New log splitter

[SWI Don]

One thing no one has mentioned that will speed up cycle time if you are doing wood < length of your stroke. ie 16-18" wood on a 24" stroke splitter. Go to your local farm supply and get some cylinder depth spacers. Farmers use them to set the retract stroke on farm equipment. My buddies splitter has a pipe with a stack of them on the axle of different thicknesses. You advance the cylinder until the throat is a little wider than your longest piece and stab spacers in to take up the extra stroke. It doesn't speed up the cylinder but since you have cut down your stroke your cut down your cycle time.

Don

 

[Whiteindustries]

Thats a heck of an idea!!!!

One thing no one has mentioned that will speed up cycle time if you are doing wood < length of your stroke. ie 16-18" wood on a 24" stroke splitter. Go to your local farm supply and get some cylinder depth spacers. Farmers use them to set the retract stroke on farm equipment. My buddies splitter has a pipe with a stack of them on the axle of different thicknesses. You advance the cylinder until the throat is a little wider than your longest piece and stab spacers in to take up the extra stroke. It doesn't speed up the cylinder but since you have cut down your stroke your cut down your cycle time.

Don

Thanks for the insight Don.I think I'll try that out.
Allan

 

[tawilson]

yeah, I've been trying to do that with clamps and such, didn't realize there was a product made to do it!

 

[jokers]

yeah, I've been trying to do that with clamps and such, didn't realize there was a product made to do it!

Yup! Tractor Supply has them here.

Russ

 

[logjammin]

thats also a good idea for a sort of go-no go gauge. space it up to what your fireplace will allow then you will know if certain logs will fit beore you split them. i hate it when i go to fill the fireplace and half the logs dont even fit. :angry2:

 

[SWI Don]

They are typically aluminum so scratching your chrome plated cylinder rod shouldn't be much of a problem. As long as your don't have some serious grit embeded in them. They typically ride along with the rod so there is not much relative movement.

logjammin

I have used them for just that purpose. I sometimes get a little greedy when I am cutting and some of the pieces get big. When they don't fit throw them to the side.

Don

 

[howel07264]

Here's some tips for hydraulic systems.[/B]

Alot depends on how fast you want your machine to move. Someone earlier said it right: PSI = power and GPM = Speed. Rule of thumb for hydraulics, assuming 85% pump efficency, is as follows:

1HP=1 Gpm @ 1500 psi

Theoretically based on the above said to run 22 GPM at 2500 psi will require 36.6 Hp engine. This however is NOT for a 2 stage pump. This is your basic single stage hydraulic pump.

The benefit of a 2 stage pump is the ability to gear down and provide higher PSI when a load is applied. A 2 stage pump will run at the higher flow until the pressure hits approx 650-750 psi. At which point the pump will gear down and provide approx 2500-3000 psi, 4 times higher than the 650-750, but the Gpm's (cylinder speed) will also be reduced by a factor of 4. On the higher pressure geared mode on a 22 gpm pump will move at 5.5 gpms.

Cylinder speeds*

4" bore @ 22 gpm = 405 in/per minute
4" bore @ 5.5 gpm= 101 in/per min.
5" bore @ 22 gpm = 259 in/per min.
5" bore @ 5.5gpm = 64.6 in/per min.
*these are for the push(power) stroke on cylinder. Retracting speeds will higher, with a large rod significantly higher, but vary dependant on rod diameter.

Power based on PSI and cylinder size

4" bore @ 750 psi = 9428 lbs
4" bore @ 3000 psi =37,710 lbs ( about 19 tons)
5" bore @ 750 psi = 14,730 lbs
5" bore @ 3000psi = 58,920 lbs (about 29.5 tons)

and for the Tim the tool man splitter...Hehe.... 14" bore @ 3000 psi = 461,700 lbs (231 tons!! I had to throw that in there)

Now bore is the internal diameter of a cylinder. I would recommend a 5" unless you are strickly doing pine or other easy splitting woods then a 4" will run just fine. The rod diameter is the nice shiny part the extends from the cylinder. This is what pushes the wedge. I would not recommend a rod of less than 2" on either a 4" or 5" bore cylinder. They most likely will bend at some point. A rod of 3" would be slick though and provide insanely fast retract speeds but a rod that big could potentially add 50%, give or take, to the price of cylinder.

