Top of brick model.
Bottom of brick model
Top of finished brick compared to real LEGO. Height is significantly off, due to a math error when I flipped the piece to mill the bottom.
Bottom of finished brick. Slightly manngled due to missing a tool change from a 3mm to a 2mm endmill. I caught the error and killed the program during the first pass, but the damage was done.
The milled brick mates snugly with a real LEGO, suggesting my tool calculations were pretty good for the 3mm endmill used to cut the bottom surface.
The milled brick mates OK in this orientation, but doesn’t really grip the green brick. I think my 2mm endmill may be a bit larger. The height difference is really obvious in this photo.
Misalignment of the top and bottom milling is really visible on this end of the brick.
Having a few hours to myself to fool around on the CNC, I found a decent parametric model of a LEGO brick and set about machining one in acetal. The surface finish is horrible, the height is off by a good millimeter and the bottom is a bit mangled by a missed tool change, but it’s fairly dimensionally accurate and mates with a real brick (the nice looking green one in the photos).
- Double check stock thickness and placement. For two-sided machining, this determines the overall height of the finished part. In this case, it was off by enough that the bottom pass poked holes in the top surface!
- Better alignment when flipping to machine the bottom. I currently drill holes and pin the stock to my spoil board. It doesn’t look like this is accurate enough.
- Double check what tool each path is expecting. I left a 3mm endmill in the collet for a finish pass computed for a 2mm bit and messed up the bottom of the part pretty badly.
- Lie to the XY finish pass. Set the endmill diameter larger than it really is. This should take care of the gouging on the sides of the part.
This time for chocolate!
Project for a friend whose son is really into Charlie and the Chocolate Factory. Mold design in OpenSCAD from logo pulled off the web. Toolpaths using MeshCAM. Bathtub mold master cut from RenShape on a modified 3040. Final mold made of food grade silicone.
Egg crate from scrap oak countertop. Finish isn’t as nice as I’d hoped, with some tearout around the edges
Bathymetric map of Salem Sound and the Beverly coast, in Massachusetts.
Some Christmas presents made on the CNC.
Trying to use up the remaining Oddity parts before I forget where they are. Hand soldering is sadly proving faster and more reliable than my stencil-and-frying-pan method.
Gave up on fancy routed tabs and catches and settled for countersunk machine screws into tapped holes.
The square baffles that separate the individual pixels for the large fireplace display are currently made of 30 interlocking pieces of laser cut cardboard. This assembly is expensive to have cut, fiddly to assemble and not particularly strong.
This is first attempt at producing this part in cast resin. This guide has been indispensable in getting started.
Hearth as backdrop for a digital “fireside chat” at Level39‘s one year anniversary. Sizes of Hearth and the fireplace surround are a bit mismatched. Might be time to build a unit scaled for a larger fireplace.