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What is the Depth of your ILF Limb U-notch?

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I'm not sure how the attached photo (left) became the de facto standard for ILF dimensions but it's not. To my knowledge, it was a drawing created by another poster (dkard) based on a set of his own limbs.

Hoyt/Easton (Miguel A. Quartino) applied for the patent for the Hoyt Dovetail System in 1983, and it was granted in 1985.

http://www.google.com/patents/US4494521

It was a propriety attachment, and not intended to be a "universal" or "international" fitting at all. It wasn't until it was reverse engineered and universally copied that it became "ILF".

The idea that there is any "standard" to follow is a misnomer. There are going to be slight differences in limb dimensions between manufacturers, and those that wish to design an ILF riser are wise to account for these differences in their designs. If they choose to design a riser with extremely tight tolerances, like DAS and a couple other custom shops did, they will run the risk of certain limbs not fitting correctly.
 

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Discussion starter · #42 ·
That's contradictory to your intital feelings...perhaps you should just meet me at Black Widow next Tuesday, and be done with metal bows? :D
Yep...it sure is contradictory and do you think I'm happy about it?

Yesterday all I did was managed to get the limbs fit too the riser so I could put the bow together and spit a few over the chronograph to get an idea of what the performance level might be and it was fast but loud...I figured that I was in for a wonderful day today and it all started with a fresh pot of coffee and a very positive attitude with me thinking I would be able to get this bow dialed in, tuned up and toned down in a jiffy.

Imagine my disappointment...it blows...and the shot note sounds like somebody whacking an oak tree with a baseball bat...I hate it...made the mistake of trying to take another run at it this afternoon...set the tiller from 1/8th positive too 1/8th negative and mounted up my 10" Bee Stinger for extra measure and it still sounds ugly...this rig sux...it's violent and loud...and over what?...so I can shoot 7GPP at 200FPS?...pass me the slow bow please. :(

I definitely love Black Widows...great bows...But I have two I'm infatuated with now...The Green Stripe TD and the American Bushman...both are easy to tune, quiet and a pleasure to shoot...as are Widows. ;)

Sound advice right there. If speed is so important I hate to say maybe a compound is a better choice.
It's not...matter fact?...today I found that I by far prefer shooting bows that do about 170-180FPS with 10GPP arrows.

I like "sweet" not violent shot reactions. ;)
 
Also, it was not long ago this red riser was the cream of the crop, you had your friend's (?Robertfishes ?) limbs on it, and it shot great, quiet, and all of that.
GO back there, to that configuration.
as with all things, there are things to the left, to the right, and there's the middle.
PROVERBS teaches - avoid the extremes, it's all about BALANCE, in all things.
And like Jeff says, or someone did, bet the RCX limbs on the DAS riser will shoot great with a bit more weight & FOC than the puny tips allow.
 
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I am not really sure what a quiet bow is. I would bet my most quiet bow would be loud to you. I was stringwalking my 72 inch Luxor with Border Premier Carbon limbs today. I noticed it was pretty quiet. Not sure if that is by my standard, or whether I am still whacking oak trees with a baseball bat, just maybe smaller oak trees and a lighter bat.
 
Jinks - it was a bit of shock for me when I got my carbon/foam KStorms... suddenly more sound (versus the TT BlackMax wood.glass) and that feeling of the bow wanting to jump/twist out of the hand. It was almost enough for me to sell the DAS Dalaa 21" and the KStorms.

Fortunately - I changed the grip to a DAS Extra Low, and played around a lot with the tiller... finally I switched the top and bottom limbs, and got it set at around 1/8" negative tiller (I shoot 3 under, with a fixed crawl)... the string has wool wraps, and limbs have small velcro strips for limb slap. Final BH is 7.5"

Net result... a very sedated quiet shot and I'm really happy with it.

As mentioned... you could always put Robert's limbs back on for that sweet shooter... I find in the ILF world, while practically all ILF limbs fit all ILF risers, you have to find the limb / riser combo that suits you. It sounded like you were pretty happy with Robert's limbs on the Elite! A few fps is not worth the additional noise and vibes.
 
Bummer jinks hope you give it another go in a day or two. Maybe try a different arrow like some have said. Maybe try a stiffer arrow. In having similar issues with my latest rig which im shooting light weight vaps. Ill stack 3 arrows in the 5 ring at 20 and then feel a pluck and its in the 2 ring at 3 o'clock. Crazy. These are the ult pros, and im sure its not the limbs.
 
