# Log Splitter tonnage rating - are they on crack, or just lying?



## BlueRidgeMark (Aug 11, 2006)

In answer to a question on another thread, I did some calculations of various pressures and ram sizes to see what kind of tonnage each would put out.

But when I look at the manufacturer's claims for tons for their units, things don't seem to add up. They're claiming more tons than should be possible if they are typically running 2000, maybe 2500 PSI, which is what I've understood them to be running.

So how do the log splitter manufacturers justify their tonnage ratings? For example, Iron & Oak claims that one of their units has 26 tons of splitting force. It has a 4" diameter ram. To get 26 tons out of a 4" ram would require a fluid pressure of 4136 PSI. Are they really running that much pressure?

How'd I get that figure? Simple arithmetic. The AREA of a 4 inch ram is 12.57 square inches. (3.14*2^2) To put 26 tons of force on that requires enough pressure to exert, well, 26 tons. 26 tons is 52,000 pounds. So, to get the required pressure per square inch, simply divide 52,000 by 12.757, and you get 4,136.

The same kind of numbers hold for the other manufacturers. 

Troybilt claiming 27 tons out of a 4.5 inch ram. They need 3395 PSI.

Timberwolf claiming 20 tons out of a 1.75 inch ram. They need a whopping 16,330 PSI!!!




So, either they are running that kind of pressure in all these splitters, or they are using some "creative" method of calculating their tonnage.

Anybody know?


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## mga (Aug 11, 2006)

ha...i've often wondered the same thing. i've read those ads and looked at that they claim to offer.

i think they're relying on the ignorance of the general public. i also have ran the calculations and they don't seem to add up. maybe they use a different formula......who knows.

good post and good question!! it should be food for thought for those who are thinking of buying a splitter.

here's a link that does calculations....look at hydraulic calculator number 1...fill in the blanks:
http://www.baumhydraulics.com/calculators.htm


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## olyman (Aug 11, 2006)

well--mines got a 6" dia bore--at 3000 psi--figures to at least 30 ton--sure will bow the 16" i beam when have big ones in--then deflects back-----


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## BlueRidgeMark (Aug 11, 2006)

TreeCo said:


> 1.75 is the diameter of the rod, not the piston.



Ah! Good - that explains _that_ one. Thanks for catching that.

Now they are down to needing 3138 PSI. Sound like a reasonable operating pressure?


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## BlueRidgeMark (Aug 11, 2006)

olyman said:


> well--mines got a 6" dia bore--at 3000 psi--figures to at least 30 ton--sure will bow the 16" i beam when have big ones in--then deflects back-----




Actually, with a 6" ram, you only need 2122 PSI to get 30 tons, so that's VERY believable. With 3000 PSI, you'd get 42 tons. Not too shabby!


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## BlueRidgeMark (Aug 11, 2006)

mga said:


> here's a link that does calculations....look at hydraulic calculator number 1...fill in the blanks:
> http://www.baumhydraulics.com/calculators.htm



Great! Thanks for the link - their calcs agree with mine. It validates my approach, anyway. Since I haven't done any hydraulic engineering, I was operating from some basic understanding, so I would not have been surprised for a hydraulic expert to come along and show me where I had missed something basic. Guess I got it right.


So what about those pressures? 3000? 4000 in the ballpark?


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## BlueRidgeMark (Aug 11, 2006)

TreeCo said:


> What would it do to your calculations if the ram was pushing the log into a splitting edge of various surface areas? (i.e.,.5, .8, 1.2 sq inches)




That's the big question - how are they measuring tonnage? What the ram puts out? That's a very straigtforward multiplication problem, as above. Surface area of the piston times pressure. Nothing complicated, so there's no wiggle room.

OR are they claiming a certain tons per inch based on the surface area of the wedge? That could make a huge difference. It's very unlikely that you'd have a cutting surface area that is MORE than the piston's area. It's going to be less - probably much less, so you'd have a multiplying effect on the final number.

