Sometimes a little makes a big difference

[Patrick NC]

I've always thought that the 23hp Briggs on my mill was a little underpowered.  Seemed to bog easily and I always struggled in hard knots and such. It cut straight,  but I never had the feed speed I thought I should have.  I always felt that I had to hold back to keep my blade speed up.
 Yesterday I was sawing some SYP logs when a customer of mine showed up to get a few cedar slabs I had ready for him. He also happens to be a small engine mechanic.  He said it didn't sound like it was running wide open. Went back to his shop and came back with a few tools and a tachometer.  After checking to see that the throttle cable was adjusted properly, he hooked up the tach and confirmed that I was only getting 3400 rpm.  Shut it down and made some minor adjustments to the linkages and governor.  Fired it back up and we had 3600 rpm which is what it's rated for. I didn't think that 200 rpm would make that much difference.  I was wrong! It cuts faster than I ever could before with no bogging down. Just stays steady against the governor with the speed control in its fastest position in a 14" wide cut. I guess I'd better pay more attention to such things.  He didn't charge me, but I took $150 off his bill for the slabs. 

[WV Sawmiller]

Jackpot! I love customers like that!

[Wlmedley]

I bought a tiny tach for that same reason.I can look at it and make sure I'm getting full throttle.My cable has stretched a couple times and had to be adjusted.

[kelLOGg]

Good customer AND good miller. 

[taylorsmissbeehaven]

In the hurry up world we live in today, its really nice when someone takes a minute to help. Those cedar slabs may have been the best you ever cut! Happy sawing

[moodnacreek]

" Against the governor"  Patrick, you are from upstate, I haven't heard anyone say that in a long time. I am also surprised 200 rpm made a difference. Doug

[melezefarmer]

I also had the same issue when I assembled my HD36. I bought a small tachometer/hour meter and found that I had set the WOT at 3300 RPM. I now use the tachometer when sawing to maximize the cut speed while still maintaining the RPM at an acceptable level.

As a side note, I did the math and the HD36 gets 3800 FPM @ 3600 RPM. Quite a bit lower than Wood-Mizer's 5800FPM.  My math may be off tough.

[Old Greenhorn]

While that 200 RPM uptick obviously made an improvement, what does not meet the eye but probably made the difference is that the 200 rpm got you up over the hump on the torque curve. These engines are designed very close and a small difference in RPM made huge difference in torque at just the right places along the curve. I could see me suffering with something like that for a long time, like you did. Gotta take another look at my 350 and get a tach.

[rusticretreater]

Yes, a little can make a big difference.  But folks confuse HP, RPM with more power when its torque(twisting power) that rules.  What you really want is to find a torque curve chart for your engine and set your max rpm just past the max torque rating.  When your blade meets the wood, the engine takes the load and drops in rpm.  This puts you right at the max torque rating so your engine is pulling the best it can in the cut.

I installed a digital tach on my saw so that I can constantly check that I am at the optimal rpm for cutting.

[SawyerTed]

I agree.

If I remember my small engine course from many moons ago, torque is best in the 2,800 to 3,200 rpm range.  So no load rpms are higher and rpms drop back into the highest torque range when under load.  

If the max rpm is set in the high torque range, the governor could be dropping the rpm out of the highest torque range.  So 200 rpm could be enough to go below the best torque setting.