Chainsaw Hydraulic Conversion

[NCMau]

I've nearly given up on a hydraulic saw for my firewood processor. It's just not feasible for the budget I wanted to spend on this project. I plan on going electric instead. If I was going to do what your trying to do I'd pull the spark plug out of the saw and pull the pull rope off the saw. I'd build an adapter to hook the motor on the crankshaft of the saw. The rpm would be far from optimal but I assume you only intended to cut a few limbs. For my project a circular saw wasn't a viable option due to the blade size needed. If you're only planning on cutting small limbs I'd use a cheap 12" miter saw blade.

For a stationary operation, electric would be an excellent choice. When possible, I have always preferred electric over other means. Years ago I converted my wood splitter with a 5 HP electric motor. It is clean, less maintenance problems and ALWAYS starts. It may not be portable, so what? I just bring the wood to it.
How are you planning to go electric?

 

[muddstopper]

Yes muddstopper you are right. Thanks for the chime. One of the main reason I wanted to use the chainsaw case is the oiler and also because everything is ready there. All I would have to do beside stripping the saw, is to adapt the motor to the crankshaft. The bulkiness is not a problem because it is mounted. One thing I did not realize that these chainsaws have such a high RPM. With that in mind, I can see that I would be making a hole in the water?. even if I would choose the biggest motor of the series, I would get an increase of HP but the speed remains the same.
So here is option No 2.
I have an Eaton H 101-1704 motor. This motor has a max speed of 1021 RPM and a torque of 497 lb/in which would produce 8 HP, if my math is correct. This motor, of course, would still not be adequate for a chainsaw but I think it would work with a circular saw setup. The speed would still be slow, but I would use a 3:1 pulley setup to increase the speed.
To make this adapter for a 12 circular saw would be no problem, as I have the arbor and the bearings on hand.
I would have preferred the chainsaw option, but I see now that it is not much of viable option.
You think this motor would work for this purpose?

I looked up the Eaton motor. It seems to be a 2.2cuin motor. With your limited 7gpm of oil flow, you would end of with a speed of about 735rpms. It would have plenty of torque and hp, but would be slow for a chainsaw. The circle saw might not be a bad ideal. You can find out what tip speed works best and use that number and your motor speed to do the math and come up with the proper size saw blade you could use to maximize cutting ability. Since you already have the motor, your biggest investment would be for the saw blade and a few hyd hoses. No need for any fancy gearing.

edited to add
I did a little research because I wanted to know what tip speed works best. It seems for most every wood cutting tool, tip speed should be between 130 to 170 fps. At what speed should my saw blades spin? Doing a little math, using a 16in circle saw and your motor speed, you would only have about 51fps of tip speed. It would see you would still need to do a 3:1 gearing to put the circle saw in the middle of the recommended tip speed. Do able for a reasonable cost

 

[4570Man]

How are you planning to go electric?

Plan 1 is to power my hydraulic pump with a gas motor and power the electric saw and electric conveyors with either a generator or from the electric company. Plan 2 is buy a large 3 phase generator and power everything including the hydraulic pump with electric. 3 phase motors are dirt cheap and are easily acquired.

 

[NCMau]

I looked up the Eaton motor. It seems to be a 2.2cuin motor. With your limited 7gpm of oil flow, you would end of with a speed of about 735rpms. It would have plenty of torque and hp, but would be slow for a chainsaw. The circle saw might not be a bad ideal. You can find out what tip speed works best and use that number and your motor speed to do the math and come up with the proper size saw blade you could use to maximize cutting ability. Since you already have the motor, your biggest investment would be for the saw blade and a few hyd hoses. No need for any fancy gearing.

edited to add
I did a little research because I wanted to know what tip speed works best. It seems for most every wood cutting tool, tip speed should be between 130 to 170 fps. At what speed should my saw blades spin? Doing a little math, using a 16in circle saw and your motor speed, you would only have about 51fps of tip speed. It would see you would still need to do a 3:1 gearing to put the circle saw in the middle of the recommended tip speed. Do able for a reasonable cost

This is good info since I am already programmed to go circular with a 3:1 gearing. I will start with a 12" blade because that is what I have on hand. If needed to, I can always step up. All I need to buy to start is minor hardware. I have the flow control and hoses that I am using for another front implement. Will post results with pics.

 

[Steave]

I have a feeling that even with my Parker motor and the speed pulley increaser, the blade would not start with the blade against the limb. With a theoretical speed of 3300 RPM, the torque would be decreased to 160 lb/in. I compare the the situation with my 2 HP table saw with develops more torque than my hydraulic motor. The blade would not run with a wood block in the teeth. It will be an operational learning curve and I am looking forward to get on with this project.

