Shopsmith Forums

Wow! I was pleasantly surprised on my PowerPro's performance yesterday, when re-sawing 5" poplar.

Previously, I had bee frustrated by the growling/banging of the headstock every time I re-sawed. So I went to setting up a speed reducer and running the PowerPro at around 6,300 RPM when using the bandsaw. --This fixed that problem.

Yesterday, there was a completely different scenario. Because of a crowded shop, I chose to use the bandsaw on the quill side of the machine. I took off the rubber spacing ring and extended the quill only about an inch or so to the coupler. Of course ran the headstock in reverse. At 950 RPM the re-sawing went like cutting butter. No noises other than the DC 3300 - no shaking - no banging - no growling.

Really weird,but very nice. Wonder why the difference between the left and right side of the headstock.??? Any ideas?

P.S. just thought this post needs a picture. One comming in a couple hours.

Same shaft/opposite end - right???

514083 Drive and Ring Assembly - possibly. In this configuration, the Drive and Ring Assembly is doing no work; it is just along for the ride.

My guess would be that some algorithm in the firmware is, probably inadvertently, not symmetrical on each side of zero torque or velocity. Maybe an encoder feedback anti-aliasing filter. Maybe a PID-loop wind-up limiter. Maybe a winding-commutation algorithm. If the developers tested the system primarily in one direction, it would be easy for a subtle control-system bug to go undetected.

Your discovery could be just the information they need to help find the problem.

dusty wrote:Same shaft/opposite end - right???

514083 Drive and Ring Assembly - possibly. In this configuration, the Drive and Ring Assembly is doing no work; it is just along for the ride.

That's bas ackwards????

Driving the Band saw from the quill 'increases' slop/backlash since that assembly is between the motor and the bandsaw. Also nylon(?) sponginess?

A conundrum fer sure!!!

BuckeyeDennis wrote:My guess would be that some algorithm in the firmware is, probably inadvertently, not symmetrical on each side of zero torque or velocity. Maybe an encoder feedback anti-aliasing filter. Maybe a PID-loop wind-up limiter. Maybe a winding-commutation algorithm. If the developers tested the system primarily in one direction, it would be easy for a subtle control-system bug to go undetected.

Your discovery could be just the information they need to help find the problem.

You smart guys make me laugh. It was just the thingamajig out of sync with the doohickey.

Bruce wrote:

BuckeyeDennis wrote:My guess would be that some algorithm in the firmware is, probably inadvertently, not symmetrical on each side of zero torque or velocity. Maybe an encoder feedback anti-aliasing filter. Maybe a PID-loop wind-up limiter. Maybe a winding-commutation algorithm. If the developers tested the system primarily in one direction, it would be easy for a subtle control-system bug to go undetected.

Your discovery could be just the information they need to help find the problem.

You smart guys make me laugh. It was just the thingamajig out of sync with the doohickey.

Which direction?

JPG wrote:

dusty wrote:Same shaft/opposite end - right???

514083 Drive and Ring Assembly - possibly. In this configuration, the Drive and Ring Assembly is doing no work; it is just along for the ride.

That's bas ackwards????

Driving the Band saw from the quill 'increases' slop/backlash since that assembly is between the motor and the bandsaw. Also nylon(?) sponginess?

A conundrum fer sure!!!

Yup, part of the thought process sure was. But do I get partial credit for realizing that there is a Drive Ring Assembly in the Headstock.

Thanks for the responses and Ideas.

Could be that the Drive Ring Assembly was the thing that was needed in the equation. Who knows?

Could it be that the added sloppiness was just the thing to dampen what was tight un-dampened revolutions from the normal side???? Yeah! this doesn't fit in with normal reasoning as anything loose used to cause the banging/growling

Guess I'll send a note to Shopsmith.

Buckeye is probably correct in his diagnosis, but I don't understand.

Yeah, Bob! The speed reducer fixes the banging/growling also.