ok, i think i may have had a change of heart about the guide rail system i am going to use. i really like the neatness, simplicity, and low weight of the v-groove rollers and track used by fiero addiction, but after looking at the torchmate again, i'm thinking i may do something similar to that.
part of my problem is that i've looked at so many different ones, it's hard to make a choice. i like the approach of the cold rolled flat bar rails for a couple of reasons: it makes the hardware much easier to obtain. bearings are just standard ones now, instead of the machined v-groove ones, and the track is just a bar now. this should work great for the tracks on the two table rails, but i'm concerned about using this for the gantry.
i guess the issue boils down to how much weight you have in the gantry and still be able to drive it around with the motors? i'm thinking around the range of the 300 oz/in motors. i know that because it needs to be able to make sudden stops and changes in direction, the weight has to factor in. i am also going to take a page from the torchmate design and raise my table rails so that there is no added lever arm between the rails and the top of the gantry, but i assume weight still will be an issue.
for the table rails i was thinking a 3/8 or 1/2 by 3 to 3 1/2 flat bar laid horizontally. this should be no problem, but for the gantry, if i were to use the same flat, but turned vertical, and then reinforced with a 2x2x0.120 tube, the weight of a 6 foot gantry would be around 50 lb without the torch assembly (mount, rails, torch). is 50lb too much to toss around with these motors, or any motor for that matter?