Splitting big logs

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Advice from sawyers on what to do with logs that are too big for your mill. September 19, 2001

I'd like to learn about different methods used to split logs that are too big for the mill. I know you can chain saw them, or use a maul and wedges, but wonder if there are not easier ways, other than taking the log to a bigger mill.

Forum Responses
This might not work for you, but it has worked well for us. We found someone with a Lucas mill. When we get logs too big for our Woodmizer, he comes in and cuts them down to size with it until we can handle them. Most of the time we swap work with him--the Lucas mill is very good at some types of cutting, not at others, and the arrangement works well for both of us. Splitting with a chainsaw is a lot of work, as is using wedges, and this eliminates a lot of time wasted.

From contributor M:
Two different ways we did it in the wood was to take a d7 winch cable, wrap it around the far end of the log and back the cat up to it, hook the line to the back of the cat and rip it through there. Not very good on the cable but it does go through in a hurry! The other way is black powder--drill a few holes and pack it in--ka-boom. I really don't expect this to help but it is the truth and probably not feasible now.

From the original questioner:
I don't know what a Lucas mill is, and I do not have access to a D 7.

I do have several cans of black powder though, but only one short end of fuse. I'm glad you mentioned the black powder, because I saw a guy blow a log that was too big for my mill 2 weeks ago and wondered if anyone else used this method. He shoved the end of his chain saw (20 inch bar) into a 48" log as far as it would go. Poured some black powder in the hole, placed in some fuse, and then packed it shut with powdered brick, lit the fuse, and boom! It laid that log in 2 pieces about 18" from each other. Not perfect halves, but nonetheless, I could handle them after that. Black powder is easy to find, but I am having trouble finding fuse.

The thing that made me a little nervous was that he used the same method to blow the log that my mother does for baking. Just dump in what looks good.

I too have a Lucas mill. As a circular saw it cuts up to an 8x8 cant. Or the head unit turned and the best is a 16x8. Take these to the Woodmizer and cut boards fast with little waste. I also have the chainsaw attachment for the Lucas. I can slab a 5' wide log 16' long in about 20 minutes per cut. But then you have to move them.

I got a blade at a scrap yard and welded two pieces of pipe on the ends. Then I used threaded rods welded to eyes on one of the ends. Then I connected a chain from these around the butt of the log and pulled the blade in about two inches on a 32" diameter white oak. Pulled it out with a bar and then used splitting wedges to open it up. The blade made a nice straight line for the split. Unfortunately, nobody has a Lucas mill around here. I hope to have the white oak quarter sawn soon.

I saw some Amish sawyers split large logs with black powder. Instead of using a fuse, they used some regular 12 gauge copper wire. Just took the wire and unrolled 20-30' or so from the spool (two lengths), stripped the ends and just used a couple of strands from each wire wound together. He then touched the other ends to a battery, one wire to each terminal, and bang, two nice halves, while he stood behind the dozer for safety. I would have used a little more wire, but it worked fine. Seems much safer than a lit fuse, and you can use the wire over (except for the very ends, of course).

From the original questioner:
That sounds like a great idea. Using fuse can be a bit scary at times. The guy I saw blow the log had the fuse burn out 1/2" above the log. We waited about 15 minutes before he went and looked to see what the problem was. He re-lit the short end and ran like ---- and luckily made it to safety in time. A guy a few miles north of me had the same problem while blowing rocks out of his farm field, only when he got to the rock it blew, and the results were not good. He and the rock where blown to bits.

How do you know what is a good amount of powder to use? It seems that if you use too much, there's obvious problems and that if you don't use enough, there's another set of problems.

From the original questioner:
A very good question to which I have no answer. The guy I watched just picked up the 1 lb can and started dumping. I am guessing he used about 1/4 of a can. It split the 40" plus log in 2 pieces and laid them about 12" apart. The one half was still too big for my saw, so he blew it again. I don't know how much powder he used this time, but the oak halves flew about 15 feet (a bit overkill I would say).

I plan on practicing with the wire to set the powder off and will measure the powder and start on what I think is the weak side. I don't burn wood, so I do not need to produce kindling.

Depending on the grain of your wood, this may work--it did for me. With a chainsaw, rip a 3" groove lengthways where you want the split to be, on either side of the log; then at one end notch out a rectangular prism just big enough to insert a hydraulic jack, and jack it apart.

What kind of battery did the Amish guy use? I am going to experiment a little with small loads first, but didn't know if I should use a car battery or if a 9 volt lantern battery would work.

I have blown quite a few big logs (and some small ones for fun). I typically use a small coffee cup full. Once I tried less, and it just split the log and I had to cut it the rest of the way. Once I used more and the pieces landed about 40' from each other. I buy my fuse at hobby stores--it is also used for model rockets.

The Amish guys used a car battery. Any battery should work as long as it gets the wires hot. If you carry a 9-volt battery in a pocket full of change, you'll find out about how this works! That's why he only used a few strands of the 12 ga wire. If you used lighter wire, you could probably get away with just twisting the ends.

