Turning a MT2 taper

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mickri

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It was suggested in another thread that I should change taper on a very large bull nose live center I have to fit the tailstock on my lathe. The tailstock has a MT2 taper. The bull nose appears to have a MT3 taper. It will slip a little ways into the MT3 taper on the headstock on my lathe. I have no idea how to turn a MT2 taper. I plan to check on Mr. Pete's you tube channel but thought that I would ask here first.

IMG_20230322_084342.jpg
 
I just turned an MT3 taper using my compound.

Depending on your lathe and the amount of travel you compound has you can use your compound. Other wise you will have to offset your tailstock.

What I did was put one of my MT3 dead centers between another dead center and the center hole of a stright shank JT3 arbor. Then I set up a dial indecator on my compound and adjusted it to zero as turned the compound along the length of the dead center. I hope that makes since. That got me pretty darn close.
 
matthewsx said:
If you have the room.


John
Click to expand...
I have a number of MT2 to MT3 adaptors and several MT3 to MT2 adaptors. All have been purchased over the years on eBay. They have generally run between $10.00 and $15.00 depending on condition (all of mine were new name brands) brand, and number of units listed at the time. This allows me to interchange tailstock held tooling between the lathes. In my case space isn't a problem. One lathe has a 60" bed and the other has a 56" bed.
 
This is how I got to doing it!

www.hobby-machinist.com

Fun With Unknownium, a MT2 Tailstock Center Drill Holder-From Scratch

I use my Shenwai SW900B lathe to do a lot of my projects. this time i wanted to make a full-time tailstock center drill holder, the problem was that i never cut a morse taper before on a lathe. i doubted my ability to make a concentric tool with a MT2 taper that actually worked. that had to...
www.hobby-machinist.com www.hobby-machinist.com
 
I already have Halligan142's formula for tailstock offset written down in my notebook. I have learned a lot from his videos.

Back to the project at hand. This bull nose live center is heavy. It weighs 12 lbs. No way am I going to use an adapter hanging off of the tailstock ram. Here is a picture of the shaft.

IMG_20230323_074531.jpg
The straight end already has a center hole. The tapered end needs a center hole if I am going to use the off set taper method. I actually don't need to off set the tailstock because I made a boring bar holder primarily to have the ability to turn tapers without off setting the tailstock.

IMG_3739.JPG

I found a morse taper chart online. The taper per inch for a MT2 is .500. The taper per inch for a MT3 is .502. If I use the compound method is the MT3 taper close enough to MT2 taper that I can use the existing taper on the shaft to set the angle of the compound?

This is my order of operation (wrong term?) if I use the compound method.

1. Dial in the shaft in a 4 jaw.
2. Drill a center hole in the taper end.
3. Turn the headstock end of the existing taper to .700. Say 1/2" to 1" long. .700 is the max OD of a MT2 taper.
4. Measure 2.5" from where I want the taper to end and turn the rest of the shaft to .5720. The minimum OD of a MT2 taper. I want to have a tang on the end to be able to push the live center out of the tailstock ram.
5. Set the compound to the same taper as the existing taper.
6. Turn the taper cutting towards the tailstock. Or cutting towards the headstock. Does the direction of cut matter? I always prefer cutting towards the headstock because I have had problems in the past with the work pulling out of the chuck when cutting towards the tailstock.
7. Part off the end leaving a short tang. Say 3/8" to 1/2."

I will have to check the length of travel on the compound. I recall it being just over 2 inches.

For the off set method this is my order operation.

1. Dial in the shaft in a 4 jaw.
2. Drill a center hole in the taper end.
3. Turn the taper end of the shaft to .700.
4. Measure 2.5" from where I want the taper to end and turn the rest of the shaft to .5720. The minimum OD of a MT2 taper. I want to have a tang on the end to be able to push the live center out of the tailstock ram.
5. Calculate the amount of off set.
6. Set the shaft between centers with the tailstock end off set as calculated.
7. Turn the taper cutting towards the headstock.
8. Part off the end leaving a short tang. Say 3/8" to 1/2."

What have I left out?
 
From my minimal experience with tapers, they are extremely sensitive to the actual taper. Just the tiniest deviation will result in low contact in the socket, which is not what you want. It will look like it is ok, but it will be prone to slipping and damaging the socket. I learned this the hard way with a taper purchased on eBay. Bluing showed the taper wasn't even close to being correct. The only contact was a 0.5mm band at the mouth of the socket. Measuring the taper showed it was off by about 5 thousandths too large, if I recall correctly.

I advise you to get a known good MT2 taper and then copy the angle using an accurate indicator.

Haven't cut a precision taper yet myself, so can't advise on which technique is more suitable. In my case, it would probably be with the compound, since I don't have one of those offset gizmos.
 
I know how to solve this.
Sell me the bullnose.
It'll fit my tailstock. :)
 
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