Rifle Scopes Tangent Theta in Spuhr - Parallax Binding

[samb300]

So I read through the old thread on this subject, and I’m wondering if there has been any definitive resolution to the issue?

I have a brand new Gen3 5-25 TT which I mounted in a new Spuhr SP4001. Torqued to 15 in-lbs with a Fix it Stick tool and there is significant binding of the parallax knob, to the level that I can’t turn the knob to reach either the min or the max travel (I'd guess the last 15% of travel is blocked in either extreme). I basically have to unscrew all 12 of the ring screws to ~10 in-lbs in order to regain the full movement of the parallax knob.

Not sure if the only solution is to go to a 2-piece ring set a-la ARC or Seekins, but the Spuhr mount is my go-to mount and I have to say I’m a bit disappointed that an optic of this caliber won’t play nice (for me) with a $400 mount.

Thanks,

Sam

 

[Kadams1563]

I was speaking to a guy the other day that has a TT as well. He was having the same issue with split rings as well. I’ll ask my other buddy who just got his in a few weeks ago if he is having any problem with ARC rings.

 

[samb300]

I was speaking to a guy the other day that has a TT as well. He was having the same issue with split rings as well. I’ll ask my other buddy who just got his in a few weeks ago if he is having any problem with ARC rings.

Thanks, I appreciate it.

I was hoping to go shooting this weekend to test the TT out; I’m glad I didn’t sell my trusty G2 Razor quite yet. I don’t think with the holiday weekend I’ll be getting any new rings over night shipped.

 

[Ryridesmotox]

Thanks, I appreciate it.

I was hoping to go shooting this weekend to test the TT out; I’m glad I didn’t sell my trusty G2 Razor quite yet. I don’t think with the holiday weekend I’ll be getting any new rings over night shipped.

Amazon has some seekins rings that say delivery by this Saturday, the 25th.

 

[Kiba]

Given the reputation for the Premier's to have parallax binding issues you think this would have been at or near the top of the list of things for TT to improve to ensure the parallax binding issue couldn't continue to happen to their new improved models...

I have a TT 5-25 in a set of Spuhr SR-4000 separate rings torqued to 15 in/lb and don't have any parallax binding issues. Can't say the same for the Premier 5-25 that the TT replaced... the parallax was totally hosed on the Premier, and unfortunately after talking to TT I found out it was a prior test & evaluation unit that made it to the PX here-- so there was zero warranty coverage or trade in value from TT on it (ouch!)

It was my understanding that the section of the tube forward of the turret box contains the parallax mechanism and lens assembly, so perhaps try backing off the torque on the front ring screws?

Pushing the front ring as far forward as you can may help, but since you're using a Sphur mount that's not really an option.

I'm still amazed you're having this very Premier-like issue with a TT... you think they would have taken every effort during their design tweaks to avoid a repeat of what Premier went through.

 

[Covertnoob5]

I use a Spuhr with my TT and 20 in/lbs with no issues. And I've used 2 different Spuhrs. I'd say it's an issue with the scope, but not the design of either.

 

[samb300]

@Kiba I did notice that the front ring in the Spuhr seemed to be more sensitive to inducing binding than the rear ring. But I’m talking needing to be 1/4 to 1/2 turn short of 15 in-lbs before feeling the binding reduce...I mean, it’s not even lightly hand tight. At the full 15 in-lbs I can’t even turn the knob to Infinity, it legit feels like I might break something if I force it.

And you’re right, with the 1-piece Spuhr there’s hardly any room to move the scope front to back to possibly better position the front ring.

 

[MACHTECH]

It's weird! Some bind...some don't. My gen2xr binds in the spuhr at 15 in/lb. My new gen3xr went in the same mount and I took it to 20 in/lb and NO binding. I can't figure it out??? All I know is that the only sure fix I have found for the ones that bind is to use an ARC mount. They do not bind at all in the ARC unimounts.

 

[RTH1800]

A scope too good to mount!

 

[MysizeisMAGNUM]

I mounted mine last week in a Spuhr to 15.5 in/lb with Rosin without issue, I brought the Torque up to 10 in/lb on all the screws then went to 15.5 in/lb. Parallax is smooth, I have 2 buddies who have mounted in Spuhr mounts 25 in/lb. without trouble.

However this isn't the first I've heard of this exact issue.