Sometimes fiddling with ILF will drive you a little crazy.A little change in tiller,diff brace height hgt,diff nock point,diff string or string (12twist?),carbon sound of limbs.You know Jinks you will figure it out because your a fiddler.I don't mean that in a bad way but trying for perfection doesn't come easy.
Don't sell that Dass (take some time relax and figure it out),because if your not fiddling with the Dass you will be fiddling with something else its in your nature and that's not a bad thing.
 
Discussion starter · #50 ·
Just currious Bill,
Did you compare the dimensions of the Robertfishes to the WW limbs? I recall you were really pleased with Robertfishes. I just wonder where the differences are between both limb butts.
Thanks Rick...besides Roberts limbs being Shorts and these being Mediums (and that may be a bit of a culprit right there)...I'll have a look tonight...at work right now. ;)
 
Bill, I hand fit your limbs using a Morrison Phoenix riser and a SF Axiom +L riser. I use a 0.375 drill bit and a drill jig to drill the limbs. I also use the same ILF "standard" drawings you posted as a guide. I knew you had a DAS riser..I did know to sand limb ends "shorter" than "normal".. Your limb butts are a little thicker than 0.450 shown in the drawing.. I am building a set of ILF long limbs for myself this week. Glued up first limb yesterday, Maple Burl veneer under clear glass, amberboo tapers, zebra wood wedge, low 40s on a 17" riser..
 
What's getting lost in the discussion about ILF dimensions and the depth of the U-notch is that in reality, the depth of U-notch is irrelevant (unless of course it's too short).

In terms of whether or not a limb is going to bind against the wall of the riser pocket, the relevant dimension is the one between the center of the dovetail fitting and the end of the limb butt or the wall of the limb pocket. It wouldn't matter if the U-notch was a 3/4" deep.

Unlike the DAS connection which has an elongated thumb crew notch that allows limb movement fore and aft based on the depth of the U-notch, the throat of the dovetail fitting itself will only allow the limb to go so far.

If a riser is designed where there is not enough space between the limb pocket wall and the center of the dovetail fitting to accommodate slight variances in limb dimensions, there is going to be a problem. Back the limb pocket wall off 1/8" and you will eliminate contact with 99.99% of all limbs out there.

If you are designing an ILF riser and you know all ILF limbs are slightly different, which any bowyer worth his salt knows, even limbs made by the same manufacturer, and you design your riser with tolerances so close that it will only accommodate a very specific size limb butt, that is not the fault of the limbs, it is the fault of your design.

IMO Moose was right.

It was only a problem because of a flawed DAS design
A riser design intended to accommodate a variety of manufacturers limbs needs to be just that...accommodating. Exacting tolerances are better suited to proprietary applications or one where you intend to hand fit every single application.
 

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and . . .

. . . just who was the shooter on the grassy knoll ? ? ?

Enquiring minds want know . . .

:hijack:

John
 
What's getting lost in the discussion about ILF dimensions and the depth of the U-notch is that in reality, the depth of U-notch is irrelevant (unless of course it's too short).

In terms of whether or not a limb is going to bind against the wall of the riser pocket, the relevant dimension is the one between the center of the dovetail fitting and the end of the limb butt or the wall of the limb pocket. It wouldn't matter if the U-notch was a 3/4" deep.

Unlike the DAS connection which has an elongated thumb crew notch that allows limb movement fore and aft based on the depth of the U-notch, the throat of the dovetail fitting itself will only allow the limb to go so far.

If a riser is designed where there is not enough space between the limb pocket wall and the center of the dovetail fitting to accommodate slight variances in limb dimensions, there is going to be a problem. Back the limb pocket wall off 1/8" and you will eliminate contact with 99.99% of all limbs out there.

If you are designing an ILF riser and you know all ILF limbs are slightly different, which any bowyer worth his salt knows, even limbs made by the same manufacturer, and you design your riser with tolerances so close that it will only accommodate a very specific size limb butt, that is not the fault of the limbs, it is the fault of your design.

IMO Moose was right.

