I’ve had almost zero problems with cutting, engraving and carving most things. It was only when I tried to surface my MDF spoilboard that I noticed my Z axis is not perpendicular.
I attempted to level it because when I cut pieces out of 1/4" plywood, the forward edges wouldn’t cut all the way through.
I estimated the amount that my spoilboard needed to be “leveled” and used a 1" spoilboard bit. Attempted to level the board by .2mm and got the following, as if my entire gantry is leaning forward.
Not sure if there is a way to shim, stiffen, or square the gantry, looking to the experts on this one!
Search for threads on “tramming”. They will explain how address this. There is a tramming jig on thingiverse.
Essentially – if the tilt is left to right of the mount then tighten/loosen core pieces. If the tilt is front to back of the mount then put shims in the mount to help even it out. The lack perpendicularity is magnified with larger bits.
I’m no where near an expert but I find there are three possible causes of this issue (and you can have more than one):
Leg length - if your legs are not the same length relative to the spoil board, you will create stepping like this. Note that leg length issues can be solved by shimming the router (see tramming below), but I prefer to get the legs at least close before shimming the router.
Deflection - if you have any slop in your Z axis and/or you move too fast for the resistance given by the large bit, you will have deflection which can result in scalloping. Facing scrap MDF at fast then slow feedrates to see what kinds of scalloping results can help to diagnose if deflection is part of the issue.
Tramming - if the router XY plane is not parallel with the face of the spoil board, then you will get this result. If tramming is the primary problem, you will need to shim the router. A tramming arm helps with the adjustment. You can find a couple on Thingiverse, plus there are pictures and more information if you search this forum.
There is a perpendicular tester Ryan made that fits on the collet and gives you a good way to easily measure it without running another job. You can also hide this by reducing the stepover.
After printing the tool for the perpendicular test, I am definitely not square on the vertical. Adding 3 shims from a cut up coke can, makes the most sense to put them here… we’ll see
