I just started my first build after lurking on here for a long time. Everything seemed pretty obvious until the actual build
I read on here that for the lowrider design it’s best to have the machine running on top of the wasteboard, because of the stability and some loss in Z-height.
We’ve built a big table for a working area of about 122x150cm using the calculator, but now I don’t really know how to go further and I have a few questions:
How do people attach their wasteboard to the table itself? I’d prefer not to drill any ‘temporary’ holes into the table. It’s a torsion box with 15mm plywood as the top surface without any holes in the table.
What type of wasteboard and what spacing of fasteners would you recommend? What type of fasteners do most people use for the underside of the wasteboard?
The kit didn’t contain any endstops, so I’m assuming we can use the sensorless homing of the tmc2209 drivers, but I read somewhere on here that it is discouraged. If possible I would like to use it, because I find it a cool feature, but if it doesn’t work well, what kind of switches should I use?
Can the sensorless homing also be used to zero to your stock?
I know I’m asking a lot of questions, but I would really appreciate any feedback.
Thank you in advance!
(The table I’m very proud of, boyfriend for scale )
Not many do sensorless homing so I’ll chime in on that portion…
First be sure you have the dual endstop firmware and all of your steppers are connected to their own controller.
I think of it more as squaring than homing. X and y are pretty straightforward. The y axis will need some kind of adjustable bumper at the end to square the 2 sides. The z axis will home upwards. You will need to add stops at the bottom of your gantry pipes and raise or lower one side to square I ended up using pipe clamps. You will also need to print some coupler savers to protect your couplers from getting stretched. Actual z homing is done downward using a touch sensor.
You will need to play with the bump sensitivity a bit to get the sensorless working right. I suggest doing it via gcode as it may take multiple tries.
Smarter minds than me don’t care for sensorless so your mileage may vary.
I would countersink some wood screws (#8 or so, if you live in the US). There is a pretty healthy region where the LR can’t reach (about 5" on each side) where you can secure a large spoil board. Dont use glue, because it will need to be replaced eventually. I also use temporary screws to attach sheet goods to the spoil board (and not to the table).
I would encourage you to take it in steps. 1) no endstops. You don’t need them at all to make almost anything. 2) touch plate for Z. 3) physical endstop switches. The bare ones without the PCB work fine and they should be pretty cheap to buy. 4) sensorless homing, if you really have to.
Anttix does use sensorless homing on Z for his low rider, but there aren’t many that do. You need to print or make something to save your couplers and the firmware needs to be created for sensorless homing. The accuracy is also in question, especially for squaring a table.
The touch plate for Z should not use sensorless homing.
If you absolutely need to put some screws in the middle of the spoilboard, consider using countersunk brass screws. These shouldn’t cause any problems for a steel bit if you inadvertently intersect one with the spindle running.
Thank you for the advice, I guess I won’t be using sensorless homing immediately, like @jeffeb3 suggests, even though it is possible in the future.
Just attaching the wasteboard still remains a bit of a question in my head. I’d like to use the table without the cnc too and having screw holes in there feels like I’m damaging it. Can I use T-nuts like people use in their spoilboard to fasten it to the table or does this introduce other issues?
I was planning on using a removable system for the Y belt, so the LR can be taken off if needed.
Thanks for the advice on the brass screws @ttraband, I hadn’t thought about that!
I used carpet tape to hold my spoil board. I also used four 2’ X 4’ pieces, instead of one 4’ X 8’ piece. That way, I can replace only the sections that get chewed up the most. So far, so good.
The router plate is quite wide, and needs to be close to the workpiece, so bulky hand screws may get in the way. But maybe if you countersunk some screws into threaded inserts you could have removable screws.
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