What blade speed for 15 hp electric LT40?

[logwalker]

I just hooked up a bicycle computor on my LT40 and found the blade speed to be only 4650 fpm no load. I think it should be up in the 5500 fpm range. Any thoughts on this.

See my other post for info on the Band Blade Speedometer.

Thanks, Logwalker

[D._Frederick]

If it saw cuts good at 4650fpm, I would not change it. The faster the blade runs, the shorter its life. With an electric motor drive, you should not stop the motor after every cut. Most type of motors will overheat if start and stop to often.

[logwalker]

I agree that everything is a balance of needs and nesseccities or somthing like that. I havn't got any experiance on the saw yet. I have been using a Western Sawyer for about 5 years and broke a ton blades with it's 16" wheels. Would sure like to avoid that. maybe ElectricAl will weigh in as he has the same setup. Thanks D._Frederick, I apprecciate your feedback. Logwalker

[ElectricAl]

I'll get my notes from our conversion and get back to you ;)

[mike_van]

I use a 10 hp 3 phase, 24" wheels, running the blade at 4800 fpm.  I used  to be  around 5400, but I slowed it up on Tim Cooks advise - worked better too !  I start & stop the blade every cut, never overheat almost 15 years this way.   

[logwalker]

Hey Mike,
What is it you like better about 4800 fpm. Is it that you break less blades or does it cut better, straighter? it looks like the current run of Woodmizer LT40's are in the 5500 range. Very interesting.  LW

[mike_van]

If I remember, I had problrms with frozen large [24"] oak, like I was under powered if I remember right - I can't fit a 15 hp in my frame without a major rebuild, Tim thought the 10 D. hook plus the blade speed was pulling the tooth into the wood faster than the saw had the power to keep up with. Something on those lines -  It also runs smoother, stops faster [helps when you shut it off like I do]  at 4800.   I had peeled a few blades off backing up with the blade running, Hemlock is the worst - one of those edges picks up after the cut, blade catches it, off it comes - My other cure for that frozen oak was limiting what I do up there in the dead of winter - I've worked outside forever, year round, that bitter cold  just isn't what it used to be - on me & the machine - think about how hard all that grease & gear oil is at 10 F.   Parts have to be running dry till they heat up.   

[logwalker]

Makes sense Mike. ElectricAl said he has good results with 5500. But like me he is running 15E. Well I guess I will keep listening to all the sage advice and learn form the experience. Gotta love this Forum. Thanks Gentlemen. LogWalker

[mike_van]

One more thing on blade speed - Make sure your wheels will take the speed you want to run - My Browning Poly V sheaves have the max. rpm  cast into them -  around 900 I think, I would have to go look to be sure. When I was first building this mill, I had a cast iron one blow up on me, no one hurt [just my wallet] :(

[D._Frederick]

When I had my mill set-up to run at about 5200 with my 7 1/2 hp Baldor, I was getting to much sawdust remaining on the boards. It was causing the blade to wander in the cut.  I changed pulleys to reduce the blade speed by a 1000ft/min,  the saw dust went from flour to coarse sand in texture and reduce the "fill-over" of sawdust in the gullet of the tooth.

The blade speed change to about 4200 helped the quality of the cut boards and increased blade life by adding a couple hours of run time before failure. I found that it slowed the sawing speed when sawing 5 1/2 inches or less, with larger cuts the speed was about the same.