Anyone have any suggestions for securely clamping round stock to prevent it from turning while I'm trying to thread the end of it?
I've got 3/8" mild steel rod that I'm threading with a 3/8-16 die. I'm clamping it in a smooth faced 6" vice and theading it there, but the rod turns on occasion marring its finished surface. Any tips on claming it more securely to prevent it from turning while threading?
Thanks
Take something like a 6 inch length of 2x4 and drill a 3/8" hole down the length of it. Then slice it in half lengthwise (right down the length of the hole you just drilled) with a bandsaw. You should end up with two blocks, each with a 3/8 diameter groove running down one face.
You've just made a poor man's collet. Lay the rod in the groove of one, lay the other block on top, and clamp the whole thing in your vice.
Using sandpaper with a vise or home made collet sometimes is enough to prevent turning. Even 320 is effective. Of course some repolishing may be necessary depending on the use of the rod. Wrap the paper with the grit side towards the rod. Dave
several good ideas on holding it are posted... My impression is that assuming that you have a decent vice and that it's actually mild steel, you're either turning the die too fast or not backing off frequently to clear chips?? A good quality die shouldn't be putting enough twist on the rod to overcome a vice, in my experience..
mac
Please remove splinters before emailing
You'd be surprised. I do this all the time and it can be a rather knarly problem. I usually just clamp a pair of visegrips onto the middle of the rod, and then put a piece of scrapwood between the handles of the visegrips and the benchtop. On why the rod is turning in the first place: it is very difficult to hold a smooth rod with smooth vise jaws, and the die requires quite a bit of force to turn. Additionally, the oil which is used to lubricate the die inevitably gets on the rod and the vise. Another solution is to file some flats on the rod and hold the rod vertically in the vise jaws.
It's a small portable vise that I was using which accounts in part for it not having enough grip on the steel rod. I could have clamped something like visegrips on it, but then they would have left a mark and those marks would appear unsightly when they're on printer cart that I'm modifying. I did solve the problem to my satisfaction though. I wrapped the steel rod in some
120 grit sandpaper and then clamped it in the vise. That was enough to prevent the rod from turning and marking itself on the vise.
Shouldn't take more than some corrugated paper (box cardboard) wrapped around and clamped in your vise.
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******** Bill Pounds
Vee blocks.
Rip two 45 cuts part way through a couple of short lengths of wood to make shallow 90 degree vee grooves, or use a router or whatever will do the same. Then you can use those to grip the rod AND hold it at any angle you like in the vice.
For rod that small, you may be able to use two pieces of softwood to pad your vice jaws and just crush them around the rod.
A slurry of graphite in alcohol makes a good tap and die lubricant too.
Is there a way to use a rod that is too long? Grind a flat on one end, thread as much as you need, custom cut to length. It takes a lot of grip to hang on while threading. It would be really great if you could use a long enough bolt that you could trap the head in the vise. You do know about all thread I assume.
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