Project advice needed

[Jim F]

OK - thanks for that. I have a test bar with MT2 on one end, and MT3 on the other. I will be checking them out tomorrow.

Two lathes, one 9A is I believe 1947, or nearby, and the other is unknown. That one is a South Bend 9C with no serial marking in the place you would expect. I am told that South Bend lathes used by South Bend, and not sold, were like that. They were all eventually sold as used when SB ceased that production, and I think mine is one of those.

So in making a 3C collet holder, the Morse MT3 is to be on the collet holder, so it will mount up the SB9 spindle. Would that be the part at the bottom left of the drawing?

I think starts out between centers, with something reference MT3 put in there, and then adjust the compound angle while an indicator touches to it, until it tracks true. Then put your steel in between the centers to cut the paper. I haven't thought it all through yet, but once the rest of the outer has been made, you abandon the centers, and stick it into the spindle MT3 directly, and then drill and bore it.

Yep, pretty much.

 

[Asm109]

I made an adapter for my Heavy 10 to convert from the spindle taper to fit 1J collets.

I put a test indicator in a holder on the toolpost and adjusted the compound until the indicator did not move while tracking the internal spindle taper.
Mounted a chunk of material in a 3 jaw and turn the OD to the proper size and taper with the compound.
Also drilled and bored the ID to the size that fits the rear of the collet.
Parted the chunk off.
Reset the compound for the angle of the head of the collet.
Pop the part into the spindle and gave it a good tap with a dead blow hammer.
Bore the relief diameter, cut the angled surface for the collet and faced and turned the OD of the flange.
Done.

 

[mickri]

I have 3c collets for my 12x36 craftsman lathe. The collets are south bend. Don't know the make on the draw bar. The draw bar has 9-752W embossed on it. I can take pictures of what I have for you. The draw bar has a .750 OD with a .500 ID. The spindle adapter is maybe 2" long. There is also an adapter to keep the draw bar centered in the spindle. You have enough travel on your compound to make the adapter.

 

[graham-xrf]

Duh - I forgot. It doesn't matter much, but facing and putting centers into the steel stock first is probably a good idea.
Also consider a small relief zone in the middle of the taper, to ensure it takes it's support force contact zones at each end.

I still haven't check out my MT sizes. That's a time zone thing. I've been getting some Zzs.

 

[Jim F]

Well, it turned out OK.
I put a MT3 dead center between centers and used a 1-2-3 block to get close to the angle.
Swept with a TDI, to get it on.
Used 4 jaw to do most turning.
Used the adaptor in the spindle to do the final boring.
Used the 4 jaw to bore and thread the draw bar.
Haven't done single point threading since 1984..............
After everything was done, chucked up a .500 drill bit.
.0035 TIR.
I am happy with that, being made on a 73 yo machine by a rookie.........
Thread protecter started life as a 1.5x8 grade 8 nut..........
There is a 4-40 set screw to hold the collet from turning.

 

[brino]

Great job Jim!

You may not deserve the "rookie" designation any longer.

-brino

 

[Papa Charlie]

Nice work, I second @brino motion.

 

[Choiliefan]

Very nice!

 

[Jim F]

Thanks guys, better response here than at PM..........
Was told that the hex needs turned round..........
There is no way my hand is getting that far back to contact the points.

 

[Jim F]

Had to go back and re-thread the draw-bar...............
I used my 1/2" collet to test when I made it.
Needed to use the 3/8", well, it did not fit.......
4 of the collets would not thread all the way in.
Used the Joe Pie method of picking up internal thread, and .020 later, all collets fit.