Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: Dan Landis on August 22, 2016, 09:08:00 AM
-
Finally getting ready to start on a bamboo backed tri lam. Is there any problem with using hackberry as a core wood? The belly will be osage, and the bow will be 64" tip to tip. and hoping to get in the low 50's for weight. I plan to cut up some staves for the hackberry and osage on the table saw. Any suggestions for a starting width using these woods?
-
I haven't used Hackberry as a center lam, but it should work. Any wood that will make a selfbow will work.
I'd cut it out at about 1 3/8", but guess it will end up closer to 1 1/4" finished width, maybe even less. It depends on your other design factors.
-
Thanks Jeff. I'm sort of following Roy's design used on the last build along he posted. Don't know how well I'll be able to taper the core using the table saw though. I'll get it as close as I can and remove more of the belly wood to tiller.
-
Dan if ya like, send me your core lams and I'll taper them for you for nutten. You just pay the shipping both ways. It won't take but 15 minutes to taper them and I owe you a favor for the material ya sent me a while back.
-
Roy, thanks for the offer, may take you up on it. I have to get something ripped out first, at this point all I have is some not so straight staves. You don't owe me anything by the way.
-
Dan if you are careful you can rip tapered lams on the table saw. Canopyboy and I probably cut 100 lams that way in his shop. If you've got a well tuned saw you can get some pretty surprising accuracy.
First we made a nice think sled (make it thick because it's going to ride on it's edge).
-
LittleBen, working on making the sled now, hopefully will get something I can use.
-
Here's where I'm at so far. Have my osage cut to 5/16 thick and Z spliced, have my hackberry center lams tapered from 1/4" to 1/8" and Z spliced, and my bamboo cut to the bow profile. I noticed when I cut the bamboo to profile that it is thicker on one side than another. How important is it that they be even from one side to another, or can this be corrected when tillering by removing more wood from my belly lam? I have no way to correct the bamboo other than a scraper or a hand held belt sander.
-
You want the sides equal. Use a small hand plane to remove material from the thicker side. Then use a toothing plane to even things up. Being careful, the belt sander would suffice. You could mount the belt sander in a vice and run the boo across it that way for better control.
You want the boo 1/8th thick at the riser, tapered to 1/16th at the tips.
-
Thanks Roy. It is tapered end to end, but didn't notice the side to side difference until I cut it to profile, then it became very noticeable. I'll see what I can do.
-
After the boo is cut to profile, I thin it down and taper it on the 4 foot edge belt sander. Then finish it up with a toothing plane.
-
Sure wish I had a 4 foot belt sander and a toothing plane. :bigsmyl: I got it looking pretty good with my 18" belt sander clamped in my vise as you suggested, and a fine toothed saw-zal blade. As soon as I get the curves bent in the ends I think I'll be ready for glue up.
-
Don't forget to pad the boo so the clamps don't indent it, I also lay a thin lam on the belly side to protect it. Don't forget to mark the limbs where the mid limb posts will be. I drill 2 small holes in the handle grip area and 2 holes on each side of the tips for tooth picks to keep the boo aligned at glue up. I do a dry layup with a string to get everything straight then clamp it down and drill the holes. I also wrap tape around the mid limbs to hold them straight. Just don't tape over your mid limb posts marks. That has happened. LOL
-
Just finished making a batch of pads. I ground the curvature of the boo into the bottom of each one with the nose of the belt sander.
-
Atta boy....
-
Glue up is complete, now for the waiting & hoping all is well when the clamps come off tomorrow evening. :pray:
-
Can't wait. Post some pictures for God sake.
-
What Ben said... :)
-
Sorry for the time lapse, been out of town for two days installing a new floor for my daughter.
Here is where I'm at so far.
Glue up
(http://i1101.photobucket.com/albums/g433/DanLandis/P8290044.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P8290044.jpg.html)
unclamped.
(http://i1101.photobucket.com/albums/g433/DanLandis/P8300047.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P8300047.jpg.html)
Handle glue up
(http://i1101.photobucket.com/albums/g433/DanLandis/P8310049.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P8310049.jpg.html)
Profiled
(http://i1101.photobucket.com/albums/g433/DanLandis/P9020051.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P9020051.jpg.html)
Handle rough cut
(http://i1101.photobucket.com/albums/g433/DanLandis/P9020052.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P9020052.jpg.html)
Now, where do I go from here. At this point I can barely get the limbs to flex when floor tillering.
-
Trap the back, lower the belly facets, and radius the belly center.
-
Roy, how wide should I trap the back, and can you explain what you mean by lower the belly facets.
-
I usually trap in about 3/16th from the edge of the limbs. I take the belly facets down to the core lam glue joint. I take the belly facets in about 1/4 inch from the side of the limb. Then round off the crisp edge caused by doing the facets.
-
Thanks Roy! Makes sense now, we'll see how much flex that gives me.
-
Dan, make sure your front/width profile is absolutely spot on first, except for a little extra width in the tips perhaps until alignment is verified, otherwise, if you start trapping and faceting with uneven widths/wavy edges, it can throw the whole works off.
If you go back and take the wavyness out AFTER you trap and facet, it will change their proportions, then you have to fix the trapping and facets anyway... so, better to bring the width to very accurate profile first. Maybe it already is, I just thought I noticed a few little spots so thought I'd mention it. Carry on.
-
Thanks Jeff, I checked the limbs with a straight edge from the tips back to the end of the 6" parallel portion, there are 2 areas where it was slightly high. Straightened them out and trapped and faceted one limb. Still need to loose a lot of weight, can barely get any movement when floor tillering/bending.
Right now the limb that is trapped is 1-3/8" at fades, parallel for 6" then tapering to 9/16" at the tips. Would it be better to make limbs narrower or remove wood from the belly?
