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Discussion Starter #1
Hey guys,

I'm a long time reader and this is my first post here. I hope I'm in the right place with my topic.
My name is Dennis, I'm an Archer from Austria who has purchased an ATF-X earlier this year. ("Upgraded" from an old Hoyt Aerotec and my fist W&W riser)

I've spent the last months with getting a proper tuning and was already kinda frustrated that this riser is super picky to set up.
All my hopes and trust in the brand were gone when I discovered the major issue with the limb pocket alignment. I've made a little video where I try to explain and show you this issue and probably the result of all my failed tuning attempts.

I'm currently in contact with my dealer but honestly, I'm super disappointed with this riser. I'm a person who wants to rely on gear, especially considering the high price point. Some major issue like this is just unacceptable in my opinion.

It would be great if you could share your thoughts and experiences with issues like that.

Really looking forward to hearing from you.

Best regards
Dennis


(EDIT: 12:42 - I've noticed that I took a wrong screenshot at the point where I'm comparing the string alignment, so you need to go back in the video in order to see the difference, sorry!)

 

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Dennis,

How far exactly can the limbs travel laterally in the pocket? I have a Nano TFT riser with NS-G limbs and if I attempt to slide them side to side, I can only move them about a half millimeter or so. This results in a net deviation of 1mm at the tip of the limb.

As a mechanical engineer, I can tell you slop is necessary, otherwise the limb would never slide in and out of the pocket. How much yours has exactly is the question. The 0.5mm of play I have on mine is about the standard in the machining world for a smooth fit. If yours is more than that, I would blame one or both of two things:

A) The T block the limbs slide into were machined incorrectly and are outside of their LMC (least material condition) specification, allowing excessive limb play

B) The spring button in the limb is too weak and is not creating enough tension to keep the limb centered in the small groove machined in the bottom of the T block.

Regardless of side to side play, the spring button should keep the limb centered by riding the groove in the pocket. Even if the T block is miss machined, the limb should not move around so much. Check how stiff it is.

Also, in regards to the alignment while strung, I'm not as concerned. As demonstrated when you strung your bow, it initially starts out centered. It only gets out of alignment when you man handle the bow yourself and torque the limbs over.
Nothing in your shot should cause the limbs be get torqued over to the side. You pull the bow back, not out. As long as the bow was aligned properly in the first place, general shooting should not cause the limbs to slide over, even with that slop in the pockets. Your groups traveling around the target is probably due to something else.
 

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Discussion Starter #3
I'm a mechanical engineer myself and handling extreme precision parts every day. I do understand the concept of "slop" and tolerances. The thing is, that I can slide the limb sideways about 1-1.5mm in the limb pocket which must result in about 6-7mm at the tip of each limb.

I'm not sure if you have watched the video completely. I'm covering the play in the pocket and also that we have tried a few different sets of limbs. Theoretically, the spring button (which is super tight) is never ever enough to keep the limb in line. its only purpose is (in my guess) to prevent the limb from falling out when attaching the limb and stringing the bow. In order to handle all the forces, the limb needs the actual support of the pocket itself.

The whole thing that bothers me is that something like that leaves the manufacture's workshop who claimes to make great products. Speaking as a mechanical engineer this is just unacceptable and pure sad. Why would a manufacturer spending all its energy in a stiff and torsion-free riser when the limbs actually can float in the pockets like Dumbo's ears in the wind?

Yes, I have forced the limbs out of line to demonstrate. The same thing happens from arrow to arrow (as I've figured out yesterday) but it's a bit quicker to show it this way than assembling the whole thing on the range and filming the alignment after every few arrows. The string is always looking for the shortest distance and if there is a way for a shortcut it will do so. Have a look on highspeed videos and you see how much a riser and all of its parts are usually twisting and moving. Now imagine having a loose side fit/support around the limb pocket and how that would look like.

The setup is super inconsistent. Just imagine having a bow that is in line with a correct (very accurate and tiny) center shoot and with the next set of arrows the bow is out of line and having a center shot that is way too extreme, or even on the other side (negative).

Don't get me wrong, I get your point but I also do have spent a few days (within the last months) with rearranging the setup because I felt my center shot was off, the alignment was off, or something else has happened and I could not figure out what was wrong. Once I had the setup it was good but within a few arrows it was off,... back and forward and all that ... You could try the bow with a bow stringer and every time it results in a different setup.

