Happy Sunday to everyone. I just finished a sign for my wife’s kennel. This is my first “real” project. I had a couple problems that were all my own doing and understand I will need to level out my setup a bit. One thing that I haven’t figured out yet is the first border cut on the left side of the pic. It is shallow compared to all the other border cuts. I leveled the work piece but of coarse if the machine is not leveled it’s not going to make much difference. But why starting from the left side top would the border run deeper? The first cut was from the bottom up and then from the left top and continued around until meeting back up to the bottom left of the first cut.
I appreciate the help!
Nice first “real” project!
Is this on an SO3?
Your eye is remarkably sensitive to changes and can easily detect differences of as little as 0.001" (under the right circumstances). How much of a depth difference is it?
This can occur for a several reasons:
A) Your machine isn’t trammed (squared up in all directions).
Did you do the procedure to ensure that your machine is all squared up?
It’s a good idea to check the depth of cut and squareness in multiple locations across the
work volume. In an SO3, the Z axis belt needs to be correctly tightened - otherwise non-linear
result can occur.
B) Your spoiler board isn’t machined flat.
The spoiler board has ridges and groves in it - or may not be as square to the frame as you expect.
You may not see this with you eye but the issue is there. Your machine needs to be used to
machine the top of the spoiler board flat. Now the spoiler board is flat and square to your machine
- as accurately and precision as your machine is.
There are spoiler board tools that can do the job very quickly. The Amana Tool RC-2243 is a good,
low cost choice from a quality vendor. It has a 0.25" shank.
C) The stock (wood) is is not consistently thick.
Wood, particularly hardwoods, aren’t consistent in their thickness or dimensions. Especially to
the tolerances that a CNC machine is capable of. To get the best possible results the stock needs
to be machined flat on top and bottom - this ensures that the stock is parallel on the top and
bottom and is the specified thickness.
This is especially important when making things that require multiple wood pieces to connect
(e.g. boxes).
This step requires that A and B have been done first.
If things are squared up and the stock is uneven and you did you touch top Z0 on the shallow
end, the thick end will have a deep groove.
D) The stock wasn’t fixtured well and it moved during machining.
Warps in the stock - especially if B and C weren’t done - coupled with not having things held
sufficiently well can allow the stock to be “sprung”. One side can “pop” and be higher than the
other.
mark
Thank you Mark.
Sorry, yes this is the SO3.
It’s good 1/16" difference.
(A) I checked the machine after putting it together and it was squared, but, I have since built an enclosure around it. The enclosure is very tight and could have pulled it out of square when screwing the pieces together around the machine. I did square the work piece from the front of the machine but noticed the border is sightly out of square which tells me something IS out.
(B) No my spoiler board is not machined flat. I will order the bit today…thank you.
I tightened the Z axis belt per instructions but will revisit that and recheck.
© The wood measures pretty good and consistent.
(D) I did have the stock tightly secured. Did a test piece yesterday with the piece not has tightly secured as it should have been…what a mess!
Since my post I checked and found that the router mount clamp was out of level but would assume that it would affect every cut the same. At any rate, I’ll go back and do as you instructed and report back with the outcome.
Thanks again for your help!
(B) No my spoiler board is not machined flat. I will order the bit today…thank you.
This is not at the 1/16" level but it is a good thing to do as it ensures the best outcome… you’re taking things as far as the machine can. 1/16 = 0.0625". Your SO3 is capable of much better than that when properly aligned, tightened, and tweaked. Something on the order 0.006 would be more like it.
See here for some tool suggestions:
but noticed the border is sightly out of square which tells me something IS out.
Please report back on your checking and potential tramming (squaring up) your machine.
With a new build, there are plenty of things that can be “off” and need adjustment. Check squareness and depth at the center and four corners. All five should look identical and be “exactl” what one expects.
(C) The wood measures pretty good and consistent.
That’s good… but don’t count on it from all sources of hardwoods. Some sources provide beautiful wood with amazing variances.
(D) I did have the stock tightly secured. Did a test piece yesterday with the piece not has tightly secured as it should have been…what a mess!
Just checking! 
You’ve had the joy of a fixture coming loose and stock moving. Been there! Done that!
mark
Please check out the squareness of your machine, esp. the spindle:
http://www.shapeoko.com/wiki/index.php/Calibration_and_Squaring_the_Machine#Shapeoko_326
Also, some fine-tuning may be needed: http://www.shapeoko.com/wiki/index.php/Tuning10
(These are @WillAdams ole standbys - thanks Will!)
mark
It turned out that my machine bed was out of square due to my fine carpentry skills. When I made the enclosure it was a bit short from the sides. Anyway when I screwed everything together around the Shapeoko frame (and it was tight) it tweak it just enough to pull it out of square. Did everything else as you said Mark and it looks like I am good to go.
Thank you,
Bill