I am thinking of building a chainsaw mill, or possibly buying one. The BIG expense is a chainsaw with enough power to run a large enough bar to saw wood at a reasonable rate. The tradeoffs of high power with low weight, desirable attrubutes of a chainsaw, surely contribute to the high cost of the PRO models. New appropriately sized PRO models in Stihl or Husky are about $1000 or so.
Since the operator isn't wielding the saw free hand so much when it is bolted into a chainsaw mill, it seems that the high HP to weight ratio which costs so much to buy is not particularly important. Sure, some designs, especially ones with the guides to slide a saw along a guide board, require hefting the saw each pass but "fancier" mills don't. If you save enough $ on the saw you could spend the savings on a better mill with frame and adjustments or have the budget to build a better mill.
So the BIG IDEA! Why not build a chainsaw expressly for a chainsaw mill? What is so special about a chainsaw? You have a chain bar, chain, sprocket, motor, clutch, handles, controls, and anti-kickback thingy. In a mill setup where you don't have to carry the saw around you don't need the handles, anti-kickback thingy, or maybe the clutch. So why not power the saw with a larger but much cheaper gas or electric motor? If you use it at home or within reach of a power cord, why not electric? If portable is THE THING then use a gas engine.
A horizontal shaft lawn mower type engine in the 5-10 HP range might do a good job. If vertical shaft models are "on sale" then yo get a mill with a horizontal saw. I'm not sure about shoving a slower moving chain into a log harder than "normal" is a fine idea so you might want to consider gearing (belting) up the RPM of the engine by a factor of 2 or whatever (just guessing).
So, we have a chain bar bolted to the moving carriage of the mill with a ripping chain driven by a sprocket that is turned by a shaft running in bearings and spun by a belt that is turned by the engine. Doesn't seem to need a clutch but you could use one if you wanted.
You could build a stationary guard that surounds the chain bar when the saw carriage is retracted to its "home" position. That would prevent you or other things from getting tangled up with the moving chain between passes and further elliminates the need for a clutch and its complexity and cost. Pull start should be fine for an engine in this size range but an electric start would be OK.
If you wanted to get fancy and up production you could use a larger engine and run more than one chain bar. The expense to build it wouldn't double but your through put would about double.
If I had two tractors, I'd consider belting up the PTO of one of them to produce the rpm to run the chain and then I'd move the wood past the saw vice saw past the wood. This would give me an electric start diesel powered mill. I need one tractor for handling the logs so for me a good deal of the time it wouldn't be practical to use my only tractor as a power source.
This is just an embryonic idea. Feel free to comment even if it is to recommend the thread be moved to another heading like Hobbies, tools, fabrication...
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
Reply With Quote
