The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: dustyjay on March 24, 2015, 08:04:08 PM

Title: Saw speed on M-14
Post by: dustyjay on March 24, 2015, 08:04:08 PM
I am sending my 42" saw blade to be hammered to be sure the tension is correct. I can't find anywhere a recommended RPM for the saw blade. I've searched around on here and looked at the original manual for the saw. I know faster is better for hardwoods. Does anybody cut a mix of species who can tell me what a good compromise speed for the M-14? Thanks!

Also, does anybody know Henniker Saw Shop in Henniker, NH? Any recommendations or stories? Thanks again.
Title: Re: Saw speed on M-14
Post by: beenthere on March 24, 2015, 08:23:54 PM
You running that blade off the tractor PTO so wouldn't the blade be running 540 rpm and you would hammer it for that speed?

This your mill?
(https://forestryforum.com/gallery/albums/userpics/34459/D9.jpg)
Title: Re: Saw speed on M-14
Post by: dustyjay on March 24, 2015, 09:04:52 PM
Yup, that's mine and 540 is what I thought it would be.
What about sawing hardwoods? I've heard a faster blade speed is better for that, but if the saw is hammered for 540, it is not best for hardwoods?
Not that I cut much hardwood.
Title: Re: Saw speed on M-14
Post by: coalsmok on March 24, 2015, 09:46:41 PM
You tension the saw for the speed you got.  Faster isn't necessarily better tooth count and feed rates go into it as well.
Title: Re: Saw speed on M-14
Post by: Possum Creek on March 24, 2015, 09:53:12 PM
Dusty, when I went to a detroit for power I wanted to get the rim speed up closer to the 8,000 fpm recommended by Lunstrum's book so now I am turning about 630 rpm on the arbor with a 46" saw and I like it much better. The table in that book shows a 42" saw would need to be turning at 728 rpm to get at 8,000 fpm at the rim but I don't know if I would run a belsaw that fast it might fly apart. I don't really known what would be best but be careful and make sure whatever drive line you use is balanced good.
Title: Re: Saw speed on M-14
Post by: dgdrls on March 24, 2015, 10:18:44 PM
Hi Dustyjay,

Blades are really hammered for SFPM/rim speed, not RPM per se.
Is your blade inserted tooth?  If so what bits and shanks?
I agree with Possum Creek on speed,  be careful and do not over-speed

Best
DGDrls


Title: Re: Saw speed on M-14
Post by: dustyjay on March 25, 2015, 07:13:10 AM
The local mill who's helping me out with this runs a 54" saw @9184ft/m as the linear speed of the outer rim of their saw, which works out to 650rpm on the arbor and 1625 rpm at the engine. They have belts and pulleys to set up the 2.5:1 ratio that adjusts the engine rpm to arbor RPM.

If I want to run more than 540rpm on the arbor I would need to run the tractor t very high rpm, which is inefficient. 540 rpm on the arbor with a 42" saw = 5935 feet per minute linear speed of the teeth.600rpm= ~6600 ft/min. That might be ok. 630prm on arbor=6924ft/min.

I could also convert to belt drive to get saw speed with lower engine speed, but that's likely more than I want to do right now. Likely I will keep it slow- 540 RPM and keep sawing only softwood.

Thanks for letting me talk through this and sharing your knowledge.

dgdrls- it is an inserted tooth saw with B or F teeth. I'm pretty sure it's B.
Title: Re: Saw speed on M-14
Post by: bandmiller2 on March 25, 2015, 08:24:21 AM
Dusty, your fine at 540 rpm, you have some leeway up and down. A saw that size could be run much faster but its a moot point with the Belsaw feed rate. Sawyer friends of mine started business with a Belsaw powered with a big Murfhy diesel they changed the mill to feed at gigback speed but had to put up with slow gigback. They soon went to a lane handset to up production. The knowledable smith that hammered my saws doesn't like to hammer below 540 says too slow and you can hear each tooth hit the wood. My current mill ran a 50" saw at 700 rpm too fast for me had it hammered for 600. Frank C.