Building a wood splitter, I need some opinions please

[dlb1999]

I am building a wood splitter basically from scratch.
I will be using an 8HP Briggs and Stratton motor with 16 gpm two stage pump. (minimum size engine for this pump)
My splitting wedge will be stationary, welded to the end of the beam.
I am trying to decide what size cylinder to buy. I don't know whether to use a 4" bore, 4 1/2", or 5".
I researched several manufactured log splitters and compared specs. The northern star ones from northern tool use a 5" for 16gpm pump but the
motor they are using is bigger than an 8 horse. I want to have good cycle times and splitting power but I don't want to bog the motor down all of time.
Since I am using the minimum size motor for this pump should I stick to a 4" cylinder??

Also- my I-beam has 3/8" thick flanges and web. The flanges are 6" wide. I forgot to measure the height of the beam but I would guess it is 8 or 10" tall.
Maybe a 4 1/2" or 5" cylinder would be too much for my beam?

I really need some advice from someone who is experienced with designing and building log splitters.

Thanks.

 

[gpsman007]

When I built mine I went with dalton Hydro

Hydraulic Supply | Dalton Hydraulics | Tie Rod Cylinders

I built one last winter and found these guys were very helpful and had the stuff I needed and the knowledge to help me set it up with a valve with power beyond so I could run a lift

 

[Deereman76]

Go Here:

Baum Hydraulics Corp :: Spec Calculator

Hydraulic calculator #1 Will Give you Force, Based on Cylinder Measurements and Pressure

Hydraulic calculator #3 Will Give you Cycle times based on Cylinder Measurements and pump Flow.

I would take a Sheet of Paper, and Calculate the Force and Cycle times for each prospective Cylinder size, then think about which one makes the most sense based on how you would use it! Good Luck!

 

[triptester]

For the components you have Iwould go with a 4" bore cylinder. With the fixed wedge you can you can keep it narrow (1" ) which gives the least resistance when splitting and also allows for adding a 4-way.
The slide for the push plate should be 6"long min. or 1" longer than the push plate is high.

 

[CJ1]

Trip has good advise. I make my wedges out of 1/2" plate steel angle them in just a little and use little to no kickers on them, just enough for bracing at the back. A 4" bore cyl at 3000psi = 36000lb I have only had maybe 3 rounds that I had to relocate on my splitter because it would not split and they were huge hard Maple chunks full of knots that we set on the splitter with a front end loader. CJ

 

[WidowMaker]

Think if I were doing it again, building or buying it would be a 2 way splitter with lift...

 

[dlb1999]

Thanks, everybody for your advice.
I did not mention that I already have a 3 1/2" bore cylinder that was given to me for free.
I was not going to use it because I thought that it was too small although it will probably work fine for most of wood I'll be splitting.
But I came up with another idea today. I'm going to go ahead and use the 3 1/2" cylinder I have but I'm going to use
quick couplers for the hydraulic connections and I'll have quick-release keepers on the pins. I'm going to buy a 4 1/2" or 5" cylinder
that I can quickly swap with the 3 1/2" one.
All split all of my 'easy' wood with the 3 1/2" and then save my big knotty chunks for last and switch
to the bigger cylinder. This way, I can take advantage of a fast cycle time when splitting smaller logs.

I hope it works out.

 

[shelbythedog]

Thanks, everybody for your advice.
I did not mention that I already have a 3 1/2" bore cylinder that was given to me for free.
I was not going to use it because I thought that it was too small although it will probably work fine for most of wood I'll be splitting.
But I came up with another idea today. I'm going to go ahead and use the 3 1/2" cylinder I have but I'm going to use
quick couplers for the hydraulic connections and I'll have quick-release keepers on the pins. I'm going to buy a 4 1/2" or 5" cylinder
that I can quickly swap with the 3 1/2" one.
All split all of my 'easy' wood with the 3 1/2" and then save my big knotty chunks for last and switch
to the bigger cylinder. This way, I can take advantage of a fast cycle time when splitting smaller logs.

I hope it works out.

I like where your head is at regarding cycle times, but I can't see myself swapping cylinders for the big roungs. I would noodle anything the small cylinder couldn't push through long before I was pulling pins and undoing hydraulic couplers. JMHO.

 

[palmrose2]

I've got an 8 horse Tecumseh mated to an 11 gpm two stage pump powering a 4" cylinder. I have the point at which the pump dives into the lower stage screwed down tight so that it rarely goes into the second stage. My bypass valve is adjusted to the max too, and although I have never put a gauge on it, what harm could a little high pressure blast of hydro do to you? (; The engine never skips a beat. This took a little trial and error.

If I had to do it over again I would probably go with a 13 gpm pump with the 4"cyl. Having an 8hp and 16 gpm pump, I would probably chose the 4.5" cyl. The 11 gpm pump was practically given to me.

