Question to the firewood gurus

[Bavarian]

For about 15 years, I own a 25 ton Speeco wood splitter. From day one, it seemed weak, at least not what I would expect. It did always get the job done but with the constant feeling that it's lacking power.

I couldn't find any technical specs, but let me crush some numbers. Something doesn't add up.
It has a 4" cylinder on it. I did not take it apart to measure, but that's the closest I could guess.
On a YouTube video, a user stated a hydraulic pressure of 3000 Psi. I doubt that number on the two stage pump.

But let's stick with these two numbers.

The cylinder provides an area of 12.56 square inches, at a pressure of 3000 psi, it's pushing at 37.680 lbs.

What does the 25 ton rating relate to?

25 metric tons would equal 55.000 lbs.

Using imperial short tons, it would still be 50.000 lbs.

These numbers are nowhere close to each other. Where do the manufacturers get their numbers?
Am I missing something?

 

[ruffdog]

The 22 ton splitters had a 4" cylinder while the 25 ton splitters had a 4.5" cylinder. Do you only have a 22 ton or a 25 ton with a small cylinder on it?

Using your math, a 4.5" cyl would provide 47689 lbs of push.

 

[Bavarian]

The 22 ton splitters had a 4" cylinder while the 25 ton splitters had a 4.5" cylinder. Do you only have a 22 ton or a 25 ton with a small cylinder on it?

Using your math, a 4.5" cyl would provide 47689 lbs of push.

4.5" M A Y B E overall outside diameter on a hot day with low air pressure.
But even then, I'd end up with 42.390.

 

[Bavarian]

The 22 ton splitters had a 4" cylinder while the 25 ton splitters had a 4.5" cylinder. Do you only have a 22 ton or a 25 ton with a small cylinder on it?

Using your math, a 4.5" cyl would provide 47689 lbs of push.

It says 25 tons on the side.

 

[ruffdog]

My 25 ton Speeco has a 4.5" cylinder. Measure on the rod end to get the inside diameter of the outer tube (cylinder bore). I just checked mine...4.5"

 

[oldnslo]

Could the cylinder be metric? 115 mm =4.528 in diameter

If I did the math correctly that is 48,3** lbs at 3000 PSI so 24 tons.

Depending on who made the pump it might go a little higher than 3,000 PSI but suspect it is purely sales since how many people actually check what the force is?

 

[ruffdog]

Could the cylinder be metric? 115 mm =4.528 in diameter

If I did the math correctly that is 48,3** lbs at 3000 PSI so 24 tons.

Depending on who made the pump it might go a little higher than 3,000 PSI but suspect it is purely sales since how many people actually check what the force is?

Speeco lists cylinder repair kits in INCH sizes. They have 4", 4.5", 5", kits.

 

[WinterDeere]

Could the cylinder be metric? 115 mm =4.528 in diameter

If I did the math correctly that is 48,3** lbs at 3000 PSI so 24 tons.

Depending on who made the pump it might go a little higher than 3,000 PSI but suspect it is purely sales since how many people actually check what the force is?

There's no need to check force. Just check pressure at cylinder inlet. Max force is achieved when pump kicks into low gear, which is probably close to 2 GPM on that 11 GPM pump. At 2 GPM, flow rate is low enough that system pressure drop is nearly zero (all 1/2" or larger lines), so it's safe for manufacturer to claim pump bypass pressure as uniform system pressure, under that condition.

22 tons would require 3500 psi on a 4" cylinder, which is indeed above the default/factory bypass pressure on many of these pumps, which usually come pre-set at 3000 psi (19 ton). But there's nothing preventing a given splitter manufacturer from turning the adjuster screw on the bypass check valve up to 3500 PSI, as many have done.

There are several members here who have a pressure gauge on their splitter, it'd be interesting to see what type of max pressure they see on a typical day of splitting. I'm sure everyone has peaked their system out into full bypass on occasion, not that interesting. But what force does it actually take to split 99.5% or 99.8% of all your firewood? That'd be a useful number for many.

 

[Bavarian]

My 25 ton Speeco has a 4.5" cylinder. Measure on the rod end to get the inside diameter of the outer tube (cylinder bore). I just checked mine...4.5"

I got to have a closer look tomorrow.

 

[WinterDeere]

I got to have a closer look tomorrow.

You can usually measure cylinder bore pretty easily at rod end, as the cylinder bore casing extends past the gland a bit. Old-school internal diameter calipers and a ruler or tape measure are the way:



If that doesn't work, measure OD by wrapping a seamstress tape around the cylinder, dividing by pi = 3.14159, and then subtracting 2x wall thickness.