Splitter Tonnage Ratings

[jthornton]

Just wondering about the tonnage of the splitter I'm designing and I wander to a hydraulic cylinder force calculator and was a bit surprised with my answers.

4" @ 3000 psig = 18.8 tons
4 1/2" @ 3000 psig = 23.8 tons
5" @ 3000 psig = 29.5 tons

So now I wander over to Northern Tool and look at the Northstar 22 ton splitter and they claim:
Ram Force (Tons) 22 but a bit further down I see
Continuous Force (Tons) 18.8
Max. PSI 3,000
Cylinder 4 in. x 24in. and the 18.8 tons sounds right so is the "Ram Force" like vacuum cleaner HP just a sales gimmick?

John

 

[John R]

We're being lied to by the manufactures, does this surprise you?

 

[motoman3b]

I believe some are rating on peak PSI which may reach 3200-3500psi for a split second under the "perfect" conditions, most relief settings are well below that though so true potential of the ram is never reached

 

[Whitespider]

Heck even the 18.8 tons of continuous force is optimistic and based on perfect conditions. That 18.8 tons assumes the engine is able to keep RPM’s high enough under load for the pump to develop the 3000 PSI, and the pressure relief in the valve is working properly and is properly set to allow pressure to remain constant at the 3000 PSI… which I pretty much doubt. I’m guessing if you monitored pressures you’d see them drop off to something under 3000 PSI (likely closer to 2500 than the 3000 PSI) when the engine comes under load and/or the relief valve opens. Real world numbers would put it closer to 16 tons continuous.

While they are not “technically” lying… the manufacturers are using deception so consumers believe they are getting more “power” than they actually are. Small engine manufacturers did the same thing for many years with horsepower ratings… some recent lawsuits have caused them to drop HP ratings and switch to listing displacement and torque @ specific RPM. Still, the “tonnage” rating is useful for comparison from one unit to another (just as the HP rating was useful when comparing engines), but don’t think for a minute you get 22 tons of splitting force when you buy a 22 ton splitter.

 

[origionalrebel]

one example i saw was troybilt on the 27 ton. the cylinder's rating is 3500 psi. from what i've read, most run the press. relief at around 2700psi. so you do the math. i seriously doubt that lil ole mickey mouse pump they use would stand up to or even produce 3500psi. not bashing troybilt because i've split a lot of nasty wood with one but 27 tons ain't happenin.

 

[jags]

I have been pointing this out for years. It is definitely deceptive advertising.

 

[Nosmo]

Huskee 35 Ton

I've got one of these and I really don't have any idea what the true ton value would be. But I have never run the engine more than about 1/2 throttle and mostly what I split is elm.
Once I was given a couple pickup loads of sweetgum and there was no problem with splitting those rounds .

Has anyone done any research on this one ?

Nosmo

 

[jags]

Not much research to do. It is pretty simple math. PSI x surface area of cylinder. You would need a gauge to know where the relief is set (from factory, typical is 2500-2700 psi). Then the size of your cylinder. Most do NOT come out anywhere near their advertised tonnage.

 

[Typhke]

Just wondering about the tonnage of the splitter I'm designing and I wander to a hydraulic cylinder force calculator and was a bit surprised with my answers.

4" @ 3000 psig = 18.8 tons
4 1/2" @ 3000 psig = 23.8 tons
5" @ 3000 psig = 29.5 tons

So now I wander over to Northern Tool and look at the Northstar 22 ton splitter and they claim:
Ram Force (Tons) 22 but a bit further down I see
Continuous Force (Tons) 18.8
Max. PSI 3,000
Cylinder 4 in. x 24in. and the 18.8 tons sounds right so is the "Ram Force" like vacuum cleaner HP just a sales gimmick?

John

Not much research to do. It is pretty simple math. PSI x surface area of cylinder. You would need a gauge to know where the relief is set (from factory, typical is 2500-2700 psi). Then the size of your cylinder. Most do NOT come out anywhere near their advertised tonnage.

Isn't the surface area from your cylinder bigger than the rod size (think that is where the first post is based on)? Because it's a double working piston, you have oil going in from the back pushing the rod and a ring around it to push it out. To push it back in, there goes oil in from the other size pushing on only the ring around the rod? Maybe that's what you mean with surface area of the cylinder but I'm just asking to learn here.
So using the rod to calculate the tonnage would give a lower value than the real capacity? Unless you know the thickness of the hole cylinder and the wall thickness so you can calculate the size of the rod + the ring around it?

I agree that the numbers in the shops are just for show, marketing tools. If we compared our splitter to the commercial ones I've seen, we could call ours way stronger than 30 tons. But really, who needs 30 tons splitting power? We used to have a splitter with a cylinder with rod size 5 1/2". Could run it up to 3500 psi and had a gauge on the control valve. Most of the time it stayed under 1000 psi splitting oak, from 5" to 30". There were times we had to raise the rpm's on the tractor to get some higher pressure but that was very rare.

