OCD Tuning Headaches

[Mighty Mouse]

It does bother me (I'm an engineer) that there isn't a Hamskea "spec" for zeroing out the rest (i.e., "with these settings on a brand X bow, you're good to go").

It's not reasonable to expect a rest manufacturer to tell you exactly where to set the rest on a given bow. Dozens of new bows are released every year and each one can be set up in a variety of ways. A Hamskea is probably the most adjustable rest on the market; they give you more than enough adjustment options to make their rests work on pretty much any bow.

It also bothers me (like I said, I have an "attention to detail" to put it nicely) that there isn't a perfect/correct way for the arrow to pass through the berger hole. It seems like some bows like the arrow "riding on top". How do I know if my bow wants the arrow to pass exactly through the hole versus a little high? Is that a function of what diameter arrow you are shooting (if it matters, I'm shooting a 5mm arrow)?

The Berger hole is 5/16" in diameter and an arrow shaft is around 1/4" in diameter, so there's a roughly 9/16" vertical range through which some part of the arrow is passing thorough some part of the Berger hole. I typically start with center of the arrow shaft through center of Berger hole, but it doesn't bother me one bit if I end up a little above or below that. You find where the bow "wants" the nocking point and rest elevation through trial-and-error by shooting, studying paper tears/bareshaft POI/broadhead POI, then making adjustments. Note that cam timing (as well as nocking point location and rest elevation) can affect a bow's vertical tune.

If I look at Hamskea's own instructions, it seems like (by default) things are set up to have the arrow riding on top of the berger hole. See the first photo. I'm picturing an arrow in the fork of the rest. It would be (unless my eyes deceive me) riding on top of the berger hole.

There's nothing wrong with that "default" setting. There's also nothing wrong with changing it.

Basically, the arrow appears to be slightly high of the berger hole and on a downward angle. I hope to pick up a T square (along with the d loop material and pliers that have been mentioned) here soon to quantify how much nock high or low I am at currently. Is anything here necessarily "wrong" (I especially ask because the current tune yields a bullet hole in paper)?

No, there's nothing wrong with having the nock slightly above (or below) level. If it tunes, it tunes.

I think my plan is to address the ATA (and likely the poundage) being off first (get the bow back to specs). From there, get the rest to where it's happy in terms of berger hole location with the T square (arrow bottom through the berger hole?). Then, tie my new loop at level or slightly (say a 1/16th) high. Does that sound like a reasonable plan?

Yes, that's a reasonable plan. Remember that (for comparison to spec) ATA should be measured with the limb bolts fully tightened. If ATA measures long, adding twists to the cables will shorten it.

I'm an engineer as well with strong perfectionist/OCD tendencies, but remember that every measurement has a tolerance. The looseness of the tolerance on acceptable rest/nocking point positions may offend your sensibilities, but that doesn't mean any deviation from your preconceived (and ill-conceived) notion of where "zero" should be is an actual problem. Also remember that shooter-related factors (e.g., grip pressure, facial pressure, anchor point, etc) can affect how a bow tunes.

 

[CodeMonkey]

Before I go further down the rabbit hole, I'd like to thank everyone for their help so far (especially sndmn11 and MightyMouse). You guys have been a really great sounding board and I think I'm well on the path of realizing that I need to invest the time and money into learning all this myself.

I still have two questions that are rattling around in my brain box:

1. Say I take a new release out of the packaging... What adjustments should I be looking to make vertically (I understand center shot for left/right) to ensure it's set up correctly? I've been religiously watching bow build videos on youtube and it seems like some folks set their nock point before bolting on the rest and others do the opposite. Bear with me, I'm slow... I'm not grasping the concept of this being bow specific because the relationship between the berger hole and the height of the launcher at full draw is all in the rest itself. Said differently, if I take a new Hamskea out the package, the height of the launcher arm in relationship to the berger hole bracket is set from the factory. I do get (now, finally) that some bows like the arrow to be in a certain spot in relation to the berger, but how the rest launcher arm relates to the berger hole is all in the rest itself (I think).
2. How close/tight are the tolerances for things like ATA, brace height, draw weight, etc.? Now that I'm going down the path of getting tools to work on my own equipment, I don't want to go down various rabbit holes trying to get things perfect (I say this as the OP of this thread...).

