I’ve been researching sawmill shed designs to cover my LT15. As an engineer (not structural), I’ve found the videos lacking, to say the least. Finally stumbled upon this video. Wow! Finally someone who knows what they are doing with the evidence to back it up. Really appreciate you sharing this information.
Thanks for the video and the explanation. I'm building a sawmill shed soon, and this just told me I need to do more homework before I start cutting lumber. Great job!!!
Excellent video. Don’t think anyone could have explained it better. Exactly what I was looking for. Actually you’ve calculated exactly what I need for my sawmill overhang. I’ll probably make a laminated beam.
Complete explanation, I tell young people, if you want to understand anything about anything in the world, take as much math as you can, all the way through high school.
Great information. I've been watching several of your videos and have come to the conclusion you must have been a professor in college at some point. Engineering math is fascinating to me. The science behind maintaining structural integrity is overlooked too often.
Thank you for this. I'd recently found that handbook for trying to figure out what I need to cut for bridge supports to support my mower and a future atv. I struggled through the pages figuring out what I needed, but with little confidence I was correct. Your breakdown and working the numbers and working the tables helped me greatly to have confidence with what I looked up. Again, thanks!
I tried pasting a link yesterday, but the system ate that comment it appears. I did a Google search for "Wood beam sizing chart". Many results. I picked one from a lumber trade association helping people use their product.
great video! excellent reference materials and your pictured formula explanations and verbal explanation really took the complex and made it easier to follow and figure out. I am looking to do the same project for my sawmill and was looking at incorporating a "Scarf joint" midway of a 30-foot span, (Maple beams: 5.5"x12"x15') for the front opening of the Mill shed. Your reference guides will help me greatly in the beam dimensions to be cut. Again, good stuff !!!
Great Video, I understand this was just an "example of the process", and is very good, but only issue might be that some folks might get confused of your use of Fb=1200. The reference material you show is for members 2 to 4" thick, 2" and wider, and your calculations are for a 5.5"x12" Beam...which is a "timber" that would be on a different but similar table by Southern Pine, and that table shows a #2 Fb value of 850...I was a little confused and thought someone else might be also, if you look at the current version of the table you show, the Fb for #2 starts at 1100 and decreases as the width increases...hope someone else who is working thru this doesn't get hung up like I did for a bit, keep the mill video content rolling, thanks
That is a good point, and a lot of these values depend on how you want to grade/rate the lumber. I'll have to go back and look in my notes but I do remember adopting 1200 as a general purpose average for SYP even before I was using that guidebook. Larger timbers could possible admit more flaws/knots/etc which is why they tend to get downgraded.
Great video. Can you explain a little more on how you were able to mix units of measure. For example, I would have thought you would have needed to convert “b” and “h” from inches into decimal feet before plugging into formula. Follow up question, and advice on how to calculate the laminating of boards together to make a larger beam? For example, my saw mill can only cut a 18’ board, but I also want a 25’ beam, so I was thinking of laminating 3 boards of overlapping lengths to create the full span. Thanks again.
That is a great question. The formula was setup with a conversion so that bending moment comes out in in-lb and the units are consistent with the other side of the equation. This was done on page 30 (#35 in PDF) of the WSDD handbook where you will see they slipped in a "12" to convert ft-lb to in-lb. So L can go in as feet while b and h are inches. Fiber bending stress Fb is in psi. Overlapping is a real pain and you'll end up having to oversize quite a bit and use loads of fasteners. You become very dependent on the fasteners, holes, and grain to resist sagging in the middle in order to handle the compression and tension loads. The calculation for that will be much more complicated. I wouldn't want to do it. With care you can work a longer log on the mill bed if you have the ability to shift it back and forth. Cut as far as you can, use a chainsaw and hand saw to carefully remove the cutoff above the blade, then raise sawhead and reposition log to complete cut. Repeat many times. It takes a lot of fussy positioning but works. I would not want to do it often but for a one-off beam it's doable. Personally, I use my Alaskan Chainsaw mill in situations like this. No limit to the length it can cut other than your patience.
Considering the loads and structural geometry involved, what are your thoughts on using expanding composite foam for anchoring your sawmill shed, car port, etc. posts instead of concrete?
I don't know enough about the foam. It would need to be able to provide some uplift resistance (concrete will have an advantage due to weight) and also resist side loads to prevent the poles from racking over.
