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Posted by 0_Qed on April 12, 2006, 10:52 pm
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Readership ,
How do you hand-cut 1/2" NC( 13tpi ) with a plain vanila tap & die set
???
Whats the 'secret' to geting the 'die' started properly ???
cold rolled rnd stock.
Ed
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Posted by James Waldby on April 13, 2006, 12:09 am
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Harold and Susan Vordos wrote:
...
> If your die is adjustable, open it up so you take two passes, one to rough
> the thread, one to take it to size. Cut or grind a chamfer on the end of
> your material, and make sure it's uniform, so it assists in starting the
> die, not only square, but concentric with the material.
...
A few times I've left some extra length, turned to root diameter,
to start a die out straight, and conversely when tapping, drilled
a little ways at ridge-diameter size to start a tap straight.
Home shop expedients ...
> Don't permit the die to start crooked with the idea you'll get it to run
> straight once started. That works about as well as a pig on stilts.
...
I've never seen a pig on stilts so couldn't say.
Your varied experience never ceases to amaze me!
-jiw
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Posted by spaco on April 13, 2006, 10:06 am
Please log in for more thread options I agree with the other posters about chamfering the end, to about 45
degrees, down to the root diameter of the thread or even a little less.
I do have a lathe, so I chuck the stock to be threaded, lock the
chuck, apply the die/ die stock to the work and use the tailstock ram to
gently push and align the die with the stock. If you have enough hands,
you can crank the tailstock ram gently as you begin threading. If you
can't do both, turn a little, bring tailstock ram up, turn a little
more, etc.. I keep the "pressure" on for about 2 turns. This has worked
well for me for many years, even up to 3/4-10. Without a lathe, maybe
you can use this general idea to make a simple fixture to do the same
thing. Clamping the stock vertically, pointing up through your drill
press table comes to mind.
Needless to say , you need a sharp die and not one of those
rethreading dies that are just used for cleaning up an existing thread.
Pete Stanaitis
0_Qed wrote:
> Readership ,
>
> How do you hand-cut 1/2" NC( 13tpi ) with a plain vanila tap & die set
> ???
>
> Whats the 'secret' to geting the 'die' started properly ???
>
> cold rolled rnd stock.
>
> Ed
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Posted by Dave August on April 13, 2006, 7:15 pm
Please log in for more thread options As an alternative to this but basically the same idea is to grind 3 flats
spots so you can hold the stock FIRMLY in a jacobs chuck in the tail stock,
Stick the die in the lathe chuck (3 jaw works nicely for hex dies collet
works well for round ones) and run the stock through that way.
I do a LOT of threading of 1/4 brass with 5-40 and I can make 'all thread'
like you wouldn't believe this way under power... I also have a small collet
holder I can put in the tailstock so holding up to 1/4 is a breeze.
--.- Dave
>I agree with the other posters about chamfering the end, to about 45
>degrees, down to the root diameter of the thread or even a little less.
> I do have a lathe, so I chuck the stock to be threaded, lock the chuck,
> apply the die/ die stock to the work and use the tailstock ram to gently
> push and align the die with the stock. If you have enough hands, you can
> crank the tailstock ram gently as you begin threading. If you can't do
> both, turn a little, bring tailstock ram up, turn a little more, etc.. I
> keep the "pressure" on for about 2 turns. This has worked well for me for
> many years, even up to 3/4-10. Without a lathe, maybe you can use this
> general idea to make a simple fixture to do the same thing. Clamping the
> stock vertically, pointing up through your drill press table comes to
> mind.
>
>
> Needless to say , you need a sharp die and not one of those rethreading
> dies that are just used for cleaning up an existing thread.
>
> Pete Stanaitis
>
>
> 0_Qed wrote:
>> Readership ,
>>
>> How do you hand-cut 1/2" NC( 13tpi ) with a plain vanila tap & die set
>> ??? Whats the 'secret' to geting the 'die' started properly ??? cold
>> rolled rnd stock.
>>
>> Ed
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Posted by The Davenport's on April 14, 2006, 5:51 pm
Please log in for more thread options >
> That works about as well as a pig on stilts.
Now THAT is a visual that I would pay some big bucks to see.
But only in person...video looses too much.
Mike
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> the thread, one to take it to size. Cut or grind a chamfer on the end of
> your material, and make sure it's uniform, so it assists in starting the
> die, not only square, but concentric with the material.