feed rate

[sparks]

The blade speed on a 25hp LT40 standard hydraulic is approx. 5330 SFPM. Which means your 158" blade will make approx 405 complete revolutions per minute.

[Dan_Shade]

Sparks, what is the pulley sizes on the engine and drive wheel? 

also, isn't optimum blade speed a property of the band more so than the saw?

[sparks]

Engine pulley is 4.00" pulley and the pulley it drives is 12.00" pulley.

[Dan_Shade]

so the engine RPM should stay above 3200 then?  my engine seems to start bogging at 3400...  maybe i'm not pushing it hard enough.

[musikwerke]

I took Suffolk Machinery's advice and up-sized the engine pulley on my 16 HP B & S (LT30) to 4.25" dia.  At 3381 engine RPM I'm driving the band wheel 1127 RPM which equals 5601 ft./min.   I'm using 1-1/4" X .045" Wood-Mizer blades and the only time my cuts aren't perfect is when I'm feeding too slowly. 

[musikwerke]

Correction to my previous post:  My engine RPM is 3181 (or thereabouts).

[jpgreen]

One way I can tell when my blade starts getting dull is the hydraulic tensioner.  As soon as it starts droping and needs more tension seems like the blade is up for a change out.

Also if the tension keeps going up periodicly, and I keep turning it back down, a breakage is on the horizon.

A stable 2000 pounds seems to be the magic point for me.

I wonder if I should up my pulley size? I need a tach to see what's going on.

[Larry]

Seems all are in agreement that blade speed is the secret to feed speed for quality and production.  So...why not directly check the blade speed?  I'm using a bicycle speedometer, ($10 from Wal-Mart) as suggested by another member some time back to measure blade speed.  I've found when the blade in the log, drops below 4,100 SFPM with my mill its going to wave.  As the blade dulls my feed slows...but the constant is my blade speed is never allowed to drop below 4,100 SFPM.  The bicycle thingy seems to be more accurate than my ear, tachometer, and or voodoo to adjust feed speed.  Granted, most times I depend on my ear, but as soon as I hear the engine start to lug I'll glance at the speedometer...quite often when sawing wider than 12".