Adjustable dies?

[Scota4570]

For my 15/16 AF 54 cal barrel, I bought a couple of 11/16-18 TPI taps and an adjustable die. 

Unfortunately the die is tapered on BOTH sides.  There was no notation about that in the description.  Threading up to the plug shoulder will not work with this die. 

All dies I have used in the past have a tapered starter side and the other side has no taper.  After going up to the shoulder with the taper side I flip the die and got right up to the shoulder.  Equivalent to a bottoming tap, basically. 

Is this a common thing?  What do I look for when buying dies to avoid getting the double taper type in the future?  Is is called double taper or ??

I have been searching the net and can not anyone else who makes dies this size.  Any ideas on who might be able to supply a correct style die?

[Bob Roller]

Sounds like a mistake by the manufacturer to me.If this is a recent purchase I would
contact the seller and see if you can get one that is right.In all the years I have been in
shops I have never seen or heard of this.I DO have a collet die marked 6x40 and it's
really a 6x32 and to me THAT IS the most useless thread I can think of.Too coarse for
such a little diameter and it should be named 32 fracture lines per inch.

Bob Roller

[jerrywh]

One thing you could do is to sand or grind one side down.  That is a very odd sized die, Did you buy it from amazon??   I am thinking I might have one that size bit not sure

https://www.mscdirect.com/browse/tn/Threading/Dies-Chasers-Thread-Rolls/Round-Dies?navid=12106027#navid=12106027+4286912313

[okieboy]

 McMaster-Carr carries one for $81, MSC carries 3 for $51-$185. 11/16-18 is a "special" thread, so tooling is going to be limited. A die being chamfered on both sides does not sound like it was designed right.
 A little late, but using either a 5/8 or 3/4" thread would probably produce less headache. 

[Scota4570]

This outfit seems to make them all like that. Check out the picture.

https://drillsandcutters.com/hss-round-dies/

I checked with a retired machinist, he has run into it before.

The work around it to use the die to even out most of the threads on the breech plug.  I normally start all threads in the lathe.  I then use a die or tap to finish them.  In this case I will likely leave it in the lathe.  Touch up the threads with the die.  Then kiss the last threads before the relief cut to take care of any not done by the die in the lathe. 

I went with the compromise size because the 5/8 thread in 54 cal leave no shoulder to seal against gas.  The 3/4 threads are so large as to leave little meat under the flats with the 15/16 barrel. 

[far55]

I just bought a 5/8-11 tap & die to use only for powder horns. I figured an import probably would not be quality steel, but would be sharp and work for my application. I found that it too will not cut to the shoulder when reversed. Roland.

[Hungry Horse]

 I’ve never seen a tap that does both taper, and bottoming, in one pass. Often if I have to tap a barrel in a size I don’t have I just start it with a taper tap, and then cut the tap off above the taper, and bottom it.

  Hungry Horse

[Bob Roller]

There are any number of Industrial Supply shops that can furnish this die
and it is not in the Special Thread" section.It is a bit odd but nothing special.
Bob Roller

[David Rase]

I have run into the same thing a while back.  Both sides of the die were tapered so cleaning up threads against a shoulder was impossible.  This seems to be a common practice on Chinese and other cheap export dies.  I have complete sets of vintage Greenfield Tap and Die company dies up to 1/2".  They were expensive but you get what you pay for.  I would not trade them for anything new.David

[Bob Roller]

There are any number of Industrial Supply shops that can furnish this die
and it is in the Special Thread" .victor Tool in Canton,Ohio has them at a very reasonable price
but be sure to ask about the back to back chamfer IF you can find someone who knows what
you are talking about.These used to be with the standard threads but not now.
Bob Roller

[Scota4570]

Thank you Bob, Victor looks like an excellent resource. 

Scot

[Bob Roller]

McMaster-Carr carries one for $81, MSC carries 3 for $51-$185. 11/16-18 is a "special" thread, so tooling is going to be limited. A die being chamfered on both sides does not sound like it was designed right.
 A little late, but using either a 5/8 or 3/4" thread would probably produce less headache.

I quit MSC after one of their employees laughed at me when I inquired about an order.
This was a few years ago and recently when I inquired about an end mill which was on sale.
They wanted $16 to ship it from Columbus,Ohio to me and I refused to be screwed like that.
I told whoever I was talking to that I can put 20 of those mills in a USPS flat rate box and send them from WV to Alaska
for $8.30 so their $16 charge was nothing but another small sale. I have all but  quit using regular
2-3 and 4 flute end mills in favor of 5-7 and 9 flute high spiral carbides from Maritool in Chicago whose
prices for these AMRICAN made tools is very reasonable without the exorbitant mailing costs.
Bob Roller

Thank you Bob, Victor looks like an excellent resource. 

Scot

.

[P.W.Berkuta]

I have run into the same thing a while back.  Both sides of the die were tapered so cleaning up threads against a shoulder was impossible.  This seems to be a common practice on Chinese and other cheap export dies.  I have complete sets of vintage Greenfield Tap and Die company dies up to 1/2".  They were expensive but you get what you pay for.  I would not trade them for anything new.David

This is how they keep the cost down on the dies. On a side note: I have a Greenfield split die that has no threads cut into it -- nothing - nada - and it was US made back in the 80's at least that's when I purchased it from a distributor.

[P.W.Berkuta]

For my 15/16 AF 54 cal barrel, I bought a couple of 11/16-18 TPI taps and an adjustable die. 


