Firewood processor help

[jonix]

If you were reaching 5000psi with the other cylinder, and now you just reach 1000 psi with the same log, I would say that something was causing all that excessive pressure in the cylinder. I don't believe that the old cylinder could not split that wood. I have a 80 mm bore cylinder in my Log splitter that had already split logs even larger than the one you had, with something like 1500/2000 psi.

but do you have an 8 splitting wegde at it?

 

[ptsg]

but do you have an 8 splitting wegde at it?

No, but I've looking to your wedge, and the vertical one, goes in first than the others, so I though that could help a bit.

 

[jonix]

well, i have been working with a single wedge splitter for years..and with 10 TON of force i was able to split almost anything..i only have about 2 M3 of pieces that i couldn´t split in all this years..and most of those were "rancas" (sorry, think google will not tell me the translation for "rancas" of a 20 ton old eucalyptus tree..it helps a bit, but think only a bit..

i was able to split 800, or even 900 mm diametters with single wedge..no big problems..

there is big diference with 8 wedge..and if you going on 12, or 16 splitting wedges on eucalyptus, then you will need real big splitting power..and a very good wedge design..

 

[muddstopper]

Heres a online calculator to help you with the math.Surplus Center your numbers appear close. Another way you can increase your chain seed is by going to a 13tooth sprocket. Since you are currently using a 12tooth sprocket, you should only need to change the sprocket and not the bar. If you go to a even larger sprocket size, you will also have to change out your saw bar to a wider one.

 

[J_J]

If you change rpm, you also change torque.

 

[muddstopper]

If you change rpm, you also change torque.

good point, doubling the size of the motor with same oil flow and pressure will slow the motor down to half speed, but increase torque. Adding pullies to increase speed will reduce torque and then you have the extra reduction in efficiency caused by using pullies and belts. I suspect his saw will not be any better,, maybe worse, than it was before the motor swap.

Something else isnt adding up here also. His numbers for oil flow and pressures keeps changing. I'm finding it hard to keep up with what he actually is working with.

 

[jonix]

I was trying us to think beyond my pressures and flows and my machine in last post..

If you read my first post, my numbers always were the same..i only mess around a litlle bit along this thread because i confused brithish gallons with american gallons, so the flows rates i have been mencioning may have had some variations..

I swap the F11-005 for the F11-010 because that was the only choice that the company give to me..i canｴt spend any more money for now..and my plans in near future is to swap the 8 GPM (or so, is not easy to convert metric to american at each frase or word) pump i have for saw circuit, for a 20 GPM one..

my old f11-005 has a limit of 14 GPM flow..i was not going any were with that, will need high pressure to get torque..the new F11-010 can work with 25 GMP, and i think is better for me work with lower pressure, and more oil flow to get the result..THIS IS WHY I SWAP MY SAW MOTORS at no charge..

As soon i can get a 20 GPM pump for saw, i will turn chain speed to around 6500 feet/minute (with no pulleys), 21 HP and 165 lbs in of torque, with 24 HP of power suplly and 1850 PSI of pump pressure..i think i am not thinking so wrong as you say..

..if i get a gear motor with 2 cu in as you said, i will have to pack and store the F11-005, and i will not have a F11-010 "for free" (this parker motor is very very expensive!)..and since my pump for saw circuit is a 8 GPM pump, i will have to buy another pump too, because i donｴt think i will go anywere with this configuration too..tell me, am i wrong? I'm trying to save some euros..

Donｴt forget that I already pay the all hydraulic circuit for months, and was not me who draw it..if it was today I would never do it this way..

so..i am still interested in your opinion about my theory: for the same amount of power suplly, we will have allways the same results at torque and chain speed, if we use diferent displacement hydraulic saw motors?

 

[jonix]

If you change rpm, you also change torque.

Torque= [ Displacement (cm3/rev) X differencial pressure (BAR) X mechanical efficiency (~85-90%) ] divided by 63 constant for N.m

Think that is wrong..if you change rpm, you are not changing torque, you are changing HP (Power)

 

[jonix]

good point, doubling the size of the motor with same oil flow and pressure (pressure will not slow down the motor)will slow the motor down to half speed, but increase torque. Adding pullies to increase speed will reduce torque and then you have the extra reduction in efficiency caused by using pullies and belts. I suspect his saw will not be any better,, maybe worse, than it was before the motor swap.

YES, THAT IS CORRECT

But..was not that "my theory" talking about? and you are saying me to change to a 2 cu inch one? "good point"?!?!?

do you know what will happen if i "double" 6 or 7 times my motor size?!?!?

 

[muddstopper]

YES, THAT IS CORRECT

But..was not that "my theory" talking about? and you are saying me to change to a 2 cu inch one? "good point"?!?!?

do you know what will happen if i "double" 6 or 7 times my motor size?!?!?

I didnot say lower pressure will slow down motor. what I said is that using the same oil flow and doubling the size of the motor will slow down motor speed. Using pullies to get the chain speed back up will negate any torque or power (at saw chain). My other post stated that you can swap out your sprocket from 12 tooth to 13 tooth and increase chain, but not enough of a difference to be worth the change. Just something to consider for future upgrades.

I suggested a 2 cuin gear motor because you can run it with a lot of flow and low pressure to get your chain speed and power in the range it needs to be. Everything is a swap off. More flow requires more engine hp, lower pressure, lower hp, High pressure, high hp. Your F 11 motors are small cuin, high rpm, low flow, high pressure motors. cutting down the hyd pressure without increaseing flow has already decreaded the cutting power to your saw. You will get the power back by using a larger motor, but then you lose cutting speed. Your running around in circles amking changes without improving the situation.

"Think that is wrong..if you change rpm, you are not changing torque, you are changing HP (Power)

You are not taking into consideration that torque at the motor is not torque to the saw sprocket. In between the sprocket and the motor, you have added a 2:1 pulley ratio to increase speed. Yes you will still have torque at the motor, but torque at the sprocket will be cut in half.
If you have 25gpm available to run the f11 motor, then you should still have the same to run a gear motor. Just use a smaller cuin gear motor, (less than 2 cuin) to power your saw.
1.3cuin gear motor using 25gpm will give you a rpm of 4442. Now before you say the gear motor isnt meant to run that fast, its not, but it will as long as pressures are kept low., and it a common practice for processor manufacturers to over flow their oil to increase chain speed. Using a PSI of 1200 will give you about 20ftlbs of torque and 17hp at the saw sprocket. Using a 13tooth sprocket will give you a chain speed of 3888 ftmin using a .404 chain. Not quite what a 3120 husky chainsaw runs, but twice the hp. File the rakers down on the chain and let the hp pull the chain thru the wood. You can go up to a 14 tooth sprocket ( you would also have to change out your saw bar),and that would increase chain speed to 4180ftmin. Going up 6-7 times motor size wont benefit you unless you have a way to get more oil flow to the motor, If all you have is 25gpm, going to a bigger motor is only going to make matters worse. Another motor choice would be a High Speed Axials Pistons Motors. thesw are sort of a compromise between a gear motor and the bent axis F 11 motors. They are made to run around 4600 rpms and create power at much lower pressures than the f 11, yet will handle more PSI than a gear motor.

Edit to add,
What size, gpms, are your twin pumps for the splitter. Is it possible that you can combine their flows with your saw circuit to increase oil flow. Probably not as you would have to much going own with the different pressure settings.