Need advise on my sawmill project

[Ken Malone]

Has anybody tried to run a saw with a 12 hp ride on mower engine and trans.?Thanks

[NewYankeeSawmill]

Mine has an 18hp Briggs and Stratton, and it struggles with some of the harder wood types. I imagine you _could_ run one, but it might take some time depending on the wood.

[Jeff]

I think some of the entry level hobbiest saws have as small as 5. What that harbor fright saw have? 

[fluidpowerpro]

The first saw I had used a 6.5 HP engine. It cut up to 18" wide. It worked fine but slow.
I think you could make 12 HP work. Assuming your using the transmission because it's a vertical shaft engine? If you use the transmission the output rpm will be really slow so you will need a huge pulley on it. You will also lose some efficiency through the transmission so I would avoid using it. Get a 90 degree gearbox instead.
At the end of the day you will be much better off using a horizontal shaft engine 

[Old Greenhorn]

The engine size will get you in the game, but that transaxle will give you nothing but grief between efficiency losses and speed. If you don't have a horizontal shaft do what FPP suggests above. The transaxle will be nothing but a time suck and disappointment.

[SawyerTed]

There are considerations regarding blade speed and cutting speed relative to hp.  

Tim Cook, Cook's Sawmill, has a good article on hp and blade speed.  A internet search will find it, I can't post the link for some reason.  

The blade speeds needed don't lend themselves to the use of the transaxle.  A gear box ($$$) can be used but there's a reason manufacturers don't.  

In the long run a horizontal engine will be the best approach.   More hp means more blade speed and more hp means more torque.  More torque means less blade speed drop which means consistency higher cutting speeds. 

[RetiredTech]

 Having worked on a lawnmower transmission or two I have to agree with the advice already given. Ditch the transmission. It's designed for low speed use. The axle is probably 3/4" - 1" which is pretty small for sawmill use. Then there's the differential to deal with and the axle bearings on some are just bored through the cast aluminum casing. It's not a question of if it will fail, but when.
 As for the motor it should work. If it's vertical shaft, I saw one DIY mill article that used a drive belt with a twist to a horizontal shaft. It seemed to work for him. I don't remember if it was in the forum or on YT. Blade speed can be adjusted by pulley size.

[ladylake]

 You should be able to find around a 20 hp horizontal shaft motor cheap.  Steve

[Ken Malone]

Ditching the ride on motor and transmission idea.Thanks for the info. I'll find a horizontal shaft motor and go from there.Thanks Ken

[Ken Malone]

I'm planning to use 2 pieces of acme rod to raise and lower my cutting head.will be a Manuel crank setup to start maybe power later on.Any suggestions on setup? sprocket sizes? Shaft orientation? Should I have 4 posts or 2. I thought 4 but I'm having trouble with it jamming.is balance an issue with 2 posts?

[jpassardi]

Have you considered a chain and sprocket or a cable lift setup? The acme rods will be slow/take many turns.

[Ken Malone]

I thought the acme rods would be more acurate.
Read that somewhere.speed is not really an issue for me.later I may add a 12v motor.

[beenthere]

It's a sawmill and the accuracy of a chain is more than enough. Should be no variation along the cut, if the slack is taken out of the chain (or whatever system is used) when moved to the next position. Dropping the head down to the next set is something that has to be taken into account. Coming up not so much.

[Ljohnsaw]

The nice thing about ACME threaded rods is it is self locking. With a chain lift you will have to deal with locking. If it is a cog like latch that it is fine enough that you can hit your desired height mark.

[mike dee]

I picked up a new 2,000lbs electric winch for $49 during covid and used it to drive a chain connected to a sprocket on the manual crank that raises and lowers my cutting head. The winch uses planetary gears and doesn't drift. Being a cheap winch it goes slow and ended up being about the same speed as hand cranking it. I use the winch remote to power up and down.

Goes all day on an old car battery that lost it's oomf to crank a car.

[Mooseherder]

I have tractor trailer landing gear on my homemade mill that my friend built.  A 12 volt electric motor moves it up and down okay.  A logger whiplashed the mill head unloading logs a couple of years ago and snapped the right side rod.  It's welded up and working but not good as new . These type gear boxes are two speed. Granny and fast granny.

https://www.truckspring.com/heavy-duty-truck-parts/trailer-landing-gear.aspx

[Ken Malone]

 I like that set up.Thanks for the pictures.you got me thinking.

[Nebraska]

url=https://forestryforum.com/gallery/displayimage.php?pid=356810][/url]

Chain lift set up on my old Timberking B16

Actually it's pre Timber King was a Belsaw product. But it is pretty accurate and the gearbox does hold its place fine. 

[Ken Malone]

  another good idea!

[jpassardi]

Another option is a dump truck tarp gearmotor - works well for me, powered through a cheap PWM controller for variable speed.

[Ken Malone]

Ya! And I know where I can get one.Thanks

[jpassardi]

You're welcome. Be sure to use a PWM controller so you can creep up on your cut height.

[moosehunter]

Ken, 
 I see that you have posted two different threads re your sawmill build. I would like to suggest that you just have one thread. Ask all of your questions on it and have all of your responses in one place.
We like following along with new builds.
Good luck!
mh

[RetiredTech]

While trying to find the sawmill build I remember seeing with a verticle shaft motor I ran across this one, and right in this forum too. It's not the one I was looking for, but it's a unique build to say the least.
Lawnmower Engine Powered Bandmill (sawmill)
It just shows what you can do with what's on hand if you put your mind to it.
Here's one picture from his gallery.

[Ken Malone]

Now the question,should bed travel on 4 posts or 2. I have started with 4 but seems to be binding a fair bit. I thought that 4 posts would be more balanced once motor and other gear is mounted.Should I rethink this? Thanks Ken