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Tiger
4th Dec 2005, 01:07 AM
Hey all,

I'm trying to cut a thread with a 1/4" Whitworth die in some 1/4' inch rod. The die seems to cut a well defined thread but when I try and thread a nut onto my new thread it struggles. I can get it on and turn the nut but only with a fair amount of effort with a spanner. I have checked for burrs on the thread and can't see any after cleaning with a brush. Any ideas would be well received.

rodm
4th Dec 2005, 01:25 AM
Turn the die around and run over your thread again. A die has a tapered start from one side and if you turn it around and recut it you will cut to the full thread depth. This is important if you are threading up to a shoulder.

If you still have problems then it could be your 1/4 inch rod is slightly oversize. If it is not too long chuck it in a drill press (chucked in a lathe is best) and carefully file the thread down a bit. Recut thread and you should be fine. Always use lubricant when cutting threads or they will come out rough.

Also check your die and die holder to see if your can screw down on the die a bit to compress it.

Tiger
4th Dec 2005, 01:37 AM
Hi Rod,

Didn't think there would be too many people on the forum at this time. Will try your suggestions and see. Got my digital caliper bought from Super Cheap Auto but it keeps giving me different values and I have to rezero it constantly, I suspect the rod could be a bit oversize (it's actually some 1/4" brazing rod).

Thanks for your suggestions.

Schtoo
4th Dec 2005, 04:06 AM
Gotta ask, why not run down to Bunnings and buy a piece of 1/4" threaded rod in brass? That's something I can get even here. ;)

Unless of course you are doing left hand thread. In that case, uhh, keep plugging away at it. :D


P.S. If you get really stuck and need to resize the rod, drill a piece of steel 1/4", then countersink one side almost all the way through. File down one end of your rod till it fits through the hole and enough to grab a hold of, then drag the rod through the hole. Lots of effort, and maybe not pretty, but it will make it closer to the right size. Wouldn't hurt to anneal the rod first either. Plenty of lube too...

Twodogs
4th Dec 2005, 06:27 AM
Try some other nuts .
There is a huge variation in the size these days.

Ivan in Oz
4th Dec 2005, 06:54 AM
Are you sure your nuts are OK??
How many do you have :eek: :eek: :D
All the same?
Whitworth, is getting uncommon these days.
Maybe BSB, BSF, UNC, UNF, UNRC, 0BA, 6mm Course or even BSP...thought I'd slip that one in;)
Have you checked the TPI or Threads / mm;
one against the other.
I require a Jeweler's Loupe for that:o

http://shopswarf.orcon.net.nz/sthrdndex.html

Grahame Collins
4th Dec 2005, 08:12 AM
Let me help !
The rod that you are attempting to thread should measure I/4" or 6.35mm diameter precisely.
If you have a 1/4'' BSW button die it should have 20 theads per inch -TPI
The thread angle should be 55 degrees.

Is the nut you are attempting to thread on a true 1/4'' by 20 TPI ?
The easy way to check is to run a 1/4" x 20 tpi tap into the nut and "feel" for obstruction.That may be the cause of he nut binding. But wait,there's more!
If it is grabbing and trying to cut the nut may be a 60 degree thead angle - meaning it is not a 1/4" Whitworth.
You may have sucess by using this freshly recut nut depedent on your needs and application.

Another possibility is that the die button is adjustable ( some are) out and is too far open.Check for a fine screw head and tighten carefully.Again measure the cut thread -it may be still too big in diameter.emebe 6.35mm OD.
If you are now confused my work here is done.

Cheers Grahame

Ashore
4th Dec 2005, 11:34 AM
Mate if you are having trouble with brass it gotta be that the die isn't right
I take it you are using a button die and not a die nut
There are two types of button dies
One type of button die should have two dimples in its outer rim and a slot cut through one side. Use the screw that fits in the dimple adjacent to the slot to tighten and cut the thread deeper.
The other has no slot and only one dimple ' these are often from cheep sets, if this is the type you are using then try running the tap from the same set through the nut, right through and out the other end
Otherwise buy yourself a propper die nut from blacklocks ( take a cut lunch to have while u wait, the service can be slow ) or a similar outlet




Rgds


Ashore

aussiecolector
4th Dec 2005, 12:36 PM
Some of the adjustible dies dont have the screw in the die but rely on a pointed screw in the die holder to keep the die open.

Tiger
5th Dec 2005, 12:32 PM
Dear all,

As some of you have stated, the die needed to compress slightly to cut the right diameter. I haven't used a die like that before, so I didn't think about tightening the screw. Once I tightened the screw, it cut perfectly. Thanks very much for your help.