I'm wondering if 5/16" tiller is too much for my bow, for after a shot the bottom limb is still vibrating while the upper is not. Any suggestions? Otherwise the bow seems fine, that is, smooth and quiet. Thanks.
That is higher than I'd normally set a bow with. Is this the 'natural' tiller, ie are the limb bolts even or is it adjusted that way?
I used to set bows to begin with at about 1/4, (6mm) low on bottom limb but as risers tend to have a slightly highter grip these days I now use about 4mm.
If you do change it, the nocking point will move so will need to be reset.
It's the natural tiller on an entry level recurve without any specific limb adjustment mechanism. However, I have been able to adjust tiller by backing out a limb bolt very slightly. I think a little less than 1/4 turn on the bottom might bring the tiller down by about 1/8" or so.
I wouldnt leave limb bolts loose, adjustable limbs have a rocking point built in to 'see-saw' on wheras your riser and limbs do not. The real answer is not to expect so much of entry level equipment, tring some different limbs wouldn't cost a fortune. However if you are determined to improve this, try malikng a full pocket length shim for the top limb. Plastic milk container is good, it's flat enough and easy to work with. This would.make the top limb stronger and would reduce tiller. The other thing to try is to reverse the limbs. The error could be coming from the riser and inverting the assembly may be a happier combination.
Whatever you do, always adjust the nocking point after a change. How did you determine the nocking point position?
I determined nocking point position by sight picture. Currently it's at about 7/16", which gives me the best compromise for the JOAD Adult Achievement distances of 18, 30, and 50 meters.
Will be able to try switching the limbs today. Thanks.
If you mean you changed the nocking point height to get a nice target aquisition you may never get the bow shooting well. The nocking point is a combination of arrow, grip, release and the limb balance.
If you don't want to go down the bare shaft route, try shooting through a sheet of paper. The idea is to get the nock and point to pass through the same hole. It may not be possible to get the perfect bullet hole but start high and keep lowering the nocking point in 1mm amounts till the hole is at least almost flat. Start just a few feet from the paper with a boss behind you. A sideways tear may not be possible to eliminate but you will see the tear become less high.
OK, thanks. May be a little while 'till I make it over to the indoor range, but they do have a paper frame setup for tuning. Meanwhile, before reversing limbs as suggested, I tried sanding off the sharp corners on the bottom of each. Lo and behold, when I reassembled the bow and restored my brace height, tiller measured 0 and the bow was quieter than ever! Definitely a much better solution than playing around with loose bolts.
It might also be worth mentioning that the bow was definitely noisier and not as smooth when I shot off of the shelf. Do I have this right, that raising the nock point as well as reducing tiller both served to weaken the lower limb in realtion to the upper?
Now all that's left is a little paper tuning and I will have the bow set up as well as I can.
The lower limb is usually slightly stronger as the arrow is shot from above centre and the grip below. Some makers have a lower grip to make the arrow more central and some raise the grip but the the arrow moves up in order to clear the hand.
Cheap limbs are often machine made with 0 tiller and if the riser is adjustable you set it by unequal limb bolts or shims. Better limbs are tillered in the factory. Glad you found reasons for the discrepancy.
Well done for thinking it through!