Should be fairly flat, but it needs to be square and honestly my tape measure skills suck. Precision hand measurements are not really my featured skill set. Here’s my idea, but I’m hoping someone will shoot it down if it is a bad idea.
Square 1 – litetally
Using the bases and the base tubes.
Make jigs:
Cut 3 pieces of flat stock:. One for the x, one for the y, and one diagonal. Center punch and drill leg holes in the stock at the correct distances.
Pin one foot, slide x and y jigs on the first foot tube.
Slide other end of x jig on foot 2
Slide other end of y jig on foot 3.
Slide diagonal jig on tubes of feet 2 and 3 to make a triangle
Attach feet 2 and 3
Remove x and y jigs
slide x jig on foot 3 and foot 4
Slide y jig on foot 2 and foot 4
10 place diagonal on foot 1 and foot 4 tubes
Pin foot 4
This seems like a good idea to me because it eliminates the error of multiple mismatched jigs. What am I missing?
When I built my Primo, I used 2 long strips for the feet. They were ripped on the table saw, and then I clamped them together, and drilled holes for the feet using the drill press.
I then put the 2 faces that were together in the drill press upwards, and set them on the machine base. They were set to be parallel, and I screwed down the bottom piece for the feet. I adjusted them so that the feet were square, to as close as I could measure, and the strips were glued and screwed down to the base.
By using the 2 strips and drilling pilot hoes for the feet like that, I could ensure that the feet were exactly the same distance apart in the Y axis. By carefully measuring where I put the holes in the strips, I could ensure that they’d be absolutely parallel in the X axis, and then by making a small adjustment when I glued and screwed the strips down, I could ensure that the machine was square. (The sheet of MDF that I had was apparently about 2.5mm out of square cut from Home Despot. The factory corners were square but the side that they cut (I had a 49X97" sheet cut down to 49X44") was out of square. Just a warning that if you didn’t cut and check it yourself, don’t just assume that it’s square.
Having a corner jig is good, it will help a lot, and you can work it to get you excellent results. Had I been thinking it through a little more, I probably would have used 3D printed jigs to place the feet on those strips, instead of the drill press holes, because that could still have let the feet move a little on the strip.
Well, I did the steps outlined above with 3 jigs out of some plywoood leftovers not yet discarded. Should mention that step 6 should use a square to align it with the table top if desired…
Foot #1 was lower left. Foot number 2 was lower right, 3 upper left, and 4 upper right.
Foot 3 had to be loosened to get foot 4 to fit in the diagonal jig. It is square.
and now it is just needs a little more assembly including a cable chain setup for the z axis and power to the controller… and two new trucks and a truck pipe clamp, but it should work for now. The core tubes are not yet true, so that will be next and drawing another crown. So far so good:
Spent a lot of time getting x and y gantry to sit square in a resting position so end stops are optional. The first assembly it would not run square unless homed. Now it is square all the time.
x motors were skipping and I found a broken wires on each motor. When fixing. I broke another due to some bad jst connection crimps. Actually got the touch screen to control the system, but ran the job over octoprint for the first test other than simple test moves.
What was to be cannibalized for an mp3dp will now be the revenue source for the mp3dp. I like that.