@@Lumber_Jack was not thinking of mixing. What did you use on the sawmill shed ? Does the true 2"x 4" etc tend to move less than 1.5" x 3.5" etc bow, check, curve, crown. TY for the reply
@@logan979 Stability is really dependent on many factors and size may or may not make a difference at all. I normally saw lumber to 1-5/8" thickness for framing projects (it will dry to 1-1/2") because I often use brackets and hardware sized for store-bought lumber. Note that 2" lumber is insanely heavy to handle when using green, so that may be a factor as well. If framing with green lumber, you can avoid stability issues if you get the lumber in place ASAP after sawing, properly nailed/braced before it starts to dry.
Fb is the fiber bending stress due to flexure, whereas compression perpendicular to grain tends to be about what type of bearing area the wood can support before the grain yields. You have to worry about this at joints, to make sure they are large enough to carry the load without crushing the grain.
Interesting video. I am getting flashbacks from my post secondary education in Civil Engineering Technology almost 40 years ago. Structural design was my favourite subject but I never got the chance to use the knowledge in my field of work. Did you also check the design for your posts (columns)?
I didn't since it's normally not a limiting factor on my structures, but it is important to do in general -- both for the vertical load and buckling concerns.
I feel like I just got an F in math class again. Lol. My worst subject by far. Did you use an LVL beam or was it pine? Is the calculation the same for an LVL as it is for pine?
I used LVL. Same calculation but an LVL has much much higher fiber bending stress values than traditional wood, so you can get by with smaller/lighter beams. Most LVL manufacturers will have product sheets that give their specs and some guidance on loads and spans.
I’ve been researching sawmill shed designs to cover my LT15. As an engineer (not structural), I’ve found the videos lacking, to say the least. Finally stumbled upon this video. Wow! Finally someone who knows what they are doing with the evidence to back it up. Really appreciate you sharing this information.
Thank you so much! I found you on the woodland mills fb group and this is helping me size the header for my new sawmill shed! WONDERFUL.
Thanks for the video and the explanation. I'm building a sawmill shed soon, and this just told me I need to do more homework before I start cutting lumber. Great job!!!
Great video, thank you for the excellent explanation of load bearing beams.
Excellent video. Don’t think anyone could have explained it better. Exactly what I was looking for. Actually you’ve calculated exactly what I need for my sawmill overhang. I’ll probably make a laminated beam.
That was fantastic! Simple and to the point! Thank's.
Excellent video! Your sawmill shed made the perfect example for explaining this information.
Very good video!!! All the info I was looking for to decide the main beams for my patio cover project!! Thank you very much!!
Complete explanation, I tell young people, if you want to understand anything about anything in the world, take as much math as you can, all the way through high school.
Great information. I've been watching several of your videos and have come to the conclusion you must have been a professor in college at some point. Engineering math is fascinating to me. The science behind maintaining structural integrity is overlooked too often.
Awesome video, thanks 👍
Wind is also considered in live load calculations
Thank you for this. I'd recently found that handbook for trying to figure out what I need to cut for bridge supports to support my mower and a future atv. I struggled through the pages figuring out what I needed, but with little confidence I was correct.
Your breakdown and working the numbers and working the tables helped me greatly to have confidence with what I looked up.
Again, thanks!
what is the name of the handbook? Thanks
@@mushinman1 at 12:28 he talks about the reference book options. There are a bunch out there.
@@MikeCreuzer Thanks
I tried pasting a link yesterday, but the system ate that comment it appears.
I did a Google search for "Wood beam sizing chart". Many results. I picked one from a lumber trade association helping people use their product.
great video! excellent reference materials and your pictured formula explanations and verbal explanation really took the complex and made it easier to follow and figure out.
I am looking to do the same project for my sawmill and was looking at incorporating a "Scarf joint" midway of a 30-foot span, (Maple beams: 5.5"x12"x15') for the front opening of the Mill shed. Your reference guides will help me greatly in the beam dimensions to be cut. Again, good stuff !!!
Thanks!
Very good vid. Thank you for sharing your knowledge and resources as well as thanks in general for your vids.
Great Video, I understand this was just an "example of the process", and is very good, but only issue might be that some folks might get confused of your use of Fb=1200. The reference material you show is for members 2 to 4" thick, 2" and wider, and your calculations are for a 5.5"x12" Beam...which is a "timber" that would be on a different but similar table by Southern Pine, and that table shows a #2 Fb value of 850...I was a little confused and thought someone else might be also, if you look at the current version of the table you show, the Fb for #2 starts at 1100 and decreases as the width increases...hope someone else who is working thru this doesn't get hung up like I did for a bit, keep the mill video content rolling, thanks
That is a good point, and a lot of these values depend on how you want to grade/rate the lumber. I'll have to go back and look in my notes but I do remember adopting 1200 as a general purpose average for SYP even before I was using that guidebook. Larger timbers could possible admit more flaws/knots/etc which is why they tend to get downgraded.
