Re: About to start building a CNC wood router

Hi Chuck,

I snipped the whole post as I'm sure you will get lots of responsese
and most will keep it.

Interesting you mentioned both a router and lathe.

If you want to do it on the cheap and plan on using all thread, then
you will need to find a source for that. I found a local building
wholesaller who deals with contractors and got a couple lengths of 12
ft 1/2-13 all thread for about $6.00 each. since my table was 10 ft
long, I figured that anything was fine to prove the concept. My
suggestion here is to look at some alternatives.

the reason I would avoid thread is that in my case, I have 13 TPI and
a 1:1 gear setup. 200 steps per revolution and a 10:1 Gecko driver.
13 x 1 x 200 x 10 = 26,000 steps per revolution or a theroetical
resolution of 0.000038461 inchs per step !

Look at that as if I used a screw with 4 TPI, it still would be
0.000125" per step.

That translates into Sloooooooow. or, maybe sloooooooooooooooooow

There was a post a few days ago about a geltleman who use a timing
belt for his machine. great idea, MUCH cheaper than linear stuff and
it would not have a problem with wood dust.

also, gear racks would offer much faster movement.

my suggestion here is to have a minimum of 4 times the steps than you
need for accuracy. that way you are only ever 1/4 a unit off.

Lastly, leave room in your set-up for larger shafts. you may find
you need to use a 3/4" and not a 1/2" but then find you can't fit
that bearing, stuff like that. Ditto for motors. Leave room for a
NEMA34 if you are using a NEMA23.

Dave