# nock groove size; center serving size ??



## ceratops (May 17, 2017)

Is there a table somewhere of actual nock groove measurements, and suggested center serving diameter to go with those different nocks? I see reference to 'small nock' and 'large nock', and LAS listing for Easton G nocks, for example, shows .088" and .098" as the two options for that nock. Listings for some other nocks I checked have no obvious size specs at all(!) which seems odd. Are the .088" and .098" standard sizes? And is that measurement taken down at the throat where the nock sits against the string, or at the tighter spot where the nock fingers first engage the string?

I recently acquired an older trad bow, and the string that came with it has a fatter center serving which doesn't really fit the nocks on the arrows I happen to have. So, I got out calipers to measure the center serving on the new bow (as well as on the bows I usually shoot), with a view to ordering some nocks... And am finding that the center serving measurements don't seem to correlate with the very scant info about nock groove size I've come across so far.

Clearly the center serving measurement has to be a bit larger than the nock groove, in order to get proper snug fit. But how much larger??


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## Stash (Jun 1, 2002)

There's no "standard size" for nock grooves. Different manufacturers, different models of nocks. Some nocks snap on hard (I mean the throat is a fair bit narrower than the bottom), some barely (throat is only a bit narrower), and some not at all. Add that to different thicknesses of different string material strands and varying number of strands, and different thicknesses of serving material, and on top of that, everyone with their own definition of what the correct nock fit is, makes it impossible to quantify it.

You just have to experiment a bit, and then write it down somewhere so you don't forget.


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## dchan (Jun 29, 2004)

Or you can actually do a quick search and read my sticky.

https://www.archerytalk.com/vb/showthread.php?t=2037374&page=2&p=1075798049#post1075798049

This will get you started to a closer number.


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## ceratops (May 17, 2017)

So the terms 'small groove' and 'large groove' have no precise meaning at all?? At least each nock manufacturer must have specific dimensions for their products... somewhere... after all, these items are mass produced, not whittled one by one by a room full of artisans. So, where does one find such production dimensions?


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## ceratops (May 17, 2017)

dchan said:


> Or you can actually do a quick search and read my sticky.
> 
> https://www.archerytalk.com/vb/showthread.php?t=2037374&page=2&p=1075798049#post1075798049
> 
> This will get you started to a closer number.


Thanks! I have read much of the sticky before, but didn't remember that part. I did some searching before asking...

After reading the string/nock info in the sticky, I have a comment - it is certainly helpful, but all very empirical - so-and-so many strands of material X with serving material Y will fit thus-and-such nock from manufacturer Z. Coming from the other direction, where I just have strings on my bows (don't know specific material, strand count, or center serving material size), I can, however, readily measure how thick the center serving is. Seems it shouldn't be that hard to go from measured center serving diameter to best nock size... Heck, I don't need best nock size, just a suggestion of 'reasonably close' would be nice.


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## ceratops (May 17, 2017)

Just wanted to add - if I sound frustrated, it isn't at anyone here on AT. It just seems that precise measurements are strangely hard to come by in this field - I've seen people complaining about how hard it can be to find all relevant dimensions for arrows, for example. Or there's the non-standard standard of ILF limb fittings. It seems that precise nock dimensions may be similarly obscured by some manufacturers. Not sure why...? I'm used to technical fields where dimensional drawings and data sheets are readily available, so this seems odd in comparison.

I guess I had imagined there was some table of known nock dimensions, and some ballpark number for relation to serving diameter - something like "Nock groove should be roughly .005" smaller than center serving diameter. Start there and experiment." But, from what people have said thus far in this thread, it seems much more nebulous than that.


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## Bender (Dec 6, 2006)

ceratops said:


> , it seems much more nebulous than that.


Uuummmm...Yeah. This.^


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## dchan (Jun 29, 2004)

Easton large groove .098”
Easton Small grove .088” 

Both are published.

Almost all the other vendors are very close to those for large or small grove..

carbon impact super club press in nocks however are smaller than even the small grove.


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## Stash (Jun 1, 2002)

dchan said:


> Almost all the other vendors are very close to those for large or small grove..


That would depend on your definition of "very close".

I'll give you an example based on what I have on my current recurve bows. 

