Log Splitter Wedge Angles

[Wood Doctor]

That is an interesting theory and using a quickie CAD program I drew up what my old splitter had for a wedge angle (from my memory) and it came out to 38 degrees. Knowing the welder that made my splitter and the fact that he was a machinist for over 50 years by the time he built my splitter, I bet he was shooting for that angle of 42 degrees. I am willing to bet that is what the angle was and my CAD skills are not good enough to get the angle right.

That same welder/machinist proposed to us that we make a wedge that was curved on the front much like an axe, but he said it was too much of a PITA for him to make, and as he pointed out we had never stalled our's only about 3 times, so why screw with it.

Homeowner woodsplitters with the wedge on the ram have the advangtage of being able to be tipped down, but commercial splitters made to handle big wood have a lift. Two different categories of splitters homeowner's vs commercial, apples to oranges. Commercial operators want the split wood to be gone from the splitting area so they pass it through a wedge and it drops off onto a conveyor and is taken away. A commercial splitter with a wedge on the ram would require an operator to handle every piece of wood to get it onto a conveyor. That is wasted energy.

I had to correct that. The common chisel angle is 25 degrees and planer angles are usually 42 degrees. :blush:

I also note that splitters using a fixed position wedge and running horizontally tend to have a slant angle (B) that exceeds 90 degrees. But if the wedge moves, they go the other way--between 75 and 80 degrees, similar to my OP diagram. Maybe the idea is that if less than 90, less force is required and the lift up you describe might be appreciated for big logs? Just a thought.

Anyway, the splitter I am now operating has a 42-degree wedge angle and an 80-degree slant angle. This little dream operates on a 6 hp engine, 2-stage, 16 gpm pump, and a miniscule 3" cylinder. It will outsplit a bigger one running on a single-stage, 16 gpm pump, 4" cylinder, and an 8 hp engine. That one has a 35-degree wedge with no slant. I'm starting to think that the better wedge design has a lot to do with it.

 

[eric_271]

This is the only one of 5 different splitters that I have run that has never been stopped or had a piece of wood stuck on it.

 

[Wood Doctor]

Looks Good, Eric

This is the only one of 5 different splitters that I have run that has never been stopped or had a piece of wood stuck on it.

Excellent, Eric! A 2-stage wedge? It looks like the front snout has about the same angle on it as the back of the wedge. It starts the splitting action and then the back of the wedge eventually takes over when the log starts to give.

I like this idea. Looks like the wedge angle on both the front and the back is between 45 and 55 degrees, but it's a bit hard to tell. Can you get a ballpark measurement on it?

This has got to be superior to anything being sold at the supply shops (like Northern Tool). Note also the taper of the bottom plate that prevents a jam up against the outer edge of the log.

 

[Curlycherry1]

This is the only one of 5 different splitters that I have run that has never been stopped or had a piece of wood stuck on it.

I used a splitter with a wedge like that and from what I found, the stringy wood had would cause the ram to have to exert more force all the way through the split. For knarly wood it the pump would kick into second stage and stay there through the whole log. With the straight hunk of steel with just a taper on the front, the pump would drop back to first stage and stay there.

I also tore three of those off my beam in the space of about 2 years and ~1500 face cords of wood. After the 3rd time we decided to got with the flat steel and never had a problem other than the steel tearing once.

 

[triptester]

I think the search for the perfect splitter wedge may be impossible to find due to many variables such as , fixed wedge ,moving wedge, cylinder size ,and mainly type of wood. Wood that splits easily will often work quicker with a wide or winged wedge especially when mounted on a ram. With stringy wood a narrow fixed wedge often works better where the following block finishes pushing the first.

 

[eric_271]

Excellent, Eric! A 2-stage wedge? It looks like the front snout has about the same angle on it as the back of the wedge. It starts the splitting action and then the back of the wedge eventually takes over when the log starts to give..

The thin knife makes it easier starting the split and yes the wide back end spreads the wood much faster. Normally I don't have to run the wedge much past half way out which shortens cycle time.

 

[eric_271]

I also tore three of those off my beam in the space of about 2 years and ~1500 face cords of wood.

The differance between this one and yours is that this one can not be torn or broken off. If I had built yours you would not have had that problem either.

 

[eric_271]

I like this idea. Looks like the wedge angle on both the front and the back is between 45 and 55 degrees, but it's a bit hard to tell. Can you get a ballpark measurement on it?

I will get you the measurements Doc.