3.5" cyl area = 3.14 x (1.75x1.75) = ~9.616" 4" cyl = 3.14 x 4 = 12.56" 4.5" cyl = 3.14 x ~5.06 = ~15.9" 5" cyl = 3.14 x 6.25 = 19.625"

The 5" cyl is twice as slow and twice as strong as the 3.5" cyl.

You probably want to do your calculations based on 2000 psi as opposed to 3000psi, as hoses in the 3000psi range are harder to come by.

I really need to get a gauge on my rig. Especially because I've been known to loan it out.

When alone, I usually run the engine around 2500rpm and it splits plenty fast enough for me to keep up with it. At 3800 rpm I can keep 3 healthy males busy splitting and stacking.

I recently fabbed up a slip on 3 way wedge. My main wedge is at a slight angle, top towards the cyl. I just slap it on when i think the splitter can handle it, which is almost always. It's a poor man's version of this. Homemade 30 ton Log splitter with log lift and adjustable 4-way blade - YouTube This is how to make a bigger cylinder fast.

 

[mga]

what size ram is on the cylinder?

anything less than 2" won't last.

 

[kyle1!]

He really needs to buy a longer beam and reconsider buying my 4x30x2 Prince cylinder :biggrin::msp_razz:

Brian

 

[palmrose2]

what size ram is on the cylinder?

anything less than 2" won't last.

I don't know where the mga quote came from, but this is a point worth talking about. IMHO a ram as small as 1.25 " is probably good enough. Mine is 1.5". Obviously clamping or otherwise holding the ram end of the cylinder becomes more important with a smaller ram, but if everything is strapped down so you can't get any side pressure I would think you would be good to go. I would sure hate to bend one.

The bigger the ram, the faster the cylinder will retract because there will be less volume to fill. I would love to have a 3" ram with a 4" cyl. Lightning fast retract times.

 

[dlb1999]

what size ram is on the cylinder?

anything less than 2" won't last.

It has a 1 3/4" ram. It will be performing a straight push with no side loading.
It should work fine.

 

[dlb1999]

I don't know where the mga quote came from, but this is a point worth talking about. IMHO a ram as small as 1.25 " is probably good enough. Mine is 1.5". Obviously clamping or otherwise holding the ram end of the cylinder becomes more important with a smaller ram, but if everything is strapped down so you can't get any side pressure I would think you would be good to go. I would sure hate to bend one.

The bigger the ram, the faster the cylinder will retract because there will be less volume to fill. I would love to have a 3" ram with a 4" cyl. Lightning fast retract times.

My push/slide is made of 1" thick plate with two 1" thick gussets. I used 3/4" thick plates to wrap under the beam. There is no more than 1/8" of clearance between any part of my slide to my beam. It is not going to move around enough to bend the rod, I don't think. I won't be exceeding the hydraulic limits of the cylinder so that should not be a problem either.

When I was asking about cylinder size earlier, I had already done all of the math concerning flow, cylinder cycle time, etc...
I just needed some "real world" opinions from people who build and use splitters. Thanks to everyone who responded.
I'll post some pics when I get it assembled in a few weeks.

 

[dlb1999]

One more question.
What are your opinions about how close the pusher needs to come to the wedge when the cylinder reaches full stroke?
Nearly touching? Or will an inch or two or three suffice?

 

[Steve NW WI]

Here's how mine is built, the plates on the sides go past the end of the ram just a 1/2" or so. It helps a lot when splitting really stringy stuff. Also, the gap between the two side plates is a good place to put those pieces that invariably get cut at an angle so they don't slide off.

 

[dustytools]

Here's how mine is built, the plates on the sides go past the end of the ram just a 1/2" or so. It helps a lot when splitting really stringy stuff. Also, the gap between the two side plates is a good place to put those pieces that invariably get cut at an angle so they don't slide off.

I like this!! I think that I will modify my push plate.

 

[dlb1999]

Here's how mine is built, the plates on the sides go past the end of the ram just a 1/2" or so. It helps a lot when splitting really stringy stuff. Also, the gap between the two side plates is a good place to put those pieces that invariably get cut at an angle so they don't slide off.

That's a cool design. I'll consider it.
If I don't do it that way, I'll make sure the pusher ends up very close to the wedge without touching it.

 

[Boogieman142]

I'd go with a 4" prince cylinder and definately wouldn't be swapping cylinders, that would get old fast. I'd put the money into a good sized W-beam first. my pusher comes 1/4" from the wedge on the one I built. The engine has little to do with the power as long as it can spin the pump. Its all the bore of the cylinder and the operating pressure. There are several of us that have built splitters here so ask away. P.S. I ordered most of my hydraulic stuff from Surplus Center - Hydraulics, Engines, Electrical and More

 

[indiansprings]

I'd put a 4.5" x 24" on it and be done. Have two splitters, one is similar to your set up, the 16gpm does a great job with the 4.5x24, plenty fast, only retract to the length of wood we are splitting anyway, so full ram cycle times seldom apply. We've not had a piece yet we haven't split yet. When building it make sure you put a big enough hydro tank to keep your hydro oil temps reasonable.