Re: Help needed to cut MT 2 taper for Tailstock Die Holder


Robert H. Blodinger
 

Mark, you always wind up with great solutions.  I thought something was wrong when I setup the .070 offset but should have followed thru after the first couple of cuts.  Jim B's idea if fine but my piece is already tapered and I would have to start from scratch again.  Looks like you win.  I will be in town tomorrow but not till mid afternoon and will give you a call.  Hope this gets to out  in time to bring one of those Threaded MT 2 pieces with you, no problem if it is the next day.

I may have screwed up tonight as I made a bad guess using a formula for set over when you know the length of the total part and the diameter of each end of the tapered part, now have about. .9 or so left on the big end and down to .72 on the small end, but my taper was too much. I decided I better quit and do it your way.

Hopefully your threaded pieces have threads I have a tap for, or guess I can take the threads off and bore the end of a rod and lock title them on so the whole thing is exactly positioned and the same length as my half finished part.

Thanks again,

Bob

I

2


On Jan 4, 2016, at 10:50 AM, mark.jonkman@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:

 

Hey Bob

One option might be to carefully measure your current workpiece and determine the current taper per foot based on the offset you used. Then calculate out how much less or more needs to be offset to get the correct offset and adjust accordingly. Like others have said the offset has everything to do with the length of the workpiece. If you take light cuts and if you have enough stock left to remove you can probably get a good match with a few adjustments. 

Another option might be to buy a #2 morse taper arbor with a  threaded end on it. Then either use the thread to attach the tool holding part or turn it off and use just the stub to connect to your tool holding portion.

I bought a couple of #2 morse taper arbor with a half inch thread on them (I think it was half inch thread) a couple of years ago from Victor Tool Exchange for something like $8 each (or something like that).  Since I sold my Heavy 10 two weeks ago I'll probably never use them. If you want one for say $5 let me know I can meet you on the downtown mall at lunch one day this week.

Sincerely
Mark R. Jonkman
 

From: SOUTHBENDLATHE@... [mailto:SOUTHBENDLATHE@...]
Sent: Monday, January 04, 2016 3:18 AM
To: SOUTHBENDLATHE@...
Subject: [SOUTHBENDLATHE] Help needed to cut MT 2 taper for Tailstock Die Holder

 I am making a Tailstock  Tap and Die Holder with feel from a Homeshop Machinist article March-April 2015 article.

I have started to cut the MT 2 Taper.  The taper is over a length of 2.803 inches.

The article advises a Tailstock set over of .070.  I carefully centered the Tailstock with a coaxial indicator ( and I know that it was already cutting exactly on center as the 1.5 inch piece I was cutting from had just been reduced from 1 11/16 in and tas true it's whole length.  I am cutting between centers.  I first cut a half in long tang half in wide at the tail end

I checked the math of the article and came up with exactly .070 for the set over (forward ).  With an indicator on a drill Chuck in the Tailstock I moved the Tailstock forward .070 and started to reduce the 1.5 in stock up to a shoulder about 3 inches from the beginning of the taper.

I reduced the width at the Tailstock small end of the taper down to .8445 an then measured at the 2.803 station large end and found that it was down to. .893, a difference from the small end of only .0485.

My goal was to reduce the small end down to .572 per MT2 specs to get the large end at the 2.803 station of .700 as per MT2 specs, a difference over the 2.803 inches of .128.

I realized then that I must have a problem because I was getting close to my final size and figured something was wrong as I was not going to be able to get there when so close and still only a difference between the two ends of of only .0485.

 I again checked the set over and it is right on .070, also the marks on the Tailstock showing set over measure .070 apart.

So do I have a problem, and if so what do I do to get the taper correct and hopefully save the part before I go too far.

Bob


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