just finished 20 ft csm on wheels

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An OPEN differential was developed for tighter cornering, and less binding in the axle which causes bucking and scrubbing on pavement and some hardpack dirt.

Limited slip has some form of clutch mechanism to LIMIT the amount of differentiation between the two sides of the spider gears. Lockers are another class entirely (I also run a Detroit locker in my truck).

Most cars do not have limited slip differentials, as they have negative effects when traction is compromised.

Rather than welding the spider gears in an OPEN differential, all you need to do is brake the opposite wheel you don't want spinning. This could be used to replace your centrifugal clutch entirely. Drive the differential via the pinion gear (where the driveshaft would go), and then use the brakes on either side to control the saw. So you'd have a brake on the saw side, and a brake on the unused side - to run the saw, the saw side brake would be off and the unused side brake would be on. Then when you wanted to stop the saw, but still idle the engine, you'd brake the saw side and unbrake the unused side.

Rather than using a whole axle, you'd just want the third member (pumpkin) from a vehicle with an independent rear suspension - such as a honda crv or similar. Mount brake rotors right to the stub shafts and go to town. I'd use a drum brake on the unused side, for the simple fact that it's self energizing and would require less force to hold on. To brake the saw, it would only need a simple friction band on a sheeve to overcome the resistance of the spider gears - power would freely flow to the unused side.
 
Jim Timber said:
An OPEN differential was developed for tighter cornering, and less binding in the axle which causes bucking and scrubbing on pavement and some hardpack dirt.

Limited slip has some form of clutch mechanism to LIMIT the amount of differentiation between the two sides of the spider gears. Lockers are another class entirely (I also run a Detroit locker in my truck).

Most cars do not have limited slip differentials, as they have negative effects when traction is compromised.

Rather than welding the spider gears in an OPEN differential, all you need to do is brake the opposite wheel you don't want spinning. This could be used to replace your centrifugal clutch entirely. Drive the differential via the pinion gear (where the driveshaft would go), and then use the brakes on either side to control the saw. So you'd have a brake on the saw side, and a brake on the unused side - to run the saw, the saw side brake would be off and the unused side brake would be on. Then when you wanted to stop the saw, but still idle the engine, you'd brake the saw side and unbrake the unused side.

Rather than using a whole axle, you'd just want the third member (pumpkin) from a vehicle with an independent rear suspension - such as a honda crv or similar. Mount brake rotors right to the stub shafts and go to town. I'd use a drum brake on the unused side, for the simple fact that it's self energizing and would require less force to hold on. To brake the saw, it would only need a simple friction band on a sheeve to overcome the resistance of the spider gears - power would freely flow to the unused side.
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I got what you are saying, we used basically the same set up for a pto winch on our pulpwood truck.My main concern was turning the pinion gear straight up and attaching it to a vertical engine via pulleys.Isn't there a bearing right there and wouldn't it be out of the gear oil and not get lubrication?The rear diffs I have on hand are out of an 86 nissan maxima and an 84 ford fairmont.Neither are huge and I was planning on cutting them down, but just welding one axle, making the other side turn.Your brake idea is good, even though I've used it myself, I hadn't thought of it for this application.Thanks.
 
It would really depend on what the driven speed was. If you were using the pinion as your input, then you'd run the problem of a (for the sake of discussion we'll call it a 3:1 diff) 3:1 gear reduction from an already low revving engine to begin with. But, if you drove the diff from one of the stub shafts, then you'd have a 3:1 overdrive. Holding the diff with the axle stubs vertically, you'd need to fill it about half way to keep the pinion oiled. I'd then mount it such that the top stub was your idler/undriven shaft and then the lack of lube wouldn't matter. Splash would handle the top carrier bearing without issue.

I'd source out another diff to do this with. I wouldn't want the weight of a cast iron housing weighing on my saw carriage if I could avoid it.

You also might get lucky and find a used/surplus right angle gear drive. There's a place in Ohio called HGR, I bet they'd have what you're after. Otherwise, local surplus or fleabay would be options as well. Surplus Center.com would be another place to check. I've ordered some heavy stuff from them in the past and shipping was quite reasonable.
 
Jim Timber said:
It would really depend on what the driven speed was. If you were using the pinion as your input, then you'd run the problem of a (for the sake of discussion we'll call it a 3:1 diff) 3:1 gear reduction from an already low revving engine to begin with. But, if you drove the diff from one of the stub shafts, then you'd have a 3:1 overdrive. Holding the diff with the axle stubs vertically, you'd need to fill it about half way to keep the pinion oiled. I'd then mount it such that the top stub was your idler/undriven shaft and then the lack of lube wouldn't matter. Splash would handle the top carrier bearing without issue.

I'd source out another diff to do this with. I wouldn't want the weight of a cast iron housing weighing on my saw carriage if I could avoid it.

You also might get lucky and find a used/surplus right angle gear drive. There's a place in Ohio called HGR, I bet they'd have what you're after. Otherwise, local surplus or fleabay would be options as well. Surplus Center.com would be another place to check. I've ordered some heavy stuff from them in the past and shipping was quite reasonable.
Click to expand...

I looked at Surplus Center, they didn't have anything in this years catalog that looked like it would fill the bill.I'll check out HGR.There are plenty of you pull it junk yards nearby and I will try them, too.I like your ideas and thanks for the help.
 
Surplus Center's printed catalog only has their most plentiful items in it. The website has more of their small lot type stuff. I'd check the site, but that would still be new components.

An industrial right angle drive rated for 10hp is probably going to cost more than a new 10hp horizontal shaft engine would. As such, there might be something to be said for finding a lawnmower shop and seeing if they have a big snowthrower with an engine to trade you.
 