 

[sndmn11]

Before I go further down the rabbit hole, I'd like to thank everyone for their help so far (especially sndmn11 and MightyMouse). You guys have been a really great sounding board and I think I'm well on the path of realizing that I need to invest the time and money into learning all this myself.

I still have two questions that are rattling around in my brain box:

1. Say I take a new release out of the packaging... What adjustments should I be looking to make vertically (I understand center shot for left/right) to ensure it's set up correctly? I've been religiously watching bow build videos on youtube and it seems like some folks set their nock point before bolting on the rest and others do the opposite. Bear with me, I'm slow... I'm not grasping the concept of this being bow specific because the relationship between the berger hole and the height of the launcher at full draw is all in the rest itself. Said differently, if I take a new Hamskea out the package, the height of the launcher arm in relationship to the berger hole bracket is set from the factory. I do get (now, finally) that some bows like the arrow to be in a certain spot in relation to the berger, but how the rest launcher arm relates to the berger hole is all in the rest itself (I think).
2. How close/tight are the tolerances for things like ATA, brace height, draw weight, etc.? Now that I'm going down the path of getting tools to work on my own equipment, I don't want to go down various rabbit holes trying to get things perfect (I say this as the OP of this thread...).

1). I do exactly as I described above. The arrow rest AND the location of the nock point work together to determine vertical "tune".

Think of it this way. Hypothetically, let's say a bow tunes with your hamskea as far back towards the string as possible at vertical hash mark 0. Let's say the nock point on the string ends up being 1/16th" above dead nuts 90deg. At this point let's say that places the arrow shafts center at the center of the Berger hole.
We are in tune, rest all the way back, nock point is above 90deg which means the arrow is slightly pointing down.

Let's say that you then read something about having the rest all the way back isn't as ____ so you move it as far forward as you can. Because of angles and stuff, your arrow shafts just raised because the rest is still at 0 and nock point location was constant, BUT the distance between string and rest changed and Pythagoras says that means the angle of the shaft changed. So, now to get back to vertical "tune" and get the shaft pointing down at the same angle as before, you'd have to lower your rest to achieve that.

So, that is why I start the setup of a new bow as I described before. The rest AND the nock point effect things together, so if I set them up where I think is really close to what it should be, 90deg off string, shaft center about 1/3 between Berger top and Berger center, I find success.

 

[CodeMonkey]

So, that is why I start the setup of a new bow as I described before. The rest AND the nock point effect things together, so if I set them up where I think is really close to what it should be, 90deg off string, shaft center about 1/3 between Berger top and Berger center, I find success.

Awesome explanation. I forgot the obvious part that the nock point is the third point of the line created by the arrow (which intersects the berger at some point).

 

[Mighty Mouse]

2. How close/tight are the tolerances for things like ATA, brace height, draw weight, etc.? Now that I'm going down the path of getting tools to work on my own equipment, I don't want to go down various rabbit holes trying to get things perfect (I say this as the OP of this thread...).

I haven't seen any manufacturer-published tolerances, but personally I'm happy with ±2 lbs on draw weight, ±1/4" on ATA, ±1/8" on brace height. All 3 of those parameters are interdependent, so making an adjustment to change one will cause the others to change as well. Trying to get all 3 exactly to advertised spec is a recipe for chasing your tail. Below is a handy reference chart showing how string/cable twists affect various parameters (it says Mathews but is generally applicable to all brands).

 

[Billy Goat]

The loop is always going to be much higher than the geometric center of the bow. The arrow should pass through the berger holes in some manner. Some go right through the middle or a little higher. Then the nocking point will be set from there........either level with the arrow or slightly higher depending on the bow. Some bows prefer "nock high".

If you really are OCD, then you've got a whole lot more steps to take in this process called archery. And it's never ending.

This isn't the case on all bows anymore. Many are supposed have the loop centered between the axles.

Easiest way I determine is with a square thru the Berger hole. If that comes close to being center of the axles, I go ahead and set the loop dead center between the axles. It's the best way to get level nock travel.

 

[Billy Goat]

I haven't seen any manufacturer-published tolerances, but personally I'm happy with ±2 lbs on draw weight, ±1/4" on ATA, ±1/8" on brace height. All 3 of those parameters are interdependent, so making an adjustment to change one will cause the others to change as well. Trying to get all 3 exactly to advertised spec is a recipe for chasing your tail. Below is a handy reference chart showing how string/cable twists affect various parameters (it says Mathews but is generally applicable to all brands).
View attachment 408268

Pretty certain hoyt use to say +,- 1/4" on their tune chart numbers for draw length and ATA, but maybe not.

