Bad vibration when bandsaw under load w/PowerPro

[mjsworkshop]

Hi All-

Suspect the powert coupler as mentioned in other posts. One on order.

-mj

[nuhobby]

Mark,

I think you're on the right track -- a loose power-coupler to the bandsaw -- based on similar postings here by our member charlese.
(If your Sanding Disk runs without vibrations, then probably your headstock is at correct calibration. But if the Sanding Disk has vibrations, then the headstock itself also needs re-calibration.)

[charlese]

Hi mj!! Yep! Been there! Frustrating, Ain't it?

If you find your coupler has any play (looseness) at all that is certainly a spot that can be the source of your problem.

May I suggest these poor man's solutions; Mount the sanding disk on the spindle and a face plate on the axillary spindle. Then, before starting, push the headstock ALL THE WAY on to the coupler. This may temporarily solve your noises.

Chris (nuhobby) had a good idea about vibration with the sanding disk alone.

[michaeltoc]

While the coupler may be the problem, it could also be the PowerPro settings.

One way to tell is if the vibration occurs when starting up and using the disc sander as well. Call Customer Service, and they will have someone call you back and walk you through the setting adjustment

[wa2crk]

Make sure that both of the drive hubs on the headstock are tight. Mine have loosened twice during use and caused some vibration as well as a "jingling" sound under no load. Tighten the set screws and try again. If the screws have a tendency to loosen a small amount of RTV or silicon caulk on the threads will hold them in place.
Bill V

[BigSky]

Are these comments about loose coupler and loose hubs just as applicable to the Mark V in general as they are to the Power Pro?

[nuhobby]

Are these comments about loose coupler and loose hubs just as applicable to the Mark V in general as they are to the Power Pro?

Not nearly so much. The traditional Mark V headstock has the loading-tool always pulling "slower" on the induction motor. It's a one-way dragging action.
With the Power Pro, the motor/shafts speeds are optically monitored and the electronics tries to maintain selected speed within a small window of error. If the load-tool has a lot of inertia, in some cases there can be overshoot/undershoot on the instantaneous shaft speeds. These effects can be exacerbated by loose couplers, for instance.

[JPG]

Not nearly so much. The traditional Mark V headstock has the loading-tool always pulling "slower" on the induction motor. It's a one-way dragging action.
With the Power Pro, the motor/shafts speeds are optically monitored and the electronics tries to maintain selected speed within a small window of error. If the load-tool has a lot of inertia, in some cases there can be overshoot/undershoot on the instantaneous shaft speeds. These effects can be exacerbated by loose couplers, for instance.

Put another way, the Power Pro both drives AND brakes.(very rapid succession)

[charlese]

Are these comments about loose coupler and loose hubs just as applicable to the Mark V in general as they are to the Power Pro?

Not in my experience! My loose fitting coupler was my favorite for 8 years or so with my old headstock. I liked it because it slipped onto the SPT (almost fell onto it) with absolutely no resistance. I still use it with both sanders and the jointer (while using the PowerPro) with only smooth results.

[wa2crk]

JPG hit it correctly about the braking. I put my sanding disc on when isolating the problem and set the speed to 4000 RPM. I know that this is way too fast for any sanding application but this was only a test. When the motor ran up to speed the flywheel effect of the disc caused the motor to overshoot the desired speed and I could definitely hear the motor put the brakes on to slow the disc down.
Bill V