> Hardware store threaded rod is not too bad, however, it's threads are not
> made for moving nuts along, they are designed for binding and locking.
You
> will not be satisfied with the movement you get out of regular threaded
> rod, it will be jerky and have a lot of backlash.  If this isn't a
> precision machine, that might be OK.   I've used hardware store threaded
> rod for stuff before, and been largely dissatisfied with what I got.
>
> The ideal thing is an ACME threaded rod, available through McMaster-Carr,
> ACME threads are designed for driving loads along.  I don't know the cost
> difference.
>

I think you'd be more satisfied with the results of hardware store rod if
you knew the cost of ACME rod. Here's an example I just looked up on the
Mcmaster web site:

1/4 - 20, 1 start, 6 foot long, P/N 6350K133, cost $111.27 each.

Let's not forget about the nuts:
P/N 6350K208,  $16.73  each.

Compare that to about $5 for a 6-foot threaded rod, and a nickle for nuts.

I have used hardware store rod on my CNC hot-wire foam cutter. 1/4-20 and
nema23 motors generate more than 50lbs of push at ~1 inch per second. No
it's not as good as ACME can produce, but I built my machine for less than
the cost of one ACME rod.

-Denny

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