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  #11  
Old 08-11-2019, 10:29 AM
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Quote:
Originally Posted by pepi View Post
To remove just turn the hand wheel on the tail stock full back the chuck or center dead or live to fall out.
Does not work on my tail stock with out a full length tang. But nice thought.
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  #12  
Old 08-11-2019, 10:30 AM
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Quote:
Originally Posted by LKeithR View Post
I've seen lots of drills with the tang broken off. A bigger drill and too much
power is all it takes. If you spin the drill in the taper then you run the risk of
damaging it. I'd rather keep my tailstock or drill spindle unmarked.
I have to get a picture later.
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  #13  
Old 08-11-2019, 11:58 AM
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MT is a taper specification that allows different manufacturers products to fit correctly in your machine.
The specific product determines whether any twisting moment is in play.
if there is no twist a tang can be optional.
if twisting is possible then a tang is added to increase the amount of power that can be used with the tool without slipping.
In theory the socket is harder than the tool so that when slippage occurs the machine is not damaged.
IIRC Chris (milomilo) had to ream a damaged taper.
sometimes removing tooling can need some innovation.
For example most lathe head stocks have a quite large MT and if used may require an adapter say MT6 to MT3 to get your tooling to fit.
to remove the tooling you need to put a piece of stock it from the back and bump it out.
The adapter that came with my lathe may have been made by the previous owner but it totally lacks any back side to bump against. If the smaller taper breaks free first I am left with an almost impossible task as I need a dog leg punch to be able to contact the back edge of that adapter through the spindle.

I have a set of MT collets that are threaded in place of the tang so that a draw bar can be used to close them around the stock. that draw bar is bumped to release the part.
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Old 08-12-2019, 08:16 PM
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Maybe missing what's being said, my lathe has MT3. This is the chuck, with a tang. It does not insert into a slot within the tail stock barrel, the set is interference.

Below a dead center, a pencil is pointing to a line on both. From that line aft in the tail stock, line is created by an interference fit/set.

If the tail stock had a slot for the tang the center would never reach a set.
I have a live center, mounted or i would have had it pictured. With the same shaft end as the dead center, no tang

Don't know all maybe there are lathes with a slot in the tail stock barrel. The question then becomes, anyone see centers with tangs?

I might suggest that tangs missing were not broke, but removed. I know when I got the chuck, the thought crossed my mind, before I mounted it.

I have drilled in to far without removing the chips, in the learning curve. The chuck spun, no marking as you can see.
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  #15  
Old 08-12-2019, 08:44 PM
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My Rivvet has the slot in the tail stock to receive a tang and if I put a center in without the tang it us a bitch to get out and I have dead centers with tangs
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  #16  
Old 08-13-2019, 07:51 AM
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Well tang, I cannot speak for older lathes regarding this. My knowledge is of the one lathe I have.

I would think, machine work that jammed so hard braking a tang. Is a much bigger problem that some scoring.

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  #17  
Old 08-13-2019, 09:53 AM
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Any tool holding method has a power limitation if you exceed that the tool will slip. My lathe is a 7.5 hp machine with an mt3 tail stock.
as the bits in the tail stock get larger the operating rpm drops.
That MT3 taper might hold against 7.5 hp
but when I set up for a 1 3/4 drill I slow the chuck to 20 RPM now my torque is multiplied by about 90 so the tool sees torque equivalent to about 600 hp. this is not normally a problem you feed the bit in and listen to your machine.
All goes well until the bit breaks through the end then it can be pulled into the work by the flutes caming on the uncut material. If the taper breaks loose all that torque is applied to the tang.
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  #18  
Old 08-13-2019, 10:22 AM
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This happened a while ago, I just found the tang recently. I had it when it first broke but it got dropped under the lathe and I found it again...

1" MT3 drill, in a 5 hp lathe.
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  #19  
Old 08-13-2019, 06:54 PM
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Hurts my teeth looking at that, nasty.

1 3/4 bit big boy, I see how the tang just could be a not so
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