What makes a "Fast Cycle" splitter?

[papossefan]

Ok, at the risk of asking a stupid question, here it goes. I have been thinking about building a new splitter. The most important thing to me is that it has the fastest cycle time I can get. I really like the simple design of the iron & oak 20 ton fast cycle splitter so I will probably be modeling mine after this. My question is, What really makes this splitter cycle faster? In my mind, the faster you can get the oil into and back out of the cylinder the faster your cycle time will be. Is this line of thinking correct? I know they are using a 16gpm pump and a 4x24x1.75 cylinder. I also can get a valve with 3/4" ports which should help but all of the cylinders I look at have the same 1/2" ports. So I am left wondering is it worth using a valve with larger ports and bigger lines etc. if my flow will be limited to the 1/2" ports on the cylinder anyway?
Thanks in advance for any advice on this topic.

Ryan

 

[rarefish383]

My home built with a 6hp engine and 16 GPM pump is much faster than my store bought 11 GPM with a 6 hp engine, Joe.

 

[Oldman47]

Bigger diameter cylinder means slower cycle time but a stronger push, more tons. Faster fluid flow in both directions means faster cycle time but that includes pump capacity, supply line diameter, control valve flow rates and return line diameter. All have to get bigger to move more hydraulic fluid and shorten the cycle.

 

[Kevin in Ohio]

Depends on what you call fast I guess. Heat Should be a BIG consideration as well because small ports, hard 90's will build it up quick. They may be using a larger than normal rod to get a faster return stroke on the ones you mention. If you want fast search till you find a cylinder with bigger ports. If you can't find one check with your local hydraulics place to have larger bungs welded on. You are correct in saying that your smallest diameter is the restriction point. If you have to have a 90 degree bend, at least use a long sweep. Hard 90's look clean in design but build heat bad. Do your layout to avoid them as much as possible.

I'm running a 5 inch cylinder with a 2 1/2 inch rod, 28 gpm pump. On the 24 inch stroke in first stage it's 8.5 seconds out and 6 seconds on return at 3/4 throttle. I'm running a bypass to save wear and tear on the valve too.

 

[mesupra]

A rack and pinion.

 

[USMC615]

A rack and pinion.

...with flywheels attached. Spot on!!

 

[Del_]

Two speed hyd pumps. Regenerative valves. Large diameter rods. Big pumps and motors. As short a cylinder as is workable, 24" for me. Auto return valve. Locking forward valve. 4 or more way wedges. Self propelled splitter. Log lift. Conveyor.

 

[muddstopper]

Iron and oak is advertising different numbers for the fast cycle 20ton than you are writing. According to there ad's the fast 20 has a 4.5x2x24 cylinder and not the 4x1.75x24in cyl you suggested. To get 20tons they probably have the pressure set at around 2500psi. Also the 8sec cycltime advertised should be about 11.2sec, give or take a few billion years. Anyways, if you copy their design and use the 4in cyl with smaller rod dia, you would have the approx 8 sec cycle time (closer to 9 sec) you are trying to match. Going to a cyl with a 2in rod will only speed up the cycle time by .2 sec, not worth the effort or extra cost of the bigger rod. To keep heat down to a minimum without a lot of extra expense, I would look for the cyl with the 3/4 ports as well as try to find a splitter control valve rated for 25gpm. the bigger ports in the cyl and valve will reduce the velocity of the oil flowing back to the tank on return stroke, which in turn will reduce heat. I would also try to build or find a hydraulic tank in the 15gpm range. Set hyd pressure to around 3000psi which would give you about 19tons of splitting force. You will need a 8hp min engine to pull the pump. To increase splitting speed, I suggest using a 4way wedge, you can make it removable or height adjustable for those few times you run into a round you cant split. I can say for certain the 4in cyl with a 4 way wedge is going to hard to stall. If you need cycle time faster than 8 sec, you can always go with the 22gpm twostage pump and a little bigger engine, but if you can keep a 8sec cycle time fed wood, your a better man than most of us.

