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Thread: How to prevent splintering when using birdsmouth router bit on VG fir?

  1. #1
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    Default How to prevent splintering when using birdsmouth router bit on VG fir?

    I've already built one 24' birdsmouth mast with vertical grain douglas fir, and the splintering and ripout was a pain to deal with. I have another mast to build and am wondering how to prevent splintering when routing (routering?). Would it be productive to soak the surface to be routed (routered?) with CPES?

    Any other ideas?

  2. #2
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Is there some reason you're not using a table saw?

  3. #3
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Doug fir is just a splintery wood. Can you take light passes and climb cut? Both of these methods will reduce splintering but might not eliminate it completely.

    What does a BM router bit look like, anyway? I can't imagine.

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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Quote Originally Posted by Jim Ledger View Post
    Doug fir is just a splintery wood. Can you take light passes and climb cut? Both of these methods will reduce splintering but might not eliminate it completely.

    What does a BM router bit look like, anyway? I can't imagine.
    Apparently they do exist.

    A table saw will be more flexible and easier, though.
    It really is quite difficult to build an ugly wooden boat.

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  5. #5
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    It's been some 15+ years since the first mast build, and I remember trying our table saw. Not sure why it didn't go well (maybe because of taper?) but I'll try again.

  6. #6
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?


  7. #7
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Routing DF is always an adventure. I’d be setting up a gaggle of feather boards on the t-saw

  8. #8
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    thanks, good advice!

  9. #9
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    A few photos might help Ron. Sorry if I’m telling you how to suck eggs but you need to rout with the grain wherever possible - if your going against the grain you can’t avoid the tearout and with DF where you’ll often get the grain reverse on itself it’s almost impossible to not go against the grain.

    You could try making plunge cuts every inch or so along the piece and then run the router along. I can’t remember where I read that idea but I’ve had some success doing it with cutting floating panels (for cupboards and doors) in red cedar where the shape is cut all around so impossible not to go against the grain..
    Larks

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  10. #10
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    I bought one of those big router bits getting ready to build my first birdsmouth mast, took one look at, thought about how splintery DF is and put it away on the shelf. The tablesaw works great.

    For taper, I mill the staves (with parallel sides) to their maximum width, run them through the tablesaw again to put the birdsmouth in and then work the taper in. To find the right taper I use the Duckworks calculator to find what the stave width needs to be to get the specified diameter and mark that out along the length of one stave, run a batten through the points for a fair curve and cut to the line. I've had pretty good success making a pair this way, clamping the remaining 6 between them and using a power plane to work the whole mess down at once. A bit like using a scarfing jig.

    Found a picture:

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  11. #11
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Larks, no pics since last routing experience was 15+ years ago; and hope I have none to show on this next mast.

    Will try plunge cuts if table saw doesn't fit the bill again.

  12. #12
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Table saw is the way to go. Tune up the saw, do tests to get the depth right, use featherboards. Cut the V before you taper the staves, if it’s not too late.
    F37051F3-DDFC-4CBF-8024-AE06E9F53C44.jpg

  13. #13
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    ^That's a good looking setup. Haven't started yet so can taper after the fact.

    Steve, thanks for suggesting Duckworks - will take a look. I like your tapering technique.

  14. #14
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Table saw for the mortise. I use a thickness planer for taper. I tape them side by side, then slowly turn the handle as they pass the blade. Very uniform tapers that way.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

  15. #15
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    I did mine (17 feet, Doug Fir) the way Steve described. Worked perfectly. Here's the heel end cutoff with a hardwood plug.
    mast section.jpg

    I'm glad you started this thread, though and to hear others corroborating that DF is splintery and terrible to use a router on. That's been my experience too.

    Mike

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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    There's a tendency, when making a mast, to let ones hands slide along the mast while walking from one end to the other. Don't do this, especially if it's a Douglas fir mast.


  17. #17
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Table saw is definitely the way to go. Take your tie with the set up and make the mistakes and adjustments on a couple of spoil boards until you're dialed in.
    Nice sharp blade, wax the table and the fence for slipperyness......

  18. #18
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    I've often wondered if the absence of your face in that shot was because you were crying, it is you Jim isn't it?

  19. #19
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Quote Originally Posted by Chippie View Post
    I've often wondered if the absence of your face in that shot was because you were crying, it is you Jim isn't it?
    Nah, Chippie, I bit my lip and didn't cry, as I was taught.

    Truth be told it was numb. Pulling it out with pliers was a bit sharp, though.

    Jim

  20. #20
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    I used the birdsmouth bit that LeeValley sells on the mast for my Somes Sound. The mast is about 24 feet long and does not have a uniform taper. So two reasons I couldn't use the table saw. I don't know how to cut a non-uniform taper using a straight fence. And, my shop's wall is about 13 feet away from the saw. I would have had to cut a hole in the wall in order to cut a 24 foot long mast stave. That wasn't gonna happen. Thus, the router bit. One must take shallow cuts and climb cut. Shallow is easy, although frustratingly slow. Climb cutting is something to be practiced and might not be for the faint of heart. I've been doing it for over forty years on all matter of wood edges, so I'm pretty comfortable with the process.

    Soaking the wood with cpes would be a waste of cpes and time.

    Jeff

  21. #21
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    Default Re: How to prevent splintering when using birdsmouth router bit on VG fir?

    Quote Originally Posted by Jim Ledger View Post
    There's a tendency, when making a mast, to let ones hands slide along the mast while walking from one end to the other. Don't do this, especially if it's a Douglas fir mast.

    I had one of those, also doug fir, go into the middle knuckle of my right index finger. It broke off when I tried to pul it out, and there it remained for about 3 months, festering away. And then one day it just popped right out. That knuckle has always been a bit FUBAR, but just for the last 50 years.

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