I was going to use Fix-it-Stix as well to mount mine however a close friend talked me out of using them and lent me a much more precise torque wrench.

 

[samb300]

I mounted mine last week in a Spuhr to 15.5 in/lb with Rosin without issue, I brought the Torque up to 10 in/lb on all the screws then went to 15.5 in/lb. Parallax is smooth, I have 2 buddies who have mounted in Spuhr mounts 25 in/lb. without trouble.

However this isn't the first I've heard of this exact issue.

I was going to use Fix-it-Stix as well to mount mine however a close friend talked me out of using them and lent me a much more precise torque wrench.

I have a Borka torque wrench I can try, but I can't imagine that the 15 in-lb Fix it Stick is so grossly out of spec that it would be anything more than a few in-lb high.

Even when I hand tighten the screws on the front cap 1/4 turn past initial contact (which I know is less than the 15 in-lb) I get binding.

I don't know that I would be as concerned if everyone else with a TT and Spuhr had the same issue, but it seems inconsistent with some people having the issue and some not.

 

[MysizeisMAGNUM]

I have a Borka torque wrench I can try, but I can't imagine that the 15 in-lb Fix it Stick is so grossly out of spec that it would be anything more than a few in-lb high.

Even when I hand tighten the screws on the front cap 1/4 turn past initial contact (which I know is less than the 15 in-lb) I get binding.

I don't know that I would be as concerned if everyone else with a TT and Spuhr had the same issue, but it seems inconsistent with some people having the issue and some not.

I agree completely with all of that!

Edit:
My process for mounting in Spuhr mounts has always been tightening the two center screws top and bottom of each ring to half the value I'm setting to. I then go through the remaining screws in a criss-cross fashion to half the torque value, I then repeat the process to the remaining torque value, slowly finishing to ensure a smooth a consistent torque.

 

[EXTREMEPREJUDICE]

Wow, pretty astonished reading this! I have 2 Heritages and have yet to have the problem but with all the accolades regarding the TT I would never suspect this issue..............especially with Spuhr?

 

[samb300]

I agree completely with all of that!

Edit:
My process for mounting in Spuhr mounts has always been tightening the two center screws top and bottom of each ring to half the value I'm setting to. I then go through the remaining screws in a criss-cross fashion to half the torque value, I then repeat the process to the remaining torque value, slowly finishing to ensure a smooth a consistent torque.

I will try that technique to see if it helps. I do something similar but more by "feel" for the initial snugging down of the 12 screws. Then I go back with the torque wrench to the full 15 in-lb value in a criss-cross pattern.

Same technique hasn't failed me in the past with Spuhr mounts

 

[MysizeisMAGNUM]

I will try that technique to see if it helps. I do something similar but more by "feel" for the initial snugging down of the 12 screws. Then I go back with the torque wrench to the full 15 in-lb value in a criss-cross pattern.

Same technique hasn't failed me in the past with Spuhr mounts

I know some guys grease the screws before installing to ensure an accurate torque without dry binding, personally I just rely on the wax put on the screws from Spuhr and don't worry much past that. Probably because my process hasn't let me down.

I was really maticulus when I mounted the TT for the obvius reasons, but to be honest I was really uncomfortable with only 15 in/lb hence why I used rosin for the first time. I'm just a gorilla like that who drags knuckles and is hard on gear.

 

[hk dave]

OP I wonder if switching the rings on the Spuhr would help? Front one on back. Know what I mean?

 

[samb300]

I know some guys grease the screws before installing to ensure an accurate torque without dry binding, personally I just rely on the wax put on the screws from Spuhr and don't worry much past that. Probably because my process hasn't let me down.

I was really maticulus when I mounted the TT for the obvius reasons, but to be honest I was really uncomfortable with only 15 in/lb hence why I used rosin for the first time. I'm just a gorilla like that who drags knuckles and is hard on gear.

Wouldn't grease act in a similar manner to Loctite, where you would have to reduce your torque value due to it being "wet"? Maybe greased the 15 in-lbs would be too much?

 

[samb300]

OP I wonder if switching the rings on the Spuhr would help? Front one on back. Know what I mean?

I get what you're saying. It's another thing I could try. But honestly unless switching the ring plates and trying to torque more evenly results in a perfect 100% free-turning parallax knob, I can't imagine risking either the scope slipping by using less than 15 in-lbs, or the internals getting messed up by using it while it binds.

