Has anyone built a hydraulic chainsaw?

[muddstopper]

I'll probably experiment with the Stanley just to see what happens. If that doesn't work I may experiment with building one, with a motor laying around. How does the bar oil on hydraulic saws? I remembered today that a buddy has a Husky pro saw that a tree fell on. It's unsuitable for hand held use because the case is busted, but I believe it still runs. If he'll sell it cheap that's a likely candidate. I also thought about powering the saw with a Honda GX motor off a pressure washer I bought at an auction with a frozen pump. I think it's 5 or 5.5 hp so in theory it should provide similar power as my 372 XP.

If you look at the pic In my first post, you will see a small brass fitting in the mounting plate. The fitting matches up with the oil hole in the bar, Some folks just gravity feed the oil from a separate oil tank. Other us a automotive electric fuel pump. Oil is controlled by a needle valve in the line. If electric fuel pump is used, a small micro switch is usually mounted on the control valve lever so that the electric pump is only running when the saw motor is running,

 

[Skwerl711]

This is all great stuff. I'm really diggin' the explanations and the math involved.

My question would be At what point do you switch from 3/8 chain to .404. I understand the difference in speed but the deciding factor should be torque applied to the chain. Am I right. It looks like you could double the torque of a gas saw with a Hyd Saw. How much torque can you apply to a 3/8 chain before it becomes unsafe? Is there some other factor i.e. chain design, raker height, or something else that acts as a safety.

I am far from building one. But the idea is intriguing.

 

[airbiscuit]

If you had space, you could always run a roller chain from a big sprocket on the hydraulic motor to a small sprocket on a jack shaft o-----0. The other end of the jack shaft would power your saw chain.

I grew up with high torque low chain speed chainsaws. When I got a high hp - high chain speed chainsaw, I was in heaven.

 

[muddstopper]

View attachment 503432 I hope this is the right doc from Oregon. If not you can search for oregon harvester technical support.
There is a certain level of safety one has to follow to prevent injusty. chainshot being one of them. running the chain to fast with to much power can result in chain breakage and flying chain links I would have to go back and reread the file, but I believe the .404 chain is rated for around 80hp

 

[4570Man]

Your link doesn't work. I'd planned on running 3/8 chain on a 28" bar because that's the same chain as my 372 XP uses with the longer bar. That means my timberline sharper still works and I won't have another length of chain to keep up with. I won't have the power some of the bigger hand held saws have so I should be alright.

 

[muddstopper]

The link was a doc i saved to my computer, not a link to a webpage. It works as posted, but the first couple of pages are just garbbley gook. I tried to find the original web page but couldnt. This is the closest I found. https://www.oregonproducts.com/pro/pdf/maintenance_manual/ms_05.pdf.

 

[4570Man]

I've about decided a hydraulic saw isn't going to work with the money I want to spend. How about an electric saw? How would a 3 hp motor compare to my 5.5 hp gas saw? On paper not good, but I'm thinking 5.5 hp is a perfect conditions lab test and 3 hp is a continuous duty rating with a brief hp increase of quiet a bit.

 

[David_Kb7uns]

Lots of info for designing a harvester saw system
http://www.oregonproducts.com/pdfs/Harvester_HandbookA106976af.pdf

Chains and bars
http://www.oregonproducts.com/pdfs/OREGON_HarvesterCatalog_vAE.pdf

Maintaining cutting system
OREGON Maintenance and Safety Manual

If you ever get a chance to go to the Oregon logging show in Eugene Oregon, Oregon/Blount inc have reps there along with all the new harvesting equipment

Read through the manuals and they detail calculating rpms, sprocket count and chain fpm speed, lubrication requirements etc.

Way back when the mill down the hill from here had a big deck saw to cut the crooked ends before going into the barker and the bar was around 5 or 6 feet long and used .404 chain with a 3 phase industrial motor, but that was back when the barker could handle 43 inch logs, now not much over 30 some inches is the max size for peeler logs.


David

 

[Bernstorm]

View attachment 502734
The saw in the pic is one I built for my processor build. This motor is a 1.3cuin axlepiston type. The bar is 24in with a .404 full comp, full chisel chain. This saw is also untested as I developed health problems and have yet to finish my processor build.

First off, I would forget trying to figure rpms as a measure of cutting speed. Chain speed is figured in feet per minute or sometimes feet per second. chains speed can be varied by drive sprocket selection. A larger sprocket will produce faster chain speed. The trick is to produce enough torque to pull the chain at the desired speed. When building my saw, I choose a husky 3120 gas powered saw to try and match. Numbers arent in front of me, but I took the hp, torque, and chains speed to try and come up with a hyd motor combination that would match the 3120 chainsaw. Here is a link to help. Chainsaw Comparisons and Facts from Procut Portable Chainsaw Mills.