Thank you!
Excellent.Thank You.
Outstanding video THANKS !!!
Thx for sharing
Super helpful! Thanks
Very helpful
Great video. Can you explain a little more on how you were able to mix units of measure. For example, I would have thought you would have needed to convert “b” and “h” from inches into decimal feet before plugging into formula. Follow up question, and advice on how to calculate the laminating of boards together to make a larger beam? For example, my saw mill can only cut a 18’ board, but I also want a 25’ beam, so I was thinking of laminating 3 boards of overlapping lengths to create the full span. Thanks again.
That is a great question. The formula was setup with a conversion so that bending moment comes out in in-lb and the units are consistent with the other side of the equation. This was done on page 30 (#35 in PDF) of the WSDD handbook where you will see they slipped in a "12" to convert ft-lb to in-lb. So L can go in as feet while b and h are inches. Fiber bending stress Fb is in psi.
Overlapping is a real pain and you'll end up having to oversize quite a bit and use loads of fasteners. You become very dependent on the fasteners, holes, and grain to resist sagging in the middle in order to handle the compression and tension loads. The calculation for that will be much more complicated. I wouldn't want to do it.
With care you can work a longer log on the mill bed if you have the ability to shift it back and forth. Cut as far as you can, use a chainsaw and hand saw to carefully remove the cutoff above the blade, then raise sawhead and reposition log to complete cut. Repeat many times. It takes a lot of fussy positioning but works. I would not want to do it often but for a one-off beam it's doable. Personally, I use my Alaskan Chainsaw mill in situations like this. No limit to the length it can cut other than your patience.
Considering the loads and structural geometry involved, what are your thoughts on using expanding composite foam for anchoring your sawmill shed, car port, etc. posts instead of concrete?
I don't know enough about the foam. It would need to be able to provide some uplift resistance (concrete will have an advantage due to weight) and also resist side loads to prevent the poles from racking over.
your preference when milling and cutting 2x4,2x6,2x8 etc example 2"x4" or 1.5" x 3.5" ? Thanks for the informative video .
No preference, really depends on the project and whether or not the lumber will be mixed with store-bought dimensional lumber.
@@Lumber_Jack was not thinking of mixing. What did you use on the sawmill shed ? Does the true 2"x 4" etc tend to move less than 1.5" x 3.5" etc bow, check, curve, crown. TY for the reply
@@logan979 Stability is really dependent on many factors and size may or may not make a difference at all. I normally saw lumber to 1-5/8" thickness for framing projects (it will dry to 1-1/2") because I often use brackets and hardware sized for store-bought lumber. Note that 2" lumber is insanely heavy to handle when using green, so that may be a factor as well. If framing with green lumber, you can avoid stability issues if you get the lumber in place ASAP after sawing, properly nailed/braced before it starts to dry.
Great video!
Thanks!
Wood Structural Design Data pdf. has been removed or unavailable now for some reason.
PDF FILE: www.hardincreekmillwork.com/wp-content/uploads/2017/05/AWC-WSDD1986-ViewOnly-0301.pdf
@@Lumber_Jack Thank you.
I find the "Compression Perpendicular to Grain, Fiber Stress at Prop. Limit" of Loblolly Pine is 790psi. Is that not the same as your Fb measurement?
Fb is the fiber bending stress due to flexure, whereas compression perpendicular to grain tends to be about what type of bearing area the wood can support before the grain yields. You have to worry about this at joints, to make sure they are large enough to carry the load without crushing the grain.
@@Lumber_Jack thank you!
Interesting video. I am getting flashbacks from my post secondary education in Civil Engineering Technology almost 40 years ago.
Structural design was my favourite subject but I never got the chance to use the knowledge in my field of work.
Did you also check the design for your posts (columns)?
I didn't since it's normally not a limiting factor on my structures, but it is important to do in general -- both for the vertical load and buckling concerns.
I feel like I just got an F in math class again. Lol. My worst subject by far. Did you use an LVL beam or was it pine? Is the calculation the same for an LVL as it is for pine?
I used LVL. Same calculation but an LVL has much much higher fiber bending stress values than traditional wood, so you can get by with smaller/lighter beams. Most LVL manufacturers will have product sheets that give their specs and some guidance on loads and spans.