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Tyler Danann
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# Posted: 6 Nov 2015 20:16
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I got a nice treat from a neighbor a few weeks back, the opportunity to use his Alaskan Sawmill!
It's more than just the chainsaw conversion, but a proper carriage-driven petrol-engine thing with a great hooping sawblade! :D:
Here's how the machine is used:
URL
Turning these logs:
Into beams like this!
I had a roof to build and got stuck in. This is how the roof turned out with the beam mounted into place.
Beams, beautiful beams!
I worked out each beam costs me roughly $3 or so (plus my time to work the mill), compared to about $40-50 each for the price of the beams, plus transporting only about a handful each trip all the way from a big city many miles away. The Sawmill was much closer and saved much time and energy.
DIY techniques for sawmilling are very much an art, not a science. In the video I try to explain things as I learned and was taught by the master saw miller but it's best to learn by experience as you rip them boards and beam!
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Don_P
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# Posted: 6 Nov 2015 23:37
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Tyler, look at the size of the rafters, then look at the toothpick diameter log beams you rested them on. I seriously doubt they are large enough for the dead load.
It is fun to make and use timbers. Next up is to learn to grade and size the material properly. Hang around.
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turkeyhunter
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# Posted: 7 Nov 2015 09:22
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Looks great and luv the rustic charm to the shed. What did you paint the end that went in the ground?? used motor oil?? that's what we us "down south"...I still have a couple gallons of creosote as well to use on the ends of posts.
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Tyler Danann
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# Posted: 7 Nov 2015 11:20
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Don. I load tested those 'tooth-pick' logs as you describe them and they are rated to 500 lbs per square-foot!
Also the 5x5s are not across the middle sections but the post areas (where it is probably rated to 2500 lbs/sq inch).
So for these 'tooth-pick' areas of the vulnerable parts 3x5s and 4x5s were used. 
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Tyler Danann
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# Posted: 7 Nov 2015 11:23
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Quoting: turkeyhunter Looks great and luv the rustic charm to the shed. What did you paint the end that went in the ground?? used motor oil?? that's what we us "down south"...I still have a couple gallons of creosote as well to use on the ends of posts.
I charred them with a blow torch then sunk them in and concreted them into place!
I have also used linseed oil too, but these excel usually when a log post is soaked in a container of the stuff (according to Mark Oehler.)
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Don_P
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# Posted: 7 Nov 2015 20:44 - Edited by: Don_P
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This is a log beam calc that might help at some point
http://www.timbertoolbox.com/Calcs/logbeamcalc.htm
First pic in this thread is what I refer to as an Alaskan mill, http://www.small-cabin.com/forum/8_5518_0.html
what you're using in the video is usually called a bandsaw mill.
Going back to look for that pic, I got the Y braced cherry post and bolster from further down in that thread mortise and tennoned together a couple of days before I tried to teach a little drivers ed. The post is propped up out of the way and the Ranger is in the shop getting a chop and weld job. That kind of post is easier with an Alaskan or a bandmill than with my circle saw, on a bandmill just take a slab, flip, and take another slabbing cut. It makes a very stout well braced post, the Y braces are grown into the post, it doesn't get better than that.
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Tyler Danann
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# Posted: 7 Nov 2015 22:39
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Yeah I changed the video as a friend advised me just before your wordings.
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Tyler Danann
Member
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# Posted: 7 Nov 2015 22:52
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Just did some calculations, the roof girders should be good for 2160 lbs/sq ft.
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Don_P
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# Posted: 8 Nov 2015 01:26 - Edited by: Don_P
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I'll bet you mean the girders are checking out with a 2160 lb total load. The number entered into the load box is 2160?
Be careful/conservative with the diameter, notice that in a round timber in your range an 1/8" dia difference equals about 150 lbs of capacity, measure carefully. (Old timers were careful with the drawknife, a deep knick in a small beam or rafter is capacity.)
Check the bending result box for size, this is what you can use for the controlling diameter on a shed, it can sag more than a house without trouble.
When that is all checked and corrected you have total pounds the girder can support.
To get lbs/sq ft;
Take that total capacity and divide it by the number of square feet the log girder is supporting. The quick way is to check the longest spanning, most heavily loaded girder, one of the bays of the center girder. It is supporting half the length of the rafter below it and half the length of the rafter above it with a span from post to post. I'm guessing from your comments that this tributary width runs 4' along each side of the girder, trib width of 8' (install your actual numbers). Multiply that by the span, in feet. From the red ladder to the right I'm guessing a span of 10' between posts, engineers actually measure to the center of required bearing area at each end support so round up those inches rather than down.
You have just described the square footage being supported by the beam... the tributary area of the beam. I came up with a trib area of 80 sq'.
Now divide the beam's 2160 lb total capacity by the number of square feet it is supporting. That result is then the allowable pounds per square foot. 2160/80= 27 lbs/sq ft allowable.
Then compare that strength to your design loads. The dead load of the roof structure is heavy timber, I'll typically use 15 psf (another way to write lbs/sq ft) then add your local live load, I think I was seeing an upper lakes forest so for an example I'll use 50 psf for snow, use your local snow load number. So I'm at 65 psf needed vs the 27 lbs allowable. My scenario fails, but I made assumptions, you know the actual numbers to use now... if I just did my job. In AL 27psf allowable is close, in MN it would probably collapse sooner than later. If it's bad you're not done, it needs work.
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