Threading a rod

[3Dsigns]

I broke the mounting bolt inside a hydraulic return filter. To make a long story short, I had new threaded end TIG welded on. Now, to make a long story short, I cut the bolt in half so it would slide back into the filter housing.(don't ask). Now I want to attach the two pieces together with on of those extended nuts(can't remember what it's called). The bolt is 10.02mm in diameter which is fairly close to 25/64''. What size die should I use to rethread the ends? I tried an M10x1.5 and it just doesn't want to start. Thanks

 

[txvwnut]

Put a good chamfer on the rod and the die should start easier than if you are just working with a blunt end.

 

[kbuhagiar]

Now I want to attach the two pieces together with on of those extended nuts(can't remember what it's called).

I believe it's referred to as a 'coupling nut'.

 

[3Dsigns]

Yep, that's it! thanks

I believe it's referred to as a 'coupling nut'.

 

[3Dsigns]

Put a good chamfer on the rod and the die should start easier than if you are just working with a blunt end.

I did that, about 45 degrees, but it won't start. So, a M10x1.5 die should work with a 10.02mm rod? maybe it's my cheap die set.

 

[woody 73]

Crazy thought, hey not the first time, if you are like me and do not own a metal lathe, chuck up the rod in a drill and try using some course sandpaper and see if that will help you get it started easier. maybe the sandpaper can take off a small bit of metal, making it easier to start the die.

 

[GeoBruin]

Are your dies adjustable (split dies)? Crank it wide open. If you need more, take pass on the outside of your threads with a file or some sandpaper as other have suggested.

 

[Stubby1743]

The 10.02mm dia. should be good for cutting an M10 thread. Are you using a split die? If so, wind the tapered grub screw in the die holder into the split in the die to open it up a bit.

Edit - GeoBruin made his post whilst I was typing mine.

 

[Rusted Nut]

Find out what thread size/pitch your coupling nut is, and use that size die.

 

[alfadan]

Most dies have a hard time starting on a rod that is right at dimension, and 10.02 sounds a little large. I don't thread metric much, but if you can get it down to maybe 9.95 (?) it should go easy. Starting a die and keeping it straight is hard to do by hand with the right tools to start them.

 

[Steve_P]

I'd hit it with sandpaper as others have said to get the die started.

Chances are you won't find metric coupling nuts in stock locally.

 

[Dave455]

10.02 should work just fine with a 10mm die.

ISO metric is different from most other standards, in that the clearances are built into the taps, which are slightly oversize. Wheras a 3/8 bolt will need to measure just under 3/8, a 10mm can measure 10mm, or in this case a tiny bit over.

As others have said, file a decent chamfer and it should work fine.

Reasons it might not -

It’s a crappy die (they are out there).

The material being threaded is too hard.

You’re trying to use the die backwards!

 

[txvwnut]

I did that, about 45 degrees, but it won't start. So, a M10x1.5 die should work with a 10.02mm rod? maybe it's my cheap die set.

Try 60 degrees and see what that does. When cutting threads with a die it takes a good amount constant pressure against the die while turning it.

 

[cannuck]

One of the most difficult things to do is get a die started straight when cutting male threads. If at all possible, I like to chuck the part/rod/fitting up in the lathe and cut a thread a bit shallow to the die will pick up and finish. Doesn't always work, but far better than nothing. The other way is to grab a hex die in drill vice, grind the start and then use drill chuck to feed into the die dead square. All require parts and tools right size and configuration to do so.