However, they never say that. There's no "tons per square inch" mentioned. I do often see the phrase, XX tons of splitting power", which is meaningless. 

Rather like the all too common, "Compare at $29.95!" Sounds like they're saying something, but when you break it down according to rules of grammar, turns out they didn't even make a sentence. They SURE didn't say that you could compare their product to somebody else's, though most would get that impression.


So I guess we're back to, "Does anybody _know_ how they measure the tonnage?"


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## CaseyForrest (Aug 11, 2006)

I had that argument too once. When you do your calculations, and figure an advertised 26 ton splitter is actually 18 on the ram, you also need to take into account the fact the the contact area on your wedge is not as much as the ram, thereby multiplying the splitting force.


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## BlueRidgeMark (Aug 11, 2006)

Yes, but what is the contact area? If the wedge is blunt - square on the end - it's easy enough to measure it and do the arithmetic. If it's SHARP, the contact area is (theoretically) zero, so your tonnage is infinite.

I don' theeen so, Lucy!

If the edge is not perfectly square, but not perfectly sharp, you've got a very complex calculation, and therefore LOTS of room for fudging the numbers!

That's why lawyers love complex contracts!


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## CaseyForrest (Aug 11, 2006)

Well, if you want to get pissy about it!!

Just kidding.

Your sharp edge does have a contact area, it has too, you can see it, feel it, and when it come in contact with something, it moves it. Not to mention as your wedge pushes in, the contact area increases which is why your pressure goes up. Thats why a sharp knife takes less effort than a dull one, the same pressure on less contact area.

I agree its hard to measure, but it can be done!!


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## JeffHK454 (Aug 11, 2006)

Good topic!

I've got a 34 ton SpeeCo , has a 5" piston and I always thought about the PSI needed to get 68K pounds of push with a piston area like that! 

I would say I could count on one hand how many times I've had it above half throttle, reduces fuel consumption and cuts way down on heat build up.

Hell, I'm overheated and out of gas way before the splitter is !

Jeff


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## BlueRidgeMark (Aug 11, 2006)

CaseyForrest said:


> Well, if you want to get pissy about it!!
> 
> Just kidding.
> 
> ...



Yep to all of that. That's why I said "theoretically". Actually, it's in that "complex calculations" area.


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## CaseyForrest (Aug 11, 2006)

I know you knew that, just wanted to make sure you knew I knew that you knew that too.


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## BlueRidgeMark (Aug 11, 2006)

Uh, _I_ knew that.


I think.


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## BlueRidgeMark (Aug 11, 2006)

JeffHK454 said:


> I've got a 34 ton SpeeCo , has a 5" piston and I always thought about the PSI needed to get 68K pounds of push with a piston area like that!



I make it out to be 3465 PSI. If we assume that Treeco's "2500 and up" is truly on the low end, as he suggests, then the tonnage ratings start to make sense. We seem to be running in the 3-4 thousand PSI range.

So what's with a relief valve set at 2250, as was mentioned in another thread?  That would cap your splitter at 22 tons.


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## CaseyForrest (Aug 11, 2006)

If you are running over 3000, check your fittings, valve, and hoses. Most are rated at a running 2500 to 3000, with a burst of double that.


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## asb151 (Aug 11, 2006)

BlueRidgeMark said:


> In answer to a question on another thread, I did some calculations of various pressures and ram sizes to see what kind of tonnage each would put out.
> 
> But when I look at the manufacturer's claims for tons for their units, things don't seem to add up. They're claiming more tons than should be possible if they are typically running 2000, maybe 2500 PSI, which is what I've understood them to be running.
> 
> ...



Blueridge,

Just for the record the Iron and Oak 26 ton has a 4.5 inch cylinder. It is incorrectly listed on their site. It is correctly listed in some in their other literature. 

Aaron


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## BlueRidgeMark (Aug 11, 2006)

Thanks for the correction, Aaron. That drops the required pressure to 3270 PSI.