 

[USMC615]

Iron and oak is advertising different numbers for the fast cycle 20ton than you are writing. According to there ad's the fast 20 has a 4.5x2x24 cylinder and not the 4x1.75x24in cyl you suggested. To get 20tons they probably have the pressure set at around 2500psi. Also the 8sec cycltime advertised should be about 11.2sec, give or take a few billion years. Anyways, if you copy their design and use the 4in cyl with smaller rod dia, you would have the approx 8 sec cycle time (closer to 9 sec) you are trying to match. Going to a cyl with a 2in rod will only speed up the cycle time by .2 sec, not worth the effort or extra cost of the bigger rod. To keep heat down to a minimum without a lot of extra expense, I would look for the cyl with the 3/4 ports as well as try to find a splitter control valve rated for 25gpm. the bigger ports in the cyl and valve will reduce the velocity of the oil flowing back to the tank on return stroke, which in turn will reduce heat. I would also try to build or find a hydraulic tank in the 15gpm range. Set hyd pressure to around 3000psi which would give you about 19tons of splitting force. You will need a 8hp min engine to pull the pump. To increase splitting speed, I suggest using a 4way wedge, you can make it removable or height adjustable for those few times you run into a round you cant split. I can say for certain the 4in cyl with a 4 way wedge is going to hard to stall. If you need cycle time faster than 8 sec, you can always go with the 22gpm twostage pump and a little bigger engine, but if you can keep a 8sec cycle time fed wood, your a better man than most of us.

Good post...straight talk.

 

[ChoppyChoppy]

Fast cycle to me would be a complete cycle in no longer than about 5 seconds.

 

[mesupra]

Less than 2 seconds for me. Depending on the wood there can be an advantage to hydro esp when using 4 and 6 way wedges.

 

[zogger]

oh noes I am going to bring it up..

I am not knowledgeable in these hydro splitter discussions at all, but still read them. I see this heat buildup with the fluid brought up a lot. Well..which is the best hydraulic fluid then, one that maintains..whatever it has to..but,,is able to resist this heat buildup better, by absorbing then dumping heat fast? There *must* be some differences out there.

 

[muddstopper]

What heats up the oil more than anything is the speed of the oil as it goes thru the valves, cyl, hoses and fittings. You can pump a lot of oil thru a small fitting but, each restriction the oil flows thru increases the velocity of the oil. Velocity of the oil flow creates friction and friction creates heat. Some of this heat is given off as parts heat up, but the oil is moving so fast thru those parts, it cant give off all the heat it accumilates. The only time the oil slows down in when its in the tank. A small capacity tank doesnt have the surface area to allow all the oil to cool off so heat will continue to build as it circulates thru the system. Tank size should be matched to oil flow and the usual recommendation is One gal capacity for each gpm being pumped. Hyd tanks should be long, narrow and tall instead of short and square to allow oil more surface contact for faster heat removal.

A point to remember is that the pump is still circulating oil, even when your not operating the control valves running the cyls in and out. Also pumps flows can be much higher than pump ratings when you are operating the control valves. A hydraulic cyl extending and retracting does change the values of oil flowing thru the control valve. The reason for this is due to the cyl rod taking up space in the cyl bore. When you are extending the cyl you are putting oil to the piston side of the cyl, the rod end has less oil holding capacity so as the cyl extends, oil flow going back thru the valve may be as much as 1/2 the amount of oil that is being pumped into the cyl. The opposite is also true, on cyl retraction, you are now putting oil into the rod end of cyl and the oil coming from the piston end can be twice as much as is entering the rod end. If you have a oil flow rate of 16gpm going into the rod end for retraction of the cyl, you could have 32 gpm coming out of the piston end. That little 7.5gal hydraulic tank should be starting to look pretty small by now.The bigger the dia of the rod, the faster the oil will be coming out of the piston end of the cyl.

