First Time Cutting Outside Threads

Because I'm a cheap ass lately, I decided I would build a new brake rod ( see: www.z1enterprises.com/detail.aspx?ID=3216 ) for my bike.

This is the first time I've ever cut threads with a die and I'm looking for some advice. I've gotten the die to start, it appears straight, and I've got a couple of threads cut. However, I'm at a point where the vice isn't holding the 6mm stainless rod still. This is requiring very very small degrees of progress before backing off and trying again (to prevent the rod from rotating).

I've tried mounting the rod in the vice both vertically and horizontally.

I'm wondering if the rod is actually slightly too big (damn you, Mcmaster Carr!) as I was able to cut the rod with the 7mm die as well (although just barely with the last tooth or so of the die).

Again, I'm new at this - don't have a clue what I'm doing.

You do not need to thread too much of the rod, just a few inches. So, try to only allow a short part of the rod to be above the vice to start. Then move it up as your die gets close to the vice. I would suggest you also use scrap wood in the vice to protect the rod. You do need to back turn to clean the die every so many turns. Also make sure you lube the rod and die as you cut the treads.

All good info, and exactly what I've read online. But when I say small amounts of progress, I mean less than 5 degrees or less of actual cutting before the rod turns in the vice. Does anyone have a die chart that I could reference (the die set I borrowed doesn't have one) as I really think the rod might be slightly too large in diameter. Any thoughts on how to address it if it is?

If it is cutting, back it off every half turn.
Keep turning back then in to cut.
Blow it off with air to keep clean, and of course have a penetrant, Tool cutting, or PB Blaster. WD40 does not cut it.

Of course stainless steel is harder to work with!

But it will be worth it when your done!
Cause you did it!

DD, is this a M6 x 1.0 thread that you are trying to cut? If so, then your rod that you are threading should be a 6mm or 0.2362" diameter rod.

Yes, the die will be a bitch to turn, you will probably be lucky to get 1/4 turn before you need to back up and clean threads. It will help to have a good, even chamfer on the start of the rod. You want to make sure that the die is started straight until the rod makes it through to the back of the die. It should self guide at that point. Make sure that it is well lubricated.

What material is the rod that you have started with?
Is the die nut adjustable? Does it have a little screw that allows you to spread the die out?

If the rod is too large, then it should be turned down to 0.2362" or 6mm for the distance that you plan on threading.

Thanks guys, that helps.

The rod is stainless 6mm rod (I'd have to look back to see what the exact type is).

The die I have is a super-basic Harbor Freight die with no adjustments at all. I suppose the types with adjustments let you "pre"-cut at a larger diameter?

It looks straight when I thread it on without the handle, so I don't think I'm binding by cutting at an angle, but I can't be sure.

testarossa wrote:

DD, is this a M6 x 1.0 thread that you are trying to cut? If so, then your rod that you are threading should be a 6mm or 0.2362" diameter rod.

Yes, sorry, forgot to answer that. It is M6 x 1.0 as I still have all the fittings from the original rod. I will have to get out the measuring tools and see what the actual diameter is.

I like using the dark, sulpher cutting oil when using a die on SS. Holding the rod in wood is probably the best way of working with it unless you have a machine shop do it for you.

By Harbor Freight I assume that means carbon steel and not High Speed Steel (HSS). Stainless will chew up carbon steel dies and spit them out, you'd be better off to get a HSS die and cutting fluid from Grainger or someone like that.

Another great question. I'll have to check the packaging - it was borrowed, don't own a set myself.

I bet if you got your rod from McMaster Carr, and it was ordered as 6mm, then that's what you got. They are usually quite good.

I agree with steell and Mfolks on their points. Get an adjustable HSS die. Harbor Freight dies make excellent paperweights. I wouldn't use them for stainless. If you lack the proper dark cutting oil, then used motor oil can work in a pinch.

You are correct about the adjustable part. They don't spread too far, but every little bit helps. Start as big as possible, and then work your way down until your rod fits into the fitting.

You can gain a little more purchase on that rod by wrapping some sandpaper around the rod. Then chuck it with the vice. Make sure that the abrasive side faces the rod. Possibly some thin aluminum pieces could be used in lieu of the wood scraps. Tighten the vice all you want with the aluminum, and the stainless bar will imprint the aluminum pads.

Why used motor oil? Just curious.