Firewood processor Hydraulic saw motor selection

[cwjr]

Hello, I have been watching this forum for a while now while I have been building a firewood processor.  I am looking for some help and opinions on what hydraulic saw motor to purchase.

I am using a 4 cylinder perkins diesel engine to run a commercial shearing 2 stage pump. It has a 25gpm and a 18gpm pump.   On the rear of the pump there is a flow divider to break the 18gpm down to 12 and 6. 

My plan is (please let me know if you have a better idea)  25gpm to run the saw motor and the splitter.  12gpm for the outfeed conveyor.  6gpm to run the live deck, clamp and saw feed cylinder.

All my components have come from an airport cargo loader all the valves are electric solenoid controlled.  I am an industrial electrician and I can easily through relays do the clamp, saw on, and saw feed with one move of the joystick,  I am going to make the saw shut off as soon as it is through its cut to allow the 25gpm free for the splitter.

My struggle is selecting the correct hydraulic motor for the saw,  I am hoping to get approx 8000 rpm so I can use the appropriate sprocket to get 8000 feet per minute of chain speed with the Oregon 404 chain (chart in the Oregon timber harvesting book)

What is anyones opinion on gear motor vs piston.  I am leaning towards the sunfab scm17

pictures to follow soon

[North River Energy]

Down the road you might wish you had dedicated pumps for both the saw and splitter, rather than sharing one pump between the two.

[TeaW]

I have a Danzco cut off saw on my processer it runs off a 20 gpm pto pump that also runs the splitter. The saw has to be retracted for the chain to stop .The chain speed is about 3500 feet per second, I would like a bit more speed but It gets the job done.

[blackfoot griz]

Hello, I have been watching this forum for a while now while I have been building a firewood processor.  I am looking for some help and opinions on what hydraulic saw motor to purchase.

I am using a 4 cylinder perkins diesel engine to run a commercial shearing 2 stage pump. It has a 25gpm and a 18gpm pump.   On the rear of the pump there is a flow divider to break the 18gpm down to 12 and 6. 

My plan is (please let me know if you have a better idea)  25gpm to run the saw motor and the splitter.  12gpm for the outfeed conveyor.  6gpm to run the live deck, clamp and saw feed cylinder.

All my components have come from an airport cargo loader all the valves are electric solenoid controlled.  I am an industrial electrician and I can easily through relays do the clamp, saw on, and saw feed with one move of the joystick,  I am going to make the saw shut off as soon as it is through its cut to allow the 25gpm free for the splitter.

My struggle is selecting the correct hydraulic motor for the saw,  I am hoping to get approx 8000 rpm so I can use the appropriate sprocket to get 8000 feet per minute of chain speed with the Oregon 404 chain (chart in the Oregon timber harvesting book)

What is anyones opinion on gear motor vs piston.  I am leaning towards the sunfab scm17

pictures to follow soon

Do you know  the PSI of the pumps?

What size and length cylinder and are you going to use for the splitter?

IMO, it is a balance game on determining the timing.  I built one and really struggled with the hydros and trying to determine the timing. Once you make a cut and start the splitting cycle, you can advance the log and start the next cut while the cylinder is retracting.  My saw/clamp/saw cylinder runs off one pump that is 15 GMP and 1500 psi.  With this combo, the saw typically cuts a block faster than the splitter can make a complete cycle. This is a 4" X 24" cylinder with about 18 GPM @ 3000psi. 

Do you have any pictures you can post to show us?

[cwjr]

my splitter (already built) has  a 6" by 30" cylinder with a 4 inch rod.  I split a lot of wood for outdoor furnaces for my own use.

My calculations based on my 25 gpm system at 2500 psi it should be about a 11 second cycle time

There is a way I can do a regenerative extend circuit to use during the easy splits.  It works by porting rod side oil back to the piston side while extending,  this will cause the cylinder to act like a 4" (the rod displacement) making it weaker but a lot faster.  If I find my 11 second cycle too slow I will go this route.

Teaw,  would you recommend the danzo systems?  seems a lot simpler to buy a prebuilt saw portion but from what I have read they use gear motors,  most of the large harvesting equipment all use piston motors that I have seen. 

my garage is fairly small,  I am going to pull my partially finished project out and take some pics of it this weekend

[TeaW]

I am happy with the Danzco connect and cut saw, the control manifold lets you adjust the saw feed speed and the feed modulating valve (pressure relief) . You don't have to feather the control valve , just engage and the modulating valve keeps it from sticking. Their bar oil pump is unique and when set for the job trouble free.
You are right about harvesting equipment but most of the commercial firewood processor's I have seen us gear motors.
Check out their web site ,there is a part about processor's that is worth reading.

