Power Station vibration tamed!

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BuckeyeDennis
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Power Station vibration tamed!

Post by BuckeyeDennis »

While looking for a Craigslist deal on a bandsaw last spring, I found a clean one (cast-iron table) AND a Power Station for $150 total, miter gauge included. Not in my state, but close enough to my brother's place in Tennessee that I could enlist him for a pickup run.

Next visit, I hauled everything back to Central Ohio, and the restoration began last fall. Everything was in pretty fair shape except for overspray on the finishes. That cleaned up well with denatured alcohol, plus some laquer thinner for a few stubborn spots. That Shopsmith finish is darned tough .. only one casting needed touch-up paint after my chemical assault.

The bandsaw had a frozen backup bearing, so I went ahead and replaced all four ... the complete set was on special for about $20. The Power Station front spindle bearing had one slight rough spot, so I replaced that as while I was at it. The old bearing came off easily with a gear puller (I wasn't worried about trashing the bearing), and the new one (about $7 online) pressed on nicely using a tube against the inner race and an arbor press.

When I fired everything up, though, I was disappointed at the amount of vibration. I had read Bill Mayo's recommendations on link belts, and decided to give those a try. I'd guess that the new link belts eliminated over half of the vibration, but I still felt it was excessive. The Power Station was clearly the culprit, as it would vibrate even with no SPT mounted. The amount of vibration was very speed-dependent, being much worse at certain resonant frequencies.

While I was cleaning up the Power Station, I had noticed that the spindle housing and the motor were mounted to one another only through the sheet-metal top of the stand -- and the sheet metal was flat throughout that section. Well, flat sheet metal is just not very stiff -- and it was making like a leaf spring between the the spindle housing and the motor. Whenever the belt speed hit a resonant frequency, the vibration got bad.

So I got ambitious and made a pair of stiffening brackets out of angle iron (2" wide with a 1/8" wall, if memory serves), and painted them with Shopsmith touch-up paint. The stiffeners span the sheet metal between the spindle housing and the motor, and are captured by their respective mounting bolts. (I did had to buy longer bolts for the spindle housing).

The stiffeners provide a much more rigid connection between the two major masses, and so greatly increase the resonant frequency -- apparently to something above the drive-belt excitation frequency, as they work like a charm. Power Station NVH (Noise, Vibration, and Harshness) is now on a par with my Model 520. :)

EDIT: One year later ... here's a link to a video of the stiffened power station in operation.
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billmayo
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Post by billmayo »

Great solutions. I find most improvements can be generated by using our senses to analyze any Shopsmith problem. Seeing, hearing, smelling and feeling will allow us to get closer to determining what is the problem and how to solve the problem. I always like to determine why the problem occurred. Thanks for the response.
Bill Mayo bill.mayo@verizon.net
Shopsmith owner since 73. Sell, repair and rebuild Shopsmith, Total Shop & Wood Master headstocks, SPTs, attachments, accessories and parts. US Navy 1955-1975 (FTCS/E-8)
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lightnin
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Post by lightnin »

Nice.. If a power station ever comes to CL near me and I find some vibration it won't scare me off now.
Bruce

I didn't know what a Shopsmith was...
Three days later I owned one...
One week later I was rebuilding one...
Four months later I owned two....
Ok Ok, I'm up to four now...
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JPG
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Post by JPG »

Another item for the todo list. Good timing! About to rehab the one I got last month. I am looking forward to digging into it as my 'other' one was obtained from e-bay and it was not as it left 'the factory'.
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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billmayo
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Post by billmayo »

I uncovered a Power Station with a bent quill and damaged plastic housing from shipping during the recent removal of all the 10ER stuff. If anyone is looking for parts, please let me know.
Bill Mayo bill.mayo@verizon.net
Shopsmith owner since 73. Sell, repair and rebuild Shopsmith, Total Shop & Wood Master headstocks, SPTs, attachments, accessories and parts. US Navy 1955-1975 (FTCS/E-8)
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BuckeyeDennis
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Post by BuckeyeDennis »

billmayo wrote:Great solutions. I find most improvements can be generated by using our senses to analyze any Shopsmith problem. Seeing, hearing, smelling and feeling will allow us to get closer to determining what is the problem and how to solve the problem. I always like to determine why the problem occurred. Thanks for the response.
Thanks, Bill. I work in machine-tool control in my day job, but it's largely computer and electronics stuff when I'm lucky, and management when I'm not. Very little hands-on on the actual machinery. Truth be told, the real machinists are WAY better than I am at cutting actual metal.
Playing with woodworking equipment gives me that hands-on time that I don't get at work. Plus, wood, to my eyes, has tremendously greater inherent beauty than metal. This new hobby is the best of both worlds .. I get to play with machinery hands-on, AND I can aspire to someday make objects of beauty that others will admire.
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JPG
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Post by JPG »

