Primitive Archer
Main Discussion Area => Bows => Topic started by: vtclimber on January 09, 2010, 05:57:19 pm
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Afternoon all. I am working on a BBI R&D, and hoping I can get (some much needed) advice on how to finish tillering. It looks like the right limb needs to bend a bit more in the last 2/3's, but I am not sure since it is an R&D.......Ay rate, advice is welcomed! Right now it is at 22" and pulling ~55#. I'd like to keep that weight and get it to about 28"...
Not the best tillering tree, but it is too damn cold to head into the shop lol.
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I would try and get more wood moving from Mid-Limb out to the final third...but then Thats just Me...I am sure that there are others out there with more expertise with R? Bows that will chime in....But to Me it looks like the Wood is working way too hard right out of the Fades to Mid Limb
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Thanks ElD. I was not/am not (?) sure if R&D's follow that elliptical pattern. I was thinking a bit more from mid limb out, but figured I would get some other opinions.
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I would also get the mid & outer limbs working more.
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Yeah....an Unbraced would help a bunch too.....I know that the last third of the Limbs do not bend like a Longbow....but the first two thirds should.. profile should almost look like a Mollegabet/Holmegaard Bow does....I know that Eddie parker...David Knight....and a bunch more have better input on this since they all have made or built R/D Laminated Bows before...I only have done R/D Staves........ :-[
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Here is an unbraced pic. I got the boo and ipe from David. That stuff is tough.....and the splinters SUCK!!
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took the liberty of throwing a line on one of your pics....to me it looks like the left limb is stiff where I put the blue line out toward the tip....if you compare that to the right limb you can see how much difference there is (distance under the string).....also in my experience as you even out the tiller (limb to limb) the weight will actually come up a little.....because the weaker limb was getting you back to the 20" by working mostly in one area only....whereas as the limbs even out they whole things got to work....just one old mans opinion.
half eye ;)
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Thanks half eye. I actually have a mark on each limb measured 16 inches from the nocks. At low brace, the difference between the distances is 1/16th of an inch. I had thought the upper limb (limb on right in the first pictures) was stiff through the reflex.....
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I think the tiller is pretty dang close. The braced pic still has reflex, so it should never get to eliptical shape.
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Justin - So to bring it down to weight at 28" should I work the whole limbs evenly, or just focus on the last 2/3 - 3/4?
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Scott....so would I take off the left right at the fade to get em even and then work the limbs out?
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It would be a lot easier to see if you would take all of the pictures on the floor like the drawn pictures. A consistent background helps a lot.
I might hit the whole limb 2 times then the outer 2/3 once.
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Justin - I'll try to get some with a consistent background tomorrow. I am trying now to keep basically the same tiller and get it down to weight at 3" under my draw length...
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Like Justin said you are very close on your bow, and its only a few scrapes from being ideal.
One trick I teach folks on these bows is how to sight down the limbs when its strung and push on the string so you can look down the limb from the grip section and see where the limb moves and where it doesn't. This perspective amplifies the flat spots in the tiller and then you can flip the bow and see the other side..
Like mentioned you will see that your limbs bend too much outside the grip and more movement is needed in the middle, but how much is needed is why I hope you try this.. No two of these r/d curves will look "identical" but very close and how the limbs work by themselves and together should be determined more by how the bow shoots and the set it hold, and not purely by how it "looks".
Make sure to have safety glasses or goggles on.. Every "renown" bowyer I have seen does this trick and this goes back decades..but most never mention it..(gee I wonder why? ;) )
Rich-tips you won't find elsewhere
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Rich, thanks for the insight. I will get back on it once I get another cup of coffee in me..
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I would say so far you got some good solid advice.. Ready to see the next pic's..
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Here are a couple more. I've worked the outer 2/3's quite a bit and I ("think") I got the bending at the fades even. Thanks for all the helpful comments. Right now it is just over 50# at 23". In order to get to at least 26" should I just keep working the last 2/3's??
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Don't do it man... it is already bending a lot out there. If you work only the outer 2/3 it will be whip tillered. A R/D does not have an elliptical tiller. The outer limbs appear straight even though they are bending. With Ipe you might not get a ton of set, but it will still be whip tillered. Search R/D tiller and look at the tiller on some other bows.
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Thanks Justin - How should I continue? Work the whole limbs to get it to weight?
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Entire limb... I think the left limb may be bending too far already in the outer 2/3. The right limb could use more bend at the fades to match the left.
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Thanks man - I may just try to even it up and leave it at the draw it is. I can shoot a shorter length, just prefer a min of 26..
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The Picture I posted helps me with whatever style Bow I am building...whether a D Bow... or a Reflex/Deflex Bow...you just use the Ellipse as a guide to see what parts of the Limbs are doing...and how close to the same each part is....that being said....Right now it looks like you have everything but the last 1/3 of the Limbs working well....you don't want the last third to curve like the rest...because it is already working as much due to the Reflex built in(i.e...profile shot)....I think Justin gave you firm Advice...don't do it!!...work the whole limbs...maybe a scrape or two more on the wood right out of the Fade on the right limb...but other than that...scrape slowly on the whole Bow now to reach you desired weight/draw...good luck ....and lets see the finished Money Shot here soon......... ;)
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Damn! That helps a lot ElD! I'll slowly work each limb to weight and get some shots up when I have it complete.
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I think you are just about there...if I was you I would PM David Knight...and let Him look at the Pictures....since He is the Master of His Own Designs....Who else could give you a better Answer..... ???
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I'll shoot him an email..
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Vt I have to agree with Justin. A d/r bow is never going to get an elliptical tiller to look right. You have to remember the resting profile and make each part bend in an equal amount. The safest and most efficient is going to be as much working limb to an equal degree.
If you are starting with a D/R profile and bend each inch to the same degree it will not be an oval. To qualify what Mike is doing with the oval. I agree that it is a great aid to help see the comparison limb to limb and overall shape but to try to match an oval your reflexed part would have to be much more stressed then the rest of the limb. Hope that helps.
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VT Look at the tiller on Brownhillbilly's bow here..This is what you want yours to look like. It looks like it came off the same form ...
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Keenan - I knew it wouldn't follow an elliptical in the same manner as a traditional flatbow or selfbow.
Rich - I am pretty sure that brownhillbilly's has more reflex/deflex. I glued mine up to "mimic" David Knight's regular R/D's, not the highly reflexed ones. I'll take another look at it though as no doubt it will help.
Thanks everyone for the input!