Let's Build a Trilam! (Finished pics on page 12... Refinished pics on page 13)

[ty_in_ND]

Hi all!

Instead of continuing on the 2016 Bow Swap thread, I thought it would be good to start a fresh new thread for this bow.  Just as a brief intro, I've been intending on building a reflex-deflex trilam for my trade partner.  The 1st attempt was going well until I uncovered a knot on the belly and it started to crack in the limb.  The 2nd one ran into some issues because I made a mistake on where I set the reflex in the limbs.  So, in addition to posting progress pictures of the glue-up and tillering, I'll be starting off at the very beginning.  Also, I'll be more than happy to take suggestions and critiques as this goes along.  I'm by no means and expert bowyer, but some of you guys are.  And hopefully, for those of you interested in this style of bow, you can get something out of this thread.

With the brief intro done, let's get started!



This is what I'm making the trilam out of.  It'll be an osage belly, walnut core, and bamboo backed.  The walnut I ripped from a larger board that I purchased from a local hardwood shop a while back.  The bamboo and osage were purchased online.  While I have only one 36" osage board pictured, I do have another (more on why it's not pictured in a bit).  So, I have a little bit of work to do to get these ready.  For the dimensions of the different pieces (I'm shooting for a 55lb @ 29" bow), I will be going with 1/4" thickness for the osage, 3/16" thickness for the walnut, and 1/8" thickness for the bamboo.  I'll be tapering the bamboo and walnut to 1/16" at the tip (with the taper starting at the end of the fades).  I'll be making the bow 69" ttt, 1 1/4" wide limbs (parallel width for 6" out of the fade, then tapering to 1/2" at the tips), and a 13" handle section.  This is the approximate dimension of the 1st trilam (it was 67" ttt) and I had to take of a bit of wood to get it to about 55lbs near the end of the tillering (that's where I stopped when the crack appeared), so I'm sure I'll get the weight I want from these dimensions.

I started of by getting the osage prepped.  Here's a picture of a little problem that needed to be addressed:



While not twisting, it has a bit of a dog leg.  In order to make sure I got a piece that was nice and parallel, I sent the board down the tablesaw along with a level.  I moved the board and the level at the same time along the fence, cutting the convex side of the board.  This left me with one side that was nice and straight.  Then, I just used the fence to cut the board to 1 3/8" wide (to give myself some wiggle room).



I was hoping to get my belly lams from this one board, but when I went to get two 1/4" thick lams out of it, I discovered that with the kerf of the blade I was using, it would be not worth it to attempt.  The board was 5/8" thick.  If it would have been 3/4" or if I had access to a good bandsaw, I would have made it.  Instead, I took the safe route and ended up with a piece that's a hair thicker than 1/4" and one that's about 3/16" thick.  If anything, I can use the thinner lam as a core for a future bow!

And this is where the 2nd piece of osage comes into play.  Since I was hoping one would do it, I left the other board at home.  I'll be getting that one trimmed up shortly (and when I do, I'll take a few pics!).  I also need to get back to finish prepping the walnut and bamboo for tapering.  I unfortunately won't be able to get at it until tomorrow, but I have all day to work on this stuff, so there will be more posts tomorrow!!

[bow101]

Just do it.........   Experimenting is half the battle what others do is copy.

[bubby]

I would taper the walnut from 1/8" in the center to 1/16" at the tips

[jeffp51]

I am looking forward to seeing this.  When the trade deadline came and went, Ty contacted me to let me know he was still working on this and that I am the recipient.  Since then I have watched him struggle to try to make a working trilam.  I admire his persistence.  It would have been easy to give up a long time ago.  I have learned a lot in watching his efforts, and I will look forward to seeing this one being a success--and not just because it is supposed to come to me.  Unfortunately, I know nothing about this building techniques.  If any of you do, I hope you will pitch in and help out.

Good luck Ty.

[ty_in_ND]

Again, thanks for the kind words, Jeff. You'll get a bow out of this yet!

Before I post more, I have to ask: Bubby, why do you suggest 1/8" to 1/16" for the core? I'm definitely open to trimming it down to 1/8", but the guide I'm following runs 3/16" to 1/16".

Other than that, more updates this afternoon (just need to edit and upload pictures!).

[bubby]

You can leave it 3/16" in the center, i don't think you posted that you were tapering it

[ty_in_ND]

Oppsie!! I didn't say where the taper would start. Both the boo and the core will start tapering at the fades. I'd be open to either reducing the core to 1/8" at the fades or starting the taper at middle (I also forgot to mention the bottom limb will be 1" shorter than the top).

I didn't get the pictures straightened out, but here's where I'm at: the osage is planed to 1/4" thickness (I processed the other board I mentioned), the bamboo is planed to 1/8", and the walnut is planed to 3/16". I also made a z-splice in the osage boards.

So, before glue up, here's what needs to happen: taper the boo, taper the walnut, and add a little flip to the osage tips. I'll be getting to these tomorrow (as well as getting some pictures).

[Aaron H]

Sounds like you are well on your way to a nice trilam.

[PEARL DRUMS]

I think you will nail this one down, Ty. I have to believe you learned a few things on that last one that will make this one a real sweety.

[ty_in_ND]

Thanks for the vote of confidence, Pearl! I think between the lessons I learned from the other attempts and the sound advice from you guys, it'll be a killer bow!

So here's the update for the day: I didn't get a chance to sneak out and taper the walnut or boo, but I do have the tips taken care of.





An example of the form I used and how it turned out after I unclamped it. I used corn oil and a heat gun to get it bendy. Man, the smell of warm osage is great!

[Badger]

   You have a little problem on your curve, the radius is too tight. You might have problems with your back and belly strips adhering tightly to the spot where it is curved.

[bubby]

I agree with badger, you might want to prebend the boo and belly. What adhesive are you using?

[stuckinthemud]

Hey Ty, good to see your still going.  Much respect! 
Andrew

[PEARL DRUMS]

Or, just slide it back on the form a few inches and re-warm it. Either fix would work fine.

[ty_in_ND]

Bubby, I'll be using smooth on.

Thanks for the input, Badger, Bubby, and Pearl. I had been planning on bending the walnut and boo after I tapered them to match the osage. However, I would be comfortable with making the angle more obtuse. I'll give it some thought while I get the other pieces tapered. I won't be able to glue up until Saturday night, so I have some time to consider my options.