I take it you have one? How do you like it? If I had the money, I'd be hard pressed to buy another splitter, based on the looks of it. Of course, this is all academic, since I don't have the money!


I ordered their maul (big & little) today, and a sledge, and a couple of wedges. Seem like nice folks.


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## Big Woody (Aug 11, 2006)

> What would it do to your calculations if the ram was pushing the log into a splitting edge of various surface areas? (i.e.,.5, .8, 1.2 sq inches)



The measure given is tons which is a measure of force. Hence contact area has nothing to do with it. Contact area is only important if you are talking about pressure which log splitter specs clearly are not. I thought most splitters would run up t0 3500 psi max which should give close to the advertised values. 

For example on my 22 ton Husky the force is 44,000 lbs. With a 4" diameter cylinder the area is 12.566 square inches. This gives a required pressure of 3501.5 psi as the manufactures of Husky told me when I called them before I bought mine. I checked into this and called the manufacturer before hand to verify what was up. 

Tractor hydraulic pressure can/should also run up to 3200 to 3500 psi for the 3 point tractor mounted splitters. I almost made the mistake of getting the 22 ton tractor mount from TSC ($450) to save money but I realized my Ford 3000 only ran about 2250 or 2500 psi which would have only given me about 15 tons instead of 22 tons. Glad I went with the briggs model instead


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## dtw902 (Aug 12, 2006)

BlueRidgeMark said:


> Great! Thanks for the link - their calcs agree with mine. It validates my approach, anyway. Since I haven't done any hydraulic engineering, I was operating from some basic understanding, so I would not have been surprised for a hydraulic expert to come along and show me where I had missed something basic. Guess I got it right.
> 
> 
> So what about those pressures? 3000? 4000 in the ballpark?




Here is another link for ya BlueRidgeMark.
http://www.surpluscenter.com/Hydraulic.htm


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## mga (Aug 12, 2006)

following all this...i checked some web sites for the parts i am using on my splitter. to achieve the maximum desired tonnage, your pump, control valve and cylinder must be "tuned" with each other...for lack of a better word.

i am using a prince LS-3000 control valve with a maximum factory setting of 2750 as you can see at this link:

http://www.princehyd.com/Default.aspx?tabid=46

the pump i am using is a haldex two stage as you see here:
http://www2.northerntool.com/product/200321057_200321057.htm

the pump, according to the haldex web site, has a maximum pressure rating of 3000 psi. so, regardless what my pump says, the final word is the controller setting....correct? therefore, is it not true that my controller, in this case, is actually robbing me of power?

wouldn't i have been better off using one of the 3000 psi rated controller valves to give my 5" cylinder the maximum pressure?

so, i wonder if they intentionally did this lower setting because it's on a log splitter...which in most cases are probably home built...as a safety precaution?


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## DanMan1 (Aug 12, 2006)

Big Woody said:


> The measure given is tons which is a measure of force. Hence contact area has nothing to do with it. Contact area is only important if you are talking about pressure



Bingo:jester:


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## CaseyForrest (Aug 12, 2006)

But isnt it easier to "Force" 22 tons onto a smaller contact area? The edge on your wedge has got to have something to do with it. 

If you have a knife edge on your wedge, compared to a rolled over egde, the knife edge is going to split with less force than the rolled edge, correct?

Disclaimer: I am not a mechanical enginer, physicist, or rocket scientist. Just trying to also understand how manufactures come up with their inflated numbers.


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## dtw902 (Aug 12, 2006)

The tons rating would be max output, say against a flat block.
The wedge just makes it easier to split with less force. 
You are not using max tonnage to split, only on knotty, gnarly
wood. 
When the cylinder stalls it is pushing max tonnage for a given 
system.


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## BlueRidgeMark (Aug 12, 2006)

dtw902 said:


> Here is another link for ya BlueRidgeMark.
> http://www.surpluscenter.com/Hydraulic.htm




Cool! Thanks!  