[thecfarm]

cwjr,welcome to the forum. Here's the picture help.
https://forestryforum.com/board/index.php/topic,61788.0.html

Looks like a lot but,it's very easy after you do it a few times. Jeff likes the pictures in your gallery so the picture will always be here.

[cwjr]

a few pictures,  a coat of paint will be put on before the hydraulics,  I sill have the live deck to build, saw, clamp, outfeed conveyor.  this is 2 months of occasional evenings and Saturdays.



  

  

  

  

  

  

  

  

  

 

[treeslayer2003]

what did you use for a drag chain?

[cwjr]

the drag chain is from the airport cargo loader that most of my parts came from, its a 120 pitch chain with plates welded cross ways on each link.  I strongly suggest to anyone building a processor from scratch to purchase a cargo loader because they are full of sprockets, drive motors, cylinders, electric controlled valves, 4 cyl perkins with multistage pump, lots of heavy steel, and joysticks.  I bought the whole machine for $750 and scrapped the parts I didn't need and got $500 back

[Randy88]

Nice job so far, keep the photo's coming. 

[cp881]

When we built our processor we bought the saw motor, sprocket, bar and chain from CRD metalwork 

  

[cwjr]

cp881  are you happy with the gear motor you bought from crd?  Do you have any idea what your motor's rpm is?  From what I have read the piston motors can run lot faster, close to 10 000 rpm but they are way more expensive.   If I can get by with a cheaper gear motor that is for sure the route I will go. 
thanks,
Chuck

[cp881]

I don't know the rpm but I'm happy with the way it cuts
Its the same motor they use on their machines , also my father has a friend that use to manufacture processors and he used the same motor

[cwjr]

Has anyone attempted to use a spring to feed the saw down on a firewood processor?   I have a hydraulic cylinder with a coil spring wrapped around the rod.  I know it will gradually decrease in force the lower the saw gets but figured it might be simpler to dump the oil out of the cylinder instead to tieing up another stage of my pump to feed it.  Just curious if anyone has thoughts on this. Thank you

[blackfoot griz]

Has anyone attempted to use a spring to feed the saw down on a firewood processor?   I have a hydraulic cylinder with a coil spring wrapped around the rod.  I know it will gradually decrease in force the lower the saw gets but figured it might be simpler to dump the oil out of the cylinder instead to tieing up another stage of my pump to feed it.  Just curious if anyone has thoughts on this. Thank you

Have you considered putting a flow control on the line that runs to your saw cylinder? 

[cwjr]

yes I have considered a flow control in the saw cylinder.  I was thinking about using a flow control to control the rate that the saw cylinder dumps to the tank but use a spring for the saw force.  This way I should be able to make it go quick till it touches the wood then it will just use the spring pressure to cut. 

Blackfoot, what did you use for a saw motor on your processor?  I am going to be running 25gpm for the saw motor circuit.

[GF]

Not sure how well the spring would work to feed the bar.  I would almost guess bar maybe doing a lot of bouncing during the cut, also its possible it could bite in hard and stall during the cut. I have a hydraulic pressure gauge on the console feeding my saw motor to monitor the pressure, the pressure for cutting softwood is different that cutting hardwood on the same diameter logs.  You may want to look at using an adjustable flow divider on the 25GPM circuit using 20 for the motor and 5 for the cylinder, you could have the pressure relief set at 3000 PSI on the 20 and 1000 or less on the cylinder circuit.

I have three seperate pumps on my build creating 3 seperate circuits.  28GPM two stage for the splitter, 22GPM on the motors (saw, live deck, and infeed deck), and a 7GPM for the cylinders (saw bar, six way splitter, log clamp).  The 28GPM auto cycle circuit relief is set to 3000 PSI, the 22GPM relief is set at 2000 PSI, and the 7GPM relief is set at 1000PSI.   All this is powered by a 40hp Kohler.   When the auto split cycle runs it usually runs about 750 PSI on splits, when it hits the six way it goes up to around 1200, or 2000 for just a little bit until it begins the split and then goes back down to around 750, while this is going on I am feeding a log, clamping, and already cutting, about the time the split cycle is complete, my next cut is complete also ready to be split.

I elected for three seperate pumps instead of flow dividers during the time. My opinion would be you need to control the speed of the cut.