As far as powder, there was nothing scientific about his method. Just a plunge cut, pour in some powder, pack the rest with sawdust, stick in a wedge that is slightly narrower than the cut, make sure your wires are in and in the powder, and get behind some cover. The ones he blew went about 20'. I guess his theory is better too much powder than too little, but make sure you're out of the way and probably behind some cover.

You could try getting hold of someone with a Peterson mill, as well. They also make a 10" version so that you can cut 10" x 10" cants or double cut to 10" x 20". Impressive machines to watch and easy to use.

From contributor P:
Why blow up good wood? Find someone with a Peterson mill--they can set it right up over the log and cut the cants for you. We have a Peterson 8 inch and have no difficulty with any size log, plus we can quarter saw efficiently.

From contributor M:
This is about the third time this has been suggested and I'm really curious on how this is done. I thought one of the drawbacks of the swingblade mill is the limited width it can cut, say, a 1x12. How would you cut 6 inch cants for me out of a 58 inch diameter Doug fir? How about 12 inch cants from a 60 inch sugar pine? Are you talking a slabber? Just curious, and maybe in the market for a swingblade.

From contributor P:
I can get as many 8 by 16 inch cants as the log size will allow. My 8 inch Peterson will cut an 8" vertical and I simply cut another 8" vertical 16 inches over, then cut 8 inches in from both sides and end up with a cant which is 8 by 16 inches. This is the biggest cant I can get with the 8 inch Peterson, but the 10 inch one would give you cants 10 by 20.

Sounds complicated but really isn't. They have designed the mill so the "double" cut is easy to do. The things I like most about the Peterson is the production and how easily it will quarter saw, plus the blade is easy to keep sharp I also have a Woodmizer Lt15 and find the 2 really compliment each other.

From contributor E:
I've watched a swing blade demonstration before. They work quite nicely but are not a production mill. They are more of a farm mill not for someone who will be lifting lumber all day!

They mow their way across the top of the log pulling cants then slip down for the next row of cants. First with a horizontal cut 8" deep following back with an 8" vertical cut pulling the cant or boards sawing row after row of boards or cants off the log.

Interestingly enough, they are only limited by their setworks. You could set one on a 20' in diameter log and mow it to the ground with enough time.

From contributor P:
I respectfully have to disagree on your comment on production of the Peterson. At this year's shootout in Bangor, Maine, Peterson was fourth overall in production ahead of three of the band saw mills costing three or four times the Peterson. The Peterson was first in production in the under $10,000 group. There are some compromises with the Peterson, but production, ie. board foot per hour, isn't one of them. As far as I can tell, you would have to spend at least $30,000 on a band mill to get the same production rate as a $9,000 Peterson. A lot of my customers pay me by the board foot and that is where the buck stops.

From contributor M:
I agree also. I think Contributor E misread my question. I've seen them cut lumber and am impressed but did not know how they would cut the large cants that you spoke of. Thanks for explaining that to me. Now how the heck do you get a 8x16 cant that is 20 feet long over to the band mill for final cutting with out a big tractor or something?

From the original questioner:
Back to the black powder method of splitting logs. Have any of you guys had a chance to experiment with powder and or using wire and a battery to detonate the powder?

I tried 2 lengths of cable tv wire, which has a small diameter copper wire center, with fine mesh wire surrounding it. I twisted the two copper wires together and touched the other ends to the posts of my tractor battery. The twisted wires got hot real fast, but so did the ends I touched to the battery. The ends I touched to the battery got so hot they started to melt. I suppose it would set off a charge of powder, but I think I will try to find some different wire, even though I have a whole spool of the tv wire.

I'm talking out of school but here is an idea.

It may be that the ends you touch to the battery are not making good contact and that is the reason for the heat. Try wrapping the wire around a nail. One for each pole and touch the nail to the battery post. Maybe the nail and the wire will make better connection and the resistance will take place at the end where you want the heat.

Let me start off by saying I haven't got a clue what it takes to set off a charge. Are you looking for heat or spark? For a spark, a coil will actually give you a nice spark without the amperage (which causes the heat). Given the low amperage you could probably get away with the small diameter wire and use a spark plug at the far end. If you want the heat you can generate from the amperage in a tractor battery, you may need to go with a heavier wire to carry the current and have a lighter gauge wire down where you want the heat. The lighter gauge wire will heat faster, and depending on the material, may act like a fuse and actually break. You want it to work sort of the way a light bulb works. A wire of the same size will heat pretty uniformly when it's shorted out, whether it's 2 feet or 20. If you could have felt the wire under the insulation, the wire was probably pretty hot the whole length.

In a somewhat careless moment I had the chance to see 1/2 inch diameter jumper cables glow red and melt the insulation in the blink of an eye. Luckily the battery stayed in one piece. There's a lot of power there. Enough to weld steel. Good luck and be careful!

That's the right idea. Try twisting a few strands of the fine mesh wire together at the end instead of the heavier core. That will insure that all the current goes through and fuses the fine wire, which is what you want. You may have to try a few times to figure out how many of the fine wires will provide enough heat to ignite your fuel.

This is essentially how model rocketeers ignite their engines.

