Trad Gang

Main Boards => The Bowyer's Bench => Topic started by: knuklhed on January 03, 2018, 07:12:00 PM

Title: a book on tri-lams
Post by: knuklhed on January 03, 2018, 07:12:00 PM

Can anyone recommend one to me? I would like to try laying one up, and want to find a good reference to help me. The variations I've seen in the build alongs have my head spinning. Or,as an alternative, if I can find a mentor close to me, that would work.
Thanks!

Title: Re: a book on tri-lams
Post by: monterey on January 03, 2018, 08:59:00 PM

There is a good instructional by Mike Westvang (dryad bows) in the fourth volume of the TBB (I think it's vol 4   :confused:   )

Ol Roy here has loads of trilam stuff posted right here on the bench.  Mostly just pictures, he don't know much about ritin.  He has a book in him but no way to get it out.!    :biglaugh:

Title: Re: a book on tri-lams
Post by: Bowjunkie on January 04, 2018, 07:10:00 AM

The quickest way to stop that head spinning is to jump in with both feet. I haven't seen a reference that walks you through it, but it isn't rocket science. I just started making them, kept a few notes, and that was that.

It took me a while to convince Roy to try them, and now that's all he wants to make    :dunno:

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 09:20:00 AM

I use 1/4 sawn Osage for the belly lam, 1/4" thick parallel, not tapered, 1 3/4" wide, 66 long. I use 1 3/4" wide red elm for the core lam, grain doesn't matter, 5/32nd thick at riser, tapered to 1/16th at the tips. I taper the boo from 1/8th at riser to 1/16th at tips. The boo has already been cut to the exact shape of the bow before glue up. The flares I make 1 1/4" wide, then hold that width out another 6", then do a straight taper to 1/2 wide at tips.

I score the glue surfaces with a toothing plane, and use unibond800 for the glue. I find the half way point between the tips and flares and that is where I place the mid limb posts mark for glue up.

Before glue up, I lay all the pieces on the bench  like they will be glued up and I run a tight string from end to end. I clamp down those pieces and drill 2 holes in the handle area where the leather grip will cover them. I drill a hole on each side of the limb tips. After the glue is applied to all surfaces, I place toothpicks into those holes to keep the parts aligned while clamping.

I pad the belly and boo side with material to keep the clamps from indenting the material when clamping. My center post is 3 3/4" high, my mid limb posts are 2 3/4" high and the end posts are 5.5" high. I wrap the entire bow with plastic wrap to keep the glue off the clamps and form.

I clamp every 2 inches, don't crank the clamps down too tight, just snug them good. I alternate the clamps every other clamp, meaning I place them on opposite sides of the bow. Clamp the bow at the center of the handle first, then clamp at the two mid limb posts next. Then go ahead and put all the other clamps on.

Unibond will dry in 24 hours at 70 degrees.

After the glue is dry, then glue on the riser and clamp it up. When ya get that far I'll posts more pictures.

That should be a start. Any questions, just ask.

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 09:26:00 AM

(http://i.imgur.com/8sC8ONR.jpg)

 (http://i.imgur.com/A893r3D.jpg)

 https://www.youtube.com/watch?v=-bRYE1hPYy0

 https://www.youtube.com/watch?v=XSwx80xjTUE

 https://www.youtube.com/watch?v=3xaxn7cDp2E

Title: Re: a book on tri-lams
Post by: BMorv on January 04, 2018, 09:30:00 AM

Monterey had it right, TBB4 under laminated wood bows.  That's about the most detailed build I've seen on tri-lams.  You'll still have to do some experimenting to get the recipe right for your setup.  I glued up tri-lam #3 last night and I'm still tweaking things a bit.  
Thanks Bowjunkie for your equal limb timing explanation on one of Roy's builds.  I started tillering that way and it balances the bow quite nicely.

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 09:34:00 AM

(http://i.imgur.com/ij5WVlD.jpg)

 (http://i.imgur.com/dzEqkpu.jpg)

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 09:38:00 AM

I taught Bowjunkie everything he knows..    :laughing:

Title: Re: a book on tri-lams
Post by: BMorv on January 04, 2018, 09:57:00 AM

Roy, your boo looks better than mine.  You only have 2 nodes per working limb, and I normally have 3.  Where do you get it again?

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 10:05:00 AM

It's called Madake, pronounced Mah-dak-ie. I get kiln dried whole poles. About $35 each, get 4 to 5 bows out of one pole. Call and ask for Jennifer, tell her it's for bow building, she knows all about that.. Tell her I said howdy.


  http://www.beautifulbamboo.com/

Title: Re: a book on tri-lams
Post by: BMorv on January 04, 2018, 10:23:00 AM

Thanks.  How's shipping considering it's a whole pole?

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 11:40:00 AM

3 of them total bill was about $130 to Pa.

Title: Re: a book on tri-lams
Post by: knuklhed on January 04, 2018, 05:27:00 PM

Thanks for all the replies. I have a few more questions. Roy, what weight are you aiming for? I want a light bow for building form first. Do I reduce thicknesses slightly to get that? And,how do you cut your tapers on the full length slats? What other woods are good for bellies?  

Thanks for the pictures,as well.

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 04, 2018, 06:52:00 PM

Shooting for 50 to 55 #.

You could make the belly lam 3/16th and core lam 3/32nds. Hard maple, black walnut, black locust, mulberry, red oak.

Title: Re: a book on tri-lams
Post by: goobersan on January 04, 2018, 07:08:00 PM

:notworthy:

Title: Re: a book on tri-lams
Post by: knuklhed on January 06, 2018, 01:36:00 PM

Roy,I see you use a few spring clamps mixed in along the way. I don't have all that many C clamps, so I'm wondering if the spring type have enough clamping force to do the job all the way along, except at the posts. The main benefit I could see would be uniformity of pressure, making it impossible to over tighten, which if I understand right, leads to starving the glue joints. (Plus, the spring clamps are just a bit cheaper than C's at HF. And, I'm a cheepsk8.) What do you think?