Now knock it off before I get the "build it myself" bug!


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## slipknot (Aug 13, 2006)

This should go down in the a-site hall of fame as one of the best threads!
I was thinking of starting one but don't know enough about hydraulics like blueridgemark! Thank you for starting this...I have been wanting to get to the bottom of this matter! Now I shall learn! opcorn:


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## monk680 (Aug 16, 2006)

Here is the cylinder size to pressure calculations
----------2250-----2500-----3000 psi
3"-----------8------8.75------10.59
3.5"-------10.8------12--------14.4
4"---------14-------15.7------18.85
4.5"-------17.89----19.88-----23.85
5"----------22-------24--------29
6"---------31.8-----35.33-----42.40


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## SmokinDodge (Aug 16, 2006)

BlueRidgeMark said:


> So I guess we're back to, "Does anybody _know_ how they measure the tonnage?"




F= P x A

Force equals pressures times area. Period. That is the only calculation that is needed for figuring the working tonnage of a cylinder.

I've often wondered how they come up with some of their ratings on the commercial splitters. It seems they are rating them as running the pump at full capacity, 3500 - 4000 psi, but when they are sold most are set to run only 2250 - 3000 psi.


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## BlueRidgeMark (Aug 16, 2006)

Smokindodgew101 said:


> F= P x A
> 
> Force equals pressures times area. Period. That is the only calculation that is needed for figuring the working tonnage of a cylinder.



Yep. But then...



Smokindodgew101 said:


> I've often wondered how they come up with some of their ratings on the commercial splitters. It seems they are rating them as running the pump at full capacity, 3500 - 4000 psi, but when they are sold most are set to run only 2250 - 3000 psi.




I think you may have hit the mark on this. It's sort of like the EPA gas mileage - it might be useful for comparing one against another, but you aren't going to see anything like it in the real world.  


These days I'm getting my truck loaded with log ends each morning on the way to work. Fella loads me up with a big knuckle boom that has a claw on the end that can pick up a 40" diameter oak log. The cylinders on that look to be maybe 8" diameter at most. I have to wonder what kind of pressure they run.  

You ought to see the hydrauliclly powered saw on this rig - it's got to be a 5 foot bar, and it goes through hardwood like The Predator would go through balsa wood. Throws a rooster tail 20 feet! opcorn:


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## BlueRidgeMark (Aug 16, 2006)

slipknot said:


> I was thinking of starting one but don't know enough about hydraulics like blueridgemark!



Hey, all I know is the basic formulas, like Smokindodge posted. It's pretty basic at that point.

But I'm glad this is a useful discussion. I'm here to learn, too!


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## monk680 (Aug 17, 2006)

Smokindodgew101 said:


> F= P x A
> 
> Force equals pressures times area. Period. That is the only calculation that is needed for figuring the working tonnage of a cylinder.
> 
> I've often wondered how they come up with some of their ratings on the commercial splitters. It seems they are rating them as running the pump at full capacity, 3500 - 4000 psi, but when they are sold most are set to run only 2250 - 3000 psi.


 That is what I posted. A 3" cylinder at 2250 makes 8 tons at 2500 it makes 8.75 tons at 3000 it makes 10.59 tons. PERIOD. Sorry for taking the time to do the calculations. No log splitters run at 4000 psi most cylinders are 2500 or 3000 psi and few gear pumps make 4000 psi. The most I have ever seen is 3625psi.