The issue with the groups traveling and the whole thing was maybe communicated a bit incorrectly (that has happened two times) what's way more common is that the groups are spreading open to on side, on the next set of arrows, they are tight or spreading open and to another side,.. bottom line, there is no consistent direction you could pick up and compensate.
 

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My only suggestion is see what the dealer says and contact W&W directly. No tips here on AT will fix a defect riser. It unfortunately just happens sometimes. All you can do is follow up on the warranty. There should be a W&W rep for your region you can contact.

The problem lies in the T-block, which is manufactured separately from the rest of the riser, so it is not the a problem with the riser itself. In which case, you are lucky because it is a small piece that can just be swapped out instead of having to send the whole riser back.
 

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the limb needs the actual support of the pocket itself. Why would a manufacturer spending all its energy in a stiff and torsion-free riser when the limbs actually can float in the pockets like Dumbo's ears in the wind?
Because it has to for limbs to have lateral adjustment. I don't understand what you mean by the limb needs the "support of the pocket". If the edges of the pocket fully enclosed the limb, you wouldn't be able to adjust them left or right.

The excessive play is coming from the slot in the t-block being too large.
 

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The thing is, that I can slide the limb sideways about 1-1.5mm in the limb pocket which must result in about 6-7mm at the tip of each limb.
This almost makes me think the t-block may actually be fine and is actually physically moving. It's hard to believe that much play exists. Are you positive the screws on either side of the limb pockets are tightened down? Just so I'm not making any assumptions here, there are the first set of screws on either side of the pocket, and underneath those are the actual set screws that move the t-block. Are these tightened all the way up against the t-block on both sides?
 

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In any ILF bow, there are 3 dimentions only that may give problems in lateral paly during use of the bow (if align system is stable and locked)

1) the U width in relationship to bolt diameter, if diffeence is more than 0.1 mm (U larger than bolt) you may have some problems that are usually fitted by a piece adhesive tape inside the U
2) the distance between the center of the U round and the cneter of the detent bolt on limbs, in relationship to same distance on parcatical condition of use ion riser
3) a very large slot in the align plate with round final part >> 11.00 mm in diameter (very seldom)

The lateral stability of the ILF detent bolt is assured by the fact that it should seat in the round part of the align plate at he beginning and if is there , will return there perfectly after each shot. If not, problem 2 above, it means that limbs and riser have different distncies, that may happen mixing limbs and risers from different makers. Very difficult this to be your case.

The pin in the detent is there only to avoid the limbs to fall our when bow is unstrung, it has no practical function than this.

Thefore, your problem may only come from 1) above. Check U size and bolt size by a calliper to verify.
 

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Discussion Starter #8
Hey guys,

The problem lies in the T-block, which is manufactured separately from the rest of the riser, so it is not the a problem with the riser itself. In which case, you are lucky because it is a small piece that can just be swapped out instead of having to send the whole riser back.
Maybe it is just the T-block but overall it is just the tip of the iceberg considering the milling errors in the cutouts, etc..



Because it has to for limbs to have lateral adjustment. I don't understand what you mean by the limb needs the "support of the pocket". If the edges of the pocket fully enclosed the limb, you wouldn't be able to adjust them left or right.

The excessive play is coming from the slot in the t-block being too large.
The limb (alignment cylinder) needs the support of the side walls of the limb pocket/t-block, the spring-loaded pin won't line up the limb, that's what I wanted to say



This almost makes me think the t-block may actually be fine and is actually physically moving. It's hard to believe that much play exists. Are you positive the screws on either side of the limb pockets are tightened down? Just so I'm not making any assumptions here, there are the first set of screws on either side of the pocket, and underneath those are the actual set screws that move the t-block. Are these tightened all the way up against the t-block on both sides?
The T-block is secured safely and does't move (locked with the counter bolts, etc..)
 

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Discussion Starter #9
Hi,

Here's a little follow up video. It's a bit hard to use the caliper one-handed while filming but it should be visible that there is a difference in the dimensions. More importantly, you will see at the end of the video how much the limbs are moving in the pocket and how much that is on the tip.

