How to eject short 2MT from sleeve?

I put a 2MT drill chuck/arbor into a 2MT/3MT sleeve before I realized that it was too short for the eject slot. Took me a while to get it out, but I wondered if there was a better way than I used. The arbor, unfortunately, has no threaded end that I could have put an extension on.

A selection of ball bearings is useful but must be small enough not to jam in the taper themselves. On a lathe tailstock where the screw doesn't reach the drill owing to a missing tang the ball will helpfully roll out afterwards.

It's normally possible to drill and tap the MT end for a screw-in tang.

The ball is a good idea. Drill and tap is good too now that I have it out, but I have lots of 2MT stuff, with no tang and no threaded hole, that I might use in the sleeve. I'll try tapping that one arbor and see how it goes.  Thanks, gents.

-Mike

Edited By MikeK on 11/02/2022 20:06:01

My running centre is too short to eject in the lathe tailstock, I just araldited a ball bearing onto the end.

Hi Richard.  Doesn't using an ejection drift on it doesn't break the ball free?

-Mike

Edited By MikeK on 11/02/2022 21:33:09

If the end of the taper or tang is not too hard, you can drill it and glue/Loctite a turned extension. I used a milling cutter to make a slot in the new lathe tailstock quill to enable use of the taper ejector rather than strain the leadscrew and nuts. The slot got extended slightly as live centres do not have a tang and are shorter. The opposite happened with my 7 x 12 mini lathe at home, the length of the MT2 limited the tailstock stroke before ejecting. I cut the tang off two chucks, the original 1/2" and the more suitable 5/16" chuck, and drilled a hole down the Morse taper just clearing the leadscrew diameter. Then a plug of brass was put down the hole just long enough to eject. this enabled the full length of quill movement practical. If you have a mill and solid carbide endmills the same diameter as the slot, you could make it a bit longer.

That's a good point about the strain on the tailstock threads from withdraw-ejecting tools. I've always done it that way and never gave it a second thought.

Drilled and tapped with a bit of stud like this sorts it out for future use. I had to dismantle the tailstock to remove this one after putting it in without realising it would not eject. No available slot to stick anything behind it to get it out.

Martin C

Neat, simple trick I recently saw on YouTube: Place a U-shaped block over the ram, between the back of the stuck tool and the front of the tailstock before winding it back.

just done this on my running center too

What a great idea! Wish I'd thought of it before I had to dismantle my tailstock...

Rob

For credit, this is the video. Idea should be obvious, though, don't need to watch it.

And this got me to thinking...

I need to remove the arbor from a chuck. It fits an M12 drawbar and all my other stuff is 3/8" so I need to remove the arbor to fit the new one. But I have no chuck wedges. And I thought about that ejection method. Hey!...I can put the chuck w/ arbor in the lathe or mill spindle and draw it back against a block to get the chuck off!

Edited By MikeK on 13/02/2022 17:12:44

I have converted more than one tool with a M12 drawbar thread to 3/8 BSW like the rest of my tooling.

A length of M12 studding is Loctited into the tool, and then face back and centre drilled.

Drill out to 5/16 and tap 3/8 BSW.

Drilling and tapping the studding before fitting is not advisable, because the thread often tears. How do I know?

Experience allows you to recognise the mistake the next time you make it!

Howard

That is a good idea, Howard. I had considered it, but I couldn't come up with a way to hold the job in the lathe for drilling/tapping. The keyless chuck with the arbor installed was pretty long and wouldn't have given me enough room. And the new Chinese arbor was $7 shipped. I'm curious, now, how you set it up in the lathe.

The arbor arrived today, replacing the first one that had a mis-tapped drawbar hole. It has 0.001" runout. Not bad, I guess. But my old arbor with an M12 drawbar hole has only 0.0005" runout, so I'll be refitting it for 3/8"-16.

Still haven't thought of how I can hold it in the lathe, though.

Mike

If I'm reading your situation correctly.
Fit chuck to arbor, and grip something round in it.
Hold that stub in the lathe chuck and use a fixed steady, on the right hand end of the new arbor, for support. whilst machining.

Bill

Hi Bill. Using a fixed steady on a taper seemed like bad practice to me. That's safe? With basically point contact I assumed the steady fingers would wear quickly and allow the work to bounce around.

Mike