screw swedge

[Stephen Olivo]

I don't know if anyone else is interested in this process.  I was watching the woodwrights shop today and they went over a tap and die that was over 100 years old and I thaught that was interesting so googled it and it brought up a pretty good link. 

 

Just thought I would share.

 

http://americanlongrifles.org/forum/index.php?topic=18831.0

 

I may have to make a plate for doing this sort of thing it seems like a fun thing to try out.  I have been thinking about making my own tap and die for a while now ...  Just because I can.

[Wayne]

In one of the woodwright books is a step by step section on hand making taps andthen on making a wooden die box to put threads on wood.

[doc]

Stephen,

          Sounds like a great project! Remember though if you don't have wrought iron you should use one of the leaded/free machining alloys because these threads aren't cut but swaged. A-36 or plain cold rolled will be too hard for this process.

[Francis Trez Cole]

that is very cool thanks

[Stephen Olivo]

Doc:  I do have some wrought.  But yeah that is one thing talked about.  Just seemed interesting.  If I do make it I will deffinatly look into those alloys.  Thanks for the coment and info.

 

Wayne:  I have those books and thats something I plan on doing when I can pull out the forge again.  Its been one of many things on my list for a looooong time :D 

 

Francis:  Your welcome :D

[rockstar.esq]

I'd like to know how these were made.  The process is swaging the screw blank so it seems like if you'd just cut threads with a tap, the resulting tool would act like a die and cut as well.  Am I missing something?

 

Thanks,

[Dan P.]

What's the difference between a swage and a regular thread-cutting die?

 

Also, I've tapped a bit of wrought iron in the past, and it can be a bugger when the tap catches on a bit of slag- it'll have you doing the snapped-tap war-dance in no time!

Not such a problem cutting the male threads (what is that called? Die-ing??).

[doc]

The reason taps and dies for wrought iron weren't made to cut like those for mild steel is because of the grain or fiber structure of wrought iron. Imagine the fibers of the iron running lengthwise along the bolt. If the threads are cut with a modern die the edge of each thread from peak to root is going to be all short grained fibers just like the end grain on a piece of wood, so it has no real structural strength.

 

On wood screws threads cut with a file instead of swedging are acceptable because the wood will always be weaker than the iron. Swedging for wood screws was used because it made the process quicker. But when it comes to machine screws. It was used for structural purposes.

 

The old blacksmiths tapered taps do the same thing based on swedging the thread for similar reasons. In both cases whether making male or female threads. It's actually more a form of extruding rather than swedging. The material that forms the thread is forced into the crevices of the tap or die as a tool is either work over the material for a male thread or force into the material for a female thread.

 

 

The use of the terms swedging or extruding is a matter of semantics.:-)

[John B]

Today they thread roll on mass produced bolts/screw, This is also a form of swaging (swedging ?)