Edited: Basically that is what I will be doing. A 2" pipe mounted on the side of the loader. I like your idea of the rope. Does the blade segment have some sort of spring action mounted with the main mast? It is not clear on the pic. If you can not find a suitable arbor, have one machined. It should be a reasonable charge.

What may look like a rope is a piece of thin wall conduit used as a stabilizer for traveling. The frame is pretty weak as far as movement side to side. Most of the time I just leave it on there when traveling or while using. It don't get in the way. Yes I had a spring between the main and the top arm when I first built it but it's not needed with the weight of the saw pushing itself down. I ended up tearing it off and found out it wasn't needed so never replaced it.

The plate between the main and the top arm does let the top pivot about a foot to help protect the blade and the frame if /when the skid steer boom lets down jerky. If I push into a limb too fast it would let the blade rise up over the limb if it needed to instead of breaking something. Mr blade is turning the same direction as the tires if I am moving forward.

I suppose you could build a super sturdy arm or frame to mount the saw on but I tried that a few years back and didn't take long to rip it to pieces. That one was mounted on a heavy wall pipe and mounted on the loader of my backhoe. I found out quickly the rigid mount wouldn't work at least not with me operating the loader. .

I don't depend on torque but you do need a sharp blade to zip through the limb and unless its a small limb never cut from the bottom and risk it getting pinched. I'm thinking you'd have to get some help and somehow lift the limb up to get a pinched blade loose, luckily I've never had to find out.

 

[muddstopper]

I dont have any experience with any kind of bucket mounted saw, so I am just speculating how the function might work. It seems to me that the saw is placed in the limb by lifting and lowering the bucket. I dont know about others, but I think I would have a heavy hand trying that and would break, bend or rip off the saw. I think a spring to allow the saw some amount of movement would be benefitual. On a processor chainsaw, Oregon recommends about 50-100 of force at mid bar, this allows the saw to cut without binding and bending the bar, ripping off bar studs, and breaking the chain. I would think something similar to control down force would be needed. If the circle saw was mounted on a pivoting arbor and a 50-100 lb rated spring was mounted, this should allow the operator a little flexibility as to how hard they bumped the saw blade into the limb. If you hit the limb to hard with the saw blade, it would just flex back, but still continue to cut at maximum speed. I might be wrong about this, but I think this is the route I would take if I was doing the building.

 

[Steave]

I dont have any experience with any kind of bucket mounted saw, so I am just speculating how the function might work. It seems to me that the saw is placed in the limb by lifting and lowering the bucket. I dont know about others, but I think I would have a heavy hand trying that and would break, bend or rip off the saw. I think a spring to allow the saw some amount of movement would be benefitual. On a processor chainsaw, Oregon recommends about 50-100 of force at mid bar, this allows the saw to cut without binding and bending the bar, ripping off bar studs, and breaking the chain. I would think something similar to control down force would be needed. If the circle saw was mounted on a pivoting arbor and a 50-100 lb rated spring was mounted, this should allow the operator a little flexibility as to how hard they bumped the saw blade into the limb. If you hit the limb to hard with the saw blade, it would just flex back, but still continue to cut at maximum speed. I might be wrong about this, but I think this is the route I would take if I was doing the building.

That's what I done on mine at the pivot point. The spring was located between the two sections and would let the top section move up and the spring was suppose to keep pressure to pull the blade back down through the limb. After beating up the spring and the adjusting chain holding it, I couldn't tell any difference in the way it cut. I guess the weight of the blade, motor, and hardware is enough to let it cut on its own.

With a 16" blade and the way it mounts with flanges on each side of the blade you only got about 5" of cutting room before you bottom out. If you need to cut a larger limb just cut it in smaller lengths until you feel safe it won't pinch your blade if you cut a little from the bottom then finish it off from the top. I'm just fighting the woods back from the fields and the farm roads and haven't cut many limbs bigger than 4".

I just purchased a new blade as the old one is missing a couple of teeth and needs sharpening. Yea, I've let it hit the ground a couple of times. I thought about arranging the holder to where there's no way to let it down far enough to hit the ground but haven't yet and probably won't.

You've got at least a million choices for blades and I settled on this one. Here's where I bought the blade: http://www.carbideprocessors.com/

The blade I used is an Oshlun 865-SBW-164032 Carbide processors site is hard for me to use.

 

[NCMau]

That's what I done on mine at the pivot point. The spring was located between the two sections and would let the top section move up and the spring was suppose to keep pressure to pull the blade back down through the limb. After beating up the spring and the adjusting chain holding it, I couldn't tell any difference in the way it cut. I guess the weight of the blade, motor, and hardware is enough to let it cut on its own.

