Holding steel rod for threading

[marcus]

Hi there, I'm trying to thread some 20mm steel rod, and am having trouble holding it. I have a reasonable engineers vise but it doesn't have pipe jaws, and as I'm having to apply a lot of pressure to the die wrench the vise won't grip and is chewing the rod up.

Any ideas about a work around to this that doesn't involve buying a new vise?

 

[disco_monkey79]

Can you use an over-long piece, and use loads of pressure on the sacrificial end, which is cut off after completion?

 

[deserter]

2 pieces if timber less than half the thickness if your rod, with a v shaped notch in the centre if each then put them around the rod and tighten your vice up tight.


~Nil carborundum illegitemi~

 

[Eric The Viking]

And use something like Trefolex as cutting compound. It greatly reduces the friction and leaves you with a much cleaner thread form. It stains "stainless" IIRC, but is fine with mild steel, brass and aluminium.

Dumb question probably: are you sure your die is still sharp? 20mm is big thread (1.5 or 2mm pitch) and it might be worn.

To stop it rotating, can you put a bead of weld on at the unused end, to catch in the vice jaws?

E.

 

[Phil Pascoe]

Lock two nuts together on the bar and put the nuts in the jaws of the vice? or if you're holding the bar horizontally, you could use two pairs. I agree with Eric - it's a big bar to thread!

 

[Steve Maskery]

If it is 20mm steel rod, then:

1 Take a piece of wood about 150 x 50 x 20mm

2 Drill two holes through it, a 20mm hole for the pipe, and a 6mm stop hole. The hole centres divide the length into three.

3 Bandsaw a cut from the end of the block, through the 20mm hole through to the stop hole.

Now you can hold the pipe, clamped in the block, with no damage to the pipe and it will not move.

Contributions of thanks can be posted to me at the following address...


S

 

[Tinbasher]

The use of lock nuts as suggested is the way to go. Also make sure you have opened your die up as far as you can for the first cuts, its a big bar to tread.

 

[Steve Maskery]

Erm, how do you attach lock-nuts to a plain steel bar?

.....

 

[Phil Pascoe]

Sorry. I'm a ***.

 

[Steve Maskery]

Yeah. Me too, sometimes. This is what I had in mind:

 

[dickm]

Couple of other suggestions - if you have clearance for the dieholder handles, you can sometimes get better grippiing by putting the workpiece horizontally in the vice, rather than vertically. In theory, it shouldn't work, but it does seem to. The other "helper" could be a Mole wrench, attached to the bar somewhere below the vice so it bears on a solid surface. There are some "Mole type" wrenches that actually have jaws which are designed to accept bar/rod material.

 

[marcus]

Thanks everyone, I've just tried Steve's idea and it works a treat.

It's a new die, but still hard work. I've got 80" of thread to cut altogether, divided between 16 rods. Will look like Popeye by the time it's done....

 

[Steve Maskery]

Again, my address is...

Spinach for supper?
S

 

[porker]

I'd thread cut it in a metal lathe and use a die to finish the thread form but I am guessing you don't have access to a metal screwcutting lathe. I also assume threaded rod is not available or not suitable for this application.

 

[Webby]

Again, my address is...

Spinach for supper?
S

Wheres Olive when you need her :wink:

 

[maltrout512]

It took some time to work out this problem, well all of 60 seconds and came to this conclusion and google took 0.30 seconds,

http://www.ironmongeryonline.com/ca...ter/750/749/?gclid=CML-z_2j17QCFWbKtAod9RIA-A

and I didn't have the problem of the bar turning in the vise.

 

[Tinbasher]

Sorry. I'm a ***.

DOH (homer) Me too sorry !

 

[marcus]

I am guessing you don't have access to a metal screwcutting lathe.

No, sadly. I think I'll do two every evening for the next seven days, should be manageble....

It took some time to work out this problem, well all of 60 seconds and came to this conclusion and google took 0.30 seconds

Threaded rod won't do, I only want thread at each end, otherwise I would have used it.....

 

[Tony Spear]

It's also worth lining your vee-notches with very coarse emery or sandpaper to get more purchase on the bar.

 

[Sheffield Tony]

It's a new die, but still hard work.

It might be easier with an old one ! The latest taps and dies I bought are made in China from rubbish and are incapable of threading anything. The dies simply will not start cutting, they just chew up the end of the rod. Even new Presto ones don't look as good as the older ones we have. I notice that whilst Presto still have a Sheffield address, they call themselves "Presto International" these days. I suspect I know what that means