Stair-stepping on a cutout?

[parkgt]

I recently made a sign using the oval pattern with the pine trees along the edge.
I cut it out of oak with the 1/8" bit taking .180" passes. One end (exit end) of the cut out along the pine trees had significant stair-stepping on each pass.

It was probably about .020" per pass and made cleaning up the edge quite a challenge. The other end was fine.

Any ideas on why?

[unitedcases]

Sounds like you need to blow out your "encoder" disc. It is on the back of the z motor. 3 screws, and a gasket. Gently take it off and gently blow it out. No matter how well you seal it back dust still gets in from the front. Anybody want to follow up, I am terrible with nomenclature.

[Digitalwoodshop]

Stair Stepping is caused by Brass Roller Tracking Errors....

Masking Tape will help....

Head Pressure check will help....

Head Level Check.....

Board only held by 1 roller.... 7 inch rule of wood....

Worn sand paper belts....

It's all about the board loosing contact on EACH PASS... Causing the Stepping....

Pictures are from BMT.... :mrgreen:Before Masking Tape....:mrgreen:

AL

[unitedcases]

Ahhh, I thought he meant stairstepping as far as depth. My bad.

[parkgt]

Thanks for the replies,

Three layers of tape on carrier board and 4" on each end.

The project was on a mdf carrier board without side rails so the contact area may have been too low after carving.

I will look into the other suggestions.

[CarverJerry]

Hey Al, you mentioned worn sand paper belts, what would be a good indicator that the belts are worn, is it like worn out sand paper (lack of grit) or are you refering to the edges being torn up like I've heard in a few posts here?

CJ I'm just trying to learn about any problems before they show up on my machine. Thanks

[Digitalwoodshop]

Yes, lack of grit.... But I change them when they are limp looking.... They are always collecting rosin on the BACK from the sawdust and new belts just move easier.... And grip the board better.

AL