This is common with the Chinese dies - that's why they are so cheaply priced. I just purchased a bunch of metric split dies and all were tapered. You might try facing or milling off the taper with a carbide tool bit it would be rough on the tool but worth a try.

[James Wilson Everett]

Guys,

Using older tools is often a good solution to such issues.  Here are photos of a typical late 19th c - early 20th c adjustable die plate.  You can make an 18tpi thread of whatever diameter you need, no problem at all.  You simply use the die cutters marked for 18tpi and work the piece down to a nice snug fit.

Jim

[Scota4570]

"This is how they keep the cost down on the dies."

I'm not sure how an extra manufacturing step cuts costs.   I would bet they don't understand how the die is used by a machinist.   They probably inferred that if one were using it to chase threads on grubby old bolts that you get twice the tool life by tapering it both sides.

I used an 1/8" parting tool to make the thread relief cut on the plug. The taper was not an issue.  It snugged a tiny bit more for the last turn or so.  I coated it with moly paste to prevent galling.  It made a moderately tight interference fit thread. 

The plug thread did work out really well for the 15/16 AF 54 cal barrel,  11/16-18 TPI plug.  I got my internal seating shoulder and good thickness above the threads, under the flats. 

This will be a chambered plug hooked breech,  with a drum.  That will allow putting the drum far enough back to look correct with the hooked breech/ tang. 

I have over analyzed, over machined, and can sleep well.   


 

[Dphariss]

For my 15/16 AF 54 cal barrel, I bought a couple of 11/16-18 TPI taps and an adjustable die. 

Unfortunately the die is tapered on BOTH sides.  There was no notation about that in the description.  Threading up to the plug shoulder will not work with this die. 

All dies I have used in the past have a tapered starter side and the other side has no taper.  After going up to the shoulder with the taper side I flip the die and got right up to the shoulder.  Equivalent to a bottoming tap, basically. 

Is this a common thing?  What do I look for when buying dies to avoid getting the double taper type in the future?  Is is called double taper or ??

I have been searching the net and can not anyone else who makes dies this size.  Any ideas on who might be able to supply a correct style die?

Grind it down on one side, the side with the least taper.
This is not uncommon. Much of this $#@* comes from Communist China these days and there is little option.


Dan

[Bob Roller]

IF you have a vertical milling machine set it at maximum RPM and IF you have a
cup wheel mounted on a secure shaft and the place the offending die on parallels
 and cover the exposed surfaces of the machine with shop towels to keep the grinding
dust off precision ground surfaces.Touch off with a light cut to establish the accuracy of the
set up and then keep removing the unwanted thickness of the die.Trying to reduce the thickness
of any larger die is a gamble and holding one in your hand is a real roll of the dice.Good luck.
Bob Roller

[T*O*F]

I've posted this before but it never seems to stick in anyone's mind.  It is easily replicated if you have a lathe and avoids all these petty problems everyone seems to have.  Today's breech plugs are $#@* because they don't take the time when making them.  At least one consciences maker did in the past.

Note the shoulders at both ends of the threads.  They are cut to the clearance diameter of the threads.  The one at the end allows the plug to seat without having to thread the barrel all the way down.  Only a plug tap is required for it to seal.  At the other end, the shoulder allows the plug to seat without have to run a taper into the barrel to keep from pulling the threads when seating it.

[Dphariss]

For my 15/16 AF 54 cal barrel, I bought a couple of 11/16-18 TPI taps and an adjustable die. 

Unfortunately the die is tapered on BOTH sides.  There was no notation about that in the description.  Threading up to the plug shoulder will not work with this die. 

All dies I have used in the past have a tapered starter side and the other side has no taper.  After going up to the shoulder with the taper side I flip the die and got right up to the shoulder.  Equivalent to a bottoming tap, basically. 

Is this a common thing?  What do I look for when buying dies to avoid getting the double taper type in the future?  Is is called double taper or ??

I have been searching the net and can not anyone else who makes dies this size.  Any ideas on who might be able to supply a correct style die?

Grind it down on one side, the side with the least taper.
This is not uncommon. Much of this $#@* comes from Communist China these days and there is little option.


Dan

Its also possible the set the die up in a lathe and cut it back with a carbide tool.

Dan

[Scota4570]

If I were grid the taper off one side that would not leave much die. 

Carbide cutters hate interrupted cuts.   The cutter will chip. 

I used a shoulder on each end of the thread as illustrated in the picture above. 

Next time I need a die I'll just buy it from the place Bob suggested.

[Scota4570]

I receive some more China dies in the mail.  All were made with the stupid double taper.  Maybe it is the way the China boys make all of them.

 I sent an email to Victor tools.  They do not specify county of origin on the tools.  We'll see what they say.  Based on price I suspect they are also selling China dies.  Hopefully they understand what I am talking about. 

MSC does list county of origin.  Their dies are much more expensive, like 5X  more on some I looked at. 

[Bob Roller]

I receive some more China dies in the mail.  All were made with the stupid double taper.  Maybe it is the way the China boys make all of them.

 I sent an email to Victor tools.  They do not specify county of origin on the tools.  We'll see what they say.  Based on price I suspect they are also selling China dies.  Hopefully they understand what I am talking about. 

MSC does list county of origin.  Their dies are much more expensive, like 5X  more on some I looked at.

I used MSC back in the days when Sid Jacobson himself answered the phone but it seems as
if they want to price themselves our of the market and their shipping charges are preposterous.
There are many competitors now with a hungry look on their faces so keep on looking.
Bob Roller