Building a small log splitter


The wood I split comes in all sizes, from ‘stove wood’ diameter, to larger trees that have been pre-split with a stump splitter.

I went with the sliding wedge, horizontal/vertical configuration for a number of reasons, but I hardly ever use it in the vertical position.

These beam sections are salvage, and the axle came from the back of a SAAB 96.  I did not originally intend for this rig to leave the yard, and this axle configuration later proved  too weak for highway travel.

As in, it bent.

The new axle is obscured in this photo by the old axle, still used as to support the stabilizers and taillights.  Note the heavy triangular bracing.

Of course, the new axle came from a SAAB 900.  This is partly because I had a few on hand, but also because I use a 900 as a tow vehicle, and one spare tire covers both.

The beam is a bit light for the purpose. This is a finesse splitter, so it works just fine so long as judgment is used in what to split and how to go about splitting it.

The galvanizing required a bit more prep work before welding.

The foot plate is common steel.  I should have used thicker stock, or a stronger grade of steel.  After many cord, and a few rounds of  “Can I borrow your splitter…”, this part has bent slightly.

The lack of ‘grippers’ on the plate allows smoother block movement onto and off of the splitter.  My chainsaws cut straight, so the blocks sit square against the foot plate and stay put.

Completed weldment.

Detail of hinge.  Common bar bored for the stainless pin.

Getting there.  Fabricating al fresco.  I need a new umbrella…

The cylinder came from a bucket truck.   The oversized rod is an advantage.  It provides a favorable volume ratio between the piston and rod side of the cylinder, which reduces retract time.  The bore itself is 3″, which is enough to split anything within reason.

I don’t take any pride in shearing knotty wood.

The original ports were only 5/16″.  Larger ports were installed after beta testing.  Extend is 3/4″, retract is 1/2″.

Another view of the glad nut wrench.  A large lathe with a 4 jaw chuck is nice to have…

Cylinder was disassembled before porting to ensure that no debris got into the system.


Wedge in progress.  The cutting edge was repurposed from another splitter build that never happened. The upper leading edge of the baseplate has been beveled.  The two lead clamping bolts now have domed heads.

The overall height and ‘back angle’ of the wedge is scaled such that my (left) hand can pass over to catch and then throw the split, without hanging up on anything.

Good design goes beyond actual construction, and into considerations for operator comfort and economy of movement.

For a time I borrowed a neighbor’s splitter.  One of the irritating points of that unit was the lack of clearance in the operators area.  i was constantly bumping into the tire, and the motor got beaned from time to time.

Beer keg hydraulic oil reservoir.  Gets you points with the local Fraternity house, but welding steel to stainless with mild mig wire makes for porous weldments.

(This version still has the tiny cylinder ports, small filter, and small pump).

Constant seepage, lack of volume, and overall aesthetic led to an upgrade.

The new reservoir.  Aluminum pipe fittings were sourced from McMaster-Carr, TIG welded to the old propane tank.  Suction and return fittings have extensions inside the tank to prevent aeration etc.  The elbows proved to be a challenge with an air-cooled torch…

The uprated filter assembly.

And the bracket added shortly thereafter.  This was some scrap left over from another project.

The original filter was rated for 20 gpm.  I had a bit of a heat problem, most likely rated to the original small cylinder ports.  That was with an 11 gpm pump.  When I re-ported the cylinder, I also upgraded the pump. And went to a larger filter.  This reduced fluid heating drastically. The new pump is rated for 13.9 gpm.   There is almost no reason not to use a pump of this size on a small splitter. The 6.5hp motor is never taxed, and the ram speed is much improved over the original 10-11 gpm pump.  Given the minor cost difference between an 11 and 13 gpm pump, there is almost no reason to use the smaller pump.

One full cycle runs right around 8 seconds, depending a bit on engine speed.

Time and motion study:


When I installed an auto cycle valve on the processor, I had this valve left over.  The original had 1/2″ work ports, while this one has 3/4″ ports.  I don’t know that it makes much difference, but it seemed like a good idea at the time.

The return line has a proper JIC fitting, which makes servicing easier than the typical hose barb.

I don’t know what it is about these Prince valves, but they seem to develop leaks rather frequently out the back of the spool.  The previous valve leaked, despite two seal kits, and this one leaks as well.


A shutoff to the tank, to make pump removal simpler, should the need arise.

When I first put this rig together, I used clear, reinforced vinyl hose for suction and return (visible in previous photos). It was fairly cheap, sort of up to the task, and I wasn’t sure how the two lines should be best routed.  After several years of use, the return line split while a friend was using the splitter, which left quite a bit of oil in his driveway.

The hose routing was finalized with the addition of the larger control valve, so it was time for some proper hose.

Most of the time, I’m splitting 16″ blocks.  The cylinder has at least 24″ of travel, which adds up to a bunch of wasted time on the out and back.

The usual solution is the addition of a selective back stop to set the work aperature.

I had a stack of 1/2″ plate slugs left over from another project.  There is no need for such fine gap adjustment, but its what I had at the time.

The stack was bolted together, turned to diameter in the lathe, and the slot was cut out of the stack with a slotting saw on the horizontal mill.

When I towed this splitter with my SPG, the foot of the original jack would occasionally hit the ground.  This jack can swing up and out of the way, and it’s easier to crank as well.

Time and motion study splitting larger blocks.