There all kinds charts giving fitting and port sizes for various flow rates. Most of the splitter valves on larger systems use 3/4in ports. A 3/4in port can flow about 30gpm before velocity and associated heat starts becoming a problem. Not saying you cant pump 60gpm thru a 3/4in port, in fact, 60gpm will flow pretty easily thru a 3/4in port, but if you do, you will see a heat build up. Using dump valves to bypass oil around the control valve back to tank wont neccessary speed up cycle time. Reason being the oil still has to flow thru the cyl ports before reaching the dump valve. If you plan on using a dump valve to increase cyl speed, its best to also use a cyl with bigger ports, or at least a bigger port on the base end, otherwise the flow is still passing thru a restriction at the cyl.

 

[Kevin in Ohio]

Spot on info by muddstopper. Layout as mentioned before will be one of the biggest considerations you should have to avoid neckdowns and "hot spots".

Notice how hose 180's are used and long sweep 90's.

Interia splitters have their place and are quicker IF you don't get on stuck. They just don't work for my application. We cut 24 inch long and do a lot of big stuff. I don't split my wood to kindling size.

I see a lot of people talk about how inertias will split everything, then say they noodle the big ones. Is that included in the split time? I don't noodle.

 

[muddstopper]

Kevin, I have to say, you have one of the best build, well thought out splitters I have seen on this site. Of course, I would change a few things to suit my operation better, but thats only because I like the wedge on beam better than wedge on cyl. And I like multi split wedges. These are all just personal preferences, not saying one way is better than the other. Just mentioning because those are some of the considerations one needs to thaink about when building their own splitter. It doesnt matter what Jimtom did designing his splitter, its building the splitter you will be using and the things that suit the operator that always trumps what someone else built.

 

[Kevin in Ohio]

Kevin, I have to say, you have one of the best build, well thought out splitters I have seen on this site. Of course, I would change a few things to suit my operation better, but thats only because I like the wedge on beam better than wedge on cyl. And I like multi split wedges. These are all just personal preferences, not saying one way is better than the other. Just mentioning because those are some of the considerations one needs to thaink about when building their own splitter. It doesnt matter what Jimtom did designing his splitter, its building the splitter you will be using and the things that suit the operator that always trumps what someone else built.

EXACTLY! I have to have wedge on cylinder because of using the swing boom to lift and hold the wood. If I didn't do it that way the hanger would swing as the ram pushed it creating a potentially bad situation. Just too risky. I cut and split where the tree falls and back down the logs length as it saves me SO many chains and resharpens as opposed to dragging everything for staging. Clean logs make for longer lasting chains. Like you said, everyone has their own unique set of circumstances and how they want to do it. Builders job is to pick ideas that will work for them and incorporate them into their plan.

If I was a commercial operator with more people my splitter would be set up different. Just as if the size of splits were to be smaller and they were shorter.

Appreciate the kind words and I can't wait to see your full on beast come to life. You have 10 times the amount of stuff to figure out than I did!

 

[muddstopper]

I have to admit, I have had a lot of help figuring out my hydraulic system from a fellow member on this site. He doesnt post a lot, but if he tells you something about hydraulics, its best to listen to him. His name is Kevin too by the way. I'll let him give his screen name if he wants to be known.

I kind of had to put my monster back on hold. Had an unexpected major expense right before Christmas that put a real drain on the ole wallet. My well went dry, if you can believe it with all this rain. To top it off, all the drilling from fixing the well ran straight down in front of my shop door, then it started raining. Mud knee deep, I hated to even walk down to the shop. Finally dried up enough to scrape away the mud, but might take a while to build back up the ole wallet.

 

[Kevin in Ohio]

I have to admit, I have had a lot of help figuring out my hydraulic system from a fellow member on this site. He doesnt post a lot, but if he tells you something about hydraulics, its best to listen to him. His name is Kevin too by the way. I'll let him give his screen name if he wants to be known.

