Aimpoint T-2 Warning

[RG7X]

I just want to share an accident that occurred to my brand new Aimpoint T-2 to prevent any previous or future Aimpoint micro optic users from repeating. So a description or warning is not listed anywhere in the manual stating that the new T-2 uses helicoils... no more aluminum threads. So, if you're like me and used loctite (blue 242) in the past, RECONSIDER on the T-2.

My screws weren't tightening all the way, so I freaked and thought I stripped the threads. Once I pulled 3 of the screws, I noticed the screws were stripped. Luckily, I had more of the tiny mounting screws so I put them in and they got really tight but still wouldn't fully tighten without spinning. At this point I thought, screw it (pun), it's tight enough so I'll leave it alone. The next day I saw a video from MrGunsNGear on YouTube and noticed he pointed out the new use of helicoils (not listed in the included manual). I now knew the wet loctite on the helicoils caused the screws to keep turning and stripped them. This has happened to me before on another mechanical project so I know better than to use loctite on screws when inserting into helicoils. So, when I slowly removed the optic from the mount... I noticed the helicoils slightly pulled out from the mount even though the screws came out easily.

So after a lot of spent money, a few stripped screws and unseated helicoils, I contacted Aimpoint (still awaiting response). I'm hoping they fix this issue and address this in the manual. I went into this the same way as the T-1... and it was no bueno.

 

[Inebriated]

Everyone I know that's ruined Aimpoint threads has had good service from Aimpoint, I would expect the same for you.

Thanks for the heads up.

 

[HankB]

Everyone I know that's ruined Aimpoint threads . . .

That's a phrase not often encountered with other manufacturers' products as the topic . . .

 

[strambo]

That's a phrase not often encountered with other manufacturers' products as the topic . . .

Well, Aimpoint's chief competitor is Eotech and it has an internal mount nobody takes off...they have other issues though.

 

[RG7X]

Everyone I know that's ruined Aimpoint threads has had good service from Aimpoint, I would expect the same for you.

Thanks for the heads up.

Glad I could help. My last customer experience with Aimpoint was 5/5. I'm anxious to see what happens here... Most helicoils usually have to be drilled out and resized so I'm not sure if I'm to expect a replacement or fix on this.

 

[jmorris]

Millspec aluminum parts all use steel thread inserts in them.

It is easy to remove them, just grab the end that is sticking out and pull it out like a spring and insert a new one to the proper depth.

If the internal tab is not broken off you can still seat it deeper.

 

[rbernie]

I now knew the wet loctite on the helicoils caused the screws to keep turning and stripped them.

Wet loctite will not cause any screws to strip, and I've never seen any data to suggest that its use is contra-indicated with helicoils. Over-torquing the screws as they thread into the inserts causes them to strip, and any lubricant on the threads (oil, grease, liquid thread locker) can cause a false torque reading - helicoil or not. Did you use a torque wrench graduated in inch-pounds to tighten the screws or tighten by feel?

In any event, I've never seen helicoils back out even when blue thread locker is used on the screw/bolt. I'm guessing that Aimpoint needs to tighten up the tap process for the inserts, literally. The inserts should be under enough spring pressure to prevent any movement *at all*.

 

[RG7X]

Update: Aimpoint responded with the response from the engineers in Sweden with "You were right, no threadlock on the helicoils" and sent a new T-2. Hope this helps out.

 

[taliv]

i don't even know what a helicoil is

i was thinking about buying a T2 though... leaning toward an RMR instead

 

[rbernie]

i don't even know what a helicoil is

It's a steel thread insert designed to provide a stronger bearing surface for steel threaded fasteners (bolts/screws). They're commonly used when the material being fastened has a much lower yield strength than steel (e.g. aluminum).

http://www.helicoil.in/helicoil.htm

 

[ranger56528]

Also used to fix stripped threaded holes.

 

[DT Guy]

In fact, the successful installation of a Heli-Coil is often accompanied by profound and effusive thanks to one's favorite deity and a promise to walk the straight and narrow henceforth.


Larry

 

[RG7X]

Lmfao

 

[OneWound]

Wet loctite will not cause any screws to strip, and I've never seen any data to suggest that its use is contra-indicated with helicoils. Over-torquing the screws as they thread into the inserts causes them to strip, and any lubricant on the threads (oil, grease, liquid thread locker) can cause a false torque reading - helicoil or not. Did you use a torque wrench graduated in inch-pounds to tighten the screws or tighten by feel?

In any event, I've never seen helicoils back out even when blue thread locker is used on the screw/bolt. I'm guessing that Aimpoint needs to tighten up the tap process for the inserts, literally. The inserts should be under enough spring pressure to prevent any movement *at all*.

In contradiction to helicoils backing out, I have personally seen it myself. In my place of employment, I've worked on products that have a helicoil sticking out maybe .050" (never cared to measure, because the unit in question were never meant for sale). In regards though, I was still able to put screws in it and torque it without issue.

 

[Snyper]

There's no logical reason why Loctite alone would cause the screw threads to strip.

 

[MachIVshooter]

It's a steel thread insert designed to provide a stronger bearing surface for steel threaded fasteners (bolts/screws). They're commonly used when the material being fastened has a much lower yield strength than steel (e.g. aluminum).

Pretty much. You are effectively using a larger fastener in the softer material. Similar concept to metal bosses in polymer pieces.

Not sure why Aimpoint chose coiled inserts, though; solid inserts, such as Time-serts, are definitely preferable, especially when the depth is known.
Harder, stronger, and can't uncoil.



The tapered type are also forever once you've run a fastener into them and expanded them into the hole. These are what we use to repair cylinder blocks like the GM Northstar and other aluminum blocks that suffer head gasket failure due to the female threads pulling away.

Heli-coil and other coil type inserts have their place, but when max strength is needed, they are not the first choice (especially for shallow threads).

 

[G.barnes]

A lot of companies are using helicoils in their aluminum products (mounts,
Handguards, etc.) so when people over torque things it doesn't ruin the part. A properly installed helicoil will take as much torque as the original threads.

 

[rbernie]

Not sure why Aimpoint chose coiled inserts, though; solid inserts, such as Time-serts, are definitely preferable, especially when the depth is known.

Cost?

 

[jmorris]

Helicoil is stainless, the timesert above is not, so it will rust but they make stainless ones too.

The timesert is a better choice sometimes than keensert (and clones) because they "time" the ID thread with the OD thread allowing the insert to be smaller in diameter (like a helicoil). The others require a larger hole to be drilled that can be a problem if there is not enough material around the threaded hole.

One nice thing about the Keensert style is that you don't need "special" taps. You can get a 3/8-16 ID insert that has 1/2-13 OD threads, for example.

I have made inserts like them myself over the years when I have needed to by drilling and tapping grade 8 bolts and cut to length (also threaded them LH for differential screws bu that's a different subject).

 

[OpticsPlanet]

I managed to bugger the receiver on a Ruger Charger, where the stock is held to the receiver. In researching my options, I came across this comparison of threaded inserts:
http://www.acmeindustrial.com/insert_comparison.html

Mark H.