So after well over a year of poor project management, I’ve finally gotten past the “part collection” stage of my MPCNC build. \o/
I originally wanted to be able to swap out the “core” of the machine in order to route wood or plasma cut metal. In the end I decided to scrap that idea - too much hassle to get to the goal, and not enough payoff.
The revised machine design is going to be built for a roughly 24x24 work area. The frame of the machine will be separate from the working area in order to provide a bit more flexibility.
Attached is a photo of the frame design. It’s made from 2x4s that will be cut down to 3-1/4" x 1-7/16" and 2x6s cut down to 5-1/4" x 1-7/16". This will help ensure that the framework is as straight as possible. The legs will be simple 4x4s with no squaring ops done.
The cutting area will be a torsion box that’s 24 x 24 x 5-11/16. The odd height will allow for a 3/4" thick spoil-board. The tortion box will be built with an open interior structure in order to allow for airflow. Once built, I’ll cut a vacuum plenum and t-track slots into the top surface. The plenum will be multi-zone, although I haven’t decided if I’ll go with four large zones or a mixture of larger and smaller zones. The drawing for this hasn’t been done yet, but I know how it’ll look in my head.
I’ve got all the dimensional lumber and sheet goods for this thing, so hopefully I’ll be able to start cutting wood soon.
I’m going to try to avoid using my ShopBot for any of this. The torsion box holes won’t look like that - I’ll use a hole saw to cut the ends and a jigsaw to cut out the center. I should probably run a roundover bit on the edges as well.
[attachment file=“full table and torsion box assembly.JPG”]
[attachment file=“quarter view of the table.JPG”]
I need to work out what the torsion box is going to rest on, but I don’t expect that to be much of an issue.
The hole at the back of the torsion box is the vacuum source, typically a shop vac.
So basically, the “best practice” here would be to not set the torsion box in place until after the rest of the machine is built? The idea being that once the machine is built, I’ll know where 0,0 is for 100% certainty and can fix the torsion box in place at that time?
I’m FINALLY getting to cut parts for the machine base!
[attachment file=“side components.jpg”]
Two 2x6’s cut down to 5.25" wide and four 2x4’s cut down to 3.25" wide. They’ll be pocket-screwed and glued together to form the side frames that you see in the renderings I posted above. They’re 60" long.
It’s not so much “patience” as “project overload” and tiny fragments of time to work on things. I’m sticking with the 4x4 build area and I’ll figure something out for the axis supports.
You’ve got a great, usable design in the MPCNC Ryan. It’s something to be proud of for sure.
