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A hack to short Morse taper for lathe

wxm

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Dec 15, 2008
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901
Location
NJ
I have this no name (imported?) chuck for a while. I came with the lathe, but it was painful to use it as the taper end was cut short by the previous owner and I would not eject when tailstock was fully retracted.

One way to address the issue is obviously replace the MT2 taper, but I don’t have the wedges to loosen the Jacob taper on the chuck end. Plus, I owner a good 1/2” Jacob chuck, don’t feel like spend too much on a Jacob taper for this import chuck.
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So here is my hack to get the ejection to work. The idea, might have from one of the post here, is to add a short round stock which extended the taper long enough so it will catch the center pin and push itself out. But I don’t really want to deal with “fishing” the round stock with magnet when switching to other inserts. So I decide to drill and tap a 1/4-20 hole and I then screw in a 3/4 length bolt...

Here a few pictures of the process, and the final “product”. The bolt is put on with lock-tite, in case I need a shorter taper for whatever reason. I can just remove the bolt.

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Didn't really have a good way to clamp down the the taper with chuck on it. So I locked the chuck on a 3/8 mandrel, and then clamped the mandrill in a collet chuck.

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Started drilling with the center drill.

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After a few iteration of the drill bits, finally ended a 7/32" hole.

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Tap into 1/4-20 thread, first with a starter tap in the tail stock
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Completed the threading with the tap wrench.

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why worry

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Nice job where there's a will there's a way as my Grandfather used to say....
Dave
 

larry_g

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I have a few of those that have come my way. The screw makes it easier to adjust for the different spindles. Good Job.

lg
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matt_i

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Mar 14, 2008
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SE Michigan
Good stuff, I am curious about the 7/32" pilot diameter for a 1/4-20. I've tapped a few (thousand!) of those and used #7 always...or a 13/64" is a good "hack" since its only off by .002". Was the material hard and needed the thread contact reduced?
 
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wxm

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Joined
Dec 15, 2008
Messages
901
Location
NJ
Good stuff, I am curious about the 7/32" pilot diameter for a 1/4-20. I've tapped a few (thousand!) of those and used #7 always...or a 13/64" is a good "hack" since its only off by .002". Was the material hard and needed the thread contact reduced?


I suppose the 13/64 might be better. It felt too “easy” when I was tapping it. But my drill chart says 7/32 and I don’t have 13/64 anyway. Guess it is ok for this applixcation as it doesn’t take too much stress.
 
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eicke

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Dec 6, 2013
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7
Just did this but used a real short 5/16" socket head capscrew. Looks more like a tanged arbor.
 

Millwrong

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Feb 4, 2018
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Canada
Nice work! MT2-JT Shanks are like $5-$10 on ebay for next time though...;) Is there no tang slot on your tailstock quill?
 
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wxm

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Messages
901
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NJ
My atlas craftsman lathe has no tang slot. There is a center pin which serves as a ejecting mechanism.
 
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