Looking for another saw for milling - 075?

[BobL]

The 075 is only 10cc smaller than an 880 and has the torque advantage so it should almost keep up with the bigger saw. it will be interesting to hear how Bob's 880 compares with his 075.

I don't know where the supposed torque advantage of the 076 over the 076 comes from but you are not the first to say this.

My manuals give these specs
076 : 6.8 Nm (5000 rpm) / 7.0 HP / Max rpm 10,000
880 : 8.0 Nm (6000 rpm) / 8.6 HP / Max rpm 12,000

I'd love to be milling with the 880 but everything is conspiring against me. It's still too hot, I still need to run the saw in and I've been dragged off by SWMBO for a weekend down south (and definitely no chainsaws allowed this time). Actually I can't complain I'm sitting on a balcony looking out through trees to the ocean, beers cold and I can sit here with my laptop and read AS, life's not all bad!

 

[BlueRider]

I don't know where the supposed torque advantage of the 076 over the 076 comes from but you are not the first to say this.

My manuals give these specs
076 : 6.8 Nm (5000 rpm) / 7.0 HP / Max rpm 10,000
880 : 8.0 Nm (6000 rpm) / 8.6 HP / Max rpm 12,000

I'd love to be milling with the 880 but everything is conspiring against me. It's still too hot, I still need to run the saw in and I've been dragged off by SWMBO for a weekend down south (and definitely no chainsaws allowed this time). Actually I can't complain I'm sitting on a balcony looking out through trees to the ocean, beers cold and I can sit here with my laptop and read AS, life's not all bad!

I think those numbers on the 880 might be inflated, it just dosen't seem likely that 10cc could make 1.6HP (assuming we are talking about the same flavor HP for both saws. and if the HP is inflated the Nm would be too (torque being a product of work and speed). but apart from any inflation the numbers of the specs of the saws themselves are a bit misleading. the stroke on the 880 is 1 mm longer and the bore is 1 or 2 mm larger (memory is fuzz here) If you look at the ratio of the bore and stroke of the two saws they are similar but if you look at the ratio of the surface area of the pistons of the two saws you will se how the 880 is a larger bore/short stroke design compared to the 075 even though the stroke on the 880 is longer then the 075. even though the 880 has more torque then the 075, the power band on the 880 is much narower then the 075 and drops off significantly as the rpm goes down such as when 36" of bar is buried in a hard wood log. in contrast the 075 has a much wider power band which means that even though it has less torque than the 880, more of it is avalable at a wider rpm range. Thus the torque advantage of the 075. There was an interesting thread over on the chainsaw forum about bsnelling hot rodding an 076 and getting it to turn 12,400 rpm. Interesting to see but I'm keeping mine stock till I hear how long a hot rodded 075 lasts when bolted to a mill.

 

[DaltonPaull]

Hey Bluerider - thanks for the link. Now I have a manual and a rebuild kit on the way! Got the rebuild kit for $10 with free shipping of ebay. The saws been running great except for a tendency to start and die a few times before it's willing to rev up and run/idle fine now that I turned up the idle a bit (chain still doesn't turn.) I cleaned under the plunger like you suggested but it didn't look too bad. The diaphragms are a bit on the 'pillowed' out side though so I'm going to go ahead and replace them.

 

[BobL]

I think those numbers on the 880 might be inflated, it just dosen't seem likely that 10cc could make 1.6HP (assuming we are talking about the same flavor HP for both saws. and if the HP is inflated the Nm would be too (torque being a product of work and speed). but apart from any inflation the numbers of the specs of the saws themselves are a bit misleading. the stroke on the 880 is 1 mm longer and the bore is 1 or 2 mm larger (memory is fuzz here) If you look at the ratio of the bore and stroke of the two saws they are similar but if you look at the ratio of the surface area of the pistons of the two saws you will se how the 880 is a larger bore/short stroke design compared to the 075 even though the stroke on the 880 is longer then the 075. even though the 880 has more torque then the 075, the power band on the 880 is much narower then the 075 and drops off significantly as the rpm goes down such as when 36" of bar is buried in a hard wood log. in contrast the 075 has a much wider power band which means that even though it has less torque than the 880, more of it is avalable at a wider rpm range. Thus the torque advantage of the 075.

I guess the proof will be in the timed cuts in a 48" diam log I have waiting for me in the yard!. It will be interesting to be able to use the same bar/mill/chain and just swap the powerheads and time them in the same log.

I wouldn't mind seeing the torque/power/rpm curves if you have them.

Cheers

 

[BlueRider]

I guess the proof will be in the timed cuts in a 48" diam log I have waiting for me in the yard!. It will be interesting to be able to use the same bar/mill/chain and just swap the powerheads and time them in the same log.

I wouldn't mind seeing the torque/power/rpm curves if you have them.

Cheers

I too am very eager to see the two saws in the same wood with the same bar chain combo. should make for a good video.

don't have the torqe curves, just relying on my experiance with bikes. Of course with a bike you can easily change the torqe curve with a pipe. I suppose this could be done with a saw but it just seemed easier to go to a bigger saw. If I was really obsessed with speed I would have a bandmill.