Thanks for the help!

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 06, 2018, 02:13:00 PM

They probably would, but I would place them tight against each other alternating sides, and buy stronger ones. You really don't need the bigger C clamps like I use. Smaller clamps like maybe 2" clamps would suffice.

Title: Re: a book on tri-lams
Post by: Kopper1013 on January 07, 2018, 12:58:00 PM

Roy have you ever thought about teaching a weekend class   :campfire:

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 07, 2018, 01:09:00 PM

No I haven't.

Title: Re: a book on tri-lams
Post by: Kopper1013 on January 07, 2018, 03:05:00 PM

Hmmmmmmm......... maybe you should    :pray:

Title: Re: a book on tri-lams
Post by: Bowjunkie on January 07, 2018, 05:14:00 PM

Yeah Roy, maybe you should.

Title: Re: a book on tri-lams
Post by: Roy from Pa on January 07, 2018, 07:20:00 PM

Roy has enough to do already.

Title: Re: a book on tri-lams
Post by: BMorv on January 08, 2018, 09:50:00 AM

knuklhed, I started out using spring clamps and they work okay with just one lam, like if you are gluing on a backing.  When I started making tri-lams I switched to c-clamps, as I didn't feel like the spring clamps provided enough force with the r/d shape and the 3 lams.  I use the 2" C-clamps and they work fine.  You ALMOST can't over tighten the 2" clamps as the tighten pin is so small (obviously don't crank down as hard as you can)

Title: Re: a book on tri-lams
Post by: stretch2 on January 14, 2018, 07:22:00 PM

tons of great information thanks

Title: Re: a book on tri-lams
Post by: knuklhed on July 07, 2018, 01:59:46 PM

It's been forever since I asked for help starting, but I finally got ready, and glued something up. It is 1/8" hickory back, 3/32" elm core, and 3/16" maple belly, around 69" ntn, 1 1/2" wide through the riser to about 6" past the fades, tapering to 1/2" at the ends. The riser is maple layered with bubinga, about 12" long and about 2 1/4" deep right now before contouring. After grabbing some mason's line to use as tillering string to start, it looks stiff in the middle of the limb, yes? I think that might be because I expected this one to be a spectacular failure :scared:, and didn't taper the lams. The fades look kind of steep to me, too. I think there is room to make it work if I play with the limb shape more, and reduce the thickness of the riser. What do the more experienced eyes of Trad Gang see? Any suggestions?  Thank you for any input!

Title: Re: a book on tri-lams
Post by: BMorv on July 09, 2018, 02:50:04 PM

Your fades have me nervous.  Can you explain how you glued it up?  Looks like the handle was flat and a lot of bend is happening right after the small fades end.
A bend through the handle glue up allows an almost seamless transition. 
 

Title: Re: a book on tri-lams
Post by: knuklhed on July 09, 2018, 08:15:56 PM

The handle was cut on a very shallow arc to follow the deflex in the lams. I think, after seeing it in assembly, I messed up by not making the riser at least a couple of inches longer each side. Now I'm stuck with what I have, and need to figure a way to save it. I don't mind making it a fairly light bow, that was kind of the plan to begin with for my first one. Any suggestions? I don't know if it is doable, but my first thought is to put another partial lam or some kind of reinforcement strip on top of the backing, to stiffen the center. But when I cut a shelf, that may not help. Maybe make the mid to outer limbs quite a bit thinner to balance the loading?

Title: Re: a book on tri-lams
Post by: BMorv on July 10, 2018, 09:53:44 AM

So there's no thickness taper on the bow?  If so, that is a big part of your problem.  Tapering the lams allows the limbs to bend in an even arch.  No taper and the middle and outers will be stiff putting a lot of stress on the inner limbs, and in your case right where your fades end.  I put between .004" and .006" taper per inch total.  So the thickness at the end of a bow will be about 1/8" thinner than near the fades.
I would try and put the taper in since you are willing to experiment with this one.  It won't be easy to maintain even taper now that the bow is glued, but you should learn a lot from the process.  And I would try and make your fades longer.  If you riser is 12" you should have room to make your fades 2.5" or more and gradually transition from limb to handle. 
These are 2 that I'm working on for friends.  These have power lams which allows me to have smaller and more steep fades.  It's especially important to have nice smooth fades with no power lam. 

Title: Re: a book on tri-lams
Post by: Tim Y on August 04, 2018, 08:05:34 AM

Hi all,
   I have been following this thread with interest. I find it packed with solid information that clearly outlines the tri-lam build process. Thanks for posting.
   Timing is everything as I, like knuklhed, am building a trip-lam too. So I have a picture and a few questions...
 BMov, how thick, at the center is your power lam? I ground mine 5/32" and 16" long, I tapered paper thin at the ends, 1/16" at 1" and 1/8" at 2" continued that taper for about 5" on each end. I intend the riser to be 12" long.
  My goal is 40 to 45# draw, stack is;
 Ipe 3/16" w/.001" taper.
 Red Elm 1/8 w/.002" taper.
Power lam. 16" long 5/32" tapered.
Bamboo 1/8" tapered to 3/32".
  I feel ready to go with this, but what do you all think...your thoughts, concerns.
Thank You,  Tim Y

 

Title: Re: a book on tri-lams
Post by: DavidWood on August 22, 2018, 05:12:06 PM

People often make reflex/deflection longbows this way. Has anyone had luck making recurve bows this way? Any pictures?