[MakerBull]

Howdy CNC people,

Long time lurker, first time poster. A couple of years ago, I designed and built a CNC machine. During that process, I used this forum extensively for design ideas, troubleshooting, and general sanity checks. I finally got around to putting together documentation of my build, so I thought I’d post it here to help out some other people.



Here is a link to my website with a full description of the build including a CAD model and bill of materials.

TLDR:

• ~2ft x ~4ft x ~5 in build area
• Xylotex drivers
• Rollerchain x and y axis with CNCrouterparts bearing trucks
• Pre-built z axis
• Aluminum Gantry, Wood Table
• ~$1500 budget including all major components

She won’t win any beauty contests, but she does what I need her to do.

[ChuckC]

Very cool! I love it.

So, in operation, are you getting enough accuracy/repeat-ability for woodworking projects? We're not talking machining precision metal projects here, so even a hundredth of an inch would be more accuracy than one might need, I guess. I'm thinking of either 2 x 8 or 4 x 8, however I worry a bit about the gantry span. Think the extrusion would work across a 4 foot + span? At that point, though I'd have to make it on edge to leave room open in the garage.

[MakerBull]

Thanks for checking it out!

"So, in operation, are you getting enough accuracy/repeat-ability for woodworking projects?

Definitely. Early on, I had some trouble with the bearing trucks pivoting in the extrusion tracks, causing the machine to get out of square. I added a moving knot on to the gantry, and I have been able to produce consistent parts that are accurate to at least a hundredth of an inch, probably better. I'm not completely confident in my measuring ability at such small scales, so I don't want to make any outrageous claims, but for woodworking purposes, I have been able to do everything I need. Also, whenever I make parts to retrofit onto an existing object, I never have trouble with fitment.

"Think the extrusion would work across a 4 foot + span?"

Yes, in order to accommodate a cutting area ~2ft wide, I made the gantry 4 feet long to account for dead space caused by the Z axis carriage, various gears, and other structures. Before making the machine, I did some back of the envelope calculations that gave me confidence that the extrusion would work with the 4 ft span. My gut feeling is that the 3060 extrusion I used should handle a longer span just fine also. The X axis is definitely not the weak point of my machine. I would wager that deflection on the 2x6's that hold up the Y axis and router runout are much bigger sources of error.

[ChuckC]

Thanks, that's good info. I'm still tinkering with a high end desktop unit that I'm still fiddling with, but now that i'm making progress-I can see the possibilities and have the bug...

I wondered just how good the wood framed ones were...