Question On How To Make An Mt3 Socket?

[turnitupper]

MT 4 or 5 reducer might have the meat you need. Made a tailstock for a wood lathe and ground it down to suit, then threaded etc.
Maybe a solution.
John.

 

[Dinosaur Engineer]

These adaptors are available commercially. I bought a MT2 1" O.D ( HDN & GND). one for less than $7

 

[John Hasler]

Find a MT3 shank (drill bit?) you can chuck up and indicate it while moving the compound.

I used this method once and got close enough to make a usable taper wiith a little bit of lapping.

 

[kizmit99]

I am so lazy I would buy a # 3 taper drill socket
from Enco for less then $2o dollars that already
has a # 3 taper in the inside...

That was actually very close to my original plan. I even ordered an MT4 to MT3 reducer for it, but in the end decided to just get the reamers and take a shot at forming the socket myself.
I've been surprised that I've been unable to find anything on the web where anyone seems to have done this... would have thought it would been a pretty common thing...

 

[Jimsehr]

Here is pic of tapered sleeve I made.

jimsehr

 

[kizmit99]

So, a bit of a follow-up and another question...

I ended up drilling, then boring a hole through the piece. Then just used the roughing reamer to form the socket...
This seemed to work ok, but I've recently been able to determine that socket is not very well aligned with the center line of the part.
So, now I'm planning on trying to fit that. My plan was to try to bored the taper directly, then just use the finishing reamer to clean it up.
I started by centering a MT3 dead center in my 4-Jaw chuck, then using an indicator on my compound slide to mimic the MT3 taper angle...



I got that all nice and precise, then realized that this is actually the reverse of the angle I really want on the compound...
I can't think of a good way to mount any MT3 tooling I have in the opposite direction, so I'm thinking about setting up my boring bar "upside down" with the cutting edge facing to the 'rear' and 'down' and running the lathe in the normal direction (counter-clockwise facing the spindle). So, with a setup like this:





My question is -- Does this setup seem correct, or am I missing something obvious?
Assuming that's correct, I'm thinking the cutter should be pointing down just a hair, and be right on center or just a hair low... (because I've found that with a boring bar like this (but in a 'normal' cutting orientation) I seem to get a better cut with the cutter rotated just a tad "up" and "high"). Since this is effectively reverse, I'm thinking pointing slightly down. Sound correct?

Thanks!

 

[rick9345]

Yes

 

[British Steel]

Yes, but put the cutting point dead on centre height, otherwise you'll not get the correct angle in the taper socket and it'll be a parabola*, not a cone - DAMHIK
Same with the indicator against the prototype taper - dead on centre height.

Dave H. (the other one)

* I think a parabola - it's definitely not straight, may actually be a catenary?

 

[John Hasler]

I think a parabola - it's definitely not straight, may actually be a catenary?

Hyperbola of revolution.

 

[British Steel]

Ah, that sort of makes sense, conic section where the sectioning plane's parallel with the axis of revolution?

But... does that hold where the surface of revolution's generated by a straight line that doesn't intersect with the axis of revolution?

Geometry was a few decades ago...

Dave H. (the other one)