I am using 24 strand 452X material with #4 nylon serving. I put my calipers on each of my currently strung 3 bows and got a range of .103" to .105" - This depended on how tightly I put the caliper jaws on, but a fair average would be .104".

I have 2 types of nocks that I use. Easton large groove G for Uni bushings and .166" ID shafts, and Bohning Blazer "double lock" nocks for Super Uni bushings and .244-.246" ID shafts. I also have some Bohning pin nocks, Bohning F nocks (.166 G size), small groove G nocks and Easton S nocks on hand. Unfortunately I don't have a caliper that I can use to measure the nock groove or bottom properly. (What's the term for the bottom of the nock groove, anyways?)

The large G and Bohning Blazers fit on my string the way I like them, with a very light snap. The large G nocks are snug on the string (they won't slide up and down with just the weight of the arrow) though, but the Blazers will. These are the ones I use.

The Bohning F nocks are the same fit, but are a bit loose inside my Easton .166" shafts. The Bohning pin nocks snap onto my string a bit tight, but are loose on the string like the Bohning Blazers.

The Easton S nocks and small groove G nocks are much tighter. Unacceptable for me.

My wife's bow has an 18 strand 452X string with #4 nylon serving. Diameter is .093". The small groove G nocks fit a bit tighter than I'd like - probably would make her a 16 strand string if she ever exhibited any interest in shooting again.  The Easton S nocks actually fit this string OK, so I would say the S and small groove G are "very close".

There are so many other nocks on the market. From memory, compared to what I'm using, Gold Tip .246 nocks and Easton 3D Super nocks are about the same. Bohning Signature nocks are much tighter. Haven't used Beiters, Carbon Express, McKinney, or any of the mid-size Easton H and X nocks.

Back in the good old days when glue-on nocks were the only game in town, Bjorn and Marco (BJ) were similar but I recall that Bjorns were a tiny bit looser. Arizona Plastinocks were definitely tighter that the others, especially in the 9/32" size for some reason.



Anyways, you get the idea.

The easiest and best thing is to find a nock that you like, and make your strings to fit it.


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## dchan (Jun 29, 2004)

Most are published somewhere to some degree. 

Beiter has very specific drawings almost like a machine drawing. 

http://tinyurl.com/y7h927vo


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## j.conner (Nov 12, 2009)

Another issue is likely the consistency of the string and center serving materials, as well as serving tension and possibly string twists. I have not seen an issue with the nock groves being off or not accurately documented, but have definitely seen differences in strings. String wear plays into it too. My preference is to start with nocks a bit tight and let them wear in the string.


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## lksseven (Mar 21, 2010)

ceratops said:


> Is there a table somewhere of actual nock groove measurements, and suggested center serving diameter to go with those different nocks? I see reference to 'small nock' and 'large nock', and LAS listing for Easton G nocks, for example, shows .088" and .098" as the two options for that nock. Listings for some other nocks I checked have no obvious size specs at all(!) which seems odd. Are the .088" and .098" standard sizes? And is that measurement taken down at the throat where the nock sits against the string, or at the tighter spot where the nock fingers first engage the string?
> 
> I recently acquired an older trad bow, and the string that came with it has a fatter center serving which doesn't really fit the nocks on the arrows I happen to have. So, I got out calipers to measure the center serving on the new bow (as well as on the bows I usually shoot), with a view to ordering some nocks... And am finding that the center serving measurements don't seem to correlate with the very scant info about nock groove size I've come across so far.
> 
> Clearly the center serving measurement has to be a bit larger than the nock groove, in order to get proper snug fit. But how much larger??


Beiter #2 nock and .021 serving (62xs) is a nice fit


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## ceratops (May 17, 2017)

Stash said:


> That would depend on your definition of "very close".
> 
> I'll give you an example based on what I have on my current recurve bows.
> 
> ...


Well, this confirms what I was starting to suspect... After my first foray with the calipers, I was scratching my head, and decided to start this thread. After reading your observations, I got out my calipers again, did an actual survey of which nocks we have in captivity, and kept notes. I had no idea that all this variability was hiding right in plain sight.

The two bows I shoot most often have strings that were generously sent to me by an AT member when I bought a used riser - he did not remember exactly which material he used in building the strings. I don't know strand count or serving specs. Although the two strings look identical, they don't measure exactly the same. String 1 measures between .0975" - .0995" at the serving. Interestingly, the string is a bit thinner at the nocking point, measuring only .0945" there. I didn't expect that, but I have shot a lot of arrows with this string.

