Log splitter questions?

[Timleech]

I haven't bothered with logs for a few years, but mother nature made us a present of half a large beech tree in a storm a few weeks ago.
While splitting the logs with an axe, I've been contemplating building a splitter for the awkward, knotty ones.
A search on here has come up with some homebrew splitters, but they all seem to be hydraulic and my thoughts were along the lines of electro-mechanical. I've got a big lathe leadscrew (40mm dia) taking up space, I could make a big bronze nut for that, and some wheelchair type (and a bit bigger) 12 & 24V motors, plus some truck batteries doing nothing. Anyone tried or seen anything along the lines I'm thinking?
Commercial splitters seem to be about 4 tons upwards (a long way upwards!), what force is really needed to split a knotty hardwood log?
My stoves will only take fairly short pieces, I don't know how much bearing the length has on splitting force required?

Thanks
Tim

[b2u44]

Leadscrews are usually very inefficient at transmitting power. Typical Acme screws may use only 20% of the input power for linear motion (the other 80% is used to fight friction). I have not seen any log splitters that use leadscrews, and I imagine that the terrible efficiency is probably why.

[Rookie machinist]

How about renting or borrowing one. If you only use it on a rarely might be alot easier.

[Mike Burdick]

Tim,

How much force the log splitter needs depends on the type of wood. A straight grained pine for example will split very easily while a knotty old cottonwood may take in excess of 30 tons. If you build a mechanical splitter I'll bet you'll have trouble designing it to produce 10 tons - that's why hydraulic power is the usually the choice. When it comes to log splitters one can't have enough power! I have a hydraulic log splitter that produces 48 tons of force with a 10 second cycle time and even that will get stuck in a log sometimes. Also, keep in mind cycle time – even 10 seconds can seem like a long time! If you're using a screw, I'd hate to think about the cycle time on that!

But...having said that....Why don't you make one with what you have! It may work and you'll learn alot! Please post back with what you finally decide!

Thanks...

[timcasbolt]

There are commercially available screw-type splitters. They are the absolute cheapest ones on the market. I would think that they would work very poorly for all the reasons mentioned above.

[bruto]

Screw driven wedges are slow, and unless you rig some kind of half-nut, which will weaken it, it takes just as long to retract as it does to split. I've seen some very cheap screw splitters advertised, but doubt they'd be much use.

At first, I thought the subject was screw-auger type splitters. Not very popular now, but a screw on the end of a cone, properly set up, will split almost anything. It's kind of messy, lots of splinters, but relatively efficient. I had one years ago, that someone gave me, that was powered by rollers. Drive a car on, chock the wheels, and put it in gear. A dead man switch was necessary to prevent it from driving off the rollers in case of a really gnarly log, but it did work.

Not an economical solution for the occasional splitter of serendipitous beech trees, but my favorite splitter is the flywheel-powered "Super-Split." I have an older one of these (fortunately inherited, so I didn't have to pay for it), and it splits almost anything you can throw at it with a 3/4 horsepower electric motor. Nasty logs can take two or three cycles, but the overall speed is so high that it still ends up being faster than just about anything else. Scary fast, in fact. You need to be really paying attention, and keep all attempts at assistance at bay. But watch the animation at the web site. It's that fast in the real world, no hype. Too bad it's so expensive.

http://www.supersplit.com/

[Duffy]

Splitting "awkward, knotty" logs is no walk in the park. I help my buddy split a mix of maple, apple, beech, and elm. We use a 65 hp deisel tractor with a hydraulic splitter on a 3 point hitch. We can stall the ram on an elm or maple crotch. I have lots of time on a handraulic splitter, and after slabbing off whatever you can, IMO the next best tool is a chainsaw. Even a mickey mouse 11 amp electric with a sharp chain will rip a block of firewood in half in about 3 minutes, and they hardly vibrate and dont roar at all. You need an AWFUL lot of knotty pieces to justify a splitter, unless it is loaned and delivered!

[Timleech]

Screw driven wedges are slow, and unless you rig some kind of half-nut, which will weaken it, it takes just as long to retract as it does to split. I've seen some very cheap screw splitters advertised, but doubt they'd be much use.

At first, I thought the subject was screw-auger type splitters. Not very popular now, but a screw on the end of a cone, properly set up, will split almost anything. It's kind of messy, lots of splinters, but relatively efficient. I had one years ago, that someone gave me, that was powered by rollers. Drive a car on, chock the wheels, and put it in gear. A dead man switch was necessary to prevent it from driving off the rollers in case of a really gnarly log, but it did work.

You mean like this?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=140203550304

Not an economical solution for the occasional splitter of serendipitous beech trees, but my favorite splitter is the flywheel-powered "Super-Split." I have an older one of these (fortunately inherited, so I didn't have to pay for it), and it splits almost anything you can throw at it with a 3/4 horsepower electric motor. Nasty logs can take two or three cycles, but the overall speed is so high that it still ends up being faster than just about anything else. Scary fast, in fact. You need to be really paying attention, and keep all attempts at assistance at bay. But watch the animation at the web site. It's that fast in the real world, no hype. Too bad it's so expensive.

http://www.supersplit.com/

I want one

Tim

[Peter S]

The conical-screw type splitters I have seen were absolutely simple (like an enlarged conical arbor as used for polishing mops). They were a cone fitted directly to the tractor PTO shaft. I think there was a small plate bolted just below, to rest the block of wood on. They were very cheap in comparison to other powered splitters, but of course they assume you already have the not-so-cheap tractor! I saw them at agricultural shows many years back being demonstrated, but not sure if anyone uses them nowadays, with hydraulic splitters available.

[bruto]

The conical-screw type splitters I have seen were absolutely simple (like an enlarged conical arbor as used for polishing mops). They were a cone fitted directly to the tractor PTO shaft. I think there was a small plate bolted just below, to rest the block of wood on. They were very cheap in comparison to other powered splitters, but of course they assume you already have the not-so-cheap tractor! I saw them at agricultural shows many years back being demonstrated, but not sure if anyone uses them nowadays, with hydraulic splitters available.

Yes, I've also seen them arranged to bolt directly to the rear wheel of a pickup truck: just jack up that side, and split against a beam on the ground. As long as you don't have limited slip, you don't have to jack up the other side. The problem I'd foresee on the tractor type is that if you ever did get a log stuck, most PTO's don't have a reverse, so it would be pretty hard to get out.