Etch Press Build

[JohnHaine]

Our small press uses BMS for both rollers - much cheaper. Some increase in weight I guess. I'd have concerns about the lower roller bending if it's ali. The main constraint on BMS type is probably machineability - a FC type would turn better.

Regarding bearings - beware using roller bearings unless you can rely on the rollers remaining aligned. The crude open cradle type are very tolerant. You can get self-aligning ball bearings.

Plate - really it doesn't matter! Since the part that does all the work is under compression from top and bottom rollers, which will also tend to straighten out any lateral bend, you could use aluminium sheet or BMS plate. If you use the latter, probably any of the laser cutting suppliers that for example supply laser cut loco frames would cut you a piece which would have clean edges and not be buckled. 1/8" would be plenty think enough. The main thing is to make sure it's smooth with no nicks or dings.