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

"0_Qed" wrote in message
...
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

Dies are a bitch to use, plain and simple.

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. Also, make sure
the material isn't oversized. If you're trying to thread hot rolled stock,
it's often out of round and oversized. While I'm not a fan of reducing
the major diameter of threads, you could cut the material undersized by
..012" and still be in tolerance for a class 2 thread.

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.

Best bet is to use a lathe and chase the thread, even if you use a die to
take it to size after roughing it oversized.. By roughing with a lathe
(single point threading), the thread will be at right angles to the
material, so the die will follow and yield a somewhat better thread than if
you used the die alone.

Hope that helps----

Harold

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

Harold and Susan Vordos wrote:

Dies are a bitch to use, plain and simple.

Yup.
Cowardly, I gave up, went to the local Fastenal store,
bought 'B7' threaded rod & nuts.


If your die is adjustable,

Solid. tear

....anip...

Many thanks for the replys.

Ed

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

"0_Qed" wrote in message
...
Harold and Susan Vordos wrote:

Dies are a bitch to use, plain and simple.

Yup.
Cowardly, I gave up, went to the local Fastenal store,
bought 'B7' threaded rod & nuts.

Smart move, actually. Cut threads are woefully lacking in strength as
opposed to rolled threads, plus the surface finish and form is often
questionable.

Harold

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


"spaco" wrote in message
...
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

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

According to 0_Qed :
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.

Some die stocks (wrenches) have an adjustable guide on the other
side which will help get the die started straight onto the workpiece.

However -- have you checked the dimensions of the cold rolled
stock? I think that it typically is a little oversized to allow
machining to final size. This makes it more difficult to thread in any
case.

If you had a lathe, you could trim the OD to the proper size,
and could also turn the end to the minor diameter for 1/8" or so to help
get the die started straight.

If your dies are hexagonal shaped, they are probably rethreading
dies -- used for cleaning up damaged threads, and not for generating
new threads. "tap and die sets" are often supplied with these -- and
with only carbon steel taps. Round dies, with a slot to the center and
a screw for adjusting the size are more likely to produce good threads,
and these should be marked "HSS" (High Speed Steel).

You don't say *which* cold rolled steel -- some steels are
easier to thread (and to otherwise machine) than others.

You don't say whether you have used any cutting fluid. Go to
the Home Depot and check around for a blue bottle of "Rigid" high sulfur
cutting oil -- usually in the plumbing department. It will stink, but
it will improve the quality of the threads.

In any case -- you need to back up the die about every 1/4 turn
to break off the chips to keep them from clogging the die. (This is
even more important for taps, which have smaller recesses (flutes) to
allow the chips to accumulate.

Good Luck
DoN.


P.S. For whatever reason, everything except your original article
seems to be marked as expired. I can probably bring them back
later, but not while in the middle of the newsreader. So -- I
don't know what others have replied.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

DoN. Nichols wrote:

Some die stocks (wrenches) have an adjustable guide on the other
side which will help get the die started straight onto the workpiece.

....snip...

Many thanks for the reply.
"Off" to find rnd, adjustable die(s) and holder, and cutting fluid.

Ed

0_Qed wrote:
...
Whats the 'secret' to geting the 'die' started properly ???
....

Take a small piece of steel or aluminum, 3/4" thick is good, 1/2" would
be OK. Drill a 1/2" hole in it. Slip this piece over your stock and
clamp your die stock to it. I have a piece with holes for all the sizes
that I die-thread. Won't work if your piece to be threaded is too short.

Bob

OR use a tail stock die holder. Even if you just remove the tail center
and hod the die in a stock and use the flat face of the TS ram to position
and hold the die against the work, you should get fairly close to a true
thread. Other advise about opening the width of an adjustable die and
tapering end of stock also good.


On Wed, 12 Apr 2006 20:12:22 -0700, "Harold and Susan Vordos"
wrote:

Best bet is to use a lathe and chase the thread, even if you use a die to
take it to size after roughing it oversized.. By roughing with a lathe
(single point threading), the thread will be at right angles to the
material, so the die will follow and yield a somewhat better thread than if
you used the die alone.

Bob Engelhardt wrote:
0_Qed wrote:

...
Whats the 'secret' to geting the 'die' started properly ???

...

Take a small piece of steel or aluminum, 3/4" thick is good, 1/2" would
be OK. Drill a 1/2" hole in it. Slip this piece over your stock and
clamp your die stock to it. I have a piece with holes for all the sizes
that I die-thread. Won't work if your piece to be threaded is too short.

Wow! You've invented the multiple sized colleted die holder.

BugBear