ByronMill
ArboristSite Lurker
Belt drive on speedPro versus other mfg.
I have read most of the posts in the LONG thread, but not all so I may have missed any previous discussion on this. Questions/observations I have about the belt drive setup. I have seen photos of the drive setup on the DR and The Wood Wolf and they both have no grooves in the flywheel on the drive side. They are just using the friction of the bottom on the belts to drive the flywheels. From the limited photos of the SuperSplit that I have found it looks like that may also be the case there. Can any of the SS owners here confirm that? Anyone can provide photos (or a link to posts here) showing the drive on a SS?
My experiences tells me that the drive setup on the DR and WoodWolf would have a significant "slip factor" when the drive hit a dead stop such as a knot or overload. This would provide some limited overload protection for the system. The SpeedPro has actual v-grooves machined into the driven flywheel. While this is a good drive design as far as transferring torque, it would by design eliminate that slip factor of the other "poor" design. Anyone else think this may be a factor in some of the breakage problems or traumatic disengagement of the drive linkage? Another point is that by machining the grooves in the flywheel the effective diameter of the driven "pulley" is smaller, causing the pinion shaft to run slightly faster. Not a huge issue, but it seems pinion speed is quite a bit faster on the SpeedPro than the others. The photos showing the pulley on the engine look like it is quite a bit bigger diameter than the ones on the DR and WoodWolf for sure, and likely the SS from what I can see. Flywheels running that much faster would be a huge increase in force applied to the pinion/rack interface and could be part of the cause for tooth damage. Running engine slower on the SpeedPro would reduce that force down to the same levels that would be seen on the other units running engine at full speed because of greater reduction ratio on the drive. In the end it is about weight of the flywheels and RPM to determine force applied. Slowing down engine and lubing the centrifugal clutch to encourage slippage to me is addreessing the symptoms, not the problem. I think this is where the belt slippage may come in on the other units. Centrifugal clutches are not designed to be used for overload slippage protection. They are supposed to be fully locked in when engaged at operating speed and fully disengaged when below engagement speed. Metal on metal surfaces will quickly wear if forced into a repeated slippage condition.
Does anyone have the details about the diameters of the flwheel/pulley setups on the other manufacturers to compare to what the SpeedPro is equipped with? How about the pitch of the pinion and rack Anyone measure the teeth per inch on the rack? (not the same as pitch, but can be used to determine diametral pitch). How many teeth on the pinion shaft for each manufacturer and the OD of the pinion shaft?
Just food for thought and to spark some more conversation. I just saw the SpeedPro for the first time at my local TSC. I found this thread and am interested in the SpeedPro even though it may need some tinkering and possible redesign. The inertia/kinetic concept is well proven and there seems to be no reason this unit cannot be as functional as any of the others.
I have read most of the posts in the LONG thread, but not all so I may have missed any previous discussion on this. Questions/observations I have about the belt drive setup. I have seen photos of the drive setup on the DR and The Wood Wolf and they both have no grooves in the flywheel on the drive side. They are just using the friction of the bottom on the belts to drive the flywheels. From the limited photos of the SuperSplit that I have found it looks like that may also be the case there. Can any of the SS owners here confirm that? Anyone can provide photos (or a link to posts here) showing the drive on a SS?
My experiences tells me that the drive setup on the DR and WoodWolf would have a significant "slip factor" when the drive hit a dead stop such as a knot or overload. This would provide some limited overload protection for the system. The SpeedPro has actual v-grooves machined into the driven flywheel. While this is a good drive design as far as transferring torque, it would by design eliminate that slip factor of the other "poor" design. Anyone else think this may be a factor in some of the breakage problems or traumatic disengagement of the drive linkage? Another point is that by machining the grooves in the flywheel the effective diameter of the driven "pulley" is smaller, causing the pinion shaft to run slightly faster. Not a huge issue, but it seems pinion speed is quite a bit faster on the SpeedPro than the others. The photos showing the pulley on the engine look like it is quite a bit bigger diameter than the ones on the DR and WoodWolf for sure, and likely the SS from what I can see. Flywheels running that much faster would be a huge increase in force applied to the pinion/rack interface and could be part of the cause for tooth damage. Running engine slower on the SpeedPro would reduce that force down to the same levels that would be seen on the other units running engine at full speed because of greater reduction ratio on the drive. In the end it is about weight of the flywheels and RPM to determine force applied. Slowing down engine and lubing the centrifugal clutch to encourage slippage to me is addreessing the symptoms, not the problem. I think this is where the belt slippage may come in on the other units. Centrifugal clutches are not designed to be used for overload slippage protection. They are supposed to be fully locked in when engaged at operating speed and fully disengaged when below engagement speed. Metal on metal surfaces will quickly wear if forced into a repeated slippage condition.
Does anyone have the details about the diameters of the flwheel/pulley setups on the other manufacturers to compare to what the SpeedPro is equipped with? How about the pitch of the pinion and rack Anyone measure the teeth per inch on the rack? (not the same as pitch, but can be used to determine diametral pitch). How many teeth on the pinion shaft for each manufacturer and the OD of the pinion shaft?
Just food for thought and to spark some more conversation. I just saw the SpeedPro for the first time at my local TSC. I found this thread and am interested in the SpeedPro even though it may need some tinkering and possible redesign. The inertia/kinetic concept is well proven and there seems to be no reason this unit cannot be as functional as any of the others.