Now other considerations that are very often overlooked on people making their own machines is hose selection. Certain criteria must be met or you will be literally be throwing speed and energy away and in some case significantly heating you hydraulic system up beyond recommended temps shortening the life of all components and wasting gas in the engine.

Pressure loss at given flow rates

10 gpm w/ 3/8" hose will drop 185 psi
10 gpm w/ 1/2" hose will drop 73 psi

20 gpm w/ 1/2" hose will drop 146 psi
20 gpm w/ 3/4" hose will drop 47 psi
20 gpm w/ 1" hose will drop 14 psi

25 gpm w/ 1/2" hose will drop 180 psi
25 gpm w/ 3/4" hose will drop 59 psi
25 gpm w/ 1" hose will drop 23 psi

These pressure drops are per 100 feet of hose. To get close to specific flow losses, look at what hose you desire to use for your pressure line and add 15 feet of hose length for each fitting the fluid must pass through. Now add 15 feet for each 90 deg fitting. Now add the length of the actual hose. Now do the same for your return line. Take the total number of feet between them both and divide by 100 feet. Now multiply the remaining number by the psi numbers given above.

Typically most systems are made from 1/2" but will loss about 180-240 psi due to friction. This friction wil be dissapated into heat and in some cases can cause chattering of a hose if the hose is quite bit under sized. Chattering hoses will rub and fail very fast potentially causing injury and sometimes burns if the system was run to long and system became super heated.

A loss of 200 psi means this to a logsplitter: the 2 stage pump will kick in at 200 psi lower, around 450-550 psi. This lower psi means your 2 stage pump will gear down when a much smaller amount of resistance to the cylinder in encountered. So instead of splitting easy stuff nice and fast it will gear down. Ever had your logger splitterbounce between fast and slow speed? This is one common cause. I personally would use 1/2" hoses at 15 psi and less. For pumps rated higher 3/4" hose to about 30ish gpms will work. Very important- make sure you hoser that runs to push stroke of the cylinder is rated for a working pressure of 3000 psi or greater. This is the down side of 3/4" hose since it costs about 2-3 times as much per foot as 1/2" hose. I should know, I sold around 23,000 hydraulic fittings this last year.

This took forever to write up but hope someone will make a little use of it.

PS- Hydraulic supplies off Ebay are a great way to go. I just spent $930 the other day on there buying stuff from a guy. All brand new. He saved me close to $700 dollars. And that's with the almost wholesale pricing I get too!

Best'o'luck!

great info! i replaced the pump on my stumper with a higher gpm unit and made it much faster. speed= MONEY!!!......regan

 

[046]

good info..

what model is the currently most bang for the buck?

harbor freight has this for $1,100
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91840

 

[046]

anyone familiar with current harbor freight offering?

they've got a 30ton with robin motor for $1,100

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91840

 

[DeanBrown3D]

splitez makes a decent splitter, all honda engines and the big ones have commercial pumps. This one is the 34 tonner:

11 second cycle time

 

[046]

splitez sure looks like an excellent machine, but 34 ton unit is $4K. way more that I want to spend.

 

[v8titan]

anyone familiar with current harbor freight offering?

they've got a 30ton with robin motor for $1,100

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91840

I'm curious to know how this 30 Ton Harbor Freight unit performs also. In general, Harbor does not have the highest quality stuff, but that Robin engine is good quality and the pump is a name brand as well. Sure would like to hear from someone who has one.

Tom

 

[mdlmjohnson]

harborfreight splitter

046: I know nothing specific about the splitter you asked about, but I would get much more in the way of specs and details, if I were you, before I bought it. A 30 ton splitter usually uses a 5" bore cylinder and develops about 30 tons at 3000psi, the max at which most cylinders used in splitters are rated.

I downloaded the manual on the Harborfreight splitter and it uses a 4.5" cylinder. That cylinder can only generate 47,700# of ram force at 3000psi and that is slightly under 24 tons. There is no way that a 4.5" cylinder, operating at usual hydraulic pressures, can generate 30 tons.

