Irregular box joint problems. Help!

Put my machine together a few weeks ago. I have a 1000mm x-carve

Its been working really well overall and very impressed with the machine.

As far as i know, the machine is calibrated properly per the assembly instructions and some of the tips i’ve seen here on the forums. This includes belts, v-wheels.

Have been experimenting with the classic box maker on both 1/2 MDF and 1/2" Birch Ply.

Using a 1.8" spiral upcut with feed rate and depth at the stock values for MDF as well as the ply. Cutting using outline, and outside of the path.

After several attempts to make a box today noticed i cant get this gap to close and notice some of the tails are irregular and not sqaure. Using calipers to input the material thickness into the classic box maker, and entering the bit diameter into the dogbone maker (although i don’t know what the threshold value does). As you can see by the pics something isn’t right and think it’s probably something to do with slop in the belts/v-wheels etc not being setup properly.

My other thought is that maybe the part when almost at cut depth is moving or something and contacting the bit during passes. I am using tabs (2 per part) and have the material held down with doublestick tape.

Any tips or troubleshooting advice would be greatly appreciated.

The gap may be due to the round corner. On the inside corner you will get a round corner the size of the bit, while the outside corners are able to be perfect 90° . To fix this you can file the inside rounds square or sand the other side round .

Calibrated steps/mm? Measured actual cutting diameter of the bit?

Slop is flex in you z. Round bits make round holes not square.

have not measured actual diameter of bit with calipers- Will do that. What do you mean by calibrated steps/mm?

what are the troubleshooting steps for slop in the Z axis?

Ok I will give that a shot just to be 100%, but can tell the tails/wall of the joint are not perfectly 90 degrees/straight (im a furniture maker so have a decent eye for this). I believe the gap is from the bit cutting off path.

Basically you instruct a move command by some amount, measure how much it really moves and recalculate a GRBL parameter.

Sorry I was focusing on the corners do you have any scrap hardwood around ? Try taking a piece of scrap and cut a straight line with your bit then measure the width of the cut with your calipers and use that as your bit diameter should get you a lot closer to where you wanna be.

Grap your spindle. Can you move it with light/medium force? Check you wheels ( all of them mostly x and z.)
And oh course as Robert said check bit diameter.

Has this been resolved?

I have the same problem and it’s nothing to do with bit size or calbiration, I’m certain, because I can cut precise parts on my X-Carve.
The box maker app for some reason cuts off path, or is generating the paths innacurately, or is adding a gap between the fingers intentionally.

Has anyone cut accurate finger joints using this app? (rotary, not laser)