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## Sparky_NY (Aug 22, 2006)

Interesting thread.. I built a log splitter last year and ran into the same questions. A little research made for even more questions! The only 2 stage pumps I could find were halidex/barnes.. those pumps are rated at 3000 psi max and the commercial units seem to all use that type pump. Even giving the splitter manufacturers benefit of a doubt on the pump, saying they found a 2-stage rated at say 4000psi, the horsepower required to run that pump is quite a bit more than what is on the units, magic once again. Another point (previously pointed out) is the supporting components, hoses, valves etc, are not usually rated for 4000 psi pressure. It seems like manufacturers are playing games somewhere.
I ended up with my splitter using 3000 psi (with a gauge to keep track of things) and a 4 inch cylinder. Interestingly, it out performs 30 ton rated splitters without a doubt. (used a friends "30 ton" splitter before I built mine).
Departing from the norm, I used a commercial 5hp electric motor. My splitting is done in front of the garage and the electric is quiet, powerfull, easy on-off, no fueling etc. Size for size, electric motors perform equal to gas units of twice the size.


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## mga (Aug 22, 2006)

sparky...that 5hp electric motor is 220...correct?


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## cord arrow (Aug 22, 2006)

i reckon it would have to be. unless of course ya had more money than you knew what to do with.

then again, in the big scheme of things, you really don't run 'em a whole lot of hours...comparatively, maybe you could go 110.


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## Canyon Angler (Aug 24, 2006)

Sparky NY,

I would like to know more about your splitter.

I bought an old farmhouse (formerly a working farm) and in the barn, there's a big hydraulic ram for a forklift-type thing. The piston must be 5" or 6" diameter, with a throw of probably 4-6 feet.

I'm thinking of trying to get the parts to make it into a log splitter...and I like the idea of electric, since I only burn maybe 3 cords a year. 

Can you tell me about yours?

What size/voltage/cost motor?
Cost of other components?
Any pointers on where/how to learn how to make one?

Thanks,

CA


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## KiwiBro (Jan 6, 2015)

W T F?
45t?
http://www.trademe.co.nz/business-f...forestry/forestry/other/auction-829793971.htm


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## Hddnis (Jan 6, 2015)

Holy zombie thread batman! 9 years old!





Mr. HE


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## Guswhit (Jan 6, 2015)

Research? Bored? I'm sure we have all been guilty of opening an old thread.


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## mn woodcutter (Jan 6, 2015)

Guswhit said:


> Research? Bored? I'm sure we have all been guilty of opening an old thread.


I normally prefer to pick up old threads instead of starting new ones about the exact same topic. Maybe we could start another fiskars thread!


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## mga (Jan 6, 2015)

mn woodcutter said:


> I normally prefer to pick up old threads instead of starting new ones about the exact same topic. Maybe we could start another fiskars thread!



or, how about another how big is a cord of wood thread?


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## KiwiBro (Jan 6, 2015)

Hddnis said:


> Holy zombie thread batman! 9 years old!
> 
> 
> 
> ...


Heck, you mean that search function is just painted on? I never got that memo;-)


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## KiwiBro (Jan 6, 2015)

But seriously, can anyone explain how that auction i linked to could ever get 45t from that splitter? Not even downhill with a tail wind could it get there. I doubt they are using super high PSI pumps in those things, and the cylinder isn't anything close to the diameter needed.


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## Joesell (Jan 7, 2015)

KiwiBro said:


> But seriously, can anyone explain how that auction i linked to could ever get 45t from that splitter? Not even downhill with a tail wind could it get there. I doubt they are using super high PSI pumps in those things, and the cylinder isn't anything close to the diameter needed.



Looks like a turd to me. It says 45T all over the place. At first I thought it was a marketing gimmick, but it spelled out 45 tons in the description. 

If they want to market it as a 45 ton, they should be held to it.


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## 1project2many (Jan 7, 2015)

Joesell said:


> Looks like a turd to me. It says 45T all over the place. At first I thought it was a marketing gimmick, but it spelled out 45 tons in the description.
> 
> If they want to market it as a 45 ton, they should be held to it.



Yeah... I was looking for the same thing. T does not mean Ton, it only implies it. But they definitely said 45 Tons. But that whole ad speaks of poorly translated Chinese marketing and I wouldn't believe any of it anyway.