 

[Curlycherry1]

The differance between this one and yours is that this one can not be torn or broken off. If I had built yours you would not have had that problem either.

Baah! I can break anything! When I tore the ones off my splitter the welder was impressed. When he said he would fix me for good and changed to the flat steel he said he was 100% sure I would not be back with that problem again. A year later I had torn the steel wedge, just like a piece of paper about 1.5" above the beam. Split the steel right in half. It was all sparkly and pretty, kind of like diamonds.

 

[eric_271]

Wood Doc

Let me know if this does not tell you what you want to know.

 

[eric_271]

Baah! I can break anything! When I tore the ones off my splitter the welder was impressed. When he said he would fix me for good and changed to the flat steel he said he was 100% sure I would not be back with that problem again. A year later I had torn the steel wedge, just like a piece of paper about 1.5" above the beam. Split the steel right in half. It was all sparkly and pretty, kind of like diamonds.

Yeah and all welders are created equal right?

 

[eric_271]

The back plate on the wedge is 1'' 1/2 thick and the sides are 1/2 thick. The knife is 1'' thick 4'' front to back and 9'' tall 4130 that I heat treated. Its all welded inside then capped and welded on the out side.

 

[Wood Doctor]

Here are the wedge angles

Let me know if this does not tell you what you want to know.

That's all I needed to calculate the angles to within a degree or so. I get 42 degrees on the front nose and 48 degrees on the back wedge.

A few may disagree a hair. I used MS publisher to draw a trapezoid for the back wedge and then added a triangle on the nose of the trapezoid. That's a bit crude but effective.

If it doen't pop, the log will start to contact the back wedge exactly half way up its sides and the back wedge will then start prying it apart as the "second stage" of the wedge kicks in. Note also that you are reducing sliding friction because almost half the wedge doesn't contact the log during the split.

Frankly, Eric, I think this is rather ingenious design.

 

[Steve NW WI]

Got to thinking a bit while reading some of the failure posts above. On my splitter, my tall narrow wedge is 16" tall. (It is also close to 20" front to back, so a lot of welded area.) Angling the top of the wedge inward (toward the ram) would give a lot more leverage toward tearing / breaking it out, and the opposite with one leaned back. If I were to make another, probably a 10° lean to the back might be a good addition, but I would lose the split through ability I talked about earlier, unless I put a similar angle on the ram.

Just some more fuel for the fire. This is kinda fun. I'm no engineer, but I'm working on a PhD in Applied Hillbilly Injuneering!

 

[eric_271]

That's all I needed to calculate the angles to within a degree or so. I get 42 degrees on the front nose and 48 degrees on the back wedge.

A few may disagree a hair. I used MS publisher to draw a trapezoid for the back wedge and then added a triangle on the nose of the trapezoid. That's a bit crude but effective.

If it doen't pop, the log will start to contact the back wedge exactly half way up its sides and the back wedge will then start prying it apart as the "second stage" of the wedge kicks in. Note also that you are reducing sliding friction because almost half the wedge doesn't contact the log during the split.

Frankly, Eric, I think this is rather ingenious design.

Lol thanks but the wedge was invented before I came along. This is just my version

 

[eric_271]

I'm no engineer, but I'm working on a PhD in Applied Hillbilly Injuneering!

Lol yeah me to.

 

[huskys rule]

I have always built my own and use a piece of 1" with a double bevel about 1.75" back then weld an x-tra kicker of bucket edge on for a double angle and to kick the log wide open.

 

[gink595]

I've played around with a couple different methods, I was using a single 1" wedge with a kickout at the bottom to "crack" the bottom.

I didn't really care for how it worked with the 4-way, the little bump out seemed to work, but If I did it again I would put it in the middle of the wedge and see how that works. The problem I had with the bump out wedge at the bottom is that sometimes a piece would want to rid up on it, and then ride the wedge up.

I have since revamped my wedge system, I haven't completed it but have tried out the songle portion of it ans it seemed to cut easier.

 

[huskys rule]

nice i had thought about doing that adjustable 4-way but never did. good job

 

[archertwo]

My front splitting wedge is as straight as I could weld it to being 90 degrees to the beam. It's made out of a 12" x 6" X 1" piece of 400 hard steel with wedges cut out of 5" channel iron to form the wedge portion on the back.
If I had it do do over again I'd eliminate the channel iron wedge portion. I think now that it's overkill.
The 4-way wedge is angled so the block coming from the first wedge hits it as square as possible. It seem to be working out pretty well. I've only split 5 cords with the 4-way attached. Time will tell.