I haven't tried this yet, but I was thinking about using, say, 12 gauge copper to get power to the log, and jumping in a very fine steel wire to tamp in the powder. I'd think the fine steel wire would heat up before the copper got hot.

How about doing this: take a good, cheap light bulb that has tab type connections (or grab a few blinker light pigtails from a junker car complete with bulb), break the glass off of it and place the filament into the powder, preferably with some fine powder poured onto it. Ever notice what happens when you break a burning light bulb? The filament instantly oxidizes, and overheats, melts, and makes a healthy spark before going dark!

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor A:
The ultimate in cheapness, availability, and effectiveness... 000 steel wool. I used to set off model rocket engines with steel wool and a length of speaker wire. I usually used a 9-volt battery for a V source. Worked great for that... requires very little current, so should work well for this application, too. Experiment by touching a 9V battery to a cotton ball sized piece of 000 steel wool. Don't hold the wool, though!

Comment from contributor B:
Try some model rocket igniters from the toy stores. That is probably what you saw on the end of the wires going into the powder. This is about the equivilant of a very hot match head when it ignites. They also work well with small wire and a 6V lantern battery will fire lots of them.

Comment from contributor C:
It takes me about an hour to split a 40" plus log with a chainsaw and wedges. Set the log on skids, wedge it to keep it from rolling. Scribe a plumb line through the pith of both ends of the log, snap a line connecting the two end lines. Go to work with a very sharp chain. Roll the log 180, repeat. Wedge in open and plunge the saw into the cut to separate the few splints remaining. The more careful you are, the less you will waste. If the grain has a twist to it, blowing it will give you two twisted halves (if you're lucky). Blowing a log apart is a novel idea, but personally I can spare the hours work without risking my life.

Comment from contributor W:
Years back, as my dad recalls, logs 5 and 6 feet in diameter were busted in two using black powder. I guess they had a formula to determine how much to use for different species and diameters. He said it worked, so long as the blow-upper was sober.

Comment from contributor S:
Real black powder is very dangerous. It is can explode unpredictably, etc. If you're going to play with a powder wedge, go to your gun shop and you'll find black powder enthusiasts today use a propellant called Pyrodex. It's much more stable. Next problem - it comes in several "speeds" for black powder pistols, rifles, shotguns and cannons.

Comment from contributor H:
I used to blow firewood as well as logs. Used an electric drill instead of a plunge cut on the big, knotty firewood pieces, to save black powder. Also, my uncle had a set of wedges with holes and a touchhole in them - more economical. Never tried pyrodex, but always used a twist of steel wool for the igniter with a long cord and a car battery. It's a blast!

Comment from contributor K:
I would recommend using pyrodex RS for splitting logs. I use it in my cannon and it is slow burning and will not accidentally detonate by static electricity. Cannon fuse is easily available in gun shops or online. For electric detonation, use a 12ga or better cable from the car battery to the charge.

For the detonator, use a single strand of thin speaker or automotive wire about an inch long firmly attached to each cable. Make sure to not let the larger cables touch or you will simply melt the cables near the battery. Lastly, never be in the line of sight of the blast no matter how far away you are.

Comment from contributor D:
My grandfather and I used to use his powder wedge to split dry red fir logs in half when we were making fence posts. His powder "wedge" was a steel tube about 10" long, roughly the same diameter as a 12 gauge shotgun barrel but thicker, with one end closed and the open end slightly tapered. A small hole was near the closed end to insert a fuse. What always amazed me was how little black powder it took to blast a log in two.

To use the wedge, my grandfather would measure course grade black powder (even larger grains than single x) with an empty 12 gauge shotgun shell, about 1/4 full, pour it into the wedge, and pack it down with a little newspaper to hold the charge in place. I'm guessing no more than 60-70 grains of powder.

Then, he would drive the open end of the wedge into an existing crack in the end of the log (basically, choosing a good spot where the log was most likely to split, the same as one would hand drive plain wedges into a crack). The wedge only needed to be driven in about a 1/4 inch, just enough to hold it in place. Then, we'd add the fuse, light it, and run.

The wedge acted like a shaped charge directed into the log, and the powder wedge would drop to the ground, only a foot or two away from the back-blast. However, half of the log would often fly 3 or 4 feet in the air and flip over from the blast. I remember once we blasted about 25 logs in half in a single morning, all at least 2 to 3 feet in diameter and 8 feet in length. It was really spectacular, one of my best memories. We also saved a ton of work getting that first difficult split done.

Comment from contributor E:
Black powder splitting wedges were common in the Pacific Northwest for splitting large diameter trees like Douglas fir and redwood.

I once used one that was a solid steel tube which was hollow along half its length and the remainder solid. The touch hole was about midway along the tube. The whole thing was about 18 inches in length. You put a powder charge in the hollow portion (not a large charge as I remember) and then used a sledge hammer to drive it into the butt of the log in the center of a natural split. After pounding it in to compress the powder charge and seat the tube, you would insert a fuse, light it and head for cover. It worked wonders on the 5-8 foot diameter logs we were splitting.

There is one caution in addition to all the other black powder/pyrodex cautions raised in the original discussion. The wedge would often blow itself out of the log, even if seated properly. Clearly a person should not stand behind the wedge.