Dimensions aren't coming out right.

[jeff412]

I have spent all day trying to cut out a project. I have cut this project at least 20 times with no problems. Now it seems to be stretching it. The project is about 24 inches long. After it carves, it is about 24 1/8 " long. It's a problem because I need the drilled holes to line up exactly. I have recalibrated and nothing seems to work. Any ideas?

Jeff

[AskBud]

I have spent all day trying to cut out a project. I have cut this project at least 20 times with no problems. Now it seems to be stretching it. The project is about 24 inches long. After it carves, it is about 24 1/8 " long. It's a problem because I need the drilled holes to line up exactly. I have recalibrated and nothing seems to work. Any ideas?

Jeff

It might be helpful if you attached the MPC and a photo of the problem board. show us each item that is out of place (or the wrong size). Give us the dimension of your actual board (or the sled it was on).
Do you still have an O-ring on the Brass roller? How did your answer each prompt? What chuck do you have?
AskBud

[jeff412]

I'll try to post the MPC in the morning. It's on my computer out in the shop. I did have the o-ring on it. I even tried removing the o-ring to see if that worked. It didn't seem to make any difference. If I took pictures of the board you wouldn't be able to see the problem. The 1/8" is spread over the entire board. It's like you took the board and just stretched it. It really seems like the x calibration is off, but it measures the boards correctly. I have the carvetight chuck.

Jeff

[Deolman]

The first question I would ask is what is the head pressure?

[AskBud]

I'll try to post the MPC in the morning. It's on my computer out in the shop. I did have the o-ring on it. I even tried removing the o-ring to see if that worked. It didn't seem to make any difference. If I took pictures of the board you wouldn't be able to see the problem. The 1/8" is spread over the entire board. It's like you took the board and just stretched it. It really seems like the x calibration is off, but it measures the boards correctly. I have the carvetight chuck.

Jeff

Jeff,
How about the dimensions of your actual board, and the Q&A session as you ran the machine?

If things are uniform, it could point to a "Scale to fit" action.
AskBud

[jeff412]

Don't remember the dimensions right now. At least 7" larger than MPC size. Q&A I tried the following

Stay under rollers
Keep original size
Center on board

Stay under rollers
Keep original size
Place on corner

[AskBud]

Don't remember the dimensions right now. At least 7" larger than MPC size. Q&A I tried the following

Stay under rollers
Keep original size
Center on board

Stay under rollers
Keep original size
Place on corner

Obviously, the board was wider than the design as well, (you got the Scale question).
Let us know the true size when you attach the MPC.
Have you ran a test of another MPC, just to prove the calibration status? If it runs well it may not be the machine.
AskBud

[jeff412]

I attached the MPC file as requested. The board is 31" long by 8.25". The machine measures the width at 8.285. I was able to adjust it to 8.249. I checked the calibration again tonight and something has gone wonky.( I think that's the technical term) Anyway. It is measuring the 31" board as 30.47" consistantly. The default X setting is 890.430. When I try to adjust it to 873.400, it tells me that the number is out of range.

[AskBud]

I attached the MPC file as requested. The board is 31" long by 8.25". The machine measures the width at 8.285. I was able to adjust it to 8.249. I checked the calibration again tonight and something has gone wonky.( I think that's the technical term) Anyway. It is measuring the 31" board as 30.47" consistantly. The default X setting is 890.430. When I try to adjust it to 873.400, it tells me that the number is out of range.

Humor me!
1. How are the 1.125 holes? Are they the correct size and perfectly round?
2. Is your rectangle the correct size?
3. Have you ran a different MPC (test) on another board (like a rectangle with one drill hole), both centered on the design board)? Did you verify the size and location?
4. What kind of wood?
5. Do you use masking tape on the bottom of the board (for the brass roller to gain more traction)?
6. What traction belts do you have?
7. Anything unusual happen prior to this problem?

I would rather know, and do all the above prior to playing with the calibration.
AskBud

[bergerud]

You may have a mechanical problem. If this behavior happened suddenly, it does not seem like a calibration issue. Your x measurement seems to be too far off. I would first make sure a sand paper belt is not rolled over and then I would check the x gear drive for a missing tooth. (It could also be the board tracking sensor but such failures have been rare.)