John,
I'm one of those builders that didn't buy a plan, but just took bits and pieces of designs I liked and tried to incorporate them into my machine. People building their first machines frequently change the design as they go.
Like many other builders I wanted the biggest and most rigid machine I could make. And also like many others that didn’t have access to a shop full of metal working tools and the skills that went with it, I will use this first machine to build my second machine.
When I was infected by this CNC virus I didn’t have a cad program so I did all my designing on large sheets of paper this worked out OK, but revisions meant do it all over again or cut and paste pieces of paper. About half way through construction and before I got top the Z axis I bought a cad program. That is the BEST way to design, revisions are a piece of cake.
I heard all the talk about roller blade bearings and gas pipe, bought a pair of skates and took the bearings out and mounted them on my movable gantry. The bearings turned to be a very inferior brand and didn’t even hold up moving the gantry back and forth while I was making adjustments. Bought some good bearings off the internet.
Mounted the new bearings on the gantry and soon realized that my movable gantry was too heavy for 1” gas pipe.
This called for a major design change, to a movable table instead of a movable gantry. I really like this better because the gantry is fixed and there is much less chance for system flex. And you are moving much less weight back and forth. This reduced the workable table size, but still big enough for the time being.
The Z and Y axis are Thomson type bearings but the movable table (X) axis is on 1” gas pipes using roller bearings. I have supported the gas pipe under the working area in an attempt to keep it from flexing.
Where am I at now? The mechanicals are all done and motors mounted. Looking for a power supply, plus I have bee side tracked on many other outside projects.
Would I go this route again? Yes, I’m retired and that means less cash, and I’m not desperate to complete it at a fixed time. Woodworking was my hobby but now metal is creeping into my interest.
If money wasn’t a factor I would buy the best plans, but probably would still modify them.
Hope you can glean something out of these ramblings.
Hager  |