BuckeyeDennis wrote:Thanks, Bill. I work in machine-tool control in my day job, but it's largely computer and electronics stuff when I'm lucky, and management when I'm not. Very little hands-on on the actual machinery. Truth be told, the real machinists are WAY better than I am at cutting actual metal.
Playing with woodworking equipment gives me that hands-on time that I don't get at work. Plus, wood, to my eyes, has tremendously greater inherent beauty than metal. This new hobby is the best of both worlds .. I get to play with machinery hands-on, AND I can aspire to someday make objects of beauty that others will admire.
'Somebody' did an excellent job cutting those angle iron pieces!

Gotta ask, what you used to cut them with. I am guessing a metal cutting band saw(and drill press).
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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BuckeyeDennis
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Post by BuckeyeDennis »

JPG40504 wrote:'Somebody' did an excellent job cutting those angle iron pieces!

Gotta ask, what you used to cut them with. I am guessing a metal cutting band saw(and drill press).
My 520 did the drill-press duty, although I did cringe at those steel chips trying to scratch up my nice aluminum table.
As for the metal sawing, I used my venerable old underpowered Craftsman table-top saw, with an 8" abrasive wheel. If you feed the angle iron at just the right speed, the abrasive wheel heats the angle iron at the point of cut to a nice glowing orange, which it then cuts like butter. Or at least easily smears it out of the way. No worries about scratching up THAT table.
A bench grinder cleaned up the slag from the edges, quick and easy.
I first heard about Shopsmith machines while looking for a replacement for the underpowered old Craftsman. Seriously, it can barely rip a 2x4 without overheating. But now that I no longer have room for the Craftsman, I would really like to keep it as my "beater" saw!
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JPG
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Post by JPG »

BuckeyeDennis wrote:My 520 did the drill-press duty, although I did cringe at those steel chips trying to scratch up my nice aluminum table.
As for the metal sawing, I used my venerable old underpowered Craftsman table-top saw, with an 8" abrasive wheel. If you feed the angle iron at just the right speed, the abrasive wheel heats the angle iron at the point of cut to a nice glowing orange, which it then cuts like butter. Or at least easily smears it out of the way. No worries about scratching up THAT table.
A bench grinder cleaned up the slag from the edges, quick and easy.
I first heard about Shopsmith machines while looking for a replacement for the underpowered old Craftsman. Seriously, it can barely rip a 2x4 without overheating. But now that I no longer have room for the Craftsman, I would really like to keep it as my "beater" saw!
A 'cover' of thin plywood/mdf/whatever will protect that nice aluminum table. Put a 'rim' around it and it will 'self register' to the table and stay put. Just be sure to not drill 'through' it.;)
╔═══╗
╟JPG ╢
╚═══╝

Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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BuckeyeDennis
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Post by BuckeyeDennis »

[quote="JPG40504"]A 'cover' of thin plywood/mdf/whatever will protect that nice aluminum table. Put a 'rim' around it and it will 'self register' to the table and stay put. Just be sure to not drill 'through' it.]

Ahh, I think that you just solved my drill-press dilemma. The guys at work made just such a cover for our granite surface plate, but it had never occurred to make one for my 520.

That still leaves me with a couple of metal-cutting tablesaw blades that work pretty well when the occasional need arises. But they generate lots of abrasive steel crud, and I generally need either a miter gage or a rip fence for these operations. So I'm thinking that the protective table cover is not an option for sawing.

My SS bandsaw has the cast-iron table. So should I be thinking about a speed reducer and a metal-cutting bandsaw blade for future needs? I need the speed reducer for hole sawing and big Forstner bits anyway. Plus I would love to turn some large pieces someday. I've never seen a steal on speed reducers ANYWHERE, so the modest promo that SS is running at the moment is somewhat tempting.
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