I think i should decide either way: use the 7.5 hp electrical motor on a short frame and keep the log stationary, or:
Go big time, and use 40 PTO hp and put the log on a roller table, to roll ut under the stationary saw head.
The method based on the rolling collar shaft, or the variant i described with pallet truck rollers on a square shaft, will be much more expensive and require a precision balanced, perfectly straight square tube driveshaft. Too expensive.
To yank a log through a 40 hp powered saw, wont be easy when using car wheels and standard bearings, as band saw guides. in other words, there is an extra investment to beef up and professionalise the saw head, before the 40 hp will come to use.
Somebody said that the weight of the motor kept the saw head in place, and prevented vibrations. Using the 7.5 hp electrical motor as sawhead
ballast as well as using rubber car tires, will be the most efficient solution, cost vs. output.
WoodMizer offers a pneumatic saw band tension kit: Using the rubber car tires will achieve the same thing
Does anyone have ideas about how to figure out the sawhead feed ? Will this require another electrical motor, or can the saw head motor, also pulls itself along on a cable, using a dog clutch to engage the steel cable pulley ?
Then i could still use multiple pulleys to achieve several cutting speeds, and tension the steel cable by a spring, to even out the different diameters of the pulleys.
I am not thinking of a winch that winds up all the cable on a drum, but something like a flat, wide pulley: It just makes 1 or 2 loops over the pulley (enough loops to get the required traction) but its only attached to the frame, at the front and rear of the frame.
The silage block cutting spades they sold over here in the 70's, had a spade movement based on the same principle.
I think i have most required materials for the frame, sawband guides and motor in house. As soon as i built the new frame for the road sweep, the band saw is next.
Please share your ideas !