Shopsmith Forums

Blame that on inertia!

neal560sl,

If you have never done so, you might want to call Shopsmith and describe these symptoms; they may be able to guide you to a better set of digital calibrations. I'm one of the early PowerPro owners who got "rapping noise" behavior on my sanding disk right out of the box. After a session on the phone with SS, they had me calibrated for a nice smooth operation.

Thanks for the info, when it gets warmer up here I may try giving them a call. My shop is not heated and we are heading back into the zero and below temps for the coming week.

JPG wrote:

rjent wrote:

neal560sl wrote:Yes, I have checked the adapter and it is the correct one. It also happens with the sanding disc's as well. I even rock them back and fourth when tightening the set screws to make sure they are centered. I have heard it is because of the pulseing the DC motor does to maintain the set RPM.

I have never had a set screw come loose on my PowerPro FWIW ....

Run the bandsaw?

Actually yes, quite a bit. Is the BS a problem child for the set screws? I will remember to check it often.

What causes it?

rjent wrote:
Actually yes, quite a bit. Is the BS a problem child for the set screws? I will remember to check it often.

What causes it?

A couple of members have had 'issues' using the PP with the bandsaw.

IIUC, the high torque pulses from the DVR motor tends to exacerbate any slop between the motor and the 'load'. That torque occurs in both directions(think speed up and slow down). Now the bandsaw is a fairly light 'load' and the power coupler has considerable backlash. I believe the DVR controller attempts to make speed alterations first a little step, then if no change is observed, bigger steps occur. Then suddenly the slop is taken up and the speed changes drastically.(overshoots the intended speed) The controller starts over, but steps in the opposite direction. Guess what. It overshoots again. What is that doing to set screw slop?

In the extreme cases, the effect was 'banging' the drive train.

I believe SS has finished the shakedown cruise and these 'problems' have not been around for us folks getting on the boat late.

JPG wrote:

rjent wrote:
Actually yes, quite a bit. Is the BS a problem child for the set screws? I will remember to check it often.

What causes it?

A couple of members have had 'issues' using the PP with the bandsaw.

IIUC, the high torque pulses from the DVR motor tends to exacerbate any slop between the motor and the 'load'. That torque occurs in both directions(think speed up and slow down). Now the bandsaw is a fairly light 'load' and the power coupler has considerable backlash. I believe the DVR controller attempts to make speed alterations first a little step, then if no change is observed, bigger steps occur. Then suddenly the slop is taken up and the speed changes drastically.(overshoots the intended speed) The controller starts over, but steps in the opposite direction. Guess what. It overshoots again. What is that doing to set screw slop?

In the extreme cases, the effect was 'banging' the drive train.

I believe SS has finished the shakedown cruise and these 'problems' have not been around for us folks getting on the boat late.

Very interesting.

I will pay close attention to the issue. I haven't used it for a few weeks, but I will monitor closely. I know digital controls pretty throughly and what you say is extremely plausible (not that I doubt you grand one ). Most of this stuff is so quick (clock cycle and response time) anymore, that they can "over react". (probably female .... ) LOL

After reading this, you may have doubts, but I LOVE my PowerPro and use it every day with no hesitation and no problems.

Yep! a new power coupler and new hubs will help, but after use these things loosen up. For example, at 900 to 950 RPM my bandsaw runs beautifully, until sawing a tight corner or re-sawing anything. It's not the bandsaw, it's the PowerPro exibiting it's way of correcting torque. I had noticed this (vibration) banging caused the set screw on the motor pulley to loosen, along with the drive hubs. Therefore some blue loctite.

Since I use the bandsaw quite a bit, I now run it using a speed reducer and setting the PowerPro at 6300 to 6500 RPM. It's a smooth operation.

Two PowerPro machines that I know of came with eccentric (off balance) pulleys attached to the motor. In other words the shaft hole was a small amount off center. Checking this by the SS factory and replacement helped in smoothing the bandsaw operation.

If you have doubts about the proper running of your PowerPro, call Shopsmith.

rjent wrote:
Very interesting.

I will pay close attention to the issue. I haven't used it for a few weeks, but I will monitor closely. I know digital controls pretty throughly and what you say is extremely plausible (not that I doubt you grand one ). Most of this stuff is so quick (clock cycle and response time) anymore, that they can "over react". (probably female .... ) LOL

I leave the 'grand' labels to the brothers in the state organization.

Now if that system were analog it would be underdamped. In this digital case I would call it overly quick responding.

Are you implying that females are 'under damped', or 'overly quick' or 'over reacting'.

If Admin is indeed a Lena Lerner than 'overly quick' it is. Actually tis so regardless of the name.

JPG wrote:

rjent wrote:
Very interesting.

I will pay close attention to the issue. I haven't used it for a few weeks, but I will monitor closely. I know digital controls pretty throughly and what you say is extremely plausible (not that I doubt you grand one ). Most of this stuff is so quick (clock cycle and response time) anymore, that they can "over react". (probably female .... ) LOL

I leave the 'grand' labels to the brothers in the state organization.

Now if that system were analog it would be underdamped. In this digital case I would call it overly quick responding.

Are you implying that females are 'under damped', or 'overly quick' or 'over reacting'.

If Admin is indeed a Lena Lerner than 'overly quick' it is. Actually tis so regardless of the name.

I don't know who wrote that .....