 

[jthornton]

Isn't the surface area from your cylinder bigger than the rod size (think that is where the first post is based on)? Because it's a double working piston, you have oil going in from the back pushing the rod and a ring around it to push it out. To push it back in, there goes oil in from the other size pushing on only the ring around the rod? Maybe that's what you mean with surface area of the cylinder but I'm just asking to learn here.
So using the rod to calculate the tonnage would give a lower value than the real capacity? Unless you know the thickness of the hole cylinder and the wall thickness so you can calculate the size of the rod + the ring around it?

I agree that the numbers in the shops are just for show, marketing tools. If we compared our splitter to the commercial ones I've seen, we could call ours way stronger than 30 tons. But really, who needs 30 tons splitting power? We used to have a splitter with a cylinder with rod size 5 1/2". Could run it up to 3500 psi and had a gauge on the control valve. Most of the time it stayed under 1000 psi splitting oak, from 5" to 30". There were times we had to raise the rpm's on the tractor to get some higher pressure but that was very rare.

I'm not even talking about the return force which is the only thing that needs to take the rod into account. The cylinder size is the ID so that is the effective area for extension.

John

 

[reaperman]

Just wondering about the tonnage of the splitter I'm designing and I wander to a hydraulic cylinder force calculator and was a bit surprised with my answers.

4" @ 3000 psig = 18.8 tons
4 1/2" @ 3000 psig = 23.8 tons
5" @ 3000 psig = 29.5 tons

So now I wander over to Northern Tool and look at the Northstar 22 ton splitter and they claim:
Ram Force (Tons) 22 but a bit further down I see
Continuous Force (Tons) 18.8
Max. PSI 3,000
Cylinder 4 inch
John

I have the 22 ton northern tool splitter and once got my finger between the wood and end plate. It may have not been a full 22 tons but it felt like it.

 

[jthornton]

I have the 22 ton northern tool splitter and once got my finger between the wood and end plate. It may have not been a full 22 tons but it felt like it.

I used to instruct my maintenance people if they thought they needed a hammer to do the job to put their hand between the hammer and the object so they could get a good feel for how hard they are hitting.

John

 

[jags]

Rod size, really has nothing to do with the surface area described for figuring tonnage on a splitter. The return of the ram is meaningless with the exception of speed.

For a splitter, it is pushing force that counts. So the area in concern is the area of the back side of the piston. Where the oil actually "pushes" the piston out.

 

[Marc]

I have the 22 ton northern tool splitter and once got my finger between the wood and end plate. It may have not been a full 22 tons but it felt like it.

When was the last time you had your finger calibrated? And over what ranges? I'd like to see the proper documentation, NIST traceable before I believe you

 

[Mac88]

When was the last time you had your finger calibrated? And over what ranges? I'd like to see the proper documentation, NIST traceable before I believe you

Good idea, but the documents are covered in blood at the moment. NIST? Didn't that used to be NBS?

I have no clue what the "tonnage rating" on my old farmer-built splitter is. There's no pressure relief, or 2-stage pump, or any of that other hocum. I have on very rare occasions encountered something it won't split, like real gnarly oak or hedge crotches, with 3 or 4 limbs and grain running 15 different directions. Back it off the wedge, give it a shot with the saw, and away ya go.

 

[motoman3b]

Rod size, really has nothing to do with the surface area described for figuring tonnage on a splitter. The return of the ram is meaningless with the exception of speed.

For a splitter, it is pushing force that counts. So the area in concern is the area of the back side of the piston. Where the oil actually "pushes" the piston out.

Unless its one of those new fancy dual directional splitters that split on the return stroke.... then rod size plays an important factor.

 

[ft. churchill]

Just look at the cylinder bore size as that give you the best reference to capacity. Regardless of the skewing of the numbers by the manufactures, a 4"bore is stronger than a 3". Another thing that you can do is calculate the different units at the same pressure. (It sounds like you've already done some on this). The psi reliefs are adjustable so you can dial up any setting you want within the limits burst ratings, pump capacity, engine size etc. I use 2000 psi as my number as it is realistic.

 

[jags]

Unless its one of those new fancy dual directional splitters that split on the return stroke.... then rod size plays an important factor.

True dat. Different kinda critter though.

 

[Festus]

My new 22 ton Northern splitter is back at the store getting fixed because the pump seized (warranty). I was thinking about installing a gauge just because it would be interesting seeing what pressure it was running. It never seemed like the pressure relief valve ever opened, but without a gauge, there is no way of knowing if it should be. Mine only has maybe 8 or 10 hours of use, but it split everything I ever put in it. As long as everything is working properly, all the numbers really don't matter. The repair guy at the store told me the engine would almost snub by the time the relief valve should open. That doesn't sound right to me, so I'll figure it out myself when I get it back. Don't know why the pump seized, but sure don't want it to happen again. Especially after the warranty is dead.