In preparation of doing acrylic etching, I decided to finally do a skimp cut to level My wasteboard. What an eye opener. No more grid :).
Two major things came to light.
The wasteboard had shallow spots. In other words, it simply wasn’t as flat as I thought it was. My bit would grind out .001 of of in some areas and not touch others. Not at any side or edge exactly but in the middle and at another spot. Looked and felt level but when I saw what was happening it became obvious it simply wasn’t. Had nothing to do with the level of my axis.
My X axis was twisted. Yep TWISTED. This is the new solid one. It was consistently carving a slight Ridge when doing the X skim cut. I was able to verify this with a square and managed to work out the twist by loosening the bolts in the brackets and using a pipe wrench to slightly counter the twist. Then tighten everything up. Such a dramatic improvement!
I suggest that people try this if they are really concerned about accuracy. I finally have a wasteboard that I can feel much more assured is level (at least in respects to the spindle).
Never heard of a twisted x axis.
The ridges in my waste board skim was caused by the bit. I used Easel and didn’t know where the step over is. I do now but when I did it I did not. Anyway The bit had a slight V in the blades. If the step over was not adjusted it would leave a ridge.
When parts do not meet reasonable tolerances that prevent proper functioning you should contact Inventables to correct that. Two extrusions and 8 wheels demand good tolerances to make it work.
Using Easel it starts in the center and goes in a square spiral. Last time I did this it left a ridge each pass. What would be the problem?
I assumed it was the large step over.
In the past I’ve laid down a sheet on top of the waste board and planed that for leveling. This sheet was screwed into the waste board.
The MDF is not dimensionally stable. Over time it can sag or warp due to humidity.
If you want a dimensionally stable waste board I’d move over to something like HDPE or ABS. It would be WAY more expensive for a big one. If you only need it for small stuff you could layer it on top.
There are special tools you can get to do the leveling process.
What tools are you referring to?
Also with 2.5" clearance when you want to put a 1.8" block and your board for setup is 1/8" thick it is a close call. One of the reasons I need to get the mod that raises the Z so I do not have this issue with my 2" blocks I want to carve.
Hi Phil,
sorry to jump in on this… I’m having the same issue with the ridges. Mine are in the x direction. Everything is perfect going in the y. I was thinking that meant the spindle isn’t square in the y direction… am I picturing that right?
This is exactly why I reported the twisted X rail. Twisted in that the “ridge” didn’t show on the left anywhere near as much as on the right. I had to loosen screws and twist the rail back to true and tighten everything back up.
My x axis was square all the way across. It’s the carriage that’s out on mine. I sacrificed an extra set of feeler guages and shimmed the bottom of the z axis out. Cutting nice and clean in both directions now.
Nice when an easy fix makes such a big difference. Bottom pic is before to the right and after shims on the left.
