I mentioned this in another thread and was asked to start a new one on the subject. The shotgun barrel is how you position a large log on your carriage. I used is quite a bit to cut big timber on a circle mill.
Typically, the way most grade mills operate is to take jacket boards off until grade starts to drop. Most mills will turn down 90° to have a flat side on the headblocks. The mills that cut off the top of the log may turn down 180°, and I've seen circle sawyers do that in order to avoid some edging. I've never had good luck with turning 180°. It always took longer than turning down.
But, on really big logs, the saw won't pass all the way through the top of the log. On my mill, I could cut 20". But, the carriage opened to 42" and there were times I put logs on the carriage and was cutting wood at 42". The way many guys cut that is to keep on taking cuts that bury the saw, then whack it off with a chainsaw. Very time consuming and it can be dangerous.
The remedy is that when you can see that you'll bury the saw on the next cut, you turn back 30° or 45°. Being exact doesn't matter. You'll be eventually cutting a square, which will result in some waste. You keep doing that until you can handle a log and not bury your saw. The reason they call it shotgun barreling is because instead of having 4 sides, the log resembles the old hexagonal shotgun barrels.
Another reason to use the method is that it can help you avoid dirt. Dragging dirt and debris down through your cut is a sure fire way of dulling your saw. It doesn't matter what type of mill you're running. Dirt on the bottom of your cut doesn't dull your blade as fast, as it's knocked away. Take off a slab, turn a bit, and you have a clean area to run saw. Whenever possible, I would take that initial slab off where there was the most defect. That way the defect would end up on the board edges when you turn your log in an angle.
As for waste, there is a little more waste. But, I always figured wood waste cost less than wasted time.
I think I remember someone or it could have been you explain that before. But what do you mean by Brushing your log?
ron you nailed it, and said it as well as could be put without writing a manual on the topic. It really just takes time in logs of varying sizes with varying cut list to understand what it takes to get the good out of the log. and then once again there are no guarantees, trim and waste are just part of the equation to grade, useable green lumber. thanks for opening the topic.
I cut for years with a 44" saw and don't remember any logs I couldn't cut. I refuse to bury the saw, makes me nervous. What I would do with a large log is to take a thin slab the saw can cut through and turn the flat down on the knees. Take another thin slab and turn down usally by then I could cut normally as the diameter is reduced, if not I repeat. this way I just get narrow boards not clapboards. I'll have to remember that trick about turning a dirty log slightly to cut into new wood though. Frank C.
Bandmiller I had a guy at a steam our steam show tell me to do as your saying . My saw will cut 21 the cant squared at 23 . Now what get out the chainsaw . I have always called it 1/8 turning works for me . Gearbox
Gearbox, sometimes the DanG log is just too big, in that case you just have to chew away at it. Frank C.
Top saw is all I say, ;D
(https://forestryforum.com/gallery/albums/userpics/22511/DSCN2659.JPG)
https://forestryforum.com/board/index.php/topic,50485.msg729351.html#msg729351
reminded me of this thread....different situation but similar idea?
Was off-bearing on a small circular saw a long while back, and a few large cottonwood were sawn this way.
The sawyer, with years of experience, loaded the log, set the carriage at the same setting as the depth the circular saw would cut. ( I suspect this one was larger than what shotgun barreling would handle, but do not know that for certain).
The saw was buried all the way, as it only reached about halfway through the log.
We turned the log up 90° and made the second cut that met the first and dropped off a ¼ of the log.
Then we turned up another 90° and sawed 1" boards until only a half log remained.
After that, pretty straight forward cutting... believe all this cottonwood was going for roof sheathing.
Made up a crude drawing of the three steps..(used to have a great MS drawing program, but can't seem to get it any more, so used Paint)
(https://forestryforum.com/gallery/albums/userpics/10180/Sawing_large_log.jpg)
Quote from: beenthere on February 06, 2015, 10:12:27 PM
Was off-bearing on a small circular saw a long while back, and a few large cottonwood were sawn this way.
The sawyer, with years of experience, loaded the log, set the carriage at the same setting as the depth the circular saw would cut. ( I suspect this one was larger than what shotgun barreling would handle, but do not know that for certain).
