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PostPosted: Sun Jun 02, 2024 1:51 pm 
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Cocobolo
Cocobolo

Joined: Thu Jan 11, 2018 9:19 am
Posts: 406
Location: St. Charles MO
First name: Karl
Last Name: Borum
State: MO
Zip/Postal Code: 63303
Country: United States
Focus: Build
Status: Amateur
The little motor-shaft-mounted air pump threw a rod after 18 years.
For anyone interested, the PWBS-14 bandsaw has a blower feature where a little nozzle blows away the sawdust from the blade while cutting. The air pump “threw a rod” and ejected the “wrist pin” out the side of its plastic case. It made a bang then sounded like a flat tire on a car.

The pump is a little actuator, connected by a rod and pin, to a metal flat that drives a rubber bellows. I the actuator is driven by a cam lobe that is pressed onto the motor shaft of the bandsaw motor. The connecting pin connecting a “piston rod” to the cam, cam out, and exited the pump, never to be seen again. The rubber bellows has a hole on it so I will not be replacing the missing pin, I will just remove the guts and button the whole thing up.

The pump is a little actuator, connected by a rod and pin, to a metal flat that drives a rubber bellows. I the actuator is driven by a cam lobe that is pressed onto the motor shaft of the bandsaw motor. The connecting pin connecting a “piston rod” to the cam, cam out, and exited the pump, never to be seen again. The rubber bellows has a hole on it so I will not be replacing the missing pin, I will just remove the guts and button the whole thing up.

The pump and cam are pressed onto the motor shaft first, and hence, behind the motor pully. The motor pully (and TWO set screws) have to be removed first to gain access to the pump internals, which are covered by a metal plate. couldn’t figure out how to get the pump off of the motor shaft so I just removed the internal parts. Right now Ikm looking at the part break out and the pump assembly and each part is listed. They are probably not available so, with the saw back in running order, I save that exercise for a rainy day.

Note that there is an opening at the BOTTOM of the pump housing, and a lubrication hole in the pump driving non-ball bearing. The grease on the mating surfaces was long broken down and dry. Lining up those holes and squeezing some lithium grease into the opening should have been a preventative maintenance activity. I’ve included some pics showing, from bottom to top:

The cam on the motor shaft
The circular rotating ring that attaches to the connecting rod
The connecting rod with pin missing
The bellows driver (square metal plate)
Rubber bellows.

For anyone interested, the AIR REGULATOR ASSEMBLY part number on the manual is PWBS14-308. I BELIEVE I will just use an aquarium air pump connected to the existing tubing to replace that feature.


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_________________
Measure Twice,

Karl Borum


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PostPosted: Sun Jun 02, 2024 2:06 pm 
Offline
Cocobolo
Cocobolo

Joined: Thu Jan 11, 2018 9:19 am
Posts: 406
Location: St. Charles MO
First name: Karl
Last Name: Borum
State: MO
Zip/Postal Code: 63303
Country: United States
Focus: Build
Status: Amateur
Already an update: all of those individual pump parts are available, in stock, from Powermatic, amazing!
The whole air pump assy is $81.99. I don’t think that feature is worth $82 plus labor si I’m going with the aquarium pump.

https://powermatic.com/air-regulator-as ... pwbs14-308

The air nozzle:


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_________________
Measure Twice,

Karl Borum


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