Firewood Processor bar pressure

[mjeselskis]

Does anyone know how much down pressure the bar should have on a firewood processor? I thought I read 50lbs on the center of the bar, but that seems really light and I'm having a hard time finding a relief valve that will let me get the pressure low enough. I'd need around 2-300 psi going to the saw cylinder to get 50lbs of force at the center of the bar.

[DDW_OR]

here is a link to the Multitek 1610EZ i was having trouble with

https://forestryforum.com/board/index.php/topic,93354.0/all.html#lastPost


  


 

[ButchC]

Hi, I am new on the site but have a processor that I built several years ago mostly out of my scrap pile. Unless you have much overkill on your saw motor HP the force needed is going to vary with the wood and condition of the chain. Watching the various machines run at shows over the years it seems that  the ones that control flow, not pressure work best in the cut however they are slower approaching the log unless the drive will allow for extremely fast cutting. My prime mover is only 20HP so the sawing speed is limited by that factor. What I did is use air to lift and lower the saw, it solves most of the problems of hydraulics doing same. The saw drops fast and raises fast but in the cut the motion slows according to how much pressure I have on the regulator. AT the top of the cut it drops fast, in the middle it slows down and at the bottom it speeds back up,works pretty well in my application. All the parts and pieces for air operation such as cylinders, regulators and valves are much cheaper than hydraulics to boot. Not sure how far you are along but something to consider. You can see it in action on my You Tube channel, look at "Firewood processor operation #2"

[NWP]

I think on my Blockbuster it's about 75 psi. The gauge hasn't worked for a long time and it it needs adjustment I just go until it works right.

[hedgerow]

 I run flow control and a relief valve on my saw on my homemade processor. I used surplus center parts relief 9-6135-50-L flow valve 9-7960-4. It all works pretty good the flow control does slow the approach to the log. If you  have not bought any of the parts to move the saw bar I would consider using air to move the saw bar. I do think you will have better control over the pressure on the saw. I thought about using air when I build mine but I didn't want to install a air compressor when I already had hyd oil for the rest of the machine. I use the same pump that runs my log advance to run the saw bar up and down. 

[OH logger]

I run flow control and a relief valve on my saw on my homemade processor. I used surplus center parts relief 9-6135-50-L flow valve 9-7960-4. It all works pretty good the flow control does slow the approach to the log. If you  have not bought any of the parts to move the saw bar I would consider using air to move the saw bar. I do think you will have better control over the pressure on the saw. I thought about using air when I build mine but I didn't want to install a air compressor when I already had hyd oil for the rest of the machine. I use the same pump that runs my log advance to run the saw bar up and down. 

what does the air compressor run on the blockbusters NWP? I ve always wondered why they use it and no one else does that ive found

[mjeselskis]

Thanks for the advice. I'm pretty far along the hydraulic route since I already have the valves, lines, sequence valve, and cylinder attached... I think I can make than relief valve from surplus center work if I move the cylinder attachment point closer to the pivot point to reduce the leverage.

[NWP]

what does the air compressor run on the blockbusters NWP? I ve always wondered why they use it and no one else does that ive found

It uses air to return the splitter cylinder, log stop, saw cylinder, and the tray tilt cylinder.  All of these extend on hydraulic pressure and return on air. 

[Hilltop366]

I have wondered if a compression spring in a link from the cylinder to the saw would let you run a fast cycle time without putting too much pressure on the saw bar.

[hedgerow]

Thanks for the advice. I'm pretty far along the hydraulic route since I already have the valves, lines, sequence valve, and cylinder attached... I think I can make than relief valve from surplus center work if I move the cylinder attachment point closer to the pivot point to reduce the leverage.

You will find that pivot point on that cylinder will make a big differance on how your saw cuts. I had forgot about that until you mention it. I moved mind a couple times to get it right. I think you will find you will have to run the flow control also. I started with the relief only first and it worked ok  but the flow control helped a lot. What I really need is more HP driving my Hyd system my 40 HP kohler isn't really enough motor . I cut mostly locust and hedge and am running a 36 inch bar with 404 chain and its a load.

[lopet]

The idea of using air pressure is to speed up certain functions. You can start your next cut while the splitter ram returns on air, or you can start splitting as the saw returns on air and using all hydraulic pressure and flow for splitting.
Yes, blockbuster is the only one who runs a compressor as far as i know.

[OH logger]

it sounds like a good and simple idea huh?

[blackfoot griz]

Mike,
Thought I'd chime in and just throw this out there. Rather than worry about the pressure on the bar, you might simply incorporate a flow control on your saw cylinder circuit that enables you to control the speed at which the cylinder extends. On the processor I built (guy that bought my place got my processor in the deal), I have no idea what pressure was on the bar, but, with the flow control, I could speed up, slow down or stop the cut with ease. On mine, if the cut was too fast, it would back up and bog down or kill the engine. Have any updated pics?   :D

[DDW_OR]

.......Rather than worry about the pressure on the bar, you might simply incorporate a flow control on your saw cylinder circuit that enables you to control the speed at which the cylinder extends.............

  
 

[mjeselskis]

Mike,
Thought I'd chime in and just throw this out there. Rather than worry about the pressure on the bar, you might simply incorporate a flow control on your saw cylinder circuit that enables you to control the speed at which the cylinder extends. On the processor I built (guy that bought my place got my processor in the deal), I have no idea what pressure was on the bar, but, with the flow control, I could speed up, slow down or stop the cut with ease. On mine, if the cut was too fast, it would back up and bog down or kill the engine. Have any updated pics?   :D

That was my initial thought and I do have a needle valve type flow control that I bought for that purpose. Then I thought the flow control would unnecessarily slow down the saw when not in the cut.

No new pictures yet, still working on getting it plumbed up so not much to show.