I'm aware about the problem now. Th point is, that I'm shocked that something like that exists. Having a technical background allows me to question such things and looking a bit deeper into the topic. I trusted the riser and never assumed such bad fitting. I don't want to imagine a person shooting this setup believing to have an accurate combo and blaming themself for a super inaccurate shooting. (I'm not talking about the 8 ring, I'm talking about the 2 or 3 ring). My 15 year old Aerotec (which I sadly just sold 3 weeks ago) was shooting super accurate and without any issues. (Common mistakes ended up in the 8 or maybe 7 ring with a good but not superb tuned bow).

So if you are considering such a riser, check these parts and the over-all quality.

Cheers,
Dennis


 

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Discussion Starter #10
1) the U width in relationship to bolt diameter, if diffeence is more than 0.1 mm (U larger than bolt) you may have some problems that are usually fitted by a piece adhesive tape inside the U
2) the distance between the center of the U round and the cneter of the detent bolt on limbs, in relationship to same distance on parcatical condition of use ion riser
3) a very large slot in the align plate with round final part >> 11.00 mm in diameter (very seldom)
Vittorio,

Sorry, I was half asleep this morning

The first thing I checked was how the U of the limb sits on the limb bolt, which is just perfect. A tight sit and no play at all. The movement starts around the bin ob the limbs which would lead to case 3 of your post.
 

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I’m not an engineer, but I have to agree with the OP’s feelings on this. That seems like a lot of play for an ultra high end riser, AND for limbs of the same manufacturer. I could understand if you were using two different limbs, although even that is perfectly normal and gives us good tolerances, I would not expect that much. On my Xceed with both Zest and NS limbs there is extremely limited movement any direction when the limb is unstrung. I hope they tighten that up.


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Well there is a kind of ‘solution’ to this. It’s not been proven in any way, it’s just something I’ve been playing around in my head for a bit, you may try it at your own risk.

The lateral stability of the limbs seated in the pocket is a result of the tight fit of the limb and the limb bolt, and the dovetail slot.....but I am suggesting that while strung up, the compression derived from the limbs themselves actually forces the dovetail to sit at the bottom of the slot, which in theory is a single point, hence a fixed position. Therefore, it shouldn’t move. But that’s just mathematical theory.

4520A2F8-6A65-4743-B114-919B557FBA17.jpg

You see, one of these bad boys probably costs around $20. You could file a V groove at the bottom to Ensure the fixed resting position remains, fixed. That way you won’t have a white elephant that you’d have to feed but nobody wants to ride on it because of the pandemic.
 

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Discussion Starter #13
@theminoritydude

In theory it makes sense. BUT the limb does get more pulled to the back and less down into the pocket. There should be way more force and friction pushing against the T block (in the direction of the top stabilizer pushing if you will) than rubbing on this single point of the circle. And since the grove and circle in this T-block is obviously larger than the cylinder of the limb, this "limb cylinder" rests on one point "symmetrical" and in line with the U-cutout. Due to the fact that the radius of the t-block is larger, the "limb-cylinder" is able to move sideways while just working against just a tiny little bit of friction due to the raising "slope" of the larger radius... so theoretically it is not possible but in reality just a tiny little amount of sideways force would be necessary to get the limb out of line. (finger release for example)

If the grove in the t-block would be a V-shape, the cylinder of the limb would be supported sideways (on one pint each side) BUT the distance how far the limb sits in the pocket would be variating depending on how far the limbs are tillered in or out (the shape of the limb's cylinder variates if pivoted (if you look on the bow from the side)). If the limbs are tillered differently the V-shape would push the limb out of the pocket or let it further in, depending on the direction the tiller bolts are adjusted.

Bottom line: the "limb cylinder" needs a proper support from the T-block's parallel side walls, the lowest point of the limb pocket (the radius of the t-block) can only guaranty the the limb is all the way in and actually needs to be either a radius or or totally flat (which is not possible if you use a milling cutter to machine this section).

I struggled a bit with the language barrier, so I hope my "explanation" makes sense. If not, please let me know and I'll to explain the theory with some drawings or a video.


