cant calibrate x tracking sensor

[bjmwoodworker]

This problem showed up when trying to make a rotary jig left side as multiple cuts in at various depths in the ends where it is supposed to keep cutting in one line slowly increasing the depth of cut. I am using a 36" flat board and head pressure is 92 lbs and board sensor shows 0 and 137. the closest I can calibrate is to 35.00 inches and if I try to change the calibration number any further, (ie something under 877.000), I get an out of range error message. I went thru all the adjustments and cleaned it and lubricated the machine. the damping spring is on and I put on a new o ring and and checked the pressure rollers and nothing seems to correct the problem. the measurement used to be ok with this calibration board but now it isn't. I am lost as what to try next help please and thanks for any suggestions

[bergerud]

Nice job checking things. I believe it is a hardware problem. Here are some more to check: rolled under belt or rubber belt touching tracking sensor? Missing tooth on an x drive gear?

Rare but it could be the board tracking sensor itself.

[fwharris]

Also a raised out feed table...

[bjmwoodworker]

well thanks for the replies I checked that the outfeed tables were adjusted and readjusted them using a 48 inch aluminum level to make sure.... no help
I looked to see if the rubber belt was touching the tracking sensor but it sure doesn't look like it is
I took the rubber belts out of the machine and removed the plastic cover over the drive gears and I cant find any missing teeth on any of the gears plastic or metal. the only thing that I have found odd, is the outside plastic gear seems to touch the casing in one spot when the belts are moving in one direction only but not in the other direction. just causes a little ticking noise but I don't think that it is causing any slow down or sticking of the belts.
I have ordered another tracking sensor on the off chance that it is causing the problem.
Does anyone out there know what the calibration range is supposed to be on the x tracking setup(4 then new value) I cant seem to get less than 876.00 without the machine saying calibration range error.
I did note that I have the newer tracking sensor with the single groove and it appears to have the wrong o ring on it (7/16 by 5/16 rather than 1/4 by 3/8 it came this way from Carvewright) anyway I tried it without the o ring as some discussions seem to indicate that it is not needed and no change in measurement error was noted. anyway still trying to find the problem Btw Bergerud is it true that you have advised us not to build your posted mpc's as you are coming out with a newer version?

[Digitalwoodshop]

Like a Radial Tire BULGING you will not see the rubber belt bulging out and touching the brass roller until the board is cranked down.

Make the Brass Roller Mounting Holes OVAL and move the sensor to the center. End of Problem.

AL

[bjmwoodworker]

hmm that is a possibility but why now when it was working fine before I will try the oval holes but it really doesn't lood like I have any room to adjust it much. I was wondering if the damping spring is too high ... mine is .5 inch high and that seems to high to me anyone know what the dimensions are supposed to be? thanks for your reply

[bjmwoodworker]

Like a Radial Tire BULGING you will not see the rubber belt bulging out and touching the brass roller until the board is cranked down.

Make the Brass Roller Mounting Holes OVAL and move the sensor to the center. End of Problem.

AL

Thanks Al who

that was the problem and I elongated the mounting holes for the tracking sensor and that fixed the problem. when I looked at the brass roller and pushed it down ever so slightly, it was causing the tracking roller to rotate even before the head pressure was applied and with no board. Guess Carvewright should redesign that mounting plate to accommodate those of us who have rubber belts. thanks again for all the help guys and gals and to you Al kudos

Bobby