 

[samb300]

@koshkin Any idea how far in front of the main turret housing the parallax internals extend? Meaning, is the reason for the binding that the front Spuhr ring is so close to the main turret housing and is clamping directly over where the parallax components move?

Would switching to rings that allow the positioning to be all the way forward where the front objective bell starts be the fix?

 

[MysizeisMAGNUM]

Wouldn't grease act in a similar manner to Loctite, where you would have to reduce your torque value due to it being "wet"? Maybe greased the 15 in-lbs would be too much?

 

[blbennett1288]

Is the erector centered up in between the two Spuhr rings. Or does the front or rear touch up against one of the rings?

What I am getting at is I have space on either side and havnt had issues.

I do the opposite. I torque the exterior 4 screws down in an “X” manner hand tight first and then do the interior 2

 

[MysizeisMAGNUM]

 

[samb300]

I tried that torque pattern. First used the Borka torque wrench to 15 in-lbs, then checked the Fix it Stick after. I got roughly 1-3 degrees of additional screw tightening with the Fix it Stick, so I’d say it’s well within spec.

I have the scope centered as well as I can between rings. The other picture shows the limit of parallax adjustment I get when turning toward infinity. No joke, it’s not binding, it feels like a hard stop.

 

[Covertnoob5]

Honest question here but any chance it’s cause the spuhr is backwards?
Also, I noticed your spuhr Sam has an extra screw to attach the base. Wonder if that’s an updated design?

 

[samb300]

Honest question here but any chance it’s cause the spuhr is backwards?
Also, I noticed your spuhr Sam has an extra screw to attach the base. Wonder if that’s an updated design?

I hope not haha. It’s a 0 MOA mount, so there really is no front or back. I honestly hate how they look mounted normally on a LH rifle, so I flip the orientation. Been working with my Razor for the past 3 years.

It’s the newer design with 5 base screws and the thicker clamp plate.

 

[BigJimFish]

15 in-lbs is not a whole lot, that is on the lighter side of average. I certainly don't think that you should have to go lower than this for your scope to work. Since you have tried both a Borka wrench and Fix-it sticks I doubt your torque reading is off by much either. Both of these companies make good stuff. Lubed fasteners are the norm and, in my opinion, what should always be used whether it be spuhr's wax, the grease I generally use use, or some other oil. So, overall, I don't think there is any issue with what you are doing with your mounting process.

As for the Spuhr, I have never had one but folks don't seem to have a lot issues with them. It certainly seems unlikely that the mount would be out of spec enough to cause an issue. If it was I would expect you could tell the misalignment when you set the scope in it. Another mounting solution might aid you with the problem, with separate rings for instance, you could put the ring all the way forward. That might take some pressure off the parallax mechanism. Still, I don't think the rings are ultimately the issue.

I expect the issue is either the scope having a defect in manufacturing or perhaps there is nothing wrong other than the knob itself being misalligned with it's markings. Parallax markings are not calibrated and conceivably the markings on the knob just don't line up well with the index mark. Maybe it got turned a little when it was set in the laser engraver. I did not catch any mention of the parallax function not working properly, only the range of motion not lining up well with the markings.

 

[blbennett1288]

View attachment 7083332

Yeah, that is not in the ISMS manuals that are included.

 

[jim996]

Should have bought an S&B PM2....just sayin......

 

[samb300]

@BigJimFish I don’t think there’s anything wrong with the Spuhr, but I’m sure it’s possible. I have another Spuhr in hand, but my Razor is in it and don’t really feel like taking that out to test it since that’s what I’m going to have to mount up to have a functioning rifle.

When the TT is out of the mount (or the Spuhr caps are loosened completely) the parallax knob is able to rotate freely throughout the entirety of its range, min arrow to the infinity symbol. When in the Spuhr at 15 in-lbs it is a good 1/4 turn from the infinity mark. I should also mention I torqued it down with the parallax at the middle of its range.

 

[Smithcollector]

I'm the guy that started the original thread last year. Mine locked up unless the torque on all the screws (tightened in accordance with Spuhr instructions) was at 15 in-lbs. TT's response was that 15 in-lbs was in Spuhr spec (albeit the absolute bottom). They were very positive the scope was perfect. I wanted to use the Spuhr, and wasn't comfortable with 15 in-lbs, so I replaced the TT with an S&B.