With a 16" blade and the way it mounts with flanges on each side of the blade you only got about 5" of cutting room before you bottom out. If you need to cut a larger limb just cut it in smaller lengths until you feel safe it won't pinch your blade if you cut a little from the bottom then finish it off from the top. I'm just fighting the woods back from the fields and the farm roads and haven't cut many limbs bigger than 4".
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I just purchased a new blade as the old one is missing a couple of teeth and needs sharpening. Yea, I've let it hit the ground a couple of times. I thought about arranging the holder to where there's no way to let it down far enough to hit the ground but haven't yet and probably won't.

You've got at least a million choices for blades and I settled on this one. Here's where I bought the blade: http://www.carbideprocessors.com/

The blade I used is an Oshlun 865-SBW-164032 Carbide processors site is hard for me to use.

Well this what I have done so far. The arm projects over 6 ft from the bucket. The 12 blade turns 3000 rpm with a tractor 1000 rpm and 3600 rpm with a 1500 tractor rpm. So I think with my modest 7 gpm pump that is all I can expect. It does okay for what I have tried so far, but nothing spectacular. I guess a bigger blade would work better but that is what I have for now being still in a prototype stage.
The head slides out from the main arm and the whole arm is stabilized by a chain with a turnbuckle. The whole thing can be quickly mounted and unmounted with just couple bolts.

The other machine built couple years ago, is a cheap version of the Samurai. It is built from a walk-behind sickle machine head driven by a hydraulic motor. It works great for small twigs but it has hard time with anything bigger that 1/2 in.

 

[Steave]

NCMau Looks good. Is the shaft left handed threads at the blade side or is that an arbor attached to the shaft. The momentum from my blade would spin the left handed thread off when I let off the hydraulic lever to stop cutting. I had to add the check valve between the two lines so the motor and the blade could coast down to a stop. I also added a set screw to the left handed nut.

Your 7 GPM flow should be plenty to run a saw. My pump has a Max 8 GPM I think. At 8 GPM it's about 4000 RPM which that's the rating on the blade. I may be off a bit on those numbers but in the ball park. The larger blade would give you more momentum and that's actually what you want due to the low torque of these high speed motors.

I've got a couple of sickle mowers laying around so quit tempting me to start building again. :laughing:That's a nice set up you have. Oh yea if I were to use a belt drive I would use the smallest width blade I could find so it could rotate as easy as possible. Not sure if it'd make much difference but every little bit of power helps.

At $80 a piece for the 16 5/16" blades I might go with something smaller in the future. 12" blades are still reasonably priced. I guess I'm going to have to break down and get a carbide blade sharpening stone or wheel. Sharp blades make a world of difference.

 

[NCMau]

NCMau Looks good. Is the shaft left handed threads at the blade side or is that an arbor attached to the shaft. The momentum from my blade would spin the left handed thread off when I let off the hydraulic lever to stop cutting. I had to add the check valve between the two lines so the motor and the blade could coast down to a stop. I also added a set screw to the left handed nut.

Your 7 GPM flow should be plenty to run a saw. My pump has a Max 8 GPM I think. At 8 GPM it's about 4000 RPM which that's the rating on the blade. I may be off a bit on those numbers but in the ball park. The larger blade would give you more momentum and that's actually what you want due to the low torque of these high speed motors.

I've got a couple of sickle mowers laying around so quit tempting me to start building again. :laughing:That's a nice set up you have. Oh yea if I were to use a belt drive I would use the smallest width blade I could find so it could rotate as easy as possible. Not sure if it'd make much difference but every little bit of power helps.

At $80 a piece for the 16 5/16" blades I might go with something smaller in the future. 12" blades are still reasonably priced. I guess I'm going to have to break down and get a carbide blade sharpening stone or wheel. Sharp blades make a world of difference.

Thanks Steave. Yes the shaft is 1 in, turned down 3/4 in on each end and LH threaded. That is the only reason I gave to a machine shop, otherwise I could have done it myself and that was my biggest expense ($80) so far as I had the other components, I like to stay with the 12 in blade but I wonder if instead of a 24 TPI, a 40 TPI would be better for this project.

I do not have a spring action on the arm, yet. I am not sure it would be totally necessary at this point. I just have to keep my mind not to go wondering and remember to feather the movements instead of dropping the bucket like a hot potato. Also. I probably want to keep the length of the arm the same. So far it seems to be a practical stable length without having miles of hoses. Anyway the project is still in the evaluation phase and if I decide to start trimming trees in the moon, things can easily change.

Also, what I am wondering if a 18-20 in lawnmower blade (with the proper safety shielding) would work. The blade would definitely increase the momentum and chop the little guys instead of being deflected by the saw blade. What you think?

BTW, I am just getting back at you. You are the one that got me going on this circular saw project. That ought to teach you to not inspire projects on to other folks.:laughing: