That trick blade balancer cost HOW much. $250?....$25?.... $2.50?...yep

[motoman]

BACKGROUND: In another thread I wondered again about blade balancing after sharpening. No need here to balance was ever indicated with the Craftsman defined "bolt" method. I had not seen a blade sharpener so started from scratch (well this is not exactly new). The bearing blade balancer below is so simple and easy to make it could be dismissed as "foolery." It is not, and will detect imbalance of 1/8 oz, maybe less. The device as show works on the Craftsman DYT 4000 Intek 24, blade pn MB 247 180054. With minor mods it should fit others.

The second pic is the unbalanced blade brought to balance with a 1/4 oz lead weight on a thin wire hook. Hard to see. :smile:

 

[motoman]

That trick ... (continued
PARTS: After several hours of fussing the following simple assembly emerged.: (1) A hard rubber arbor whose OD rides on the "star" tips of the blade hole, and whose ID is a push fit for a 5/16" bolt. (2) a 5/16 x 3-1/2" bolt with minimum thread count. (3) 2 each "608 " ball bearing, without shields if possible. (4) 30 inches of 2x3 or 2x4 wood.

The arbor is a bologna-cut from an old double-wall vacuum hose. The material is stiff rubber Once cut it is a hard finger press fit into the blade. The ID must be a snug fit onto the bolt shaft.
My bearings may be from an old Hoover vacuum cleaner roller. They are currently available as skateboard bearings. Try ebay, toys, outdoor,skateboard bearings, see 8 for $5. Maybe roller skates?
Match cut 14" wood uprights and match drill 1 " holes as rests for the .868" OD bearings.

 

[motoman]

That Trick... (continued)
HINTS: A stiff arbor and a snug shaft fit in the arbor is key. The weight of the blade holds the outer bearing races stationary on the wood while the inner ones turn with the blade. If you buy new bearings remove the shields permanently and wash out the grease. Place a drop of 10w oil in the races. The bearings must remain LOOSE on the shaft. To assemble place one bearing on the bolt and push the shaft through the mounted arbor. Put on the second bearing and mount the blade-bearing assembly into the uprights. Blade must not touch wood. Bring blade to horizontal. If balanced it should stay. Otherwise grind on slope within reason , and on end if necessary , and check balance again. Repeat until satisfied . I was able to leave the whole assembly together when sharpening. Blade below is not balanced.

 

[motoman]

That trick... (continued)
FIRST RESULTS: Writer sharpened and balanced 3 blades. The bolt may be better longer, say 4-1/2" to 5.0." The reason is that the bearing-blade assembly is a little hard to seat in the uprights with the loose bearings which slip along the bolt. A longer bolt should allow more upright separation and more piggy room to position the bearings in the wood holes. The blade with the 1/4 oz imbalance required grinding on the blade end as I had tried several hard passes on the slope without complete balance. FINIS :thumbsup:

 

[okiepc]

Very good information, I may look into this. :thumbsup:

 

[motoman]

That trick... (continued)
FIRST RESULTS: Writer sharpened and balanced 3 blades. The bolt may be better longer, say 4-1/2" to 5.0." The reason is that the bearing-blade assembly is a little hard to seat in the uprights with the loose bearings which slip along the bolt. A longer bolt should allow more upright separation and more piggy room to position the bearings in the wood holes. The blade with the 1/4 oz imbalance required grinding on the blade end as I had tried several hard passes on the slope without complete balance. FINIS :thumbsup:

Last nite I dreamed other countries bought up all the US wood so no blade balancer uprights could be built. It ended ok 'cause you can hold the bearings with your hands and watch for blade deflection or
balance. So it's a pocket balancer.

 

[motoman]

Product improvement you may have already done. The holes in the uprights are really not necessary. Much easier to erect cradle style shown.

 

[chance123]

"VERY" well done!! Brillient !!

 

[lostinbaja]

Jeez, the manual for my Woods mower shows a mower blade hanging on a nail that was driven into the side of a workbench to be used for balancing the blades....Honest!

 

[motoman]

Jeez, the manual for my Woods mower shows a mower blade hanging on a nail that was driven into the side of a workbench to be used for balancing the blades....Honest!

Yeah, The jury is still out on this, but very animated. Look for recent thread .