'Bit Depth Does Not Match'

[swobee]

I just received my second CompuCarve machine after the cut motor on the original unit stopped engaging. This happened within four weeks of purchasing it through SEARS, where I opted for the 5 year warranty (appears so far to be a prudent choice) so I exchanged the entire machine through my local store after trying to deal with their support department over the phone to no avail. The replacement machine had problems right out of the box, which I was able to diagnose as a bad compression sensor switch on the front roller and get replaced after more frustrating delay. Complaints aside, I am now getting a message stating 'Bit Depth Does Not Match' when I try to use any of the bits from my 11-piece accessory bit set. The machine just repeats the homing process over and over to no avail. It does not seem to matter which bit I have installed. The error first appeared while carving a project that entailed a design around the border constructed with dingbats and carved in centerline text with the 60 degree V-bit. I then tried to edge rout a board (the same board after the machine ejected it during carving and ruined the project in hour 7 of 7.5 total carving hours) through the onboard menu using a 1/2" roundover bit to the same effect. Is this a calibration issue or possibly something larger? Any suggestions are greatly appreciated. Additionally, I am hoping the board ejecting when nearly done carving was an isolated incident.

[dbfletcher]

Are you using the qc? That message indicates the the mesurment it took at the beginning of the project (when u cycled thru the bits inthe project) does not match the measurement it takes right before it starts to use the bit. I would watch the bit flag cosely to make sure it is extending all the way out durring both measurments. Also try to note how many times it touches down on the bit flag. two is normal... three indicates it had a problem with one of the first two. With the qc this also serves as a warning message that the bit may not be seated fully in to the qc. Make sure the locking collar is fully engaged each time you insert a bit.

If you are using the rock with out collars, that just means you didnt insert the bit the exact same way you did during the first measurement. Typically you are fine to just select continue and be ok in that case.

Hope that helps,

Dug Fletcher

[AskBud]

Listen to the machine. If it is telling you that the bit depth does not match, and you have a QC, you may not have the bit seated properly in the chuck.

Last week i got the message and decided to ignore the warning, as I knew it was seated properly! Needless to say and I saw it touch the plate, but the machine was correct. The truck went down, and the bit engaged the wood and was pulled right out of the chuck. No damage to the chuck or machine, but the bit shot around the inside like a bullet!

For safety sake, remove the bit, check the screws, and place it in the chuck again.
AskBud

[swobee]

Thank you each for your replies. An improperly seated bit was my first suspicion; however, I never had a problem like this with my first machine and exchanged bits many times without issue just as I do with the replacement machine. That led me to suspect the chuck itself, which to my fairly limited knowledge is a QC as I have not upgraded it. I have read some posts here where members accuse the QC of causing problems. The issue I have with this diagnosis is it only becomes an issue with bits from my accessory set, not the 1/16" carving or 1/8" cutting bits. one thing I did notice is that it seems to fully touch the bit flag on the right side of the machine only once during homing, on the first attempt. On the second measure the bit descends only half way to the plate, if that. The very consistency of the error, coupled with the fact that it happens only with the accessory bits leads me to suspect a calibration or sofware error. The fact that the board ejected erroneously during carving on the machine's first run seems also to be too closley related to such an issue to be coincidental. Thoughts?

[dbfletcher]

As far as I know, the bit MUST always touch the bit plate at least twice. Less than that I have always just seen it go back and ask for you to insert the same bit. I would try and figure out why it isnt descending all the way on the second attempt. I'm sure Bud will have more info on things to look for. I would make sure the z-rails are clean and free from defects as well as the belt that drives the z. I know i've seen posts about cleaning the "no mans land" but I dont have the specificis of how that is accomplished.

Doug Fletcher

[AskBud]

Thank you each for your replies. An improperly seated bit was my first suspicion; however, I never had a problem like this with my first machine and exchanged bits many times without issue just as I do with the replacement machine. That led me to suspect the chuck itself, which to my fairly limited knowledge is a QC as I have not upgraded it. I have read some posts here where members accuse the QC of causing problems. The issue I have with this diagnosis is it only becomes an issue with bits from my accessory set, not the 1/16" carving or 1/8" cutting bits. one thing I did notice is that it seems to fully touch the bit flag on the right side of the machine only once during homing, on the first attempt. On the second measure the bit descends only half way to the plate, if that. The very consistency of the error, coupled with the fact that it happens only with the accessory bits leads me to suspect a calibration or sofware error. The fact that the board ejected erroneously during carving on the machine's first run seems also to be too closley related to such an issue to be coincidental. Thoughts?

Just a warning/observation.
The 1/2 inch shank bits do not tighten, in the adaptor, by the screws.
The collet turns with a wrench, and some of mine were loose when the kit arrived.
AskBud

[liquidguitars]

Sounds like your using the QC, if so you should not receive this error unless the QC or spindle, the truck or bit is loose.

Thank you each for your replies. An improperly seated bit was my first suspicion; however, I never had a problem like this with my first machine and exchanged bits many times without issue just as I do with the replacement machine. That led me to suspect the chuck itself, which to my fairly limited knowledge is a QC as I have not upgraded it. I have read some posts here where members accuse the QC of causing problems. The issue I have with this diagnosis is it only becomes an issue with bits from my accessory set, not the 1/16" carving or 1/8" cutting bits. one thing I did notice is that it seems to fully touch the bit flag on the right side of the machine only once during homing, on the first attempt. On the second measure the bit descends only half way to the plate, if that. The very consistency of the error, coupled with the fact that it happens only with the accessory bits leads me to suspect a calibration or sofware error. The fact that the board ejected erroneously during carving on the machine's first run seems also to be too closley related to such an issue to be coincidental. Thoughts?

[swobee]

As far as I know, the bit MUST always touch the bit plate at least twice. Less than that I have always just seen it go back and ask for you to insert the same bit....

This is exactly what it does. The machine will cycle through the homing process, then ask me to insert the bit I just did before cycling through again. I should have some time tonight/tomorrow to troubleshoot further, and will inspect the Z-axis rails closely at that time. What I'm having trouble getting over is the fact that I did an entire carving utilizing the 1/16" carving bit with no issues and only encountered problems when I got to phases employing my accessory bits. The accessory bits required have all been used by me on projects with the first machine so I don't think they are the issue, but I will be sure to check the collets as well. STUMPED.

[swobee]

Sounds like your using the QC, if so you should not receive this error unless the QC or spindle, the truck or bit is loose.

Is there a specific process for evaluating these areas? Reasoning leads me back to the fact that the machine executed a complex carving with no loss of detail or resolution, and only gave me this error when installing the accessory bits. If anything was loose in this area would my carving not have suffered a loss of quality?

[dbfletcher]

Well... you keep saying that with the shorter bits the machine is not able to touch down on the bit plate on the second "touch" in the setup phase. My guess is for some reason the machine is detecting some resistance on the second check before it hits the bit plate... so the motor current spikes and the machine thinks it hit the plate at two very different measurements. Obviously the carving an cut bits are quite a bit longer than most of the accessory bits so the z doesnt travel as far when checking them on the bit plate. The machine not being able to successfully touch down twice with the shorter bits is the clue.

Hope that helps,

Doug Fletcher