String 2 has measurements between .0945" - .097", with .094" at nocking point. This string has had fewer shots, but I use the same arrows on both bows.

Next I looked at my son's bow - this has an 8125 string purchased at a local range; don't know strand count or serving material. That string measures .0995" -.1025", with .098" at nocking point.

I then looked at two wood handle student bows that I bought when my kids and I were starting out. No specs on those strings. One measures .0955" - .097", .0935" at nocking point. The other measures .0965" - .0995", .0965" at nocking point.

Turning to the flock of arrows that has gathered here since we started archery - note that they are all push-in nocks, and all have similar size nock grooves (or so I thought in my ignorance!), and (I thought) were suitable for use on these various bows.

I tried clipping the various nocks onto various strings... Tightest were the nocks on the Carbon Impact Super Clubs I recently bought for my son (dchan had mentioned that these nocks had smaller nock grooves, and sure enough...). Unfortunately, son's bow has the thickest serving of the five measured, and the Super Club nocks don't even want to clip onto the string. Duhhhh. That possibility never occurred to me when I bought these arrows.

Next were some complete Easton Vector arrows purchased from LAS (these have Easton N nocks, which are apparently mainly sold for use in Genesis arrows). These nocks are also too tight to use on son's bow. They clip onto the string on my bows, and seem pretty much OK (not too tight or loose) when the string is down in the throat. However, the fingers/ears of the N nocks seem unusually tight, and I'd worry about them hanging onto the string too hard upon release.

Next up were some unknown/unlabeled nocks that came on some Easton Apollo arrows I bought used. Fit OK on my two bows, a bit tight but probably acceptable on son's bow. Couldn't buy more of them if I wanted to, since I don't know what they are.

Then there are the nocks on the arrows that son and I are actually using most frequently at the moment. Good fit on my bows, OK on his. Again, I don't actually know the brand of these nocks (came on finished arrows purchased locally, so I could at least find out what brand these are). Some of these nocks have the letters 'CP' on the side... In case anyone recognizes brand from that...?

Finally, I have some Bohning F nocks (came with the mark-down VAPs I bought from LAS some month ago, but haven't yet fletched). On these nocks, they make a satisfying double click as I push them on, but then, the string on my bow just rattles around in the throat of the nock. Seems a better fit on son's bow with thicker string, but still a bit loose in the throat.

So, my head is spinning a bit. This seems to be a much more ad hoc and 'by feel' process than I ever imagined.

On the F nocks, is it bad to have that loose feel when string is seated in nock? The nock is firmly held on the string by the ears/fingers, so no dry fire risks...

Incidentally, the trad bow that started me down this road of inquiry has a Dacron string, with center serving thickness measuring .1065" - .1105" - so clearly looking for a larger groove nock than those we have on hand.

I'm posting all this annoying detail mainly to illustrate how variable this stuff really is. Despite being involved in archery for nearly two years now, I had no idea!


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## ceratops (May 17, 2017)

I'm afraid my previous post was so long that the couple of questions in there were really hard to find... 

Some of the nocks I looked at above (Easton N, and especially Bohning F) have ears/fingers that seem particularly tight as compared to the width of the groove down at the throat (I mean the bottom of the groove; I'm not positive that 'throat' is technically correct). So, a nock like that makes a nice secure snap when putting it on string, but then the string may be somewhat sloppy seated down in the throat of the nock. This seemed particularly true of the Bohning nocks. Is a loose/sloppy fit at the bottom of the groove a problem? I do use two nocking points, so the arrow nock would be constrained from sliding up/down on the string during the draw.

If one made the serving diameter larger there to reduce slop, then the snap on at the ears/fingers would be harder also -- is a tight fit at the ears a problem as the arrow comes off the string during the shot? Intuitively, it seems undesirable for the arrow nock to really 'hang on to' the string as the arrow tries to separate from the string...

I'm trying to figure out which parameter is more important, as it seems that one can't have reasonable snap-on/off force, combined with non-sloppy fit down in the throat -- at least not with nocks like these.


