Belt Disk Sander Repair

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Forum topic by wjt99 posted 03-26-2018 03:30 AM 1127 views 0 times favorited 11 replies Add to Favorites Watch
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26 posts in 2117 days

03-26-2018 03:30 AM

The woodshop where I volunteer has a Craftsman disk/belt sander. It is a Craftsman 351.225930

It works but is really noisy. I decided to take it apart and see if I can repair it. The user manual has no information on how to do this.

I need to get the drive belt off and it has stumped me so far. This belt has what appears to be an idler pulley between the motor pulley and drive shaft pulley. How is this adjusted to release the tension ?

If someone has been inside this machine I would appreciate any advice.

Thanks, Bill

11 replies so far

View Woodknack's profile


13002 posts in 2982 days

#1 posted 03-26-2018 05:36 AM

There should be a tension lever.

-- Rick M,

View wjt99's profile


26 posts in 2117 days

#2 posted 03-26-2018 02:05 PM


If there is a tension lever for the drive belt (NOT the sanding belt) please advise where it is located.

Thanks, Bill

View Kazooman's profile


1408 posts in 2554 days

#3 posted 03-26-2018 02:26 PM

Can you post some pictures?

View lndfilwiz's profile


114 posts in 2202 days

#4 posted 03-26-2018 02:33 PM

From what I can see on the schematics the pulley has to be taken off behind the disc sander.
I downloaded the schematics form sears and posted the link!

-- Smile, it makes people wander what you are up to.

View Woodknack's profile


13002 posts in 2982 days

#5 posted 03-26-2018 08:15 PM

There’s no spring or lever on the idler? Something keeps it taught. A spring, a bolt.

-- Rick M,

View JollyGreen67's profile


1676 posts in 3364 days

#6 posted 03-26-2018 09:25 PM

It has been my experience with Craftsman power tools that to disassemble and repair said objects there is a warning that states “Only qualified Sears repair personnel have access to this part”. What! I told the sales repair center the stupid tool is mine, and does not belong to Sears – plus it is way past the warranty period. She still refused to order the part – bearings for belt sander motor. Hah, I went around her and got the bearings elsewhere. That was the last time I bought a Craftsman power anything. I still have some Craftsman power tools, but when they die, they die, and something else will take their place.

-- When I was a kid I wanted to be older . . . . . this CRAP is not what I expected ! RIP 09/08/2018

View MrUnix's profile (online now)


7579 posts in 2800 days

#7 posted 03-26-2018 09:36 PM

Parts diagram doesn’t show any idler pulley that I can see. If it’s a standard v-belt, then you should be able to wedge it off the pulleys with a bit of effort and maybe a screwdriver or two.


-- Brad in FL - In Dog I trust... everything else is questionable

View johnstoneb's profile


3131 posts in 2774 days

#8 posted 03-26-2018 09:39 PM

The parts breakdown doesn’t show an idler. I have a Rikon similar to that and the motor slides to tighten the belt. The bearings are very noisy on it also and have been since it was new.

-- Bruce, Boise, ID

View wjt99's profile


26 posts in 2117 days

#9 posted 03-27-2018 02:30 AM

I know the parts diagram doesn’t show an idler pulley. See photo – not sure what else to call it. Perhaps it drives a fan for dust collection ??

I wound up removing the belt by pulling the drive shaft for the disk and belt. Only way to see to reinstall it is to reverse this process. An odd design.

The three bolts that secure the inner drive shaft bearing assembly to the frame had worked loose. They were riding freely between the casting and the inside of the drive shaft pulley. The result was the shaft was floating and causing the disk to move horizontally which occasionally caused it to make contact with the frame making sparks.

In addition the outboard bearing was damaged as well as the drive shaft on that end. We milled the drive shaft down to accept a custom made collar. A new bearing was installed. I started to put the unit back together but came to a halt when I added lock washers on the cap screws that hold the inner bearing to the frame. I need longer cap screws. Back to the hardware store tomorrow and will continue this educational program.

Photos attached as requested.


View wjt99's profile


26 posts in 2117 days

#10 posted 03-27-2018 05:27 PM

I have started reassembling the unit with repaired components. It was going well until I got to the drive belt.
The drive shaft is installed but now the only way I can see to install the belt is to roll it over the pulleys as suggested by MrUnix.

Perhaps a new belt will have enough flex to let me do that. The old belt may have the same affliction I have – old & stiff – which may explain why I couldn’t remove it.

I looked in the manual under specifications and realized it wasn’t just me when I needed to get an assist from a young neighbor to carry this tool into my shop for repair. It weights 110 lbs.

Work in progress.


View wjt99's profile


26 posts in 2117 days

#11 posted 03-28-2018 02:50 PM

Repair completed.

I was able to roll the old belt onto the drive shaft pulley. In order to place the belt on the motor pulley and over the idler pulley I set the unit up on blocks after removing the bottom plate.

The machine runs smooth and quiet with its new parts.


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