I kind of had to put my monster back on hold. Had an unexpected major expense right before Christmas that put a real drain on the ole wallet. My well went dry, if you can believe it with all this rain. To top it off, all the drilling from fixing the well ran straight down in front of my shop door, then it started raining. Mud knee deep, I hated to even walk down to the shop. Finally dried up enough to scrape away the mud, but might take a while to build back up the ole wallet.

Life has a way of happening doesn't it.

James at Splitez helped me out and I had been kicking ideas in my head for years on what would work best for us. SO much nicer now.

This site is such a treasure trove of info and I try to give back as I have learned so much from others here. It's all about trying to save others from falling into the pitfalls that we did or were told to avoid before we did something that would be costly. Even scrap prices and scrounging makes this stuff hard to do on a budget anymore. I will repeat this. For the average guy, you can NOT build one cheaper than you can buy a new premade unit. If you have a special situation or most of the materials at your disposal, then yes, it can be done. Otherwise, don't go into this thinking you'll save a ton a money. You won't.

 

[muddstopper]

I'll agree, building by scroungeing isnt as easy as it was just a few short years ago. Scrap metal is down to around a penny a lb. Folks just aint scraping out old equipment like they used to. Its still out there, you just have to be first in line to get it. Back when scrap metal was around 20cents a lb, anybody that had a big old piece of machinery in the back forty was scrambling to get it to the scrap yard.

A lot of over thinking can go into building a splitter too. "I wants", sometimes outweigh the "I needs". I think just about everybody here "Wants" a splitter like the one you built, but how many folks actually "Needs" a splitter like that. A homeowner that doesnt have the same time restraints as someone splitting wood to sell, can get by really well with one of the store bought machines.The difference in a 9sec cycle time isnt really that big of a difference than a 12 sec cycle if you only splitting 4 or 5 cords a year, a little bit every day until its all split. For a commercial wood producer, that extra 3 sec of speed can equate to a lot of wood split if your splitting 10-20 cords a day every day.

I travel during the week for my job so I aint home every evening to do any wood gathering or processing. I usually harvest all my wood in one or two outings using trailers and hauling in log lenghts. I dump the logs beside the wood shed and buck when time permits. When I have it all bucked, I will call up the boys and have a splitting session. We might process 4 or 5 cords and stack in the shed in one day and I'm done till next year. Fast splitters take a lot of support to get maximum production. Working by ones self, I cant keep up with a 9sec or even a 12 sec cycle time machine, I would be plumb worn out in about an hour, or less, if I even tried. I dont even run my machine at full throttle most of the time. I like the fast cycle times when I have plenty of help, but help seems to be getting harder and harder to find these days.

 

[GM_Grimmy]

I feel I have a fairly quick hydraulic splitter that Alex built for me. It was a collaboration of both our minds to get the right components, as I chose a 28 gpm 2 stage pump setup. I'm using a 30 gpm main cylinder valve but for the log lift and 4 way, I'm using a 25 gpm valve, as well I was having troubles finding a 30 gpm rated valve, but the tank design was efficient enough to rid of some of the heat, I also have a hydraulic cooler to keep things cool as well. This combination has proven to work well, as I can get some heat into the oil, but I can also keep the temperature down as well. I am running a dump valve, but it wasn't to speed things up, as it was so I wouldn't be overloading the main valve. I have about 64 gallons per minute on the return stroke from a 3.75" rod on my 5" bore, 24" stroke cylinder. I wanted the bigger rod as with my previous splitter that I returned, I was waiting for the ram to get out of the way before I could grab the next piece or set the next one down. While they hydraulics are quick, having the adjustable 4 way is where I make more pieces that are done and I'm grabbing the next piece. It'll speed up a little more once I get my 6 way....for when you get that right sized wood to push things through.

I think a lot of people don't realize the gpm that is coming from the main cylinder on the return stroke. It's usually higher than what your valve is rated for and you generate heat there. Which not all heat is bad. I don't like my oil going over 140, and my cooler does an excellent job making sure it doesn't.....even in 89 degree weather (when I first got it home, I had to test it out, it was 89 out that day).