Jim Timber said:
Surplus Center's printed catalog only has their most plentiful items in it. The website has more of their small lot type stuff. I'd check the site, but that would still be new components.

An industrial right angle drive rated for 10hp is probably going to cost more than a new 10hp horizontal shaft engine would. As such, there might be something to be said for finding a lawnmower shop and seeing if they have a big snowthrower with an engine to trade you.
Click to expand...

I can get a 13hp horz. shaft for less than a gear box, I'm just trying to use what I have on hand.I'm afraid if I asked about a snowthrower at my local shop, I would get some strange looks.:msp_biggrin:
 
Yeah, well there's only one joint in town that sells gator up here. I think we're even. ;)

I'm really wishing you guys had won the civil war right now though. States rights should trump the feds. :angry:
 
I have the Harbor Freight 11hp Predator Honda clone engine.WORKS GREAT.Cant beat the warranty.Cost 299.00 349.00 for 13 hp.
 
engine size

13 hp aint enough smoke for a 36 inch or larger csm. just remember when you run through a gearbox, you lose some power. my 18 hp twin b&s pulls hard at times you want the largest engine that you can find. also the lightest.for a portiable mill
 
greasefittn said:
13 hp aint enough smoke for a 36 inch or larger csm. just remember when you run through a gearbox, you lose some power. my 18 hp twin b&s pulls hard at times you want the largest engine that you can find. also the lightest.for a portiable mill
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I was planning on using a 17hp Kohler if I build a CSM, that's the engine I have.The reason I brought up the gearbox is I was also kicking around the idea of building a bandmill with the same engine and using the rear diff. on it.
Also, I don't want my mill to be portable, I'm building it on a 23' long schoolbus frame that I will weld either flatbar or maybe angleiron to for tracks and some overhead trolly wheels for the wheels.It is important to me that I build it as much as possible out of what I have laying around or can scrounge for free or cheap.That's my criteria, may take a little longer, but I'll get there.
 
Ok, you want some out there engineering ideas? :D

Take the bus, use the engine to power a line shaft (some of those "little" allison tranny's have PTO ports on them), run the bandsaw off that shaft and also drive the head with it. Keep the bus functional and now you have a self propelled portable mill. I bet you could also rig some hydraulics to run off your line shaft and then you could have a grapple arm to load the logs.

In case you're not familiar with line shaft power transmission - it's how metal lathes deliver power to the carriage for power feeds. This allows your tool to traverse a lot of distance without a lot of extraneous hardware.
 
mill power

the 13 hp harbor freight engine for a band mill is ok . for a csm its not. the bus frame is a good idea however, you dont want to run the bus engine just for the mill way to big!
 
Power transmission?

I've been reading this thread with interest. Got to wondering if it would be possible to use something like a gear box from a tiller perhaps turned with the input shaft up, coupled with a lovejoy to the engine. ?? This may have more problems than it's worth. Just a thought or a what if.
 
transmission

I dont think the ratio is correct with a tiller transmission . go to a u pull it junk yard and look around at all the zero turn mowers and other things that are there. I think that you will find something that will work remember, you want to keep it simple, easy to fix , when it breaks. and light.
 
Milling logs and ripping set up on chainsaw.

I have a 55 CC Husqvarna chainsaw w/20" bar. I use a Carlton ripping chain with teeth at 10 degrees. I have been milling 10" in diameter cedars and it does drag sometimes but I'm getting through ok. I was wondering if anyone could give me some advice on how to optimize my midrange saw with either a different bar (besides the factory one), different kerf of chain, bigger sprocket, etc. Before anyone mentions it I do keep my chain sharp and serviceable while cutting. Thanks.
 
Jim Timber said:
Ok, you want some out there engineering ideas? :D

Take the bus, use the engine to power a line shaft (some of those "little" allison tranny's have PTO ports on them), run the bandsaw off that shaft and also drive the head with it. Keep the bus functional and now you have a self propelled portable mill. I bet you could also rig some hydraulics to run off your line shaft and then you could have a grapple arm to load the logs.

In case you're not familiar with line shaft power transmission - it's how metal lathes deliver power to the carriage for power feeds. This allows your tool to traverse a lot of distance without a lot of extraneous hardware.
Click to expand...
I like the way you are thinking, but...
Alas,I only have the frame.
I have a line on a 16 H.P. 2 cylinder horz. B&S.I just purchase 2 20' sticks of 1"x1/2" flatbar for my tracks to weld to the frame and I have a beam trolly I'm going to use for wheels to run the carriage on.It's coming along.
 
greasefittn said:
I dont think the ratio is correct with a tiller transmission . go to a u pull it junk yard and look around at all the zero turn mowers and other things that are there. I think that you will find something that will work remember, you want to keep it simple, easy to fix , when it breaks. and light.
Click to expand...
Agreed, I'm thinking idler pulley for the transmission.
 
idler pully for clutch?

Its better to use an electric clutch from a riding lawn mower. they are only about 5 bucks at the local u pull it around here. ps the belt needs to be tight so it doesnt slip. I have had problems with one belt with 18 hp.
 
greasefittn said:
Its better to use an electric clutch from a riding lawn mower. they are only about 5 bucks at the local u pull it around here. ps the belt needs to be tight so it doesnt slip. I have had problems with one belt with 18 hp.
Click to expand...

I may do that.My thinking with the idler clutch set up was this, I have a big spring and idler set up off a woods finish mower.The spring keeps tension on the idler until you disengage it, I thought that would help reduce slipping.
I've about set my mind on a bandsaw rig now, too, so I may just go ahead with the electric clutch.
 
electric clutch

the clutch takes 3 to 6 amps to work, depending on the brand of clutch so the b@s engine should have a 13 amp alt in the flywheel so you will be fine with it. just remember to keep the belt tight.
 

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