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## "TheBlindArcher" (Jan 27, 2015)

ceratops said:


> Well, this confirms what I was starting to suspect... After my first foray with the calipers, I was scratching my head, and decided to start this thread. After reading your observations, I got out my calipers again, did an actual survey of which nocks we have in captivity, and kept notes. I had no idea that all this variability was hiding right in plain sight.
> 
> The two bows I shoot most often have strings that were generously sent to me by an AT member when I bought a used riser - he did not remember exactly which material he used in building the strings. I don't know strand count or serving specs. Although the two strings look identical, they don't measure exactly the same. String 1 measures between .0975" - .0995" at the serving. Interestingly, the string is a bit thinner at the nocking point, measuring only .0945" there. I didn't expect that, but I have shot a lot of arrows with this string.
> 
> ...




Welcome to archery, where insanity is defined as doing the same thing over and over again and expecting the same results. 

Bought some aluminums [2315s] which came with these huge, beefy, "manly" nocks... throats so tight they barely clip on to any of my compounds. "All the world's greatest cosmic powers, itty bitty living space"


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## ceratops (May 17, 2017)

I'm still hoping for feedback on the question(s) in post #14, so will bump the thread once... thanks in advance...


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## dchan (Jun 29, 2004)

In my opinion, release tension is much more important than sloppy fit once snapped on. A nock that releases cleanly and the same every time will be more consistent. 

being able to move up and down on the string is easily fixed by double tie on nocks or even double crimp on nocks if necessary. Also if your string hook is good, and you are not trying to give the arrow 1/4" on each side with your fingers (should almost be touching the arrow without putting pressure on the arrow) 

The way I test my string fit is to snap the arrow/nock on the string, then holding the bow horizontal, letting the arrow just hang from the string, a light tap on the string will cause the arrow to drop off the string. YMMV but that's my personal "best fit" if they don't stay on or fall off too easily, it's time to change the nocks or string because the wear of the nocks or string is starting to affect the consistency of the fit.


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## ceratops (May 17, 2017)

"TheBlindArcher" said:


> Welcome to archery, where insanity is defined as doing the same thing over and over again and expecting the same results.
> 
> Bought some aluminums [2315s] which came with these huge, beefy, "manly" nocks... throats so tight they barely clip on to any of my compounds. "All the world's greatest cosmic powers, itty bitty living space"


Ah, Aladdin... I was thinking Marvin from Hitchhiker's Guide at first... "brain the size of a planet," etc. etc.


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## ceratops (May 17, 2017)

dchan said:


> In my opinion, release tension is much more important than sloppy fit once snapped on. A nock that releases cleanly and the same every time will be more consistent.
> 
> being able to move up and down on the string is easily fixed by double tie on nocks or even double crimp on nocks if necessary. Also if your string hook is good, and you are not trying to give the arrow 1/4" on each side with your fingers (should almost be touching the arrow without putting pressure on the arrow)
> 
> The way I test my string fit is to snap the arrow/nock on the string, then holding the bow horizontal, letting the arrow just hang from the string, a light tap on the string will cause the arrow to drop off the string. YMMV but that's my personal "best fit" if they don't stay on or fall off too easily, it's time to change the nocks or string because the wear of the nocks or string is starting to affect the consistency of the fit.


Thank you. That is a nice definitive response! If having the nock release the same way every time is so important, does that imply that nocks should be replaced every so-and-so-many shots? I currently replace nocks piecemeal, as they get damaged from arrow impact, or sometimes if one feels too loose on the string. From what you say, I'm suspecting that variability in nock tightness in a set of arrows is not a good thing, and that all the nocks in a set should be replaced periodically?


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## Stash (Jun 1, 2002)

I'd say that replacing all the nocks in a set regularly would be a good idea for a world class competitive shooter for whom a millimeter difference in impact point on a single shot can mean elimination, but probably not necessary for the rest of us. You should be able to notice the difference if one or two nocks feel different than the rest.


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## ceratops (May 17, 2017)

I just noticed another detail, which is related to questions discussed in this thread -- namely, inconsistent nock groove size among supposedly 'identical' nocks from the same manufacturer. I wonder how common this issue is??

As part of a recent LAS order, I noticed that Cartel Striker nocks are on clearance ($.07 per nock). They seemed to have the small groove size I wanted, and (reading some information about the Cartel arrows they're made for, it sounded like they would be only slightly oversize to fit inside our assorted arrow shafts -- I was hopeful that a little bit of sanding might make them fit adequately). Anyway, at the clearance price it seemed worth taking the chance, and I ordered 5 dozen of them.

