Pulley and belt calculations?

[farmsc]

Evening, guys.  I've not posted for a while, been working on setting up the old Sergeant Log beam saw.  Got everything bolted up and belted, just need to find the right size pulley for the mill itself.  I used to have the formula, but can't seem to find it.  I have a 10" drive pulley turning 1019rpm's.  I've been told I need to turn this 42" blade between 450 and 500 rpm's.  Any ideas on the mill pulley size to get this speed?  Thanks for any info, and I'll post a pic or to in a couple days when we finally get to cut something with it.  Kevin

[mitch]

Hi farmsc:

I spent some of my best days near Seneca.... at Clemson in the mid 1960's.

D = 10 x 1019/500 = 20.4 " or about 20 inch for the mandrel pulley.

See this link

http://shagbarkfarms.com/LmbCalc/V-Belts_F.html

mitch

[VA-Sawyer]

Farmsc,
Mitch has the correct formula except I would divide by 475 instead of 500. You said you wanted it to run between 450 and 500 rpms. Using a 20" pulley will result in a speed slightly over 500 rpm.
D= 10 x 1019/475 =21.4 "
A 21" pulley will give you about 485 RPMs
A 22" pulley would give  about 463 RPMs
VA-Sawyer

[farmsc]

Thanks, guys.  I knew this was the right place to ask!  The pulley I have found is 21" so I got lucky.  Kevin

[mitch]

Are you using flat belts or vee belts to drive the mill?

[farmsc]

Flat belt, 6" wide from an H farmall.  This is a very old(turn of the last century) mill that will not be running production, just for fun.  Kevin

[dail_h]

   Make sure the radiator is in good shape on your H,it's likely to look like old faithful

[farmsc]

Oh yeah, I've been there plowing with her.  She got a brand new coolerator this spring before the sorghum cane went in.  I ended up bending and welding 1/8" metal plate around my v-belt pulley that came with the mill.  Hooked up the H for the first time last night and she really sang!!  Hope to put the first log through it this weekend after the last few adjustments are made!!

[D._Frederick]

Farmsc,

You will find that the Farmall H's 26 hp will not run a sawmill very well, (unless you are sawing tooth picks.)

We tried our Farmall M for sawing, it was slow going, it would take a couple minutes to make a 20 ft cut.

We bought a Case LAE industrial engine, about 70hp with the high compression pistons, worked much better.

[mitch]

Concerning low power for an old circular sawmill ...... check this 1923 add for an American #2 sawmill.

[Tremel]

Steam HP is different than petro HP.  A 10HP Steamer is equivilant to a 35HP Petro engine.   There are some mathmatics behind all of this, but I don't have them in front of me at this time.

We run an 18HP steamer on a Frick OO mill at our club and when we can't run steam, we use an old 80HP 6 cylinder diesel engine.  That steamer can out cut the diesel any day.

My JD 720 (60HP) takes all she got to run a 54" blade on 20" hardwood logs.

The mill I'm setting up now has a White 6 cylinder gas engine (around 100HP).  I run the mill at 450 RPM's (Due to babitt bearings).  I may change out the bearings and repound the blade to run at 600+ RPM's.  We'll see...