-
1 1/4 at fades to 1/2 at tips. Then redo the trap and facets. If it's still too stiff, take a rasp and flatten the center of the belly equally, then round over the 2 edges you get from doing that. That is if you have enough belly thickness. You should cause your belly lam was 5/16th to start. I make my belly lam 1/4 thick.
-
Dan, I don't know what your target draw weight is, but if memory serves, 1 3/8" is wider than any BBO bow I've made. Do like Roy said and narrow it, maintaining good accurate edges and trap it again. Verify or remark an accurate centerline before you begin to ensure you don't remove more from one side than the other.
You should get a little movement floor tillering before you even put the belly facets on.
For reference, I've made a slew of BBO bows from 60-70# @ 28" that were barely 1 1/8" wide.
If it's still too heavy, don't go more narrow than 1 1/8" or so without critiquing and possibly working down its thickness.
-
Jeff, target wt. is low 50's. So far I've narrowed it to 1-1/4", trapped the back, re did my center line, and cut new facets on the belly. Still feels pretty stiff, but getting some movement. The osage on my top limb is slightly thicker than the bottom, so I'll start removing a little from the belly on that limb first, then go from there. Also, need to do the tip overlays and cut in the string nocks.
-
Just thought of another question, how do you finish out the handle area? I made this one 13" as in the last build a long that Roy posted. Do you let it a full 13" or is it shortened as you shape it. A little shorter would give me more working limb.
-
It gets a little shorter but not much.
(http://i47.photobucket.com/albums/f165/ROY-CHRIS/IMG_7880.jpg)
(http://i47.photobucket.com/albums/f165/ROY-CHRIS/wtrilam6.png)
(http://i47.photobucket.com/albums/f165/ROY-CHRIS/wtrilam5.png)
-
Thanks Roy, I sort of assumed that was how it was done, but just wanted to make sure. I'm really trying not to mess this one up.
-
How thick are you at the fades, mid limb and at the tips?
Have you had the long string on to give you a reading of the drawlength at your intended finshed weight? If so how far with a taut to the belly longstring?
-
Mike, I have not put a string on it yet. I just glued the tip overlays on today. Right now it measures about 3/4" at fades, 5/8" mid limb, and 1/2" at the tips.
-
That's a little thick, Dan. The bow I'm working on now is 11/16th at the fades, 1/2 at mid limb, and 7/16th at the tips. It's 61 tip to tip and pulling 57 at 28". If it was 64 tip to tip, it would be pulling about 50 pounds.
-
Sounds like I need to remove some wood from the belly and re do the facets.
-
When you remove wood from the belly, be careful and make sure you have a nice even taper from fades to tips. Go slow and do not make any deeper areas along the way. That's how hinges start.. Put the bow in a vice and kneel down and look across the belly surface. Take off any high spots first before rasping the entire belly. Then proceed making the belly a little thinner. I'd start out removing 1/16th of material first. Then redo facets, etc and check floor tiller.
-
Well, after removing some wood from the belly of both limbs I found 2 pin knots across the limbs in the osage. The first one is about 3" out from the fade and the other is about 10" in from the tip. The one close to the fade I think will be gone till I get it tillered, the other one is still fairly deep. Hopefully it will survive.
-
I hate when that happens. Is the Osage 1/4 sawn?
-
Yes, I cut it on my table saw. I cut around several others, but didn't notice these. Any hope it will survive, or am I wasting my time?
-
I doubt it will. Ya have pictures?
-
Will try to get some up tomorrow.
-
OK
-
Here's the pics. The first one is the one closest to the fade. I believe this one will be gone until I'm done tillering. The second one is small but pretty deep.
(http://i1101.photobucket.com/albums/g433/DanLandis/P9060054.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P9060054.jpg.html)
(http://i1101.photobucket.com/albums/g433/DanLandis/P9060058.jpg) (http://s1101.photobucket.com/user/DanLandis/media/P9060058.jpg.html)
-
If you just stop removing wood from those areas and otherwise tiller the bow normally you might be ok. Leaving those knots just a little thick makes a big difference.
-
The first pin knot picture scares me. I had the exact same thing on a bow a few months ago and it developed a crack right through the knot area. I super glued it and worked it on the tree and it opened back up. I knew I could never trust it and cut the bow up.
The second pin knot doesn't look all that bad, but taking more wood off could reveal a monster.
You could try finishing the bow, but those 2 areas will always be on your mind when you shoot it.. Finish it and send it to Bowjunkie as a gift.. :)
-
At this point I'd get it to where it could be shot and shoot it 3-4 hundred times, and then if it held up perfectly, continue to finish it.
-
Roy you are so kind, always thinking of others :bigsmyl:
-
Ya Dan, I really like Jeff. LOL
-
Got it bending to 25" today. Pulling around 52#. I shot about 30 or so arrows through it with a short draw and it felt pretty good. Hope to get it tillered out to 28" tomorrow. The upper limb is showing a little stiff at this point. Will try to get a pic or two up tomorrow.
-
Great news, Dan..
-
Finally finished the tillering, now pulling 52# @ 27". Been shooting it every day, have 150 arrows through it so far. When done shooting the tips are about 1" behind the handle, after resting a few minutes it is even with the handle. Lost most of my reflex to set. If I were to make another one with hackberry core lams I would make them 3/16" or 1/8" and taper to 1/16". I only have about 1/8" to 1/16" of osage left on the belly. I'm sure this contributed to the set.
Pics to come soon.
All things considered I ended up with a great shooting bow, if it survives. Not too bad for my first attempt at a tri lam bow.
-
Cool beans, Dan.
-
Congrats, Dan.
-
Thanks guys, couldn't have done it with out ya!