Calibration range error

[maimino@comcast.net]

Setting up to run a rotary project for the first time. Running the rotary calibration, the machine rotates well past the starting point for the calibration. I use the arrow keys to rotate it back to the starting point, press 1 to keep, and the machine gives me a Calibration Range Error. Any suggestions?

[dbemus]

Check this thread: New Rotary Jig. Calibration error

[maimino@comcast.net]

Thanks, but I read that entire thread before posting. I checked the head pressure and my problems continue regardless of how many times I try.

[SteveNelson46]

Awhile back Bergerud developed an alternate setup for the Rotary Jig. Essentially, it eliminates all of the pulleys and belts and uses a drive rail instead of a belt rolling on the rubber belts of the CW. We talked about it in the senior member forum and I have used it exclusively since then. It really does work much better than the original design. One only has to calibrate once and the jig works good every time. If it's okay with him, I will post the pics and the setup info here. However, I must add, this is not a project for the faint of heart. It requires tinkering and modifications to the jig.

[maimino@comcast.net]

Thanks. I would be interested in learning about the mod.

For what it's worth, the head pressure is 90 pounds. The jig is set and aligned per the instructions. I've gone over it, step by step, at least two dozen times. The jig simply does not want to calibrate.

[SteveNelson46]

Try playing with the head pressure. Crank the head all the way down on the jig and "bump" it back a little. Also, be sure the project board is not too tight in the jig.

[maimino@comcast.net]

So, the bottom line here is this (correct me if I am wrong): pay $350 for a rotary jig from LHR, find out it does not work as advertised, hack it apart, and try to build a mod that actually works. Such mod no doubt invalidates the warranty and guarantees no support on the jig going forward (assuming there ever was a warranty on the jig in the first place).

Am I the only one that sees a problem with this?

[SteveNelson46]

Here is a pic of my setup. Note the absence of all belts and pulleys and the shim under the right end of the jig for leveling. The ends of the jig are resting on the alignment plate on the left and the sliding plate on the right.

[bergerud]

I spent quite a bit of time experimenting with the rotary jig to determine why it is so sensitive to head pressure. My many rail driven prototypes were not sensitive to head pressure at all. My conclusion was that the problem is caused by the use of smooth idler pulleys with the timing belt. Squeezing the teeth of the timing belt against these smooth pulleys alters the effective length of the timing belt as it rolls along. This distortion would vary with head pressure.

Since this system is so sensitive, the cause in this case, may be difficult to determine:

Maybe you need to shift the rubber belts on the CW closer to the squaring plate. (Is the timing belt completely on the CW belts?)

Maybe the rubber damper under the board sensor is missing or not pressing the brass roller hard enough against the timing belt.

Maybe the jig is pressing the board sensor down so far that the O ring is rubbing on the front CW belt.

Maybe you have the wrong O ring on the board sensor? (Try taking it off.)

Maybe the timing belt manufacturer has changed the properties of the rubber belt. Maybe you need a different belt.

That is all I can think off at the moment! I hope you get it working.

[maimino@comcast.net]

I uploaded a video of myself going through the calibration process. If anyone sees what I am doing wrong, I'd appreciate it.



Also, here are some photos of the jig, the setup, and the scale showing the head pressure that I get by "leaning" on the machine a bit.