Need your tillering option

[4est trekker]

I recently added an 7" glued-on reflexed tip to this 63" ntn oak pyramid bow.  It pulls 40# at 26".  Before redoing the tips, I had about 500 shots on the bow and the tiller was even and slightly elliptical.  After redoing the tips I've developed a slight tiller problem.  Let me know where I need to scrape.  The bottom limb is on the right in the picture where the bow is on the tillering tree.  Thanks in advance for your help!

 

 

 

[AkDan]

I'm not the greatest at this...really just beginning but I'd love to throw it out there and see how fast I get corrected LOL     :p    ...really just to see if I'm learning anything.

To me the left limb looks pretty good..the right limb looks flat from about mid limb out, just a skosh.  I get crosseyed looking at these things so far LOL so take it for what it's worth, my guess.

I am curiuos is the bow that noisey you really need two sets of silencers?   Seems like most of the selfbows I've come acrossed are whisper quiet.  Just curious....

[Art B]

Describe your grip (straight/high wrist, medium grip or low wrist/full contact) and the way you draw the bow (split-finger or three under).

Anyhow, if you shoot split finger and use some heel pressure with your grip here's why your lower limb flattened out at mid-limb. Because of the heel pressure of the bow hand there is added strain (which the upper limb does not receive) on your lower limb just outside the lower fade area. From the repeated shooting and the heel pressure this sequence of events didn't allow your limb to properly bend at mid-limb. In other words, the greater strain on the lower limb is taking place at the lower fade instead of mid-limb.

You know, folks talk about making the lower limb a tad stiffer but no one is specific about where. Not much you can do about fixing this problem but for your next one try beefing up the area right outside the lower fade to compensate for the added strain of the bow hand. This will force the lower limb's mid-section to do more work and bend properly. ART

[4est trekker]

AkDan: Thanks for your advice.  I, too, get a little crosseyed sometimes after looking at the same bow for awhile.  It's nice to be able to post a picture and have someone else critique it (or not, sometimes      depending on what shape the bow's in!).
Regarding the silencers: I'm a music teacher, and so the smallest overtones catch my attention.  When I shoot indoors with one set of silencers, I can still hear a faint overtone coming from the string at release.  With two, it squelches it because I've placed them just below what would be the "node" where that overtone is being produced.  But yeah, the bow is whisper quiet, especially now.

ArtB: Thanks to you, too.  I shoot with the bow grip seated firmly in the crotch between my thumb and index with medium heel pressure.  As I don't have a picture, imagine the shape your hand makes when reaching for a a round doorknob.  Your diagnosis sound spot on.  So...do I just keep shooting this bow and expect the problem to continue or stay static as it is?

[Art B]

Things are going to stay pretty much where they're at with the grip you described. As long as you draw the bow and feel even strain on both limbs then you'll be OK. I suspect you'll lose a little efficiency and feel some added shock to the bow. But if you happen to draw the bow and feel the lower limb give a little bit then just take a little heel pressure off of your bow hand.

If you will move those puffs in to 1/4 the length of the string then that will eliminate those two extra ones. Just take your string and fold it once, then fold it again, and that will give you the best possible balance for string vibration. ART

[AkDan]

4est...I know what you're saying about harmonics..played in the army band for a handful years    

Wanted to ask, do you have problems in your tree with the bow wanting to roll?  If not could ya post the cradle portion.   I dont mind having to use wedges, but if there's a better way I'm all for it.

[4est trekker]

AkDan; Usually I don't have any problem with the bow rolling because I don't shape the profile of the handle completely until after I've tillered the bow.  Because I build predominantly board bows, I can leave a small flat area on the back of the handle that keeps it from rolling.  However, when I have to tweak the tiller after the bow is finished as I am doing (or trying to do!) on this bow, I use a small clamp to hold the bow square in the tree.  It's not pictured above, but I just use a short Irwin ratcheting bar clamp.  I don't put a lot of pressure on it...just enough to keep it from rocking.  However, I'll still use wedges from time to time to keep everything lined up.

