8020 extrusions

[Techtchr]

Well I have the X and Y axis of my HF mini mill hooked up to the steppermotor system, and already my mind is going on a new project. I'll post pics when I'm done with the Z in a couple more weeks. BTW it uses 145 oz/in motors and a gear reduction system with a 20T drive gear and a 60T driven gear. Should be slow but fairly powerful. I also made my own leadscrews out of acme rod so that i could get rid of those damn 16 pitch lead screws. (sorry couldn't afford the ball screws until I prove it works)

I was surfing CNC websites on CNC gantry style routers, and came across some people using 8020 extrusions for framework. I thought this was interesting. In looking over my Enco catalog I received in the mail today, I found sliding parts for these extrusions under the heading linear bearings in their index. My question to you all is: Do these things slide effortlessly enough that I can build a gantry style router and power it with 23 frame steppers of the 145 oz/In range like I did with the HF mill? What I would like to do is build a gantry router capable of milling a 1/2 sheet of plywood or mdf or even cut out the profile for an electric guitar from ash. (kids would think this is cool) Slow is OK cause I am paying for this experiment, like most things I do at school. Precision? 1/16" in 4' ok?

What's your opinion?
Matt

[egpace]

Sounds like a great project, I'd like to make one on a smaller scale myself. As the wheel was already invented, I suggest you contact a manufacturer & pick their brains. Ask for detailed specs on their motors, drives, ways materials/shafts, accuracy, etc. Be upfront & let them know you're considering constructing one yourself or possibly purchasing one outright.

Check out the link below

http://www.techno-isel.com/CNC_Routers/CNCRouter_B2.htm

[Techtchr]

Egpace,
Very nice web site. Another one to drool over. I have a fairly small budget for supplies at school. In general Anything that looks like a tool in my budget gets thrown out.I try to put supplies like 8020 extrusions in as "they" don't know what the heck it is. They assume it is a consumable used for class projects and in a way it is. So the moral of the story is if I don't get it in to my budget and I want to do the project I figure out a way to finance it myself. Thus the need for being cheap. I have two HF minimills at school that I bought to convert to CNC last year. One is half done. Imagine my surprise when I came to school this year and the little school elf with the bar code labeler had a "Property of SCS" bar code sticker on my mills. (I digress)

The gantry router is my brain child for building a machine large enough so that we could make 2D and thin 3D shapes that could be milled for my Engineering Design class or CIM class, and not be a small model. My method for financing most of these things is by using the money I make repairing musical instruments on the side. BTW, I'm not complaining. I get to work on fun stuff with kids most of the time, without the administration bothering me, and when i show them a piece of equipment that i bought and we converted I get a gold star.

Matt