My Issue -
I am using the Bitzero V2 to zero the Shapeoko to my stock, but cuts in the stock are not perpendicular or parallel to the edges of the stock when I expect them to be.
I got my Shapeoko 3XL last December and have been slowly getting into CNC. I managed to get a Bitzero V2 almost right away and I’ve been using it the whole time. I have done all of the calibration tasks including creating and surfacing a spoil-board with inserts and getting the router almost perfectly perpendicular to the spoil-board.
Today I have been trying to cut a shape into the side of a piece of stock, where the stock is my finished part. What I am seeing is that the cuts are not perpendicular / parallel to the stock.
If you look closely at the ‘door’ on the right, the left edge of the door is leaning to the right - the distance between the side of the stock and the edge of the door is smaller at the bottom then it is at the top. The same thing is true for the piece on the left, it is just less pronounced.
Method 1 - don’t touch the Bitzero when probing.
I secure the stock to the spoil-board and place the Bitzero snug against the bottom left of the stock. Using the precision ground rod that came with the Bitzero I run the XYZ probe. When the probing is taking place I can see the Bitzero block move slightly when the router prob touches the inside of the circle, should that be happening? Doing this method produced the cut on the right - the left edge deviates by 2mm to the right over ~75mm in height.
Method 2 - hold the Bitzero as tight as possible when probing.
Same setup as before but this time I hold the Bitzero with my fingers to try and stop it from moving when the router probe touches inside the circle. This produced the cut on the left - where the left edge deviated by only 1mm over the same height (so an improvement, but 1mm is still a lot over such a short distance.
Am I using the Bitzero correctly? Is it correct to assume that the Bitzero will virtually square the stock to the gcode?
Other considerations -
My stock is square, I measured it against more than one right angle (I also have a picture for proof ). The Bitzero fits snugly in the corner with no play at all.
Thanks so much for reading, any suggestions would be great!
Good day Captain!
Unfortunately, the BitZero will not square the stock. In order to ensure that the cut geometry is square to the piece, you have a couple options. Off the top of my head, you could cut a fence in place and register/stage your work piece off of that or use oversized stock and cut the outside contour to your final desired dimension.
To add to @RoughDraft40’s answer and address your other questions:
- it’s fine/better to hold the BitZero v2 during probing if it’s moving when you don’t (that depends on a variety of parameters, there have been a few threads on that). Not need for “as tight as possible” though, one finger should suffice (be careful at all times, when your hands are in the work area, probing or otherwise)
- the BitZero will “only” establish a single reference X,Y,Z point in space, that’s why it cannot manage orientation of the stock around that point and relative to machine axes.
- you may consider using a corner square like the one on the store, to align your stock to the machine’s axes in a consistent manner (after careful initial installation of the corner square)
Thanks for the replies @RoughDraft40 and @Julien ! I guess my question didn’t need all that info so I appreciate that you read all that! I will look to make my own corner square as my threaded board has 50mm spacing between the bolt holes.
Have a great day!
Captain Kirk, as a new user to add on as the guys have laid out, the sets the XYZ as a single point as a reference and doesn’t know anything about the orientation of the work. That said what I’ve learned to do:
When cutting out an object where you end up cutting all of the way around the exterior, you need your work piece to be close to “square” on the machine but it is less critical. One major thing however to consider though is grain direction in getting it lined up. One example I have of this is when I made some signs out of a companies logo, my last cut was an outside offest cut taking my square stock into the actual shape of their logo.
When cutting on an existing object, it is critical to make sure the stock is square to the x/y axis on your Shapeoko. What we did was put in a wooden fence, and then used the manual jog feature to trim up the fence. Using the manual jog allows you to be sure your fence is square to the machine, because you used the machine to cut it. Other option is to purchase and or make a square as Julien suggest, but you still need to ensure you get it square to the machine with the mounting. Tons of videos out there, I’d recommend this one from Chris Powell, start at 6:30 and he covers it in about 1 minute.
Cheap and Easy Wasteboard, Fence, and Clamps for your cnc router - YouTube
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