I was hoping this was something that might get "fixed without notice" by TT and am sorry to hear it's still an issue. Bottom line in my book is that for that kind of money I don't want to have to worry about something this basic.

I was indifferent to their glass compared to the S&B, but really liked the turrets and the zero feature. Coincidentally I'm needing a new scope right now and was thinking about giving TT another look, so this thread was very timely for me, thanks OP for posting.

 

[Sixfivesavage]

For reference, my 318i had the same issue with a 4002. Took some trial and error but the front ring ended up being around 12 inch pounds before it would bind. Been running it that way a while and it seems like its staying put.

 

[samb300]

@Smithcollector did you sent the TT back for inspection? Or did they assure you it was ok over the phone?

I can’t get it to not bind when I’m anywhere near 15 in-lbs, so I’m concerned it’s worse than what you experienced. Even following the torque pattern above it’s not even close to having full parallax rotation.

 

[Saf3sh00t3r]

Okay boys...I am going to tell you my recent warranty work and discussion with TT.

I sent my scope back because the parallax straight up broke....on a Spuhr.

They covered the shipping to them and finally called me and told me they would fix it, but said "you over-torqued the scope." I explained that "I have 2 of these scopes, one was torqued at 18-20 and the other new one the same why do I only have an issue with one?"

The gentleman said he would fix it and asked what rings I was using. I explained Spuhr. He explained again I over-torqued the front ring and broke a bushing for parallax adjustment, but that he doesn't recommend spuhr and he only recommends Badger rings or mounts.

I explained that it didn't make any sense, since the documentation clearly states 25 in/lb was recommended as a not to exceed. Also said to him, Spuhr is one of the top and most used mounts in the shooting community.

He said that the design of spuhr causes issues and he only would recommend Badger.

We went back and forth, he said he would fix it. On later communication they explained they were getting spuhr mounts to test (I had offered to send him a mount), but that Hakan Spuhr told them 15 in/lb would hold the scope no problem as long as it was tightened evenly.

So, they fixed my scope quickly and got it back to me. Its working now, on my Spuhr mount no issues at 15 in/lb, but I also used rosin to avoid any loose issues.

Keeping all this in mind, I did ask why the scoped were so delicate, he said they use extremely tight tolerances...I explained having owned schmidt and nightforce, they took a beating especially on barricades. He asked I be gentle with the scope...I told him I didn't buy a scope for bench rest, but for PRS style of shooting and sometimes I hold it down when on barricades. He said I should not use more than 15 lbs downward pressure....anyway, blah, blah, blah...more back and forth...I explained that it is my go to scope but I wasn't getting the warm and fuzzy.

In the end he stood by the product and got it back to me in good working condition. I don't see any new special instructions on their website. I haven't seen anything back from them on Spuhr recommended torque specs.

The glass is amazing, the reticle is great, and really like the scope. Am still wondering if the parallax will break again...It sucks to have that uncertainty. I get it shit breaks, mechanical shit breaks, but was surprised on this one.

Lastly, What I did do, is went 20 in/lb on the rear ring and 15 on the front ring with rosin on both.

Good luck, but If you feel it binding back off until it doesn't down to no less than 15 in/lb.

 

[Saf3sh00t3r]

@Smithcollector did you sent the TT back for inspection? Or did they assure you it was ok over the phone?

I can’t get it to not bind when I’m anywhere near 15 in-lbs, so I’m concerned it’s worse than what you experienced. Even following the torque pattern above it’s not even close to having full parallax rotation.

Sorry, but it's probably already broken, does it click at all? mine did. Better yet, take it outside and see if you can focus past 300 yards. If you cant adjust, the parallax adjustment is fucked and broke. Email and call them. They had to tear down and rebuild my scope...mine took 5 weeks due to other reasons...like holidays and UPS screwing up.

 

[jim996]

Mmmm.......that’s disappointing in a scope that costs thousands. You shouldn’t have that uncertainty that you can break it on a PRS barricade.

I’ve actually dropped my AXMC off a bench with my PM2 mounted in a Spurh and the rifle landed on the eyepiece (stock was folded at the time). After my heart had started again, I picked it up fearing the worst and all that had happened was the glass in the cheap bikini scope cap had broken. No damage at all to the scope and it didn’t even lose it’s zero.

