PowerPro Rattle on Startup

[Matanuska]

Yes, I've noticed the eccentric can slip down if the small stop screw on the eccentric falls into the slot on the headstock while rotating the eccentric. Smart idea on checking for parallel shafts - I think I may be able to replicate the Wixie functionality using my iPhone angle finder.

- Steve

[DLB]

Yes, I've noticed the eccentric can slip down if the small stop screw on the eccentric falls into the slot on the headstock while rotating the eccentric. Smart idea on checking for parallel shafts - I think I may be able to replicate the Wixie functionality using my iPhone angle finder.

I modified an eccentric for a stop screw function that would limit travel of both the eccentric and bearing in both directions. Then put it aside until I had an Idler out. Then forgot all about it because mine has not moved since I got the belts squared away. If I come across it I'll put it with my spare PP Idler Shaft. Your phone should work fine for this.

More recollection, directions based on the machine in DP vertical setup for clarity: My motor pulley was too 'low' in reference to idler pulley for the belt to run true. Motor pulley was not against the stop as it should have been, this corrected about half the error. The motor mount setup includes two dovetail 'slides' that will allow the motor to move 'up and down' in the motor mount if you loosen the (4?) setscrews that lock it. I think the setscrews are item 104 on the exploded PP diagram, not externally visible but accessible through holes or slots. Mine was maxed out, motor would move 'down' in the mount but I needed to go 'up.' This part is vague in my memory but probably intuitive if you look at it: I machined some aluminum on the motor mount to deconflict whatever was acting like a stop preventing 'upward' adjustment. My best guess at this is that the fan cover and/or its mounting screws were hitting the mount at the end of its range. If you are lucky your machine is not the same, this wasn't difficult but involves removing the motor. I did check to see if I had drilled my headstock correctly, but my only reference was the same drilling guide I used to drill it. Not surprisingly, correct per that reference.

- David

[Matanuska]

I did a quick check of the shafts using your lathe plate trick and found all three were dead on parallel. The iPhone angle measurement only reports to the nearest degree but both the motor pulley shaft, the idler shaft, and the spindle shaft had identical measurements in all directions.

While I had access to the eccentric sleeve, I removed it, cleaned it up, and found it then moved quite freely while doing the tension balancing. In fact, it didn't seem to matter which grooves I put the idler belt in - the idler shaft and eccentric moved up or down on their own to remove any offset while running unclamped. I settled on 2 grooves above and 2 below because that made the eccentric & shaft ride up against the stops. The eccentric also almost rotates on its own to a neutral position while running unclamped as the belts naturally balance their tension with each other.

Since the startup rattle only occurs in table saw mode, with some hesitation I attached the sawblade and lower guard while the machine was in the DP position. I rotated the guard around 180 degrees to cover the exposed portion of the blade nearest me during the tension adjustment. This allowed me to get immediate feedback on the impact of the eccentric position on the startup rattle. I found I could minimize, but not eliminate it. The rattle seemed to be coming from either the quill lock or the saw blade end of the quill. Not sure why, but loosening the quill lock seemed to reduce the rattle.

I pulled both the quill and the quill lock assembly to see if I could find a source for the rattle, but the quill bearings looked fine and all the quill lock parts were present in the correct order. Unable to think of anything else, I remembered to check the set screw on the fan assembly end of the motor and found it was loose. I added some thread locker, this time blue(!), and re-tightened the set screw. Fingers crossed that this will turn out to be the source of the rattle once I get everything back together, but I'm not sure why the rattle seems to be coming from the other end of the headstock.

Steve

[JPG]

Internal echo???

The drive sleeve pulley has 13 grooves. The poly-v belt has 9 ribs. Centered simply makes sense.( 2 above and 2 below)

BTW the Mark VII has 13 ribs. No pulley change.

[DLB]

... Fingers crossed that this will turn out to be the source of the rattle once I get everything back together, but I'm not sure why the rattle seems to be coming from the other end of the headstock.

Very possible to cause that result IMO. I think a loose fan can cause or increase torque jitter, a common complaint among PP owners for causing noise, loose setscrews, etc. The mechanical portion of the RPM sensors are on the fan, so rotational movement of the fan will create error, which the controls will be constantly trying to correct. I don't know if the control uses timing info, but if it does it is the same sensors and similar issue for error.

- David

[Matanuska]

No joy. Headstock is all back together, setscrews tightened, quill & idler bearings inspected, shafts aligned, lock wedges adjusted, and belts tensioned but still rattles briefly on table saw startup at 3450 rpm unless jointer is also attached. I guess I'll just have to live with it.

[edma194]

There might not be anything loose. What else have you tried to start up at 3450RPM? I think the heavy cutting head of the joiner has more inertia to overcome at startup than a saw blade. That rattle might just be a result of the motor compensating for faster than expected acceleration. Unfortunately the sound might come from chattering in the bearings which can't be a good thing over time.

Also, you didn't mention how old this PowerPro head is. Can you tell us the date code and the software version from the control panel at startup?

[Matanuska]

Yes, I think it's down to rotational inertia, speed controller feedback, and vibrational harmonics. I'm not sure what other attachments I could turn safely at 3450 rpm besides the jointer or the table saw to test it. It doesn't happen with an empty spindle. I installed my DIY PP upgrade 3 years ago, but it still has the 2011 firmware. Does anyone know if there is a later version and if so, whether it's possible to update it?

Firmware version.jpg (214.16 KiB) Viewed 943 times

[edma194]

I'll check both of mine. One from 2011 I think, the other a few years later. You can run a 12" sanding disk at 3450. You can run a saw blade on the right side of the headstock and a sanding disk on the left side at the same time. Running something on the left side and not the right will reveal if rattle is dependent on which end of the headstock is driving something. CAUTION!! It is dangerous to run a saw blade on the left side of the headstock with no blade guards!!

[edma194]

Older PowerPro shows version 9.02xa05. Newer PowerPro shows version 9.08csa16 like yours. The older one is in a 2011 headstock, looks factory installed, I know nothing about the history of this machine. The newer is a self-upgrade from some later date. I did encounter some rattling with the bandsaw on the newer PowerPro for a while. Went over the machine to lock everything down and what was left seemed to be the motor cranking up. I believe this was on the 1/4" hardwood setting, I don't recall the RPM. It wasn't consistent though. The bandsaw is now connected to the old PowerPro but I haven't tried it yet.