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BBH twins build along (For testing).
superdav95:
Just a couple updates. I got both tillered to about 50lbs just passed brace height with bend looking good on both. No issues or anything yet. I also cut in the shelves and added the string knocks. I went with Buffalo horn nocks. They are very durable and I kept them pretty light. Tips will narrow more upon finishing from here. I like to shape up my nocks to an angular shape to get them both the same dimensions then glue them on and shape and round them on the bow. As for the shelf I cut with a pull saw my shelf line and then use a chisel and chip out the pass to that line cut. Files and rasps do the rest of the shaping. I’ve been taking my time to get my inners moving early on in my tiller. I find this helps me avoid whip tiller. At least for me. I also do not go over my intending final draw weight during the tiller process. I usually get to my intended draw weight at brace height about 6” or so in this case 50lbs. Then I brace it and continue my tiller from there strung at low brace. Thanks for following along on this journey.
Selfbowman:
Looks good Dave!
superdav95:
Some bad news guys. I developed a bad hinge on the upper mid limb while tillering out to 26”. I found the likley cause. It appears to be a thick glue line section next to it. I’m guessing it was creating a stiff spot and partially causing a hinge. As I attempted to balance this out it just ended up too underweight. I abandoned this one and moved on to the next one. I may end up trying to salvage this later with a belly lam of bamboo slats on each limb. As for the second bow it went well all the way to 28” at just over 52lbs. It looked balanced and had just a little under 1/4” positive tiller upper limb. This bow is an asymmetrical bow. I shot it in and it shot very well. It shot hard and fast and worked my way up to 28” draw. After about 20 shots I noticed a more pronounced bend right near a knot on the belly of the upper limb. I had figured it was ok as it was mostly removed during tiller but it may in fact be an issue after all. Bow still shoots amazing but I worry about it lasting and blowing up eventually. I think I’ll belly lam this one first with boo slats on each limb belly. This will allow me to remove more of the issue at the knot on the belly and salvage the bow (3rd pic shows this knot). I’ll get to work on this one first as it shot so well. It still held 4” reflex after all this too which is promising if I can do the belly lams. I’ve drawn a pencil line on the delay to show where I’ll start removing wood to prep for belly boo lams. (See second pic) The other one I’ll wait a bit in for now and save it for another project down the road. Oh well all good for learning. My take away on these bows as they stand now is incomplete really but one observation I made is the bow that had the thicker boo strip had a tougher time getting tillered. It caused for more belly wood removal then ideal for stability. Here’s a few pics
Selfbowman:
That is pushing the limits. Amassing you kept so much reflex. The knot is the culprit for sure. This design requires real good wood . The design has more inner limb stress due to the reflex. Especially when most of it is in the last 10” or so. Your going to do it Dave. Your right there.wont be long and the task will switch to arrows.
superdav95:
Hey gang. Here’s an update on these bows. As you know if you e been following this thread both these bows had issues. The second one shot very well up until it started failing a bit near a belly knot. It basically was stressed around the remnants of what was left of the knot and threw the tiller off. Still shot ok but looked funky. I set it aside until recently. I decided to boo laminate the belly. I’ve done boo laminated bellies before but have always scraped and sanded the nodes and re tilled much the same way a self bow. This proof of concept bow is nothing new but had checked a few boxes for me as something I wanted to try anyway and this bow was a great candidate for it.
I was very careful to pre tiller this bow after removing about .150” thickness on the belly of each limb. This allowed me to get rid of most if not all of the troubles around the knot that had caused issues. I pretillered the bow after removing this belly wood to good looking balanced brace and then to about 20”. At this time it was about 32lbs at 20”. I then proceeded to prep my belly slats. I decided to go with a very slight taper from the tip at .120” down to about .140”. I went thinner at the transition fades around .100” to allow for the bend at the fades. I decided to stagger the nodes and place nodes midway of the nodes on the back to spread out the irregularities of nodes somewhat. You can see the pic where I’ve marked with arrows of node placements. Glue up went good. I used the usual inner tubes and double wrapped the area at the bends in fades. I clamped this down with several clamps after wrap. I took a good look at the bends to ensure even bending in the boo slats prior to glue up. The one slat had slight more crown then the other so comparing bend is important I think. Keeping tips aligned after glue up is important too. As far as tiller after the glue up of belly lams I did a little side tiller only. This allows me to keep the surface of the belly slats untouched. I think this made the difference on this bow. Tiller isn’t perfect but fairly decent considering side only scraping. Time will tell. I’ve got about 50 arrows through it now and it seems great. It is around 67”ntn and pulls about 55lbs approx. the new mass of the bow is 629grams. It was around 600 before. Not a deal breaker. I need batteries in my digital draw weight reader! I took the rare opportunity with my wife around to take a couple short vids. Sorry about my scruffy appearance. I’m a all day work clothes kind of guy 😀. I’m sure you guys get it! The bottom pic shows the reflex at about 4.5”. This was bout 30min after shooting today out to full draw for about 50 shots. The reflex was about 4” immediately after unstringing the bow. I was quite pleased with this!
Anyway the speeds are very good. The bow shoots very straight no matter what I fire through it. The chrono readings seen in the video are promising even at only 27”draw. I later had slightly better readings at 28”-29” draw but my wife ditched me and thus my camera person.
At 27” draw at 10gpp the video shows readings of 186 and 187. Very respectable I would say for all wood bow.
At 27” draw at about 7gpp arrow the video shows reading of 195fps. Not too bad.
Later in the day I shot a 202fps with the same arrow at 7gpp and was closer to 28-29” draw.
Also shot a 188 and 189 with 10gpp at 28” draw later also. Not a ton faster but a little bit and it was a nice cloudy day for my chrono.
I’ll post some pics here too but here are the two video clips of the above readings for interest.
https://photos.app.goo.gl/LiHDU9pxXU9JXadi7
https://photos.app.goo.gl/Y2LgnrZD8cqfz1sL9
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