I think the TT scopes look amazing and the glass quality looks unreal. I was considering one but this has definitely put me off them until they start building them tougher.

 

[MysizeisMAGNUM]

 

[MysizeisMAGNUM]

 

[MACHTECH]

Now they just need Mr. Spuhr to build them a test machine called "the squeeze" that squeezes the tube at 20 in/lb. If they pass that test, I'll buy another.

 

[Smithcollector]

@Smithcollector did you sent the TT back for inspection? Or did they assure you it was ok over the phone?

I can’t get it to not bind when I’m anywhere near 15 in-lbs, so I’m concerned it’s worse than what you experienced. Even following the torque pattern above it’s not even close to having full parallax rotation.

Over the phone, I didn't send them the scope

 

[samb300]

Well, I appreciate all the responses and info I’ve gotten from everyone. I am in no way trying to stir the pot or sway anyone in to not buying a TT based on this. As an engineer, I understand there is inherent tolerance stacking that can occur in any manufactured product, so maybe I have an example that has internal components that are slightly closer to the tube and are more prone to binding than other examples.

@Saf3sh00t3r I don’t believe my scope is broken, but I haven’t taken it out to the range yet. Once I take it out of the Spuhr the parallax knob does rotate fully with no clicking that I can tell. I made it a point not to force the rotation when it’s binding out of fear that I would damage it. I will need to check the parallax at distance though.

Ultimately, I’m not going to dump the TT just because it doesn’t play nice with a Spuhr. Hell, rings are $200 cheaper than a Spuhr so I’ll call it a cost savings haha. But I am concerned that the design isn’t as durable or overbuilt as most other scopes, as least in the front tube where the parallax mechanism is. And I’m also concerned that maybe something internal did get damaged simply by the Spuhr being torqued to 15 in-lbs.

At this point I’m going to buy a set of ARC M10 rings and see how that works. Assuming there is no binding with those I will confirm at the range that the parallax works. A big factor in buying a TT in the first place is the magic parallax that doesn’t need to be adjusted past 300 yards!

I’ll probably give TT a call next week as well to talk through this, just in case it needs to be sent back.

 

[Saf3sh00t3r]

Well, I appreciate all the responses and info I’ve gotten from everyone. I am in no way trying to stir the pot or sway anyone in to not buying a TT based on this. As an engineer, I understand there is inherent tolerance stacking that can occur in any manufactured product, so maybe I have an example that has internal components that are slightly closer to the tube and are more prone to binding than other examples.

@Saf3sh00t3r I don’t believe my scope is broken, but I haven’t taken it out to the range yet. Once I take it out of the Spuhr the parallax knob does rotate fully with no clicking that I can tell. I made it a point not to force the rotation when it’s binding out of fear that I would damage it. I will need to check the parallax at distance though.

Ultimately, I’m not going to dump the TT just because it doesn’t play nice with a Spuhr. Hell, rings are $200 cheaper than a Spuhr so I’ll call it a cost savings haha. But I am concerned that the design isn’t as durable or overbuilt as most other scopes, as least in the front tube where the parallax mechanism is. And I’m also concerned that maybe something internal did get damaged simply by the Spuhr being torqued to 15 in-lbs.

At this point I’m going to buy a set of ARC M10 rings and see how that works. Assuming there is no binding with those I will confirm at the range that the parallax works. A big factor in buying a TT in the first place is the magic parallax that doesn’t need to be adjusted past 300 yards!

I’ll probably give TT a call next week as well to talk through this, just in case it needs to be sent back.

Call and ask Chrystal to get Andy on the phone. He is the CEO and oversees issues like this one.

Again he recommended badger rings/mount. So if you’re buying something...

 

[blbennett1288]

I remember a thread from @NoLegs24 where Crystal states the tubes were good for 25in-lbs and they actually upped the torque spec.

https://www.snipershide.com/shootin...ged-torque-spec-response-from-ati-tt.6915154/

 

[samb300]

Call and ask Chrystal to get Andy on the phone. He is the CEO and oversees issues like this one.

Again he recommended badger rings/mount. So if you’re buying something...

Thanks for the contact info.

Is it bad of me to say having to use Badger rings is where I draw the line? If I can’t use a Spuhr, and for some reason I can’t use M10 rings either, that effectively kills the scope for me. Nothing against Badger rings, but aesthetically I’m not a fan, and I’ve never heard anyone have issues with ARC rings.