Moreover, the 1 3/4" rod is pretty marginal for a cylinder that generates that force. I have a 2 1/2" rod in the 5"bore cylinder that I am using in the splitter that I am building.

Also, a splitter that can generate even 24 tons (not to speak of 30) needs to have a pretty strong structure or it will be subject to twisting (deflection in the beam) at maximum pressures. The spec doesn't say the beam size, but it looks like about a 5 1/2" I beam. H beams are stronger and by way of contrast I am using an 8x8 H beam on the 30 ton splitter that I am building. I'm not saying that this is necessary; I've probably overdesigned mine, but anything less than a 6x6 with reenforcing gussets and endplates may not be adequate.

Finally, the manual specs say that it has a 2.5 gal hydraulic reservoir. That is very thin for a 16gpm pump; the usual rule of thum is 1 gal of reservoir for each gpm of pump capacity. The reason is the need to dissipate the fluid's heat. Excessive heat may build up in the hydraulic fluid, especially under heavy or continuous operation. Heat buildup is increased by smaller diameter hydraulic tubing and the specs do not disclose the size of the tubing/hoses.

Bottom line is that there are lots of ways to save $$ when building a splitter but lots of them affect the quality and durability of the machine in important ways. Generally, you get what you pay for. Were it me, a splitter is not a machine that I would try to cut corners or save $ on. I'm not saying that the HF splitter won't do its job; I haven't inspected or used one and I don't know; but the description of it leaves me with enough doubts so that I wouldn't spend my money on it without a lot more information.

Hope this helps. Good luck.

 

[DDM]

I didnt know harbor freight sold anything that wasnt a quality import.

 

[CaseyForrest]

I downloaded the manual on the Harborfreight splitter and it uses a 4.5" cylinder. That cylinder can only generate 47,700# of ram force at 3000psi and that is slightly under 24 tons. There is no way that a 4.5" cylinder, operating at usual hydraulic pressures, can generate 30 tons.


You are correct if you are figuring pressure on the surface area of the ram. But you also must then figure out how many square inches the face of your wedge is, the point I mean because thats where all that tonnage is being applied to.

 

[mdlmjohnson]

ramforce

CaseyF, I'm not sure that I'm following you. The total ram force doesn't (I think) get any greater or less, regardless of the area of the area of either the wedge or the push plate. Since the wedge itself is generally sharpened the area of the knife edge is negligable and thus the ram's force is concentrated on a very small area indeed. As for the push plate (on splitters where the wedge is fixed and the cylinder/rod pushes the log into it) I don't think the ram force isn't either increased or decreased by the area of the push plate.

Have I got this wrong? Or am I just misunderstanding your point. I thought that the "tonnage" of a log splitter was the ram force generated by the cylinder and that, I think, is solely a function of the cylinder area multiplied by the pressure (in psi) of the hydraulic fluid.

You're obviously more experienced and knowledgeable about this stuff than I am, so I would appreciate your patience in explaining what I have missed.

 

[046]

thanks... this helps a ton!

ratings can and do get inflated. sure would like to hear from someone who has owned one of these.

046: I know nothing specific about the splitter you asked about, but I would get much more in the way of specs and details, if I were you, before I bought it. A 30 ton splitter usually uses a 5" bore cylinder and develops about 30 tons at 3000psi, the max at which most cylinders used in splitters are rated.

I downloaded the manual on the Harborfreight splitter and it uses a 4.5" cylinder. That cylinder can only generate 47,700# of ram force at 3000psi and that is slightly under 24 tons. There is no way that a 4.5" cylinder, operating at usual hydraulic pressures, can generate 30 tons.

Moreover, the 1 3/4" rod is pretty marginal for a cylinder that generates that force. I have a 2 1/2" rod in the 5"bore cylinder that I am using in the splitter that I am building.

Also, a splitter that can generate even 24 tons (not to speak of 30) needs to have a pretty strong structure or it will be subject to twisting (deflection in the beam) at maximum pressures. The spec doesn't say the beam size, but it looks like about a 5 1/2" I beam. H beams are stronger and by way of contrast I am using an 8x8 H beam on the 30 ton splitter that I am building. I'm not saying that this is necessary; I've probably overdesigned mine, but anything less than a 6x6 with reenforcing gussets and endplates may not be adequate.