I opened one of the five packages at random, tried the nock on various bowstrings, and was pleased with the fit. And, fortunately, a quick pass with a strip of sandpaper was indeed enough to make it fit inside a number of different arrow shafts. So, I dumped the contents of the five packages into a bin in my arrow parts box. A little while later I took out another nock at random, and tried it on one of the bowstrings... and it was MUCH tighter than the first nock I had tried. After scratching my head, I noticed that there was a very slight color variation among the nocks -- the faintly lighter orange ones have the larger (good) groove size, and the slightly darker orange ones have the tighter (bad) groove size. I then sorted the 60 nocks into separate piles by actual groove size, and it looks like I got 3 dozen of the ones that fit well, and 2 dozen of the ones that are too tight.

Still not a bad price for 3 dozen decent nocks... but what's up with the size variation between parts from the same manufacturer, with the same part number?? Is this a common problem across manufacturers? I assume some are better than others... at least I hope so!


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## dchan (Jun 29, 2004)

well cartel is generally considered an "entry level" product, and you get what you pay for.

DC


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## ceratops (May 17, 2017)

dchan said:


> well cartel is generally considered an "entry level" product, and you get what you pay for.
> 
> DC


Okay... the listed original price was these nocks was $.50 each, not much different than per nock price from the 'better' brands. So, price would not have been a good guide in this case.

Which brands would you consider trustworthy, in terms of consistent nock sizing?


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## TER (Jul 5, 2003)

ceratops said:


> Still not a bad price for 3 dozen decent nocks... but what's up with the size variation between parts from the same manufacturer, with the same part number?? Is this a common problem across manufacturers? I assume some are better than others... at least I hope so!


It is not a problem across other manufacturers. Cartel just makes poor quality products. They always have. There is no reason for them to start making decent quality products because they sell enough garbage each year to remain profitable.


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## ceratops (May 17, 2017)

Seems the message is simply that Cartel makes junk, and that one is unlikely to run into this nock size inconsistency with other manufacturers? If that's it, I won't worry -- I still got 3 dozen usable nocks for under $5 out of the deal. Still, hard to understand how a manufactured product ends up with this much variation; I suppose they have different molds, and no QC to make sure the molds actually measure the same...


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## f_thomas (Oct 12, 2006)

I ordered a dozen VAP V1 that came with nocks and they are too large on an 18 strand string. I ordered two dozen Bohning Blazer F Nocks from LAS. I live overseas and the cost of shipping through an air freight forwarder- $20.00 min. plus 12% Value Added Tax plus $ 1.00 exchange fee makes it critical to get the right thing. Returning for exchange or refund is out of the question. 

I went out to LAS and reading the reviews of the Bohning Blazer F Nock, one person noted that there are two throat sizes .120 (which appears to have come on the arrows I orderd) and .106, which he said is what LAS delivers. Hope so! I bought 2 dozen and will know for sure when I get home. I will post an update.

Bohning says the F Nock is .168 so should fit the VAP V1's.

It is enough to make you crazy! The OP's question is a good one and is one I would like to know the answer to. When I place an order for shafts from the States I need to be sure the components are the right ones!!!! The added cost is one thing, but it also adds AT MINIMUM two weeks for delivery.


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## f_thomas (Oct 12, 2006)

Well, the Bohning Blazer F Nocks from LAS were a much tighter snap on, but still totally loose at the throat. Two nocking points solves it sliding up and down.

I used the finger flick on the string to test each nock and it seemed good to go. They are not nearly as secure as the nocks on Win&Win Challenge arrows I have been shooting, which are more a constant size. 

Back in the Trad days I would have boiled some water and dipped each nock in hot water in a cup and lightly pinched the tabs together. Not sure if that is a good idea. It will not change the throat (bottom of the slot) tightness at all. Is throat the right term as is mentioned above?

Are Pin Nocks easier to fit? More consistent?


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## j.conner (Nov 12, 2009)

I found that the stock F nocks fit fine but when I switched to pin nocks they were loose, and had to then order the small groove Blazer pin nocks. In the long run, I will modify my string making / serving formula to fit the standard nocks.


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