Thread Cutting, Metal

[custard]

I want to cut a thread on the ends of some 8mm diameter router rods. Anyone have any advice on how I can ensure the thread is cut straight and isn't twisted when using only a die in a die holder?

Also, what type of steel rod is best for this application, mild steel, silver steel, stainless steel etc?

 

[marcros]

are you holding it in the lathe chuck, and using a lathe tailstock die holder?

 

[porker]

As marcros says a tailstock die holder would be best but I assume you don't have this. Do you have a drill press and a drill press vice? I would put the rod in the chuck and lay the die holder flat on the table or held flat in the vice and wind through by rotating the chuck by hand remembering to back off to break the chips. Use some cutting fluid. This ensures it is perpendicular.
Material depends on application. mild steel will be easiest. silver steel only if you intend to harden it and stainless can be challenging depending on grade. What quality are the dies? The cheap carbon steel die sets are good for thread cleaning but may be almost impossible to cut a new thread. A quality split die should be OK though.
HTH

 

[AndyT]

Do make sure that you taper the ends of the rods. Ideally you would do that on a lathe but you could put it in a drill press and use a large file. The file MUST have a handle on it. If the taper is square your thread is very likely to be square too.

 

[custard]

I've got a woodworking lathe and a drill press, I think I'll follow Porker's procedure. Thanks for the advice, much appreciated.

I'm going to buy a HSS tap and die set, any advice on a good brand name to look for?

 

[AES]

+1 for what everybody above has said. Porker's method will work well.

+1 also for putting the chamfer on the end (but square please!) as Andy says.

Unless you anticipate doing a lot of male and female thread cutting, personally I would advise against buying a set of taps and dies - you'll use less than half of them, and they're not cheap, especially if buying good quality. But if you're set on a set (sorry!), although several here have complained about the cheapo sets from Aldi and Lidl, I bought a set a while ago and they were/are perfectly satisfactory for general now and again jobs - certainly not made of cheese!

But if you want decent (read good) quality that will last your lifetime, then try:


The Tap & Die Company;

Or Chronos Ltd;

Or Tracy Tools.

All good to deal with and when they say “British Made” they mean just that. Just a satisfied customer usual disclaimers.

Links at the top of the General Metalworking section (I put a couple of them in there myself, and have dealt with them).

HTH

AES

 

[AndyT]

There was a 4 page discussion on this in the metalworking forum which might be useful https://www.ukworkshop.co.uk/forums/tap-and-die-recommendations-t75309.html

 

[woodpig]

You could try one of these.

http://www.irwin.com/tools/taps-dies-se ... ck-handles

I rarely buy anything in sets, just buy what you need at the time.

 

[Hitch]

If you choose mild steel, make sure you specify 'bright mild steel'...

Black mild steel is the basic cheapo rod, which is usually far from round, and can vary in diameter. Its also covered in mill scale.

 

[woodpig]

If you choose mild steel, make sure you specify 'bright mild steel'...

Black mild steel is the basic cheapo rod, which is usually far from round, and can vary in diameter. Its also covered in mill scale.

Quite right.

Best if you can get it is Precision Ground Mild Steel but expect to pay more.

 

[Cheshirechappie]

If you choose mild steel, make sure you specify 'bright mild steel'...

Black mild steel is the basic cheapo rod, which is usually far from round, and can vary in diameter. Its also covered in mill scale.

+1 to that. I'd also add that it's worth specifying Free Cutting Mild Steel, sometimes described as FCMS or as En1A. It's intended to machine easily, which helps in any cutting application. As someone said above, a good dollop of thread-cutting compound (Trefolex or Rocol RTD are good, but there are others) helps a lot, too.