Finally, the manual specs say that it has a 2.5 gal hydraulic reservoir. That is very thin for a 16gpm pump; the usual rule of thum is 1 gal of reservoir for each gpm of pump capacity. The reason is the need to dissipate the fluid's heat. Excessive heat may build up in the hydraulic fluid, especially under heavy or continuous operation. Heat buildup is increased by smaller diameter hydraulic tubing and the specs do not disclose the size of the tubing/hoses.

Bottom line is that there are lots of ways to save $$ when building a splitter but lots of them affect the quality and durability of the machine in important ways. Generally, you get what you pay for. Were it me, a splitter is not a machine that I would try to cut corners or save $ on. I'm not saying that the HF splitter won't do its job; I haven't inspected or used one and I don't know; but the description of it leaves me with enough doubts so that I wouldn't spend my money on it without a lot more information.

Hope this helps. Good luck.

 

[CaseyForrest]

CaseyF, I'm not sure that I'm following you. The total ram force doesn't (I think) get any greater or less, regardless of the area of the area of either the wedge or the push plate. Since the wedge itself is generally sharpened the area of the knife edge is negligable and thus the ram's force is concentrated on a very small area indeed. As for the push plate (on splitters where the wedge is fixed and the cylinder/rod pushes the log into it) I don't think the ram force isn't either increased or decreased by the area of the push plate.

Have I got this wrong? Or am I just misunderstanding your point. I thought that the "tonnage" of a log splitter was the ram force generated by the cylinder and that, I think, is solely a function of the cylinder area multiplied by the pressure (in psi) of the hydraulic fluid.

You're obviously more experienced and knowledgeable about this stuff than I am, so I would appreciate your patience in explaining what I have missed.

Allright, if you have a 4 in cylinder, the surface area of the ram inside the cylinder is 12.56 sq in. If you are running 2500psi you have a 31,400 pounds of splitting force.....On the cylinder. Now, the surface area of the knife edge on your wedge is not 12.56 sq in, its WAY les than that, so the tonnage on your cylinder gets mutiplied slightly. Lets say that the area of the knife edge is 1.4 sq i, then you multiply your 31,400 by the 1.4 and you get your tonnage at the wedge....which comes to just under 44,000, which equates to 22 ton. 22 ton is normal for a 4" splitter.

 

[v8titan]

Pounds of splitting force equals= (hydraulic pressure in psi) X (piston surface area in sq. in.). I have never heard of the size, shape or color of the wedge entering into the calculations but it may be how HF does their calculations.

I agree with TC. Splitting force is spec'd in force (pounds) not in force per unit area (pounds/sq. In). Therefor bringing the area of the splitting wedge back into the equation means absolutely nothing in determining the total force that the ram is capable of generating. I'm not sure how the HF guys get away with claiming that their unit is 30 tons unless they are running abnormally high pressures which is not likely.

 

[v8titan]

I did a litte more research myself on the HF splitters. For me, I just plan to split 4 to 6 cords per year so I'm not looking for a production machine. Someone said that the oil resevior should have 1 gal of oil per each GPM flow rate to allow for heat disipation. This may be true for a production machine that is running many hours at a clip. I see myself splitting maybe an hour at a time or so and don't really worry too much about overheating the oil. Maybe you need to keep an eye on that.

Here is a thought I had about how the HF splitter is spec'd. To generate 30 tons of force ie. 60,000 lbs with a 4.5" cylinder, you need oil pressure of 3774 PSI. This may not be unrealistic. I visited the Haldex web site, they use these pumps on the HF splitters, and found that there are 2 stage pumps that max out a 4000 PSI. The problem I have is that I don't know what model pump the HF splitter uses. Another interesting thing I noticed is the 24 ton HF splitter (91839) has an 11 GPM pump and the total unit weight of 498 lbs. The 30 ton unit uses the same 9 hp motor and what appears to be the same 4.5 inch cylinder but it has a 16 GPM pump; this unit weighs in at 663 lbs. Obviously they beefed up something to allow for the higher splitting force, my guess is the I beam is heavier. Maybe it is running at the higher pressures after all.