Sunday, January 21, 2018

4cm thick wood cnc project: shelf

The lighter wood is about 4cm thick. Both of the sides are cut from a single plank of timber which left the feet with a slight weak point at the back. Given a larger bit of timber I would have tapered the legs outward from the back more gradually. But the design is restricted by the timber at hand.

The shelves are plywood which turned out fairly well after a few coats of poly. I knocked the extreme sharp edges of the ply so its a hurt a little rather than a lot if you accidentally poke the edge. This is a mixed machine and human build, the back of the plywood that meets the uprights was knocked off using a bandsaw.

Being able to CNC thick timber like this opens up more bold designs. Currently I have to use a 1/2 inch bit to get this reach. Stay tuned for more CNC timber fun!

Friday, January 5, 2018

That gantry just pops right off

Hobby CNC machines sold as "3040" may have a gantry clearance of about 80mm and a z axis travel of around 55mm. A detached gantry is shown below. Notice that there are 3 bolts on the bottom side mounting the z-axis to the gantry. The stepper motor attaches on the side shown so there are 4 NEMA holes to hold the stepper. Note that the normal 3040 doesn't have the mounting plate shown on the z-axis, that crossover plate allows a different spindle to be mounted to this machine.

The plan is to create replacement sides with some 0.5inch offcut 6061 alloy. This will add 100mm to the gantry so it can more easily clear clamps and a 4th axis. Because that would move the cutter mount upward as well, replacing the z-axis with something that has more range, say 160mm becomes an interesting plan.

One advantage to upgrading a machine like this is that you can reassemble the machine after measuring and designing the upgrade and then cut replacement parts for the machine using the machine.

The 3040 can look a bit spartan with the gantry removed.

The preliminary research is done. Designs created. CAM done. I just have to cut 4 plates and then the real fun begins.