3/4-16 to MT2 Spindle Adapter

[astroracer]

I have a small MEAD H/V 6" Rotary Table and I needed to adapt a small 3" Sherline chuck to it. The chuck has 3/4-16 threaded back and the rotary table is an MT2 Taper.
I used a piece of 11/16th diameter aluminum to make the spindle adapter, you 'll see why so small shortly. Chucked up in the lathe I set the angle tool post at about 1.5 degrees and started cutting.

Once I had it close I started checking the fit and adjusting the angle until it fit in nice and tight with no slop. I don't really know what the angle is but it is a little under 1.5 degrees on my tool post.

I drilled and tapped the back side for a 1/4-20 "draw bolt" to pull it tight into the table.
I had a few miss-steps getting this project off the ground. Trying to thread the end, with that 3/4-16 die was not working. I couldn't get the thread to be parallel to the body of the rod. The only solution was to put on the taper THEN thread it in the lathe with the adapter slipped into the MT2 tailstock.

This worked well and got me a concentric thread. I left the threading die "loose" in the lathe chuck so it could follow the thread out of the chuck. With the tailstock locked down I rotated the lathe chuck by hand and got the die threaded on about the length of the die.

Next post

[astroracer]

The reason I went small on this is, I couldn't get the die started square, no matter how hard I tried, with a piece of 3/4" stock. The die would just peel the end off. With the 11/16th stock it had the ability to start a bit deeper in the die and it wasn't cutting as much off so I was able to get it to start square and concentric which is what this piece needs.
Well, after I had the threads started in the lathe I did as much as the taper grip would let me. After it started spinning I pulled the spindle out and set it up in a collet block in the vise to finish the threading. Once I had it threaded I backed the die off and turned it around so the sharper "trailing" side could finish cutting the threads all the way to the shoulder.

After taking it out of the collet block.

Mounted in the table with the draw bolt pulling it in tight.

The chuck attached and locked in place with a jam nut.

Now, on to adding detents to that spindle I was talking about previously.
Mark

[C-Bag]

Thanks Mark. I love seeing I'm not the only one on the planet who's "just want to get from A to B" takes them back around by way of Z just to get to B I learn a lot from those kinds of excursions but I sometimes can't figure out a good plan of attack and sometimes I just chicken out.

I needed almost the same thing for adapting my 3" chuck to my 10" rotary table. I ended up getting a MT2 arbor blank that has machinable end ($12+shipping and tax), then chickened out and sent to my brother who's the real machinist and had him cut the big oddball threads my HFT 9x20 lathe uses. After seeing your excursion I wish I would have at least tried to mess with single point cutting the threads. Now that Marv gave me the wonderful tip of practicing on PVC first. But who knows if my lathe can cut that thread......Next project.

Thanks for posting.

[Paul Jones]

C-Bag,

I am sure that after you start practicing with PVC doing single point threading on your lathe you will find it really easy. Marv has a great idea about using the PVC material first for practice because it won't hurt your lathe or you if something goes wrong.

Good luck, Paul

[C-Bag]

Thanks for the encouragement Paul. The whole process seems overwhelming right now. I asked my SO to find my copy of Machinery Handbook that had dissapeared when we moved. To be fair I found that years before I even had my lathe or mill so it got "tidied" because I didn't even have an application yet so it was sitting around gathering dust. Bless her heart she doesn't like clutter and that's anything that is not being used.

But Marks project made me crack that book for the first time. And the section on single point threading while only two pages long is throughly daunting. There is a threading guide plate on the lathe, but right now it looks like Chinese, or Greek . Guess I'll hunt up the old pete222/tubalcain vids on single point threading and see if I can get it to stick to my Teflon brain.

[Paul Jones]

C-Bag,
I like the YouTube videos by pete222/tubalcain for his explanation of single point threading. In fact he just published a new video on single point threading for Imperial-based lathes missing the thread dial (this method also applies to cutting metric threads on lathes designed to cutting threads per inch). However, you will have to watch his earlier videos for all the setup details he skips in this video. He is a wonderful teacher. Let us know how this turns out.
Regards, Paul

[DIYer]

Thanks astroracer! We've added your MT2 Spindle Adaptor to our Machining category, as well as to your builder page: astroracer's Homemade Tools. Your receipt:

MT2 Spindle Adaptor by astroracer

tags: spindle, adaptor

[bbutcher85]

I have a small MEAD H/V 6" Rotary Table and I needed to adapt a small 3" Sherline chuck to it. The chuck has 3/4-16 threaded back and the rotary table is an MT2 Taper.
I used a piece of 11/16th diameter aluminum to make the spindle adapter, you 'll see why so small shortly. Chucked up in the lathe I set the angle tool post at about 1.5 degrees and started cutting.

Once I had it close I started checking the fit and adjusting the angle until it fit in nice and tight with no slop. I don't really know what the angle is but it is a little under 1.5 degrees on my tool post.

I drilled and tapped the back side for a 1/4-20 "draw bolt" to pull it tight into the table.
I had a few miss-steps getting this project off the ground. Trying to thread the end, with that 3/4-16 die was not working. I couldn't get the thread to be parallel to the body of the rod. The only solution was to put on the taper THEN thread it in the lathe with the adapter slipped into the MT2 tailstock.

This worked well and got me a concentric thread. I left the threading die "loose" in the lathe chuck so it could follow the thread out of the chuck. With the tailstock locked down I rotated the lathe chuck by hand and got the die threaded on about the length of the die.

Next post

Nice job. I also made a similar adapter for my 8 inch rotary table but for a MT3 taper and a 1.5-8 thread to fit my Atlas chuck. I discovered when cutting tapers that it works well to use a dial indicator mounted on the compound. I have another 2" travel dial indicator mounted on my lathe bed to measure travel. To measure the taper just move the carriage some known distance and measure the change in the first dial indicator. You can find exact dimensions of Morse tapers on the internet or in Machinery's Handbook.

Bob

[astroracer]

Hi Bob, thanks for the tip on the dial indicator. What this little job taught me was to develope the O.D's of the taper first. For a #2MT the head and tail diameters are .700 and 0.576, 2.56 inches apart. Grooving the material to these diameters gives an excellant visual to get the taper turned to the right size.
Mark