iDRY Vacuum Kilns

Sponsors:

4" vs 4.5" Hydraulic Splitting Cylinder

Started by Rougespear, October 07, 2019, 09:32:29 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Rougespear

I'm in the stage of paper planning my firewood processor build.  I am wondering on people's thoughts of a 4" vs 4.5" splitting ram through 4 and 6-way wedges?  With the 4" I can get the cycle time down a bit running a 30gpm hyd pump but I sacrifice power.  I NEVER split crotch wood... almost always relatively straight grained birch, fir, larch, pine and cedar that arrives by the truck load.  

For comparison, my only experience is with my 3.5" 12-ton 2-way splitter I currently use.  It does well up past 20" rounds of fir... but I somehow feel it wouldn't handle a 6-way wedge at all.

Thanks!
Custom built Cook's-style hydraulic bandmill.

sawguy21

You are correct about  the smaller ram having more speed but less power but I'm thinking you will want more than 4.5" with a six way. They need a lot of power which may bend the shaft. I modified a 30 ton portable splitter, cranked up the pressure relief valve and that was the result. The head which my boss fabbed was a work of art though. :D
old age and treachery will always overcome youth and enthusiasm

Al_Smith

Much ado about cycle time on home builts .I've got a home built with a 5" cylinder that will obviously split anything and it's fast enough I don't run the engine at full throttle,don't need to .
Now were it two strapping 20 year olds feeding it cycle time might be a big deal but an old  70 plus year old it just wears you out to try and keep up with the machine .That said were it myself I'd opt for the 4.5" . 

Al_Smith

Now another thing about bending cylinder rods .Some designs they just anchored the cylinder on the back side which is more prone to bend the rod than anchoring the front and back and having the slide built as such it won't  rise up or allow side movement .Mine BTW is anchored with four  1" grade 8 bolts and a stop block .So what I'm saying is it's all in the design IMO .Build it battle ship strong it will last forever .

Hilltop366

Lots of on-line calculators available, by using a couple of these https://www.baumhydraulics.com/Home/Page/speccalculators you can get a idea of the differences between the two sizes.

If I did it right and used 2500 psi for pump pressure you would be looking at around 8000 lbs more pressure with the 4.5" and 1.5 more seconds in cycle time (extend and retract) not counting time spent at the high pressure/low speed stage of the pump. 

That is assuming you are using a two stage pump.


GAB

On the return cycle you are not trying to do any hard work.  So if you could find a say 5" cylinder with a 4" rod you would pump a lot less oil for retraction of the piston and it would be less apt to bend. i.e. the best of both worlds.
GAB
W-M LT40HDD34, SLR, JD 420, JD 950w/loader and Woods backhoe, V3507 Fransguard winch, Cordwood Saw, 18' flat bed trailer, and other toys.

Rougespear

Speed is an issue in this case as the splitter has to cycle at a speed suited to the cutoff saw.  I think I'll grab the 4.5" for now and build the splitter's push block "battleship strong" haha.

I will be using a 30gpm single stage pump to run the splitter and hydraulic saw.

Thanks for the input
Custom built Cook's-style hydraulic bandmill.

doc henderson

I have a 5 inch cylinder, with a 2 inch rod.  32 inch long cylinder.  a 18 hp motor with  a 28 gpm pump 2 stage.  I would want the most power if you are going to do a multi splitting wedge.  no fun spending time getting a 6 way unclogged. sounds like mostly soft woods.  the retraction time is not bad with a detent valve.  if you are using this as a business, I would tend to overbuild, especially if your customers and family depend on it.  If you are using a power beyond plug, it is my understanding that both operations will not be happening at the same time.  so the saw would occur and then the splitting.  At 30 gpm, cycle time should be ok.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

Rougespear

When designing to split 20" rounds, how close to the center of that (10") is a good place to have the splitting ram push?  Or in other words: how high off the I-beam is the cylinder's centerline?
Custom built Cook's-style hydraulic bandmill.

barbender

A 4.5" cylinder should have a pretty fast cycle time with a 30gpm single stage, and a lot of power! 
Too many irons in the fire

doc henderson

so my 5 inch cylinder centers are 5 inches up off the H beam slide surface.  it leaves 2 inches under the external cylinder.  I used to have a 10 inch tall pusher and this pushed on the center of this.  my splitting wedge is 18 inches tall and my BIL was splitting a gnarly 30 inch log and it pitched back over the pusher and bent the top slightly.  all my pusher parts are 3/4 inch plate.  I straitened this and added more plate to the pusher with reinforcement, making it 16 inches tall.  I have had no issues having the rod attach  at 5 inches, and pushing up to 32 inch logs.  with a 16 inch pusher and an 18 inch wedge.