The saw was buried all the way, as it only reached about halfway through the log.
We turned the log up 90° and made the second cut that met the first and dropped off a ¼ of the log.
Then we turned up another 90° and sawed 1" boards until only a half log remained.
After that, pretty straight forward cutting... believe all this cottonwood was going for roof sheathing.
Made up a crude drawing of the three steps..(used to have a great MS drawing program, but can't seem to get it any more, so used Paint)
(https://forestryforum.com/gallery/albums/userpics/10180/Sawing_large_log.jpg)
With this set up when you are finished or almost finished with the second cut and the 1/4 of the log falls away is there danger of it damaging the mill or people? It just seems like it could be a LOT of weight that suddenly drops off the carriage and on to what ever catches it.
Let them down easy on the off-bearing rolls. Shouldn't have to drop far, just roll off. IIRC we had a big cant hook holding them from rolling too soon or too fast.
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Good post Ron.
That is how I was taught to saw on circle mill. I operated a mobile dimension mill for 20+ yrs it could handle dirty logs because the saws turn up into the logs so as long as the end of the logs were clean you could cut all day with stellite tipped teeth,I will often roll a dirty log back so as to saw through from the clean cut side to avoid dirt with my bandmill.
Brushing the log is where you advance the log just a bit and run it past your saw to true up your log. It usually ends up being a shower of sawdust without cutting any shim. It rarely works well.
Beenthere, not sure if that guy was experienced, brave, or just plain nuts. Any slip or failure of the holding dogs in a situation like that would surely result in a catastrophic failure. Just shotgunning a 40" hardwood log, that is twice the height of the operating height of the headsaw can be nerve racking. Burying the saw even more so, but to have the log hanging clear out there in the dogs and the saw buried in the center of the log is just mind blowing to me. I hit myself in the teeth with my coffee cup just thinking about it. :D
I tried that once with my Belsaw!!! didnt work to well!! log got bound on the board splitter!!! what a PITA !!!! i ended up shutting down and finished ripping the log with a chainsaw to get it unbound.The second thing i did was shorten the splitter so it was only 6" higher then the carriage.I find spending the time rolling the log more often is the safer way. Don
Quote from: Jeff on February 07, 2015, 08:23:30 AM
Beenthere, not sure if that guy was experienced, brave, or just plain nuts. Any slip or failure of the holding dogs in a situation like that would surely result in a catastrophic failure. Just shotgunning a 40" hardwood log, that is twice the height of the operating height of the headsaw can be nerve racking. Burying the saw even more so, but to have the log hanging clear out there in the dogs and the saw buried in the center of the log is just mind blowing to me. I hit myself in the teeth with my coffee cup just thinking about it. :D
My thoughts exactly. Wow! How could you cut anything square and parallel?
He was VERY experienced.
I wouldn't recommend the technique to anyone, as the results can be like loggah had to deal with.
For sure, not a lightweight mill like a Belsaw. I don't recall the name of the mill but it was not huge.
The offbear rolls were two sawn oak 2x6 with lathe-turned wood maple rollers.
Square and parallel... all that was done when edging. But the boards come off the same thickness as long as the dogs stay tight and the log advances without rolling. Am sure there were some blocks on the bunks to assist that to happen when dogging the ¾ log piece.
Just wanted to show what I recall as a way to saw a large log. Maybe should have said "Don't try this at home". ;D
That sort of reminds me of a local logger who was VERY experienced in cutting trees. When he had trees hang up in another tree, he simply cut down the tree that had the hung tree. He did that for 21 years. He didn't do it for 22.
Sounds like you are questioning his experience in this example I showed. I won't try to argue the point. I know who he was and what he knew about sawing with circular saws.
It was shown as an example of what can be done. Will leave it there, or admins can remove it.
I think the question of experience is a mute point on this one. It is a question or risk. Between Ron and I we have about as much experience with large circle mills as you might find anywhere. Perhaps with more experience yet we would gain the ability to take more risk.
I'm sure that operation could be done if you were using some sort of special designed fail safe dogging system that maybe bolted the log down, but I would never, ever try that with either normal hydraulic, mechanical or air powered sawmill dogs. Ever.