New 8020 frame CNC Mill

Good evening everyone I have been lurking around this site a while but I figured I would share my build as others have done. 2 years ago I did build a smaller 80/20 mill so that I can mill some aluminum parts for my telescope equipment, it was a 12x18 moving bed machine.Attachment 264226.

I had done some relief work in wood and fell in love with it so started planning on a bigger machine as I had requests to do signs. So here I am with the start of the build and some questions to boot also as all this stuff is self taught. Never did any machine work in my life I am a computer geek.

So I wanted to do a moving gantry this time and a large cutting surface so decided on a 24" x 48" inch machine, that was 80/20 framed with linear rails. So on Ebay I went and started looking for linear rails with carriages and after about 2 weeks I got luck and found a pair of 48" linear rails with 4 carriages. After getting them I took them all apart de-greased them and used the grease I use on my telescopes that allows for smoother motion. I had to put things on hold as Christmas was coming up and well with 2 kids and a wife, I can't just keep buying myself stuff. :) After Christmas I got back on ebay to look for 24 - 36" linear rail with carriages for on the gantry. Again I was in luck and got a 31" rail with 2 carriages, then started looking at the 8020. I was going to go with 2040 material but decided on the 3030, plus I found a great deal on 2- 56inch 3030 with the ends tapped already. This was was perfect as it allowed for a longer table so I can have just about a 48" cutting area. For the gantry arms I am using 1545 and found a piece 59" long for a cheaper price then 2 - 24" 1545 pieces. I am debating on if I should allow the X axis to be adjustable in height if need be or make it stationary. At first I was thinking of going R&P but I think I am going to go with ball screws instead, thoughts? I bought 2 - 6" x 6" x 5/8" aluminum to use as a connector plate between carriages and 1545. This is what I came up with

Attachment 264234.


Well that is what I have for now welcome any comments and thoughts.

Bob

So I was originally going to only use one linear rail with 2 carriages on it, but I see others have a dual system. So I am in search of either another one like I have or another dual rail/ carriage system.

A bit off topic, but I'm curious how your first machine worked out for you and what you liked/didn't like about it (other than size). I'm considering a similar build myself. Aluminum extrusion frame, fixed gantry, moving table. I'll mostly be machining aluminum or wood. I'm also hoping to have a decent Z height to facilitate swapping the spindle for a extruder head and using it as a 3d printing platform. Anyway, I like the look of your old build and curious how it worked out for you.

As for your question about 2 rails vs one, is that for your Y or X axis? I see in your photo you have the gantry bolted directly to the bearings on the Y axis with the rails mounted on the sides. I've gotten the impression in my research that if your rails and bearing blocks have 4 races you should be OK with a single rail for an axis. If they are only 2 races you may want 2 parallel rails. I'm also wondering if you'd be better off having the Y axis rails on the top of your extrusion so the weight of the gantry pushes down on the top profile rather than the side profile?