atlas tail stock

[smirlex]

while using the tail stock on my atlas 12 x 36 lathe today i changed bits and had trouble with the drill spinning. i would swear there was a recess that held the tang to prevent spinning yesterday. am i losing my mind?

I was taught that the tang on a MT was there for removal only & not to secure the device. That the taper was all that was required. The taper, male & female had to be clean, free of grease or oil, & no high spots. & if the tang was called upon to prevent the device from tuning it could break it off. I've never seen this happen tho. Thanks
Hope this keeps me from being deleted.

 

[Bill C.]

while using the tail stock on my atlas 12 x 36 lathe today i changed bits and had trouble with the drill spinning. i would swear there was a recess that held the tang to prevent spinning yesterday. am i losing my mind?

The tang is used by other machines like drill presses to keep the holders from spinning. The tang fits inside a slot built into the spindle and/or adapters of these machines. Lathes don't used these tangs. Manufacturers used common supply sources.

 

[iron man]

I got tired of the chuck spinning so I re-reamed the taper till it was smooth again then in the key slot I installed a small setscrew no wider than the keyway with a drop of locktite the setscrew stays put and it reaches up and just touches the beginning of the tang closes to the taper I can drill with any drill now and the most that could happen is I could lose a setscrew this has worked for years on my other lathe and I would not change it for anything. more damage is done by spinning than anything else you could do.. Ray

 

[timmeh]

The tang is not there to drive, it is only there for removal. Regardless of what machine it is in. The taper is what is designed to "drive".
"Taper shank drills have morse taper shanks for holding and driving. The tang at the end of the shank is used for ejecting the drill from socket or sleeve."
(Ron Culley's Fitting + Machining)

 

[Bill C.]

Tangs are used in heavy duty drill presses, radial arm models. I agree lathes as far as I can recall don't. GE used to give each apprentice a set of sleeves to use with tang drill bits.

 

[tertiaryjim]

One solution is to drill a offset hole in the tailstock quill so a spring-pin inserted in the hole will just clear the tang.
If the drill slips just a bit in the quill it will catch on the pin for an extra bit of hold.
The pin would, of course, have to be recessed in the quill enough to avoid any rubs.
I'm certain, considering the condition of many drill-presses I've seen, that the tang often helps drive the drills.
Have also seen twisted tangs and drills with the tangs gone.
Wish people would learn to clean and dry their holes. Ha!

 

[turnitupper]

One solution is to drill a offset hole in the tailstock quill so a spring-pin inserted in the hole will just clear the tang.
If the drill slips just a bit in the quill it will catch on the pin for an extra bit of hold.
The pin would, of course, have to be recessed in the quill enough to avoid any rubs.
I'm certain, considering the condition of many drill-presses I've seen, that the tang often helps drive the drills.
Have also seen twisted tangs and drills with the tangs gone.
Wish people would learn to clean and dry their holes. Ha!

What would you use? A bidet?.
John.

 

[tertiaryjim]

John
A bidit might be appropriate for some of the yahoos I've worked with.
Gotta go spread some paint on the frames for the wheels to go under my grinder.
Need to be able to role this machine out of the way so I've room to tear something else apart.

 

[RJSakowski]

If the tang was designed for ejecting the taper and not as an anti-rotation device, why would it have two flats? You could eject it with just a reduced diameter stub on the end.

 

[John Hasler]

If the tang was designed for ejecting the taper and not as an anti-rotation device, why would it have two flats? You could eject it with just a reduced diameter stub on the end.

I suspect that when tapers first came into use they could not be consistently made with sufficient accuracy to work without a tang to prevent rotation.