[George Tsoukalas]

I don't see any problem except that the lower limb is slightly stiffer which is the way it should be.    Jawge

[4est trekker]

I'm going to post this as a separate thread, but I thought I would put it here since it's related to this bow.  I read somewhere on TradGang about flipping images and then using them to help prescribe where to adjust tiller.  I had my wife take a picture of the bow above at full draw on tree, copy and flip the image, and then overlay the two on top of one another.  The result is a double image of the bow, one facing one way, one facing the other.  If you cut the picture in half as I have, you can easily see how both limbs line up inch for inch along their curves.  You can see in this picture that the outer third of the the bottom limb is stronger than the outer third of the top limb.  Now, one can argue that that's the wrong place for the limb to be stronger, but I'm posting this mostly as a guide for how photography can help you from going crosseyed while tillering!      

 

[4est trekker]

ART: Thanks for tip about the silencers...I'll do that!  

George:  Thanks for your input.  I appreciate it.

[George Tsoukalas]

4, I agree with Art that the proof is in the drawing of the bow. A digi cam and an understanding person to snap a shot as you draw helps in assessing tiller. I used to use a Polaroid. Remember those? I used to use a full length mirror. Lately, I draw in front of a window at night with a light on. I wonder what the neighbors think? I like the lower limb just slightly stiffer and am not sophisticated enough to worry about where (sorry, Art).    Jawge

[Art B]

String up some of your older bows George and recheck 'em on your tillering tree. Let me know what your see. Did that to a few of mine and was surprised. Although all of mine retained their positive looking appearence, but once drawn down, I could see that the inner lower limb was taking most of the set while the rest of the limb wasn't carrying it's share of the load. Got the same results as 4est. So, if you don't get the same results, then I can argue that you compensated for the "extra" stress that the bow hand's heel pressure adds and therefore do care where you add the extra strength to the lower limb.    

ART

[George Tsoukalas]

Art, what makes you think that I have old bows? LOL. Actually, I do have a lot hanging around. Too badly tillered to give away. The set on my bows usually happened (happens) mid limb on and is usually under 2 in. I should mention that when I said I leave the lower limb slightly stronger I mean at full draw. My bows are, shall we say, irregular in appearance. The one I'm hunting with this year has a Holmegarde style lower limb and a Meare Heath upper. Why? I dunno. Just kinda happened. Art, we'd have a blast making shavings together. BTW I'm not disagreeing with anything you've said so far. I'm just calling into question my own discernment.    Jawge

[Art B]

Hey, I too think we could make some fine shaving together George, and hopefully a bow or two.
 

Yeah, I have to keep all the bad ones also. Don't know why though, even the good ones can go bad rather quickly in the hands of the uninitiated.  :(  

ART

[George Tsoukalas]

Art, we have fun while making bows and that's the name of the game. This is my hobby, my friend.    Jawge

[Art B]

My hobby also George. A good on' to have if you ask me!  Keeps me young at heart if nothing else...............and upright. Keep it fun always my friend. ART

[4est trekker]

I tried what you (Art and Jawge) said taking pictures at full draw with the bow in the hand and using feel to judge tiller.  I took pictures of myself drawing with different grips and watched how the limbs changed at full draw in each.  I also closed my eyes and pulled the bow several times while taking a video.  Thanks for your help, guys!

[4est trekker]

Forgot to mention...when I used too much heel pressure the inner third of the lower limb did take more of the brunt than it should.      Now, can you tell me exactly why, Art?    :confused:   Again, thanks guys!

[Art B]

You sort of answered your own question there 4est. You're applying pressure or pushing in on the bottom of the handle causing it to force greater strain in that particular area (inner limb). Kind of a bracing effect. Top limb doesn't receive this bracing effect.

ART

[George Tsoukalas]

4, you pretty much want to have even pressure. I like the lower limb slightly stiffer so you may note the lower one coming toward you slightly.  No tipping. Your bow's not a waitress.    Jawge