# ILF Specs



## Georgemay (May 27, 2008)

perhaps patent docs could be of use?
http://www.google.com/patents/US4494521


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## >--gt--> (Jul 1, 2002)

Bob Furman said:


> Does anyone know where I can find a document detailing the ILF Specifications?


There is no such thing.


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## joebehar (Nov 13, 2012)

I have these for ILF limb fittings. Does that help?


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## Bob Furman (May 16, 2012)

Georgemay said:


> perhaps patent docs could be of use?
> http://www.google.com/patents/US4494521


Thanks, that is helpful.


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## Bob Furman (May 16, 2012)

>--gt--> said:


> There is no such thing.


George,

Since ILF is considered a standard, how are other manufacturers suppose to manufacture various items that confirm to these standards?


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## Bob Furman (May 16, 2012)

joebehar said:


> I have these for ILF limb fittings. Does that help?
> 
> View attachment 1819686
> View attachment 1819687


Thanks, that helps much.


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## DruFire (Jan 10, 2013)

Bob Furman said:


> George,
> 
> Since ILF is considered a standard, how are other manufacturers suppose to manufacture various items that confirm to these standards?


the problem is they don't. Its more of a ILF Suggestion, not Standard.

And youll find those number won't match up to some W&W limbs, SF limbs, New Hoyt limbs, Uukha limbs... I am sure theres more.


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## Warbow (Apr 18, 2006)

Bob Furman said:


> George,
> 
> Since ILF is considered a standard, how are other manufacturers suppose to manufacture various items that confirm to these standards?


They aren't. Not sure if Easton ever enforced the HDS patent or not, but thank goodness so many makers have created compatible equipment, even without an actual 3d party standards org to dictate the standard. (Also, the ATA, unlike its former self the AMo, is now prohibited by its own bylaws from creating standards; it can only create "guidelines". And the ATA technical committee is chaired by Gregory J. Easton, so if Easton/Hoyt doesn't want the ATA to create a guideline based on the expired HDS patent it seems unlikely that it would.

The ad hoc "ILF" standard has been a boon to archers around the world, and, I expect, the competition has inspired to Easton to work harder to compete - or to just create a new, incompatible limb system


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## Bob Furman (May 16, 2012)

Georgemay said:


> perhaps patent docs could be of use?
> http://www.google.com/patents/US4494521


Btw, that appears to be the Compound patent. The recurve patent is located at: http://www.google.com/patents/US4091790


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## Bob Furman (May 16, 2012)

DruFire said:


> the problem is they don't. Its more of a ILF Suggestion, not Standard.
> 
> And you'll find those number won't match up to some W&W limbs, SF limbs, New Hoyt limbs, Uukha limbs... I am sure theres more.


I know the Uukha and the new Hoyt (aka Formula) never claimed to be ILF. I always knew there were subtle differences in others, but one would think that if there is a inferred standard that there would be some sort of specs for manufactures to follow.


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## Bob Furman (May 16, 2012)

>--gt--> said:


> There is no such thing.


So does this mean that every manufacture following ILF Guidelines must reverse engineer the specifications from Hoyt Limbs or Risers?


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## DruFire (Jan 10, 2013)

Bob Furman said:


> I know the Uukha and the new Hoyt (aka Formula) never claimed to be ILF. I always knew there were subtle differences in others, but one would think that if there is a inferred standard that there would be some sort of specs for manufactures to follow.


I just meant in a measurement sense.
The inno primes and powers have this "padded" area for the limb bolt to sit on.
Hoyt seems to have followed this with there ILF quattros.
View attachment 1820007


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## Bob Furman (May 16, 2012)

DruFire said:


> I just meant in a measurement sense.
> The inno primes and powers have this "padded" area for the limb bolt to sit on.
> Hoyt seems to have followed this with there ILF quattros.


I added a thicker nylon washer under my limb bolt  Btw, that extra padding is a great idea and shouldn't be an issue with any Hoyt risers a sthere is plenty of space where the limb bolt slips into place.


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## limbwalker (Sep 26, 2003)

Georgemay said:


> perhaps patent docs could be of use?
> http://www.google.com/patents/US4494521


Fascinating. I owned several Hoyt Pro Medalist TD/2's and TD/3's and never realized Earl had a version with a limb alignment system. Makes sense, for those cast risers. Just didn't realize it had been created. Makes one wonder if the alignment system was ditched in favor of the tiller adjustment system of the TD-4 ?


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## gster123 (Dec 17, 2012)

limbwalker said:


> Fascinating. I owned several Hoyt Pro Medalist TD/2's and TD/3's and never realized Earl had a version with a limb alignment system. Makes sense, for those cast risers. Just didn't realize it had been created. Makes one wonder if the alignment system was ditched in favor of the tiller adjustment system of the TD-4 ?


Hi John, 

Not too sure if this is the same thing but there is a bit of a description of alignment systems back in Earl Hoyt's day in the "Tuning your Hoyt Avalon Plus" article written by Denise Parker in the 90's - the quote from the article is as follows - 

"Recurve bows began to be manufactured with adjustable limb pockets in the 1990’s, but really adjustable pockets have roots back to the 70’s. Earl Hoyt patented an adjustable limb pocket system in May of 1978. In his patent, Earl described the advantages in that you could adjust the tune according to individual’s hand placement or adjust the line slightly to improve clearance. But the misunderstandings of today, were the same reasons Earl Hoyt didn’t introduce adjustable pockets back in the 70’s. Bringing an adjustable pocket system into manufacturing would give the appearance that Hoyt was making up for imperfect tolerances, not improved and more accurate tuning methods. So Hoyt focused its attention back to exacting its tolerances and the recurve market did not see this pocket system until the 90’s, when the market demanded it.

Just as Earl Hoyt had claimed back in 1978, adjustable pockets are not, against popular belief, made to cover manufacturing inabilities, but rather to expand the methods available to the archer for tuning their bow to their personal form and equipment preferences."

Cheers 

The full .pdf is available here www.arrowstar.be/downloads/Avalon_Tuning.pdf

Sorry if it is off topic for the OP.


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## limbwalker (Sep 26, 2003)

> the same reasons Earl Hoyt didn’t introduce adjustable pockets back in the 70’s. Bringing an adjustable pocket system into manufacturing would give the appearance that Hoyt was making up for imperfect tolerances,


Interesting quote. Thanks for the link. And what a concept - a female elite archer writing about tuning a recurve. That's quite refreshing actually.


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## Borderbows (Apr 4, 2009)

gster123 said:


> Hi John,
> 
> Not too sure if this is the same thing but there is a bit of a description of alignment systems back in Earl Hoyt's day in the "Tuning your Hoyt Avalon Plus" article written by Denise Parker in the 90's - the quote from the article is as follows -
> 
> ...


and the left and right adjustment?


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