Last fall I was back south visiting the kin folks and stopped by planekrazie’s and he had his CNC running. I was really impressed with the things he was doing with it and never saw such a machine before. I had been wanting to build a plastic item for a couple of years but prototyping injection molding was out of my price range plus with my limited ability with CAD there were sure to be many mistakes. Well the wheels started turning and off I went to the next stop.
On the way back to Iowa we stopped by inventorjohn’s in KC and he was constructing a machine. All the parts were there so it was an education for me. I was introduced to 8020 aluminum, stepper motors, G-code, and all that stuff. Within a week the CNC was up and running and I was hooked.
Got back home and started lurking on the zone and searching for any information I could find regarding CNC routers. Ordered a copy of David Steele’s plans and got all kinds of ideas. I ruled out the skate bearings as my drilling and machining ability is next to none. So kept looking on eBay for linear rails and stuff like that. Purchased things from time to time and some I resold as they were not what I thought they were. Ordered the motors and controller from Xylotex so I could play with them on the table as I made plans for the building.
I got the X and Y rails eBay and a good deal on a complete Z axes unit. So I stared at those for awhile and realized it was time to figure out how to start building the thing. I had virtually no tools and a garage full of junk so I ordered a drill press, miter saw, table saw, taps, dies, drills, and on it went. I spent my whole budget on stuff before I even got started building the machine![]()
What I wanted was a machine large enough for a full size router and had good accuracy. I decided on a gantry with a low center of gravity and to tray a belt drive for at least one of the axes. I used a 3x3 t-slot piece for the gantry and bolted it to an aluminum plate that was attached to the Y bearings (I got mine set up X and Y like the computer screen so I don’t have to stand on my head looking at the machine bed.) Faced the t-slot with a 1/8” aluminum plate and mounted the X rails then bolted the Z thing to it. I went and ordered a K-2cnc router mount and am very glad I did. So next was putting the rest of her together.
I went ahead and did some what of a continuous belt for the Y as that seemed much simpler than the mechanism in David’s plans. Very happy with the belt as it is extremely fast and accurate (as far as I can measure). I had purchased a big old ball screw for the X and it seemed to be perfect except slower than molasses. At 6 turns an inch the best I could get out of it was 30 ipm rapid and about 20 ipm cutting and she still would stall the 500 oz stepper with any kind of load. Everything was working perfect except the slow ball screw. I had to change that over to a belt drive. Came up with a good setup and had all the parts except for the belt and pulleys. I went and cut a belt clamp out of nylon as I sure didn’t want to buy another one of those things as they cost more than the belt. Put it all together and away she went. I have the rapid set at 300 ipm and can go much faster but I don’t want anything flying through the air. Se can cut as fast as the Bosh motor can handle it and seems very accurate. For me the belt is the way to go as it is a cheaper setup and well I am happy. That was the only major modification I did to the machine after completing it.
Still have a problem clamping my material level when I work on a full sheet (she is only 24” x 20” cutting area) but I will figure it out as time goes on.
This was a little long winded but I haven’t posted before so trying to make up for lost time. There are some pictures of the building process on my web site if anyone is interested http://www.ecmarsh.com/cnc and I will post more pictures here as time goes on.
Thanks to everyone at the zone for all the ideas and valuable information, Ernie
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