Tapering a Osage slat question

[razorbak]

Ok I’ve had the worst luck known to bow building in my last dz attempts none have survived due to various circumstances to long to list I’m getting ready to glue up a z splice Osage bamboo backed bow my 13th attempt of making a worthy hunting bow for this season. I have been pouring thru all these threads for months watching countless beyond videos on board/ 3lam/stave bow building reading thru countless old issues of PA that I accumulated over the years watching old DVDs re reading all volumes of the “bible “ especially volume 4 I thought everything was going good on bow #12 I had received the best looking hickory slats and successfully z spliced and glued up a hickory backing while adding a couple inches of reflex. I pre shaped the profile on both prior to glue up. I added nock overlays and blended every thing from fades to taper ing of the limbs knocked the edges off on all corners I even went and taped up the backing so I don’t knock it around while doing the initial floor tillering and stayed away from power tools using only my files and scrapers and while floor tillering the backing about 12” on one end cracked and the hickory fibers lifted so I stop immediately and tried to scrape gently and sand it until it was gone going down 1/16” and took more off the belly wood and in process of floor tillering again it snap more fibers and grain and the belly just compressed like a hinge so I tried to trap the back even more and that worked for 2 minutes then it just splintered so scrap that so the big question I have now is I also purchased Osage slats that was really questionable with knots and weird grain run off but I didn’t want to deal with 3 rivers again so I z spliced and fitted the slats together and profiled the shape and I did that on my last bamboo backing that I had from 20 years ago that was still in great shape  I thinned the backing and tapered it as flat as I can and stopped there as I don’t know where I heard read or saw that I should taper the core so that’s where I’m stuck do I taper on the back or belly before I glue it up ? I got a 12” power lam that I was going to use in this as well and I do have another piece of hickory backing should I glue that up as well? I just don’t want to blow up another bow as it’s getting quite expensive and I don’t live anywhere close to Osage and I have no luck in getting good Osage but that’s another story   I have built a few bows in the past from boards to staves that was successful and have given them away 20 years ago and now this is all I want to do and hunt with so basically I have zero experience compared to you guys

[mmattockx]

Good lord, that is pretty much unreadable without some punctuation and paragraphs.


Mark

[superdav95]

Razorbak,   It can be very frustrating to use questionable wood for laminate bow builds.  I realize getting good laminate material can be a challenge and can get expensive.  I personally don’t make hickory backed bow builds.  I’ve made some decent ones that turned out pretty well but not any improvement over a self bow.  If using a hickory board for a backing slat, it’s very important to get grain that is as straight as possible and to a single ring on your back.   I’m sure others will chime in here too.  In my opinion boo slats are better.  As far as boo slats I make my own from large mosso poles.  I’ve ordered some decent slats from various places with mixed results.  I usually get about 1/3 or more of them in a batch that is not suitable for my liking for laminate bows.  For me the boo slat is the most imported part of the build to get right and get choosy on a boo backed laminate.  This is my experience anyway.  I’ve used less then ideal belly wood for laminate builds and turned out good bows because of a good solid boo backing slat.   There really is a whole conversation or thread alone that can be dedicated to choosing good boo for backing bow builds.  Just to name a few… mode placement, proper taper, width, thickness and crown, and retained moisture.  To me the bigger discussion is the boo slats used instead of the belly lam.  Don’t get me wrong the belly wood is also important.  Here’s another observation I’ve made with boo backings.  Tapering evenly and taking measurements every couple inches to make sure tapers are even on both limbs.  I usually taper my slats thickness of .125” at handle section out to around .0900” at the tips.  This depends on crown of the boo used.  High crown can still work but generally you’ll end up with a narrower bow build.  A lot of factors come into play.  I try to use the largest poles I can find which gives me the flattest crown boo slat.  Boo backs can easily overpower the belly wood and cause frets or compression fractures.  In my opinion this has more to do with slats being too thick and not being tapered properly.  Some guys trap the boo backing to help with this.  I try to avoid too much of this.  Obviously choosing good dense belly wood has the makings of a better bow. Grain orientation is important too.  Lots of threads on here about that.  We really should have a thread started on good boo slat prep and selection.   I kind of went off on a tangent here and may not have answered your question directly but hopefully gave you something that might help you out. 

[razorbak]

Sorry about the non paragraphs lol
Texting from a phone is hard sometimes
I totally get the bamboo issue have had that problem in the past but this last piece of bamboo is pretty good I got little more than 1/8 in middle tapering out to less than 1/8” gonna sand some more. Should I taper on the Osage slat like on the back or the belly?