 

[samb300]

I remember a thread from @NoLegs24 where Crystal states the tubes were good for 25in-lbs and they actually upped the torque spec.

https://www.snipershide.com/shootin...ged-torque-spec-response-from-ati-tt.6915154/

I read that thread as well as the previous TT/Spuhr thread before purchasing mine. I figured it wouldn’t be an issue for me but I guess I was wrong.

My assumption is the new 25 in-lb limit applies to Badger rings only...

 

[NoLegs24]

Man, there's been a lot Gen3XR's going back for service work.... Wonder what's going on....

 

[Saf3sh00t3r]

Man, there's been a lot Gen3XR's going back for service work.... Wonder what's going on....

To his credit Andy did say they have hundreds of QC checks. That alone takes 2 weeks.

Because of ups issues he got people to work overtime and get my scope back in time for a match. They even overnighted the scope from Canada.

 

[Covertnoob5]

Couple notes I’ll contribute here, I just got my TT back from them. I sent it in for what I thought was a canted reticle, but apparently it was an error in my mounting/testing. To my surprise, I got a call from Andy Weber Thursday morning to chat about my scope that was sitting on his desk. He had just finished testing it personally. Nicest guy ever.
I just got my scope in the mail yesterday. They overnighted it back to me which floored me. Honestly awesome CS.
And for those concerned about more than 15/in lbs I had my gen2xr in a spuhr at 15/in lbs since November, in a good amount of matches, no issues. I now have my current one in a spuhr at 25in/lbs no issues.
So it’s definitely possible to use these scopes in a Spuhr and at more than 15/in lbs.

 

[Saf3sh00t3r]

This is the scope, works great now out to 1000 yards. This barricade work was at 533 yards yesterday.

 

[BigJimFish]

@BigJimFish I don’t think there’s anything wrong with the Spuhr, but I’m sure it’s possible. I have another Spuhr in hand, but my Razor is in it and don’t really feel like taking that out to test it since that’s what I’m going to have to mount up to have a functioning rifle.

When the TT is out of the mount (or the Spuhr caps are loosened completely) the parallax knob is able to rotate freely throughout the entirety of its range, min arrow to the infinity symbol. When in the Spuhr at 15 in-lbs it is a good 1/4 turn from the infinity mark. I should also mention I torqued it down with the parallax at the middle of its range.

Hmm...

You mention tolerance stacking and badger rings in other responses. I think that it is likely you are right on with the idea of tolerance stacking and your sample perhaps being on the tight side due to several parts being simultaneously at that end of their tolerance range. Certainly, it seems that your scope has a problem with the parallax binding in a way that reminds me of the PH scopes that these TT's are based on. The mention of the BO rings has me thinking about 3 cap screw rings vs 2 cap screw rings. There is more overall force applied when you add a third screw though you are also generally spreading it out more. I would think they would try their product out with Spuhr rings but perhaps not. You might have better luck with 2 screw rings, it certainly seems at least plausible. I don't think you should be having the issue at all though. What you are doing is not in any way outside the norm or unreasonable.

If you go with the ARC rings, ignore the factory advised torque specs and work up from a much lower level. The factory torque specs on those crush at least a few of the scopes on the market regularly. Ted says I am just ignorant and that the Chinese scope I crushed is garbage. He assures me that those specs don't crush his S&B. Perhaps so, but those specs do regularly crush at least one other brand that makes scopes north of $3k so not everything expensive will stand up to his superior wisdom. I'm not sure exactly where you should start with torque. ARC rings have just a single screw of much different size and thread pitch than other mounts. The torque should definitely be higher than typical but lower than the recommended 50 in/lbs. 30 in/lbs worked fine for me when I did a review a while back but I have no reason to believe that is the optimal amount or equivalent in psi on the scope tube to the normal ~18 in/lbs of conventional rings. All I can say is that in a sample size of two scopes, 30 in/lbs not crush the tube or loosen up on me and that made it a significant improvement over the 50 in/lbs recommended.

 

[jim996]

Really dumb point to make here but are you all sure you aren't overtightening the spurh mounts and bending the tubes? Please don't flame me but the Spurh has multiple bolts (very similar to the forks on a motorbike) and what can happen is as you torque one of them, the others will then seem loose so you go and torque them up as well and around the pattern again. It's very easy to end up over tightening all of the bolts.