A riser design intended to accommodate a variety of manufacturers limbs needs to be just that...accommodating. Exacting tolerances are better suited to proprietary applications or one where you intend to hand fit every single application.
Limb filament is actually from the end of this limb butt to the leading edge of the ILF fitting not the center. This is were it make contact with the ILF channel or groove. There are different sizes of limb fitting to consider. 3 rivers sell them. Uuhka has the smallest as far as I know, Borders larger and taller for the thicker limb butt. This has been reported on here before. Jinks riser may have a adapter plate that short and required replacement.
Dan
 
Bill, just a thought..have you considered making your own limbs or bows? With your back ground in precision manufacturing I think you could do it. Building bows is my hobby, I have a dedicated 12x24 shop just to build bows. I have friends who race cars, bass fish or drink booze as their hobbies..building bows is cheap compared to what my friends spend on race car engines, tires and fuel..one of my friends recently bought a $50,000 bass boat.. Our house is decorated with my homemade bows.
 
This isn't the first time Bill has stepped out on the high-rise ledge. We TT gawkers have seen him here before and know how this is going to turn out...Bill is going to jump! Jeez, Bill jumps when things turn out splendidly....it's just a matter of when. The good news is that, unlike the rest of us, Bill has way more than "nine lives", can afford it and will survive to pursue his OCD quest for the perfect "grail bow". I learned long ago that I would be way better off perfecting myself to shoot as accurately as the bow I own is capable of, rather than take on re-financing of second wives, mortgages, bruised foreheads, etc. To each his own....good luck and Godspeed!
 
Limb filament is actually from the end of this limb butt to the leading edge of the ILF fitting not the center. This is were it make contact with the ILF channel or groove. There are different sizes of limb fitting to consider. 3 rivers sell them. Uuhka has the smallest as far as I know, Borders larger and taller for the thicker limb butt. This has been reported on here before. Jinks riser may have a adapter plate that short and required replacement.
Dan
Technically speaking, you are exactly correct Dan. The fact remains however that in terms of making sure a limb doesn't bind in an ILF riser, the relevant dimension is between the ILF fitting (which acts as the limb stop) and the end of the limb butt. Yes, their are slightly different sizes of fittings available, but the differences in those are much less even than the differences in limb butt lengths. We are talking about thousandths instead of a eighths, sixteenths or thirty seconds.

This actually supports my original contention that if a bowyer is designing an ILF riser with the intention that it will accommodate various ILF limbs, and the minute differences in commercially available ILF dovetail fittings causes a limb to bind in that particular design, he flat out screwed up.

To illustrate the point, let's assume I worked for Rubbermaid and it was my job to design a universal silverware caddy. Knowing that all spoons and forks are slightly different in size, I choose to design my caddy using one brand of silverware as a template, and the tolerances of my caddy are so tight that it won't accommodate any spoon or fork that is slightly larger than the one brand I chose to use for my template.

When Rubbermaid starting getting a rash of complaints about spoons and forks not fitting, I guess could tell my boss that it isn't my fault, it's the fault of the dang people making the silverware, but I think I'd be looking for a new job.
 

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When I ordered an original DAS riser I had my own limbs. David told me to look at his site because I would have to send them in to ensure they would fit onto the riser. When I got them back the limb butts had been ground down in order to provide clearance with the riser wall. No biggie but it wasn't a secret back than. I guess because the risers aren't produced any longer people must have forgotten this.

Jinks, I know those limbs can be made to quiet and smooth. My friend Scott string walks. His bow was setup without any silencers and was pretty quiet and smooth. Sometimes things like string material and strand count can make a huge difference. It may be as simple as trying a softer material to get a smoother, quieter bow. Some of my favorite bows and setups took me a good month or two to arrive at the right spot. I've had bows that I was frustrated with for the first couple weeks but I'll keep working at it until I get it right. It isn't until I've had one for a few months that I'll consider selling it because it may take that long to figure out if it'll work for me.

One other thought, why use light arrows if you stick with closer shooting? Nothing wrong with a heavier arrow if the bulk of your shooting is 30 yards or less.

Than again, nothing wrong with sticking with the wood bows either.
 
When I ordered an original DAS riser I had my own limbs. David told me to look at his site because I would have to send them in to ensure they would fit onto the riser. When I got them back the limb butts had been ground down in order to provide clearance with the riser wall. No biggie but it wasn't a secret back than. I guess because the risers aren't produced any longer people must have forgotten this.
Unfortunately, fitment has been and still is an issue with some ILF limbs and the risers being produced for 3 Rivers. It's been brought to their attention and supposedly they are looking into having it corrected with their machinist but I'm not sure if anything has actually been done yet or not.
 
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