[superdav95]

I would depending on style of bow and layout.  For a pyramid bow style I would keep belly lam pretty even and then tiller as needed.  For their builds I do pre taper the belly lam as well as the boo slat.  Getting them measured evenly helps in tillering.   The boo adds a lot of draw weight fyi. 

[willie]

13th attempt

can you identify a part of the build process which you find the most challenging?

are you often changing your designs?  every change adds new challenges,

maybe starting a new build coming off a succesful build of a simpler design?

[razorbak]

Most challenging for me is tillering I won’t lie  I use the gizmo religiously
I try to follow a basic design depending what wood is being used like Osage I go 1.5” at the widest point of limb. Mild flip tips steaming or dry heat and on the hickory wood I give it a mild reflex and  1.75 at the widest tapering down to 3/8 or 1/2” tips
When going with board bows I down to 2 or 2.5” at the widest and all of these are at between 64 to 66” tip to tip. Various reasons that the bows been breaking are crap wood
I haven’t been rushing on these builds I do every in stages. I figured the latest batch of woods I’ve gotten from 3 rivers would have been better quality but as I found out that’s not the case
Last bow breakage was at floor tillering stage and not far into it

[superdav95]

Sounds like you got a bad batch of materials.  Best of luck on your hunt for good bow material.  It makes a big difference being picky with materials.  You shouldn’t be breaking bows at the floor tiller stage.  That is an indicator that your materials may be sub standard. 

[willie]

When going with board bows I down to 2 or 2.5” at the widest and all of these are at between 64 to 66” tip to tip. Various reasons that the bows been breaking are crap wood

I would find it frustrating to have a lot of work into producing and gluing up multilaminates and  having poor success.

gizmos are best suited for designs that call for consistent bends, ie pyramid limb profiles.  your lengths and widths seem fine unless you are asking for poundages that stress the wood too much

Rather than online suppliers for lams such as mentioned above, a decent hickory stave with a natural back would work out better? but

what poundage are you hoping the hunting bow will be, and what part of the country are you working in.?   humidity is important in materiel selection  maybe find a local stave?

[razorbak]

I been in the woods looking for good hickory lately no luck yet  as I’m not gonna cut a sub par tree And  yes I’ve had no good luck getting decent material from various sources and after spending about $800 in wood the last 4 months and getting ghosted by a guy who owes me a good Osage stave that I paid for instead of a horrible knot ridden cracked piece of crap. I tell you if and any bad luck for a budding bowyer I achieved that and yes I’m looking to make a mid 50 ish bow

[razorbak]

Btw I just finished gluing up my last bamboo slat to the last pc of bamboo so let’s hope number 13 survives I will unwrap tommorow afternoon and clean up the glue boogers and hopefully glue up a riser block tommorow evening and hopefully by Friday I’ll be tillering

[razorbak]

Fellas I appreciate all the info you fellas have posted ! This is how I learn since no one I know is even remotely interested in bow building of any kind

[willie]

looking for good hickory lately

for mid 50 at 64-66 inches maybe someone will suggest a conservative width for hickory

[Eric Krewson]

I have made a lot of bamboo backed bows. For your bamboo, level the belly of the slat, draw your bow pattern out on the slat as perfectly as you can, cut out your pattern and sand it to the point that every edge is 1/6" thick, this will naturally taper your bamboo slat from the handle to the tip.

1 1/4" is plenty for a BBO, if you go out to the suggested 1 1/2" you will have a lot of bambo and almost no belly wood.

Use your bambo bow blank pattern to draw the bow profile on your slat, make the osage core slightly larger than your bamboo pattern because the bamboo may shift a little during glue up.

Don't worry about grain runout on your core slat, your bambo wild hold things together. I used my twisted tight ring osage for most of my BBOs, with over 50 of these bows in the books none of them ever failed because of grain runout.

Here is an example.



Taper core slat by making a 1/2" mark on the sides at the end of fade and drop that mark 1/16" every 6" until you get to 1/4" and carry that measurement all the way to the tips. I file to the line on the edges but leave the belly slightly rounded to give me more wood to tiller. Where the side measurement is 1/4" I leave the overall thickness about 1/2".

 

[Eric Krewson]

I have a lot more pictures but for some reason I can't transfer them to IMGUR to post here.