36" acme supplier need

[originator]

I use 1/4 20 acme on a smal benchtop, maybe 12" and it works great for PCBs and tight tolerance stuff. I haven't seen anything thick than 1/4" that has 20 TPI. The mnew machine being built is 36 long, and I think that 1/4 will sag a bit too much. For 36" is 3/8 a good solution, or at least the most TPI I can get short of 1/4 material? This machine is supposed to be for doing large format PCB's for signs, where the LED traces are routed out, s it has to be tight. I was going to order an 80/20 table this week, hoping for the best. The last missing links are the the threaded rod and ABL nuts to fit.

Thanks

[jeffs555]

http://www.nookindustries.com/acme/AcmeCharts.cfm
This page has charts showing the size of acme rod to span a given distance. A lot depends on the type of bearings used. The minimum recommended size for 36" is 1/2-10. If you want inexpensive acme, try www.use-enco.com
If you want a little better and more expensive try www.mcmaster.com