First post, second machine

[george w]

Hello all. I have lurked through these forums for some time and am about to start gathering parts for a second machine build. The first machine is aluminum 28 x 40 and currently in use, so thanks you CNC zone. I was able to learn quite a bit by reading these forums and trial and error.

I am going to assemble a second machine either 48 x 60 or 60 x 60. I am looking at 1.5" diameter linear rail and would like to mount them under the table so the gantry hangs on the rails as opposed to riding on top like I see in most builds. I am wondering if the bearings care how they are oriented or if there are other reasons this is a bad idea? Would 1 1/5" rail sag at 60" long?
This machine will also be aluminum, but I am in the very early stages of planning. The gantry will likely be fabricated using .5 sheet and 2x2 tube.

Could a smaller diameter rail with supports be use the same way?



Thank you.

[TOTALLYRC]

Originally Posted by george w Hello all. I have lurked through these forums for some time and am about to start gathering parts for a second machine build. The first machine is aluminum 28 x 40 and currently in use, so thanks you CNC zone. I was able to learn quite a bit by reading these forums and trial and error. I am going to assemble a second machine either 48 x 60 or 60 x 60. I am looking at 1.5" diameter linear rail and would like to mount them under the table so the gantry hangs on the rails as opposed to riding on top like I see in most builds. I am wondering if the bearings care how they are oriented or if there are other reasons this is a bad idea? Would 1 1/5" rail sag at 60" long? This machine will also be aluminum, but I am in the very early stages of planning. The gantry will likely be fabricated using .5 sheet and 2x2 tube. Could a smaller diameter rail with supports be use the same way? Thank you.

I have looked at updating my machine with the rails underneath and I was wondering the same thing. I wonder if sideways mounting is possible?

At that distance Iwould use 1.5" supported rail. Of course that is my opinion and ymmv.

[george w]

I will do supported rails. I ordered material for the frame this week