 



 


 


 


 

I used a 32 inch long cylinder, and use stops to make it a shorter cycle time for my goal of 16 inch firewood.  the 10 inches of stops makes it a 22 inch opening for odds and ends, shooting for my target length.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

doc henderson

I made an 8 way wedge that fits in front of my 18 inch single wedge, but do not use it often as I am splitting hardwood such as mulberry, elm, oak.  any branch points ect. can really jam it up.  As you prob. know, each component will have to tolerate the pressure and force generated by your machine, and the occasional whoops when a split pushes the whole thing sideways.  I like the 2 stage pump as it is slower at the highest pressure, giving you a chance to "Abort" if needed.  In a huge log, I will back up some part way into the split to let the log center itself, so I do not torque anything.  in case the split does not line up with the rod and pusher exactly.
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

doc henderson

my pump/valve is set to bypass at 3k psi x 2.5 x 2.5 x 3.14 = 58,875 pounds of splitting force.  if I did the math correct, and if not I am sure someone will chime in!!! :D :D :D.  your flow is 30 gpm, do you know your psi?  how are you running the saw and the pusher?  off the same pump with power beyond?  Ts? separate pumps?
Timber king 2000, 277c track loader, PJ 32 foot gooseneck, 1976 F700 state dump truck, JD 850 tractor.  2007 Chevy 3500HD dually, home built log splitter 18 horse 28 gpm with 5 inch cylinder and 32 inch split range with conveyor powered by a 12 volt tarp motor

moodnacreek

Go for a 4 1/2" with 3" rod. It will be worth the cost of having one made if that's what it takes. We have been running one for years with just over 25gpm. 30 will be better than ours and will have a nice return.

Rougespear

Thanks everyone for the thoughts.  Really helps solidify my plans.
Custom built Cook's-style hydraulic bandmill.

blackfoot griz

One other consideration would be the ports on the cylinder. The ports need to be big enough to handle the flow. Restriction= heat build up.

Rougespear

Most everything I see off the shelf runs SAE8 ports... so probably on the small side of passing 30gpm.  I could upsize them... just haven't welded on hyd cylinders in my life before.  I'm a good welder, just have to figure out the process for cutting out the old ports and welding in the new ports in such a fashion to NOT destroy hyd seals.  I'm open to suggestions as it seems few people take the time to enlarge ports on shop-built splitters.
Custom built Cook's-style hydraulic bandmill.

Nathan4104

I have a 3.5" cylinder on my processor, but I had the rod changed out to a 3" I believe.  (16 or 20gpm pump I believe) It was as big as the machine shop could put in. They also opened up the ports. It made the return about a second faster, which does not sound like much till you realize you wait 6 seconds per log to make the next cut, and how many logs per cord.... makes minutes! And is just satisfying to see it retract a bit faster! 
I split mostly softwood and birch through a 4 way wedge no issues.  
Good luck on your build! 

Al_Smith

IMO it would be very difficult to bend a 2" rod even on a 5" cylinder if the anchor points and the slide are solid and true to the point of thrust .It's all just the laws of physics .
Then comes the tonnage rating .A 5" at 3000 PSI is just short of 30 tons,a 4"  just short of 20 which gives rise is to how pray tell how can  a 4" be rated at 27 tons ?They lie ,simple as that .
Then comes what do you want to do with it ,run it wide open all out or make it last .Directly from a Parker -Hannifin design book it shows the increased longevity from just a pressure drop of 500 PSI .

jmur1

Fully agree with the rod size increase.  This does make a difference in the cycle time and the rod bending resistance.  Also a big supporter of the piloted dump valve.  I have two running on mine for both the split cycle and the return.  Both cycles run all your oil back through the control valve which is not necessary.  If you dump a percentage of it back to tank it will noticeably improve the cycle time. 

I was running a 5 inch cylinder through a 6 way head and had more force than I needed - (often resulting in damage).  I convert to a 4 and found it to be nearly perfect for the hardest wood I am doing.   Knotty cherry, and beech.  (Also running lots of ash that it flies through)  

Either way  - If you can figure out how to run a multi wedge without needing a sledge hammer, Ill cheers that!

jmur1  
Easy does it

hedgerow

Rougespear
Don't cheap out on the hyd cylinder it's the heart of a processor and will get cycled a lot. I would go with a five inch with a 3.5 or a four inch rod. Get it made with 3/4 or 1 inch ports and use a pilot dump valve that bigger rod size really speeds up the cycle time. Check places like Surplus Center in Lincoln Ne or get a machine shop hyd shop to build one. If you have enough horse power you can ran a single stage 30 GPM pump you get the right cylinder that processor will be fast. 

sawguy21

I am not far from him, he has a top notch local machine shop. Princess Auto in Kamloops or Kelowna is a one stop shop for things hydraulic.
old age and treachery will always overcome youth and enthusiasm

Hilltop366

One of the slickest ways I have seen to speed up splitting time was a firewood processor Youtube video I had seen that the processor used two single acting hydraulic cylinders, the pushers were tied together at the back with a chain and a roller so that when one cylinder was extended it also retracted the other one. The pushers and cylinder rods were covered with a large box tubing that was set on a 45° from flat and it was designed so that when the pusher closest to the saw was extended the block of wood would slide over the pusher into the second one.

Almost halves the splitting cycle, no wait for the return stroke, no need for extra large cylinder rods to speed up splitting time.

hedgerow

Quote from: Hilltop366 on October 09, 2019, 06:09:50 PM
One of the slickest ways I have seen to speed up splitting time was a firewood processor Youtube video I had seen that the processor used two single acting hydraulic cylinders, the pushers were tied together at the back with a chain and a roller so that when one cylinder was extended it also retracted the other one. The pushers and cylinder rods were covered with a large box tubing that was set on a 45° from flat and it was designed so that when the pusher closest to the saw was extended the block of wood would slide over the pusher into the second one.

Almost halves the splitting cycle, no wait for the return stroke, no need for extra large cylinder rods to speed up splitting time.
If you could post that link I would like to see that processor. Sounds like a neat way to do it.  Thanks 

Thank You Sponsors!