Hi all

For my z axis control, I'm contemplating a twelve inch mild steel rod with six inches polished and six inches threaded. The router assembly will be attached to two of those rods, one on each side of the router with the half above the router being the threaded half.

If I were to manufacture those rods by using a hand held die, would I end up with a poor quality or reasonable quality threading?

In other words what are the expected tolerances for accuracy and wear for hand threaded rod. I'm considering 10mm rods. I'm assuming that stainless steel is impractical.

Given this is all new to me, what can I expect or am I needlessly introducing poor quality into my design?

Thanks in advance

Andy_ck87028

Andy,
Taking your time, using a high quality die, cutting oil and the die kept perpendicular at all times to the rod being threaded there is no reason I can think of that it should not be as accurate as non-precision threaded rod.

I would suggest starting with a piece longer then needed giving you a little latitude for a good die start then cut it to the needed length.

I thread a lot of rod by hand. It takes a lot of practice to get a good straight thread. Once you have it square, there is no reason you cannot run it as long as you want. Good dies, good cutting oil, and patience will get the job done.

Why do you need to thread it yourself? Why not buy threaded rod at a hardware store?


Jon

Why do you need to thread it yourself? Why not buy threaded rod at a hardware store?


Jon
Is the threaded rod that you can buy at hardware stores good enough for cnc foam cutters?
I was thinking of using acme threaded rod, but it's hard to find in small diameter sizes like 1/4'.
Bill

If you are building a foam cutter of any size, go for larger than 1/4. I have one with an axis of almost 5 feet using 1/2-10 acme, and I wish it were larger. Smaller rods will "whip" on you to a degree when you are doing higher speed positioning moves.

Ya, no kidding they WIP. and its not that they WIP its that they are warped. OR they will warp with use. The half inch is much less likely to warp on your. and your best bet is to use the stainless steal threaded rods. Because they are a harder metal, But even then finding a NON screwed up one just due to the delevery sytem is often a hard to do thing.

i tried to thread my own length with a die but it ended up looking pretty bad. the thread itself was ok but it ever so slightly corkscrewed. i ended up buying a lenght of stainless steel "allthread" (threaded rod) 1 metre long (16mm x 2) for only AU$24. over all it only 0.04 mm difference in effective thread dia along the whole bar. ti looks like it was thread rolled. all i gotta do now is screwcut a nut to fit nice and snug.

make yourself a backlash free nut stuart76, get 2 nuts and a firm spring to go between them, and some sort of sleeve for them to ride in so that they cant rotate freely of each other. if you monkey with tat stuff you will see how it would work. I made a set of acme backlash free nuts for my foam cutter and was amazed at how many little annoyances it eliminated as compared to using backlash compensation in software.

wow that was rather off topic, out of the blue, but hay hehe ok.
there are a number of ways to make anti backlash nuts. But to be honist. I denouce using springs and multi nuts on THREADED (non ball bearing) rods, to make anti back lash nuts. They put a lot of wear on the screw/nuts threads making them build up a horid fine metal filing in the grease. To be honist you'll get the same low/no backlash results using a CONNECTOR nut for connecting threaded rods. They are about 1" long and you can solder them to a peice of metal. Then make some kind of a simple adjustable mount setup. but there so LONG that there is NO room for any back lash. If there is any back lash its far smaller then 1/100th or even finner. dont bleave me? try it. In the worce case it i wll cost you a buck.

Im sorry, the post previous to mine mentioned making a nice tight nut for his new stainless threaded rod. I didn't feel it too much of a stretch from leadscrew to leadnut. Also if one is worried about the cleanliness of their leadscrew grease, there are nuts of other materials available, nylon, brass and more exotic stuff. I know the connectors that you speak of, and they can be an easy way out. However if you think about it, a perfectly made connecter nut and a perfectly made lead screw would have just as much endplay as a regular width nut correct? The reason the longer nuts are tighter is due to the accumulation of tiny errors and flaws within the surface of the threads themselves. Once those flaws wear down, and they will wear down since they are heavy contact points, you will begin to develop endplay again, as well as metal flakes in your lube. Just my opinion for what its worth, probably not very much.