Also, I'm usually willing to experiment different things but after this several month long journey of setup failures and considering the price point of this riser, I'm not willing to spent a single cent or extra minute on this riser. I'm running a business myself and if on of my customers is spending such an amount on one of my products (or less, obviously), he/she can expect a proper working product. In the rarer case mistakes happen, I'll do everything and show the best support possible in order to fix it. That's a proper way if you are in direct contact with customers doing direct business 1:1, but since W&W is a major brand and obviously not able to offer such a support platform, they should at least take care that no failed product leaves the manufacturer's workshop.

Best regards
Dennis
 

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Something here just doesnt add up.

The spring button in the limb has a flange at the end that keeps it in the slot in the T-block. If that much slop existed, the flange on the spring button wouldn't be able to grab the edges of the slot and you would be able to pull the limb vertically straight out of the pocket. Are you able to do that?

If not, I suspect the block is in reality, moving.

Your calipers are also blurry in that video. Post the readout and I can cross check against my riser and confirm if the t-block is out of spec. Measure at least three times and take the average.
 

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Something here just doesnt add up.

The spring button in the limb has a flange at the end that keeps it in the slot in the T-block. If that much slop existed, the flange on the spring button wouldn't be able to grab the edges of the slot and you would be able to pull the limb vertically straight out of the pocket. Are you able to do that?

If not, I suspect the block is in reality, moving.
That’s what I thought. I wonder if he is turning the superficial set screws instead of the actual adjustment set screws.


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Discussion Starter #16
Guys, I'm not that silly....

Obviously I have removed the set screws to get to the actual screws of the t-block adjustment... These screws are countered against each other (similar concept as tiller bolts, obviously). After that was done I've put the set screws back in place... THE T-BLOCK IS NOT MOVING
 

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Discussion Starter #17
Something here just doesnt add up.

The spring button in the limb has a flange at the end that keeps it in the slot in the T-block. If that much slop existed, the flange on the spring button wouldn't be able to grab the edges of the slot and you would be able to pull the limb vertically straight out of the pocket. Are you able to do that?
Exactly, that's the case
 

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Guys, I'm not that silly....

Obviously I have removed the set screws to get to the actual screws of the t-block adjustment... These screws are countered against each other (similar concept as tiller bolts, obviously). After that was done I've put the set screws back in place... THE T-BLOCK IS NOT MOVING
But can you pull the limb vertically out of the pocket? If the slot is too large, that spring button wouldn't be able to grab and stay in the pocket. That flange is only 1mm wider than the diameter of the spring button. You said earlier you had 1.5-2mm of slop. If thats the case, the limb should slide out of the pocket from the top.

Post the readout from your caliper measurement so I can cross check.
 

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Discussion Starter #19
On the top corner of my riser it sums up to probably 1mm (I was just looking on the limb moving and guessing based on that), if I take the caliper it shows me a difference between the grove and the limb cylinder of about 0.3-0.4mm which is already quite a lot in the world of CNC machining.
And since I'm able to get the limbs out of line just by stringing the bow and shooting or with my bare hands it's just not acceptable.. I'm currently uploading another video, please give me a few minutes.
 

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"If the grove in the t-block would be a V-shape, the cylinder of the limb would be supported sideways (on one pint each side) BUT the distance how far the limb sits in the pocket would be variating depending on how far the limbs are tillered in or out (the shape of the limb's cylinder variates if pivoted (if you look on the bow from the side)). If the limbs are tillered differently the V-shape would push the limb out of the pocket or let it further in, depending on the direction the tiller bolts are adjusted."

Firstly, how far the limb sits already directly affects the sitting depth of the dovetail cylinder section in the slot in any normal configuration. In fact, due to the location of the pivot point of the limb against the T-block, a 'V' groove would actually reduce the sitting position range by shifting the original single contact point into two contact points, towards the pivot point. Second, your concerns about how far in the limb would go into the pocket is addressed by A) The gap between the stem of the limb bolt and the U shape of the limb butt, which at minimum distance is at least 2-3mm, and B) Any adjustments to the limb bolt would have very negligible changes due to the largely perpendicular directions of the two parameters in question. I mean, I'd be very happy to try this myself but (ok, i have a bag of these T-bolts, wife is a dealer)......I would prefer someone else going through the trouble instead of me pissing me wife off. What I COULD do, is file to increase the gap of the slot so it is a positively loose fit with the dovetail, and give it a V grove with an angular file. If I ever do something stupid, I'll post the results.
 
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