Carving Errors, Help

I have engraved before and it some small defects but acceptable. Now I get some real inaccurate straight lines and some letters have circular cuts that look like growth. Note the letter H and the rectangular cut. I am using a 90 degree V bit on plywood, the plywood seems soft under the veneer. I would like to get super accurate like many of you folks. Any assistance would be appreciated.

Thank you.

How does the preview compare?

If the preview doesn’t match what was cut, the basic points of adjustment for a machine are:

It is also important to be sure that the collet is correctly tightened, the endmill fits correctly and doesn’t slip, and the router is mounted securely in the mount, and that the mount doesn’t shift. Note than endmill pullout can happen gradually, especially when profiling against tall walls.[4]

Also feeds and speeds may be a consideration: and see for concepts on this and for a testing technique and see the series #MaterialMonday: #MaterialMonday on YouTube

Beyond that it’s usually a matter of Calibration and Squaring the Machine c.f.,

I went down the list.
Set Screws - OK
Eccentric Nuts - no slop but needed some tightening
Belts - x axis needed tightening
Collet - OK

Bellow is another carve after I made the changes. I have also included my v bit and settings.

Looks like you’re making progress!

Remaining things to check:

  • the material itself — some materials carve more cleanly than others
  • feeds and speeds — a bit of care here can help difficult materials carve more cleanly

Unfortunately, V carving in Carbide Create doesn’t afford too many controls, but hopefully by adjusting feeds and speeds and depth per pass you should be able to achieve a setting which works well.

For smaller, more detailed cutting it may help to use a narrow V endmill, possibly with a sharper angle.

When the machine is on, if you try to move the router by hand (left/right and front/back), is there any slop or none at all ?

Unrelated side note: I remember going from poor V-carving results to excellent one when I purchased a good V-bit (the one from Carbide3D’s store in my case) instead of the very bad and cheap one I had initially purchased. But I see you are use a Bosch V-bit, maybe something like this one ?

I wonder if it could be good for cutting large V-grooves, but not so good for doing small V-carving in letters ? It does not look very pointy. Just a random thought.


I’m suspicious of the “flute length” in the tool definition. I’ve seen on the Bosch site where .75 is indeed what they are calling flute length, which is pretty weird as that number doesn’t appear anywhere on the chart you posted.

If my math isn’t messed up, the actual length of the item labeled “E” is about .3977 == sqrt((9/32)^2 * 2). That’s what I would consider the flute length, but I’m actually not at all familiar with Carbide Create, so maybe it has another idea. In any case, making changes to that part of the tool definition might be worth looking at.

Oh, and I also see that Bosch calls this “1 flute,” but I believe it is actually 2. Can’t imagine that causing your issue, but it will probably affect what CC comes up with for feed rate.

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Per Rick, I change the flute length and flute count. Not much changed. I am getting a 60 degree v bit today. Will test it later today.

Julien, could you better describe this slop?

The error seems to increase on the left, and diminish on the right — usually when this happens it’s caused by the machine being unlevel / out of tram.

Please check that the table and wasteaboard are level, the Y-axis rails are level and parallel, the X-axis gantry rail is level and square to the Y-axis rails, and the Z-axis is plumb and square.

Please see: Wasteboard Plans with threads

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Julien is probably in bed now as he is in Europe. What he was asking is if there are any unwanted movements (slop) when the Shapeoko is powered. The spindle and carriages should not move in any direction when you try to move any of the axis, the router itself should also no move in any direction.

Have you checked that your router is trammed properly where the router is perfectly perpendicular to the wasteboard in the X and Y direction?


This is also what can happen if the Z zero isn’t set exactly right - namely, a touch low. It doesn’t take much. Also, as Will says, it seems a little different left to right, which indicates the bed isn’t parallel to the axis perfectly. V-Carving is extremely sensitive to bed level, squareness, and zero.


When the Shapeoko is powered I cannot manually move the spindle or carriage. I am currently away from my machine. I will run some tests on the Z zero position and move it up little by little. I will also check on whether the machine is trammed properly. Thank you all who are assisting, I do appreciate it.

This “H” letter is apparently the one having the most severe deviations, I would maybe try to V-Carve “HHHHHHH” instead of “ECHONTT”, just to see if the same defect happens from left to right.

Z-belt: how tight is it ?

Feeds and Speeds: what values are you using ? Probably irrelevant in plywood for such a shalow V-carve, just curious.

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Sorry for the slow response. All the belts have a snap like a guitar string. Here is my update. I flattened my waste board and then proceeded with a test carve. I have enclosed an image of a resulting test carve. It has turned out much better. But if you zoom in on the T you can see the tops on the inside have a slight shift/wobble.

I would like to try to get it perfect. Any other recommendations?!

Leave a roughing clearance and take a finishing pass.

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one of the things I usually end up doing for Vcarve in carbide create is to change the depth per cut (in the settings for the bit set it to manual); I’ve found that if I stay below 0.1" there I get better results on average (less chance of my work holding coming loose etc etc). CC will just do multiple passes which is just fine with me

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What is a roughing clearance and what is a finishing pass? How do those differ from a single pass? And can I execute that with carbide create/motion?

Roughing clearance is how much material is left uncut in a roughing pass

A finishing pass is a light cut which only removes the material left by a roughing pass

Carbide Create won’t do this automatically, see:

for an example of how to do this manually.

with carbide create, the simplest thing to try to see if this helps is to greatly reduce the max depth per cut, it effectively simulates the roughing/finishing thing.

if you want more of a “true” roughing, you can use the offset tool, make an inside offset of say, 0.02" and first vcarve that before you, in a separate toolpath, vcarve the original shape.

I think I found the problem. My friend sent me gcode made in aspire and the result was cleaner and after a few tweaks it’s gotten to where I am happy with the carve. I think carve on carbide create has some room for improvement. I like it for its simplicity. But I may have to get gcode from my friend for some carves. The other attempts at finding a solution were necessary as a maintenance check on the Shapeoko. I have attached an image, this was the first carve attempt with gcode from aspire. Thank you all for your help.