GF

[blackfoot griz]

I also used and bought mine from CRD--it works fine and obviously has been proven.  The unusual thing is that they are a directional motor (most hydro motors are reversible). I had to redo my motor mount because of this. They can be ordered cw or ccw looking at the shaft.  I have the specs at work as I found an additional source for the motor.

I would suggest that a flow control will work fine for this application. For starters, you really don't need a big diameter cylinder for the saw motor(the smaller ID the faster). Secondly, the flow rate=speed. On mine, I can make it go anywhere from way too fast to stopping the saw cylinder during the cut.  The chain keeps spinning even though I have stop the saw cylinder which makes it easier to resume a cut.

Not knocking your spring idea, and if you go for it, I will be anxious to see how it works, but, with so many commercial and home made processors out there I would think somebody would have travelled down that path already. I have not seen it though.

If you are running 25 GPM to this motor, it will be plenty fast IMO. You likely will be waiting for your splitter to return home. I am only running 15 GPM @ 1500 PSI and this is divided up to the saw motor, clamp and saw cylinder more often than not, I am waiting on the splitter to return home.

NOTE--I was typing my response when GF added his...He's the man with stuff.  His processor is a work of art.  Mine is a whole lot uglier-but-functional!


 

[dave_dj1]

Not sure how well the spring would work to feed the bar.  I would almost guess bar maybe doing a lot of bouncing during the cut, also its possible it could bite in hard and stall during the cut. I have a hydraulic pressure gauge on the console feeding my saw motor to monitor the pressure, the pressure for cutting softwood is different that cutting hardwood on the same diameter logs.  You may want to look at using an adjustable flow divider on the 25GPM circuit using 20 for the motor and 5 for the cylinder, you could have the pressure relief set at 3000 PSI on the 20 and 1000 or less on the cylinder circuit.

I have three seperate pumps on my build creating 3 seperate circuits.  28GPM two stage for the splitter, 22GPM on the motors (saw, live deck, and infeed deck), and a 7GPM for the cylinders (saw bar, six way splitter, log clamp).  The 28GPM auto cycle circuit relief is set to 3000 PSI, the 22GPM relief is set at 2000 PSI, and the 7GPM relief is set at 1000PSI.   All this is powered by a 40hp Kohler.   When the auto split cycle runs it usually runs about 750 PSI on splits, when it hits the six way it goes up to around 1200, or 2000 for just a little bit until it begins the split and then goes back down to around 750, while this is going on I am feeding a log, clamping, and already cutting, about the time the split cycle is complete, my next cut is complete also ready to be split.

I elected for three seperate pumps instead of flow dividers during the time. My opinion would be you need to control the speed of the cut.

GF

I would think you would be better off to use a spring for the return, a 3 way valve, this would free up hydraulics while the saw is retracting.
Just a thought.

[dave_dj1]

Has anyone attempted to use a spring to feed the saw down on a firewood processor?   I have a hydraulic cylinder with a coil spring wrapped around the rod.  I know it will gradually decrease in force the lower the saw gets but figured it might be simpler to dump the oil out of the cylinder instead to tieing up another stage of my pump to feed it.  Just curious if anyone has thoughts on this. Thank you

Sorry I quoted the wrong post on my above comment. This is the one I was after.
dave

[cwjr]

thank you very much for the opinions!
  I have admired GF's processor,  the paint job is absolutely amazing!  GF  did you use a saw motor from CRD also? 

the part that is messing me up is most hydraulic saws use a bent axis piston motor to get super high rpms, but the crd ones appear to be a gear motor. I want to know how happy people are with them.  I do not think it is worth buying a expensive piston motor that will cut faster if I am going to be waiting on my splitter to return anyways. 

I think I am going to build it using my cylinder with the spring wrapped around it and if it gets too much bounce or gets crazy on me I will just take the spring off the cylinder and rework the hydraulics. 

[GF]

I agree if you plan on using a spring use it on the return, but you also have to think about if you hit something in the log like barb wire, it would be nice to have hydraulics to back the bar out.

I did not get my saw motor from CRD, I was able to get the number off the CRD motor and cross it over and purchased my motor through Surplus Center, its almost the same motor but I think it was a little less RPM.  RPM is nice but torque is also very important.

[cwjr]

GF, do you happen to know offhand what saw motor you bought from surplus center?   they have lots of them with aluminum housings and a 9/16 shaft, I think I am looking at the wrong ones because they are really low hp according to my math.
any help would be greatly appreciated

[cwjr]

A few pictures before I start painting it.  Still trying to find a decent price on a saw motor and then I will add the saw assembly after painting.   Processor is built completely out of scrap metal.   The amount of grinding involved is ridiculous!