# How many turns on the limb bolts?



## williamskg6 (Dec 21, 2008)

I have limb bolts on my Cartel Midas that are turned in all the way. I am thinking of reducing the poundage for a while because the draw weight is just a hair too much for me and I'm making errors because I can't comfortably hold quite what I've got. What I don't know is, how many turns can I back out my limb bolts? What intervals are commonly used to adjust (1/2 turn, 1/4 turn, full turn?) and what is the usual outcome of those intervals? I don't want to go down a lot in weight, but I think I need to get it to a level where I can work more on my form and release than on fighting the weight.

Also, since I don't really have experience adjusting these limb bolts (if it wasn't obvious already), the procedure seems to be, loosen the locking bolt on the side facing me, then adjust the limb bolt, then tighten the locking bolt. Am I correct? 

Thanks in advance for your valuable input!

-Kent W.


----------



## limbwalker (Sep 26, 2003)

Just don't turn out the limb bolts past the edge of the riser, and you should be fine.

You are correct about the sequence. No rules of thumb for how much or what the effect is, since every bow is different. Use a bow square to check the tiller and a bow scale to see how much weight you're reducing.

John


----------



## williamskg6 (Dec 21, 2008)

limbwalker said:


> Just don't turn out the limb bolts past the edge of the riser, and you should be fine.
> 
> You are correct about the sequence. No rules of thumb for how much or what the effect is, since every bow is different. Use a bow square to check the tiller and a bow scale to see how much weight you're reducing.
> 
> John


Do you generally find that the tiller is dead even on your bows? Thanks!


----------



## limbwalker (Sep 26, 2003)

Depends on the limbs, not the riser, usually.


----------



## Blades (Jun 25, 2012)

limbwalker said:


> Just don't turn out the limb bolts past the edge of the riser, and you should be fine.
> 
> You are correct about the sequence. No rules of thumb for how much or what the effect is, since every bow is different. Use a bow square to check the tiller and a bow scale to see how much weight you're reducing.
> 
> John


For those who dont have edges to measure from (like my horizon) is there a set rule of number of turns for safety? If I remember correctly, I thought it was turn the bolts all the way out (without the bow assembled) and then turn 3 full turns in? or from the bolts all the way in, never pull more than 6 full turns out?


----------



## HikerDave (Jan 1, 2011)

Blades said:


> For those who dont have edges to measure from (like my horizon) is there a set rule of number of turns for safety? If I remember correctly, I thought it was turn the bolts all the way out (without the bow assembled) and then turn 3 full turns in? or from the bolts all the way in, never pull more than 6 full turns out?


This from the Hoyt 2012 recurve manual

Note:
From the bottomed out position, the tiller bolt should only be
backed out to a maximum of six complete turns

On my HPX ten complete turns out is disengaged from all threads, so Hoyt wants at least four turns engaged. On my Hoyt Excel the useful range of adjustment is less than 6 turns out because the butt of the limb won't contact the tiller bolt past about 4 turns, indicating that the dovetail has jammed before that point.

Regardless of what the bow manual says, you should be sure that at least three turns of threads are engaged but that's a bit risky because you'll have to remember to set tiller only by increasing the tension on the bottom limb bolt or risk getting a face full of wood and carbon fiber. (On a PSE X-Appeal about 10 turns of the bolt are engaged at the lightest draw weight position so thread engagement isn't a factor at all in the adjustment range.)


----------



## lksseven (Mar 21, 2010)

I, too, have read/heard that, for safety, the limb bolts should be turned in at least 3 revolutions.


----------



## Seattlepop (Dec 8, 2003)

lksseven said:


> I, too, have read/heard that, for safety, the limb bolts should be turned in at least 3 revolutions.


Where are you people getting this information? The old Hoyt manual said no less than 6 threads "engaged". The new Hoyt manual says no more than 6 threads from the bottom. This is a change in the way we used to think about the topic and my concern is *if* the newer Hoyt bolts do in fact only require 3 threads engaged, should we assume that this new standard should be used in reference to any other riser unless specifically addressed in its respective manual? Sounds dangerous to me.


----------



## williamskg6 (Dec 21, 2008)

limbwalker said:


> Depends on the limbs, not the riser, usually.


Do you have a link or preferred site/document that describes how you properly set tiller? Right now, since both limb bolts are in all the way, my tiller is dead even.


----------



## SD40 (Dec 25, 2005)

I was told five threads of engagement is full strength.


----------



## limbwalker (Sep 26, 2003)

Check your user's manual. Hoyt is usually pretty good about providing good user manuals. 

Williamsk, There are plenty of good documents out there that cover tiller. Murray Elliott's guide is usually one I refer new archers to. It's very comprehensive and easy to follow. Should be a sticky on this forum if you ask me...

http://www.archersreference.co.uk/download.html

John


----------



## DK Lieu (Apr 6, 2011)

You (in a generic sense, and not to anyone in particular) should not try to play engineer unless you are sure of what you are doing. The strength of a threaded connection is something that is taught in every machine design class in any halfway descent mechanical engineering program. There is a formula for calculating the amount of thread engagement necessary for full strength of the joint. It involves the thread pitch (and thus the cross-sectional area of the thread) and the diameter of the bolt (and thus the cross sectional area of the bolt at its root). For standard thread sizes, the amount of thread engagement necessary is usually somewhere between 3 and 5, with more engagement necessary for finer threads. When I design a threaded joint with standard threads, I always specify a minimum of 5 full threads of engagement. However, this is for standard threads: either ISO, UNC or UNF. The threads on limb bolts may not be standard. Also, the strength of the joint depends of the quality of the material for both the male and the female threads, and also the quality of the fit and finish of the threads. I have no knowledge of these qualities from the manufacturer, and I am not inclined to guess at them. So my advice is to always follow the manufacturer's recommended limit if they are available. This is what I do, and I cringe whenever I see limb bolts turned way out from what would be considered normal. For most risers on the market. it seems that 4 full turns from dead bottom is the adjustment range. Hoyt apparently switched to a finer pitch thread a few years ago, giving an adjustment range of 6 full turns from dead bottom. I will go even further by saying that you should turn out the limb bolt even less than the manufacturer's recommended limit if it does not give you at least 5 full threads of engagement.


----------



## limbwalker (Sep 26, 2003)

DK, since you're on this thread (no pun intended...) - which is stronger? A fine pitch or coarse pitch thread?


----------



## williamskg6 (Dec 21, 2008)

Thanks for all the input everyone. I've decided to turn out my limb bolts 2 full turns from all the way in, then set positive tiller of about 1/8" and start testing. Didn't realize I was opening yet another can of worms!


----------



## DK Lieu (Apr 6, 2011)

limbwalker said:


> DK, since you're on this thread (no pun intended...) - which is stronger? A fine pitch or coarse pitch thread?


For the same depth of engagement, fine pitch thread will be stronger.


----------



## cc46 (Jan 22, 2005)

On my GMX, there is about 9 1/2 turns on the bolts. I use the 5 closest to full in. And given about one turn for tiller gives a range of about 4 full turns for tuning, that's about 2 1/2#s to 3#s on 38# limbs. I've never had a problem with strength of the thread engagement but I cringe when I see limbs out flat to the riser, and hope that shooter is a couple of targets away.


----------