One thing that may happen (I doubt it in this case) is the rating may be similar to generator and motor ratings. In order to get a higher number they'll quote a peak number... something the unit's capable of producing but can't sustain consistently. In the case of hydraulics there's often a pressure spike right as a relief valve opens. I've heard it called "cracking pressure." If the system spikes to 4500 psi immediately before the valve opens (that would be a very poor relief valve, btw) and maintains 2500 psi system pressure, then technically it does create a bunch of force for the briefest time. It's chitty marketing because the machine can't possibly maintain that pressure, but it's not technically wrong.


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## Pulp (Jan 7, 2015)

Good engineering stuff here.
BUTT-- splitting efficiency also is dependent on structure of the butt species( crotch, grain structure, 'knots', etc...). 
Some of the so-called "rapid splitters" use speed , not PSI for the job. And then there's the power variety: gas, electric.
Way over my rating.


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## firebrick43 (Jan 7, 2015)

Hey kidsssss. Take a five, ten, twenty dollar bill out of your momma's purse. 

Get on the number 9 bus and go downtown to meet a man named Martinez, his s$&t the bomb. It will get you so HIIIIIIIIIIGH!!!!!!

O yea he has a log splitter for sale to. Best one ever!


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## Jerryv88 (Jan 7, 2015)

1project2many said:


> Yeah... I was looking for the same thing. T does not mean Ton, it only implies it. But they definitely said 45 Tons. But that whole ad speaks of poorly translated Chinese marketing and I wouldn't believe any of it anyway.
> 
> One thing that may happen (I doubt it in this case) is the rating may be similar to generator and motor ratings. In order to get a higher number they'll quote a peak number... something the unit's capable of producing but can't sustain consistently. In the case of hydraulics there's often a pressure spike right as a relief valve opens. I've heard it called "cracking pressure." If the system spikes to 4500 psi immediately before the valve opens (that would be a very poor relief valve, btw) and maintains 2500 psi system pressure, then technically it does create a bunch of force for the briefest time. It's chitty marketing because the machine can't possibly maintain that pressure, but it's not technically wrong.



Figures don't Lie, but Liars Figure!

That is why they don't rate small engines in hp anymore, just displacement. The marketing people know that most people don't question the numbers, they just look for the biggest one. The hp numbers they slapped on things were so unrealistic that someone finally sued the manufacturers.

It would seem that the same thing could happen to splitter manufacturers.

Jerry


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## Hddnis (Jan 7, 2015)

Jerryv88 said:


> Figures don't Lie, but Liars Figure!
> 
> That is why they don't rate small engines in hp anymore, just displacement. The marketing people know that most people don't question the numbers, they just look for the biggest one. The hp numbers they slapped on things were so unrealistic that someone finally sued the manufacturers.
> 
> ...





What happened was a law firm sued the manufacturers, and as part of the settlement that netted the firm millions of dollars, the manufacturers cannot use hp numbers and must use displacement.

In the end the consumers lost. Chinese engines are still sold by hp and that is part of the reason they are so popular, people know basically the capability of the motor they are getting.



Mr. HE


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## John Sparnon (Nov 17, 2016)

Some countries still use 2,240 pounds to the ton as australia did when i went to school. This was spelt as TON. I think 2,000 pounds was spelt TONNE and was called an American Tonne. This would have a large effect on the pressure calculations for the log splitters. Just a thought.


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## EXCALIBER (Nov 21, 2016)

I think what everyone is missing is even if your pump is rated to 3000psi, the pressure in the system is regulated by the control valve (also a relief valve) which is always set 200-250 psi below the max pump pressure to save the system. The relief valve starts opening before the pressure even reaches the 2800psi and as the pressure builds the valve opens more and more. Last year I replaced my swisher "22 ton really less than 17 ton" splitter control valve with a Prince log splitter valve 25gpm and it came set to 2250psi relief valve adjustable to max 2750. Even at that my splitter will split anything you throw at it but only running 8 inch single wedge.


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