Author Topic: Broken screw in die  (Read 719 times)

Offline AVTUR

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Broken screw in die
« on: January 12, 2020, 07:29:05 PM »
I have a little problem. How do I get the broken bit of a screw out of a die?

I think the set up to cut the thread was OK. The screw broke at the die during the second pass. The lathe spindle was being turned by hand and a thread cutting lubricant used. The material was mild steel.

I am making 7 screws and this was the fourth. I put it down to pure exuberance; that is, not backing off frequently.

 :'( :'(

AVTUR
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Online Jo

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Re: Broken screw in die
« Reply #1 on: January 12, 2020, 07:33:27 PM »
12BA = it is small, so get a jewellers saw out, poke a thin metal cutting blade through the hole in the die and having tensioned the blade in the saw frame carefully cut into the screw. Move the blade into the next hole and cut again into the screw. Repeat down the split in the die.

It should come out  ;)

Jo
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Offline Jasonb

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Re: Broken screw in die
« Reply #2 on: January 12, 2020, 07:43:20 PM »
You can also expand the split die a little and see if you can get the broken bit to turn and screw out.

Offline AVTUR

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Re: Broken screw in die
« Reply #3 on: January 16, 2020, 03:47:45 PM »
Jo and Jason

Thanks for the suggestions. I should be collecting two new dies from a local supplier, in the next village, in the next few days.

I think I will encapsulate the die in clear plastic and keep it as a desk trophy.

AVTUR
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Offline zeeprogrammer

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Re: Broken screw in die
« Reply #4 on: January 16, 2020, 06:47:33 PM »
I think I will encapsulate the die in clear plastic and keep it as a desk trophy.

I like that.  :Lol:

If I did that for all my most memorable failures...we'd be out of clear plastic.
Come to think of it...some of my stuff should go into opaque plastic.
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Offline awake

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Re: Broken screw in die
« Reply #5 on: January 16, 2020, 09:11:24 PM »
How small is a 12BA? Yet another option, if you have a mill, is to get some cheap carbide endmills from eBay or other sources, assuming you can find some small enough. Spin the endmill as fast as you can, and peck out the screw.

I had to do this recently after breaking a tap in a part - in my case, 2mm endmills were an appropriate size. Obviously, the larger the endmill, the less fragile!
Andy

Online steamer

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Re: Broken screw in die
« Reply #6 on: January 16, 2020, 09:13:04 PM »
I see at least 2 plausable ways to do it.   I'd go for the ball end mill myself...but the piercing saw will work if the screw isn't hard.

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Offline tghs

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Re: Broken screw in die
« Reply #7 on: January 16, 2020, 09:36:55 PM »
being at under 1/16th for 12BA take a dremel and grind out the threads,chips and burrs in the round holes near where break happened,, then try a #60 drill from the back side,, it may spin out.. no use wasting a HSS die..
what the @#&% over

Online Jo

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Re: Broken screw in die
« Reply #8 on: January 17, 2020, 07:53:35 AM »
The tapping size for a 12BA is 1mm. Things will happen very quickly with power tools in the  die  :paranoia:

Jo
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