The Drive Belt Tension Gauge is a measurement tool to check drive belt tension on LT10, LT15START, LT15, LT15WIDE, LX150, LX250, LT25/LT27, LT28, LT30, LT35, LT40/LT40HD, LT40HD Super, LX450, LT50, and LT70 model sawmills. In addition to following the maintenance schedule in your manual, the drive belt tension gauge will help keep your sawmill in great condition so you can continue to enjoy your Wood-Mizer for years to come!
Proper drive belt tension is a critical setting on your Wood-Mizer sawmill. A loose drive belt can cause problems like wavy cuts or diving blades. An overtightened drive belt can cause premature wear and failure on many parts of the sawmill including cylindrical drive bearing, drive belt, and even engine failure.
The drive belt used on your Wood-Mizer is a V belt design. The V belt transfers power from the drive pulley to the driven pulley. A properly tensioned belt will sit in the V groove of the pulley so that the sides of the belt are the only surfaces touching. This position allows the belt to grip the pulley and still have some slippage if the drive gets in a bind.
The only way to properly set the drive belt tension is to use a belt tension gauge (Part #016309). Belt tension is set by the amount of pounds (force) it takes to move the tightened belt a set amount of inches. To find this setting for your sawmill, refer to the Drive Belt Tension Measurement Guide on this page or review in your sawmill manual.
How-To Videos
How to Check Drive Belt Tension for 2015 and Before LT15, LT28, and LT35 Portable Sawmills
How to Check Drive Belt Tension for 2016 and After LT15, LT28, and LT35 Portable Sawmills
How to Check Drive Belt Tension for LT40 and LT50 Portable Sawmills with AutoClutch
What if my drive belt is too loose?
A V belt that is too loose will sit too high in the V groove and slip too quickly. A belt set this way will cause the blade speed to slow down in the cut because the power from the engine is not getting transferred to the blade. A belt set too loose will wear out quickly as the slipping causes heat to build up, which burns the belt.
What if my drive belt is too tight?
A V belt that is overtightened sits too deeply in the groove. This will cause the belt to deform riding only on the pulley at the bottom of the belt and small area of the side. The belt will fatigue quickly with this setting. Overtightening is the worst case for the belt and the sawmill. When the belt is over-tightened, the side load put on the engine and cylindrical drive bearing exceeds allowable specifications. This can cause major damage to the sawmill components. An over-tightened belt will slip faster, making you think that the belt is loose, causing you to tighten the belt even more.
Drive Belt Tension Measurement Guide
Model | Tension at Deflection | Maintenance Schedule |
---|---|---|
LX25 (All Power Plants) | N/A with gauge refer to manual | Every 50 Hours |
LX55 (All Power Plants) | N/A with gauge refer to manual | Every 50 Hours |
LT10 (All Power Plants) | 19/64” (7.5mm) @ 14LB | Every 50 Hours |
LT15START (All Power Plants) | 1/2” (13mm) @ 14LB | First 20 Hours then Every 50 Hours |
LT15 (All Power Plants) | 1/2” (13mm) @ 14LB | First 20 Hours then Every 50 Hours |
LT15WIDE (All Power Plants) | 1/2” (13mm) @ 14LB | First 20 Hours then Every 50 Hours |
LX150 (Gas) | 3/16” (5mm) @ 9LB | First 20 Hours then Every 50 Hours |
LX250 (Gas) | 3/16” (5mm) @ 9LB | First 20 Hours then Every 50 Hours |
LT25/LT27 (All Power Plants) | 7/16” (11mm) @ 14LB | First 20 Hours then Every 50 Hours |
LT28 (All Power Plants) | 7/16” (11mm) @ 14LB | First 20 Hours then Every 50 Hours |
LT30 (All Power Plants) | 7/16” (11mm) @ 14LB | First 5 Hours then Every 50 Hours |
LT35 (All Power Plants) | 7/16” (11mm) @ 14LB | First 5 Hours then Every 50 Hours |
LT40/LT40HD (All Power Plants) | 7/16” (11mm) @ 14LB | First 5 Hours then Every 50 Hours |
LT40HD Super (All Power Plants) | 7/16” (11mm) @ 18LB | First 5 Hours then Every 50 Hours |
LX450 (All Power Plants) | 7/16” (11mm) @ 18LB | First 5 Hours then Every 50 Hours |
LT50 (All Power Plants) | 7/16” (11mm) @ 18LB | First 5 Hours then Every 50 Hours |
LT70 (All Power Plants) | 3/8” (9.5mm) @ 14LB | First 20 Hours then Every 50 Hours |