Either way, I agree with what you said. However I'm not afraid on a lot of cam systems to purposely go out of spec.


And ATA will vary depending on which side of the bow you measure, so keep that in mind. When making changes don't accidentally change sides and then wonder why it jumped so much.

 

[CodeMonkey]

Once again, thanks for everyone's help. I think I had the "come to Jesus" moment about working on my own bow. I have it on good authority that Santa will be bringing me a bow press, vice, and associated goodies. I'll likely ask Santa for that instead of a new bow because I think the investment in the tools/knowledge is worth it versus a new bow that's probably an incremental improvement over what I currently own.

In terms of the bow, I have her set up now where I think I want it. My timing was slightly off, but was resolved by twisting the yoke cables (I learned this is a good way to fine tune) equally. Arrow is now at the point where the bottom of the arrow crosses the center of the berger hole and I'm slightly nock high. All specs are dead on (draw weight, draw length, brace height) except for ATA, which is still 1/2'' long. Knowing what I know now (that messing with ATA isn't an independent operation and will likely mess with everything) I'm not going to touch it (as much as the number not being what it "supposed" to be is bothering my OCD). Like I said, brace height, draw length, and draw weight are all perfect (could the tune chart be off?). She shoots bullet holes through paper and I'll likely try BHs here shortly.

 

[sndmn11]

Once again, thanks for everyone's help. I think I had the "come to Jesus" moment about working on my own bow. I have it on good authority that Santa will be bringing me a bow press, vice, and associated goodies. I'll likely ask Santa for that instead of a new bow because I think the investment in the tools/knowledge is worth it versus a new bow that's probably an incremental improvement over what I currently own.

For what it is worth, I still use a bowmaster press because once I get things set, I don't have to fiddle until I change strings again. Once you have tuned your bow, it is very very easy to put new strings on and get it right without pressing a bunch because you know where things need to be and how to get there having learned from the first time.

So, if you want to find a way to save a few hundred dollars, keep that in mind.

 

[Jimbob]

My Dad, brother and I went splits on an apple press years ago. Then bows changed and the press didn't work anymore, so I just bought a bowmaster. I have used that for a long time to tune multiple bows. Sure it would be cool to have an awesome press set-up but I have done everything I have wanted with that bow master, which includes changing limbs on my Hoyt Carbon spyder turbo.

Bow master and bitzenburger fletching tool have allowed me to get very technical with my tuning.

 

[Mighty Mouse]

For bows with press-less cam adjustment (e.g., Bowtech Deadlock or Elite SET) or static yokes, a Bowmaster style press can be a good option for tuning, but I wouldn't want to try to use one to pull an axle to adjust shims/top hats. The inability to adjust the width of the fingers on a Bowmaster also makes it a bit of a crapshoot as to what bows it will actually work with. Case in point: I had to take the rubber guards off one of my Bowmaster split limb brackets and widen the space between the bracket fingers with a grinder to get it to fit around the bottom cam on my Hoyt Helix. I also welded some pads on the ends of the fingers to help grab the press nubs on the Helix limbs. After those modifications it worked great, but it wouldn't work on my Helix out of the box.


If you're serious about doing your own tuning and other bow work, a "real" bench-mounted press is money well spent. I recently bought an LCA EZ Green press, and my only regret is that I didn't buy it sooner.

 

[Jimbob]

I changed top hats on my vertix with my bowmaster. Are there better presses? Yes. Will a bowmaster do everything on every bow? NO!

However, I have done everything I have needed (changing strings, limbs, and top hats) on 10+ bows with the bowmaster so it has worked for me.

 

[Mighty Mouse]

I changed top hats on my vertix with my bowmaster. Are there better presses? Yes. Will a bowmaster do everything on every bow? NO!

However, I have done everything I have needed (changing strings, limbs, and top hats) on 10+ bows with the bowmaster so it has worked for me.

Interesting that you were able to do a limb swap with a Bowmaster. My Bowmaster doesn't have enough range of travel to let the limbs fully relax. Maybe some models have a longer jack screw than mine.

 

[Jimbob]

Interesting that you were able to do a limb swap with a Bowmaster. My Bowmaster doesn't have enough range of travel to let the limbs fully relax. Maybe some models have a longer jack screw than mine.

I’m sure it depends on the bow model as well.


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