I have a general question that probably has a complex answer.....will 25hp run a 30" inserted blade at "hobby" feeds in softwood? I calculate 1150 rpm at 9K fpm rim speed.
Quote from: Bullheaded on February 25, 2025, 05:33:58 PMI have a general question that probably has a complex answer.....will 25hp run a 30" inserted blade at "hobby" feeds in softwood? I calculate 1150 rpm at 9K fpm rim speed.
Are you using a high RPM or high torque engine?
How large are the logs you intend to saw?
Are there going to be any flywheel(s) in your system and how large are they?
How fast do you plan on feeding the logs into the blade?
How sharp are your inserts?
Some one should be along soon with more questions that you will need to factor into the mathamatical equation for you to get to your answer.
GAB
How many teeth? That matters more than the blade diameter. One rule of thumb is to have 2 to 3 hp per tooth, and that seem to scale pretty well. My little mill is only 13 hp, but the blade only has 6 teeth. A full size circle blade might have 50 teeth, but is going to need 100+ hp to drive it.
Problem with just slowing the feed is the cutters are no longer working efficiently. Each time they move through the wood they have to cut the wood fibers, no matter the size of the chip they are making. So slow cutting, and the cutters dull quicker.
So my little mill throws out wood chips similar to a full size circle mill, but of course I can only feed at 1/10 the speed. But it's cutting as efficiently as possible.
Ian,
The 2-3hp per tooth is a very useful rule of thumb that I will work with. If I end up bringing that bolt mill home, I will likely buy a new blade using that info.
Gday, when I started out I had 18hp (big long stroke hp) driving a 36 inch spring set blade, Itcut fine but it's much nicer with now being driven by a 371 detroit putting out around 60hp.
Cheers Jack jr