Ripping Douglas Fir 2"x6"

Discussion in 'Materials' started by mariobrothers88, Oct 29, 2020.

  1. mariobrothers88
    Joined: Sep 2020
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    mariobrothers88 Senior Member

    Hi guys the plans for the boat I am building call for stringers that are 1.5"x0.75" Douglas Fir. The smallest size boards I can find in my area are 2"x6" (actual size 1.5"x5.5"). I was thinking of using a table saw to cut it into 7 pieces of 0.75" x 1.5", but the carpenter who was working at the store said that it would be too difficult to cut into such small pieces and the wood would splinter. I have a table saw at home, but is it worth trying to do it myself? I can import smaller pieces but it would be much more expensive and a big hassle. Does anyone know if it's possible to cut the douglas fir 2x6's into smaller size stringers with a table saw? Or should I not even bother and import it? Thanks for your help!
     
  2. Barry
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    Barry Senior Member

    Those are really small stringers but the fir will cut into 3/4 inch pieces without issue. Sharp blade and slow feed. You might have a few break at knots so you want to buy CLEAR fir. Clear fir might not be available in longer lengths and you did not say what the lengths are that you need. You can be selective when picking through a stack of wood. I would expect that you can try a specialty store that may have longer lengths than a standard lumber yard
     
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  3. Rumars
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    Rumars Senior Member

    Of course you can. Plane the boards edge first so that you have a straight edge on the fence, then cut a little wider and plane the other three faces to final dimensions.
     
  4. missinginaction
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    missinginaction Senior Member

    I'd agree with Barry. I'd approach it like this. Lay the 2x6 flat on your table saw and set up your rip fence and an out feed roller. The 2x6 is ready to go in one dimension, it's already 1-1/2 inches thick. Assuming a blade that's 1/8 thick you should be able to rip 6 pieces that are 3/4" thick in the other dimension. Be careful of your fingers, especially on the last couple of cuts. I've always had good luck setting my blade so that the teeth are just clearing the piece I'm cutting. Maybe 1/8 inch above the piece.

    Good Luck, MIA
     
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  5. mariobrothers88
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    mariobrothers88 Senior Member

    Thank you everyone for the replies I really appreciate it- I will try to make the cuts the way you all suggested!

    The other thing I need is 1"x3" boards of Douglas Fir. Is that possible to cut from 2"x6"? I was thinking of cutting the 2"x6" in half to make a 2"x3" board, then cutting that in half to make the 1"x3". However, I would have to make it in two cuts since my blade isn't big enough to cut the 2"x3" in one pass. It would be a difficult cut and I would have to be very exact and precise on both passes so it lines up perfectly, but should be do-able I hope! Any suggestions would be greatly appreciated!
     
  6. Rumars
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    Rumars Senior Member

    After you cut the 2x3 cut some of the thickness away on the tablesaw and use a planer to get the final dimension.
     
  7. mariobrothers88
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    mariobrothers88 Senior Member

    Thank you for your input Rumars! I was hoping to cut the 2"x3" exactly in half with the table saw so that I can have 2 pieces of 1"x3" instead of just 1 piece and a lot of sawdust. Do you think that I won't be able to make an accurate cut of the 2"x3" by trying to cut in half with the table saw with two passes?
     
  8. Rumars
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    Rumars Senior Member

    It depends. Cutting a nominal 2x usually results in one 3/4" (1x) and one 1/2 actual sizes.
    You always loose wood when sawing, the sawblade kerf thickness has to be acounted for. Then you probably want to clean the sawmarks, so the planer or jointer also takes some wood away. How much depends on how straight your saw can cut. If the end result is acceptable depends on what you actually need, and what you start with. I'll do this in millimeters, it's easier to understand. You have a piece 38mm thick (2x) wich you cut in two perfectly with a 3mm blade, the resulting pieces will each be 17.5mm thick (presuming your tablesaw is that accurate, do a test run before). Cleaning the sawmarks brings them down to 17mm each. A nominal 1x is 19mm thick, is 17mm OK for you? If yes go ahead, if no saw so you get a 3/4 and a 1/2, or use thicker stock like 4x6.
     
  9. kapnD
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    kapnD Senior Member

    The header on your posts says you’re in San Diego?
    Last time I was there, DF lumber was available in all common sizes.
     
  10. mariobrothers88
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    mariobrothers88 Senior Member

    Hi guys thanks for all the advice!! I've been ripping the stringers out of 2"x4" with pretty decent results. I noticed about 10-15% of the time, the stringer breaks usually where the knots are. It's not a big deal to just not use those pieces with the stringers and use the good ones that didn't break, but I'm worried that it might be a sign that there's an issue with the wood. I'm currently in mexico which is not known for great quality wood. I've picked out the best ones and they claim that it is Douglas Fir- but I wouldn't be surprised if they sold a lower quality wood and just marked it douglas fir. I'm not familiar with douglas fir but I thought it would be stronger. My stringers are really thin though (per the woods plans) so would this be typical to have a few of them break given how thin they are (1 1/2" x 3/4")? I've attached photos as well. Thanks for any advice!!!
     

    Attached Files:

  11. BlueBell
    Joined: May 2017
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    BlueBell "Whatever..."

    1 1/2" x 3/4" is pretty beefy.
    DogCavalry is a member here with lots to say.
    He recently ripped some 5/8" for a SeaSled build.
    Check out his thread.
     
  12. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Looks like Doug fir.

    Any wood will break where the knots are more than 50% of the thickness.
     
  13. Rumars
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    Rumars Senior Member

    God invented epoxy so you can make wood long again. Just scarf the pieces back after you cut out the knots. This is the beauty of epoxy, you can use lesser grade woods by glueing togheter the usable parts.
    What are the strips going to be used for? Strip planking?
     
  14. Will Gilmore
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    Will Gilmore Senior Member

    Construction grade lumber is the low grade lumber. You will have to hand pick and visually inspect the pieces you are using, as you have discovered. Look for clear (knot free) pieces and grain that runs as straight and full length as possible, to get the strongest results.

    For scarf joints, cut them at about a 7 to 1 taper for strength.

    You have probably already noticed the construction grade lumber comes finished out at sizes smaller than the dimensions they are sold under. This is because they are named for their rough cut size, then run through a planner and a molder to round corners and finish rough, splintery faces and even out thickness for a more consistent look. This usually takes them down by 1/2" in thickness and width, but wider boards may be a much as 3/4" shy of their rough dimension.

    -Will (Dragonfly)
     

  15. fallguy
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    fallguy Senior Member

    Friends. He is building ply on timber frame boat. His reference to stringers is an error. These are just frame parts.

    A couple of things...

    First, select wood with more grains than less. And select wood with less knots than more. But select! Don't go grab a random stack. Count the knots in a board. Some have many, others less.

    oftentimes, you select wood and can plan the knots for clear sections..a bunch of knots in the same rip section renders the rip junk...look for boards with random knots

    also toghter grain lumber is stronger

    when you rip; there is no reason to rip off the milled edges; you can put them up on the ply side. A 2x6 os 5,5" wide. To yield 3/4" wide strips, select boards with no edge bow so they will rip true first cut.

    With a 1/8" blade; each cut is 7/8", yield is 6, yield no different thin kerf
     
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