrewed.

You make a new back plate shaped object that fits the chuck.

Make it say 1/2 inch thick.

Drill holes where the studs go and machine it so the chuck fits properly.

Now the clever.

Mill away material on the back side area of the holes.

You have 2 options, one is cross drill the heads of the bolts so a pin can be used to tighten, or make or find a thin wrench.

Get a set of bolts sized to the chuck of a length that allows chuck to be secure to the plate.

Remove material from heads to make them thin enough to allow plate to mount to rotary table and a thin wrench to tighten them.

Last, drill holes for Allen screws to bolt to table.

Sent from my SM-G781V using Tapatalk

 

[Alberto-sp]

Thank you!

 

[Shotgun]

I would turn a thick "pin" that dropped in the RT center hole, and centered on the one on the chuck. Then bolt it to the RT exactly as you propose.

 

[Eddyde]

Caution, you can't drill all the way through a 3 jaw chuck like you can with a 4 jaw because the scroll plate that moves the jaws is in the way. The adapter plate sounds like your best option.

 

[Manual Mac]

Eddyde , you are right, (somehow) I’d forgotten about that.
Alberto, sometimes the impossible just takes a little longer.
Think of it as an interesting project.
And most important, Have Fun.