Chuck Spindle Adapter

[sergeantmasoner]

Hmmmm....

I wanted to be able to swap my small 5" 4 jaw, or other chucks from my HF 93212 7x10" mini to my C.Atlas 101.xx 12x33" and back. The HF has a 66mm three hole mounting bolt pattern with a 55mm register, and the C.Atlas has a 1 1/2"-8 spindle nose. Rather than having to bolt and unbolt the chuck from an adapter on the C.Atlas, I figure it would be easier to bolt an adapter to the HF and unscrew the chuck FROM the adapter to go directly on the C.Atlas and back.

Step I - Need a way to test the fit of the adapter. Produce a test mount with the dimensions of the HF mounting nose. This mount screws on to the C.Atlas spindle directly and has a register recess of 55mm diameter. You can see the progress in the picture below. This started life as a 1"x5" aluminum block and progressed through a screwed up attempt to make a faceplate. Oh well, I salvaged the material for this! Next, I'll have to produce a bolt patter of three M6 mounting holes at 66mm diameter.
This mount will also serve as an adapter for the actual adapter blank so that I can turn it on the C.Atlas.

Step II - Produce the adapter which will allow the mounting of a chuck with 1 1/2"-8 threads to the HF. The adapter will bolt directly to the HF and will have the necessary 1 1/2"-8 mount nose.

 

[bazmak]

The idea of swapping chucks and tooling between machines is worth its weight in gold.Keep us all posted.Regards barrys

 

[digiex-chris]

yeah I did this to swap between my lathe, dividing head, and horizontal mill. Very worth the effort.

 

[sergeantmasoner]

Well shoot! Failure. Axis don't match up. I think I have my process wrong. Instead of making the adapter on the C.Atlas, I need to make it on the HF. Making it on the C.Atlas caused me to have my part several thousandths off center on the HF. I think what I should have done was make the adapter on the HF by mounting the blank turning the nose and threading it for 1-1/2 inch by 8 tpi.

 

[newdirection]

I think you are right on that idea. Once you get your blank drilled and mounted on the HB and trued up, you will have to probably make a stub with the 1-1/2" thread so you can get that to run concentric on the Atlas lathe. I assume you have a chuck for the Atlas that you can use to fit the stub into, once you have that in hand you can use that to check your internal threading. Sounds like a fun project.

 

[digiex-chris]

The way I do it is use whatever lathe is handiest to cut the spindle side mating feature (threads in this case). Then remove it and install the un-finished adapter onto the spindle it will mate with (the HF in this case), then use that machine to cut the chuck side feature.

On the case of machines where it's not suitable for turning the chuck side, like the adapter for an old dividing head I had to make, I started with the above method, then using a chunk of scrap on the lathe I copied the target spindle nose. Without removing that copy from the lathe, I screwed the unfinished blank on that. Then I cut the chuck side feature.

That way, it's always perfect. No indicating anything in.

 

[newdirection]

That is what I was getting to, you just put it more Eloquently digiex- chris ! LOL
Good description of the process.

 

[bb218]

Keep in mind the thread is not what is holding the plate true to the spindle. There will be a short diameter on the spindle nose and a shoulder, they are what assure's the chuck runs true, all the 1 1/2 thread does is pull it back Mike

 

[sergeantmasoner]

I do have a couple of chucks for both. Thanks for the comment!

 

[sergeantmasoner]

I somehow got both registers right, just off center of each other. I think by making them both on the HF that the axis will line up much easier. Those registers take me more time to turn than any other part of the process. Like they say, you can take it off but you can't put it back on.

 

[sergeantmasoner]

DOGONEIT! Now I'm out of 2"x3"x3" and 2"x4"x4" metal. Gonna have to order some more before continuing.

 

[sergeantmasoner]

This is what I am wanting to end up with to mount on the HF. I do not yet know how to do threads on Sketchup so imagine 8tpi on the spindle.

 

[digiex-chris]

And the HF spindle is the left side and the chuck you want to mount goes on the right side? My lathe is very similar, with a flat back and a depression like that.

I bolted the depression side (of the welded adapter) to the lathe it was going to run on to turn the threads and the register for the taper adapter (held in my hand) I was screwing on to finish.

That poor lathe wouldn't go slow enough for that diameter in 4140. Needed carbide and light cuts. Took all day.