A lot of people have used this motor, .7 cu in PARKER MGG2-BA1A3 HYD MOTOR to build their saws. Some have tried the .58cuin motor and not been satisfied with the results. I cant say whether the complains are from poor motor selection or poor hyd design. I will say that even the .70 motor in the link will never be able to match a 3120 chainsaw when it comes to torque. Even tho those little motors are rated for 5000 rpms, you cant put the pressure to them to get the torque numbers you need.

Gear motors are usually limited as to rpm speed, even if you can throw more pressure at them to get the torque needed. You can compensate some on the speed by using a larger sprocket, but then you sacrafice torque losses. I chose the axial piston motor because it will produce more torque and higher rpms than a standard gear motor. This particular motor is a Poclain model M1. It is 1.3 cuin and can produce 4641ftlbs of torque. It does take a lot more oil flow and pressure, which means bigger hyd pumps and engine hp, but it all depends on how badass a saw you want to build. A 3120 chainsaw has 8.9hp, the axial piston motor will put out 25hp at 2000psi.

I just saw this old post. Very good as I am designing a hydraulic chainsaw to go on my mini-ex, near the bucket using the thumb hydraulic. The purpose would be to cut higher limbs in trails and maybe weeds under fences (if this doesn’t work, I will make a “hydraulic super weed wacker”.

 

[Mack84]

Hi all I know I've been trying to find more info on small logging cut off saws myself with not much luck so decided yesterday to start building my own, the saw unit attaches over the thumb, I'm using a hyd drive pole saw I got on market place for $300 and will use a small ram and sequence valve so saw will not drop until up to full speed. As I only started this yesterday, still have to plate out the rest of it and start fabricating mounts and guards etc. Hopefully have more pics for you in the next few days as I progress. I'm fitting to my 1.5 ton excavator but no reason similar style couldn't be adapted to Fel with forks and crowd arm or a 4 in one bucket.
Cheers

 

[Mack84]

Hi everyone, I made a little more progress today, it's getting closer , once guards and hydraulics are done I'll make a extended linkage for the thumb to get it at the right angle and also fabricate a whole new beak for it similar to a hardwood fork grab

 

[VroomVroom]

I worked on a 690 john deere excavator with a fab tech forestry harvesting head in it to cut, limb, and then cut to length for pulp. Out of all the functions on the machine such as opening and closing the knives, rolling the tree through the head, spinning the head and even the boom and track functions on the machine, believe it or not but that saw seemed to take the most power. Sawing the tree off to length seemed to bog the machine down more than any other hydraulic function.

 

[Mack84]

Hi everyone, I gave the saw grab a quick trial run, just gotta set limits and flows then start fabrication of guards, and extend alter the log forks about so saw handle and hoses clear the ground when say is in rest position, video is to large to post so here is my link to the first trial run on YouTube,

Cheers
Mack84

 

[Mack84]

 

[VroomVroom]

Seems like it works well. It does seem to take a lot of power doesn’t it. The machine I worked on also had a tiny piston putting tension on the bar to keep the chain tight.

 

[Smokeydog]

20” bar limbsaw.
Surplus Center Parker motor.
Adjustable chain oiler.

Controlling bar speed and or pressure a concern.

 

[Mack84]

View attachment 752439
View attachment 752441
View attachment 752442
20” bar limbsaw.
Surplus Center Parker motor.
Adjustable chain oiler.

Controlling bar speed and or pressure a concern.

Smokeydog, I have put these flow control valves on that ram of mine to adjust drop rate of cylinder, you could install the same or similar to control flow to saw if you needed

 

[Mack84]

It's not too bad considering its only on a 1.5 ton excavator. Hopefully the last trip to the hydraulic shop today to get a inline check valve then I can finish the rest of it off and give you all a finished product next week.

 

[Smokeydog]

The top (red) section is simply hinged so weight and gravity controls the downward force on the bar.

Forward, reverse saw gets out of a bind.

Currently 9/16”, 0.325, 0.063 on 7 spur drive gear. Gathering some broaches to use 3/8 chain drive rims. Hard to find drives to fit small hydraulic motors. If I recall correctly at 12gpm, 2500psi, 5,000rpm makes about 15 hp.

 

[airbiscuit]

Here is Smokeydog's hydraulic chainsaw build it thread. Pretty good read.

Hydraulic limb saw project.