Torque value, red dot crossbolt to Optics rail

[FatCatsDad]

What would the recommended torque be for mounting a Vortex Red Dot to a Weaver rail on a Rem. 870 ?

It's a single cross bolt and appears to be about 3mm in diameter.
I've used the low mount that was included rather than the high mount pictured on the box.

 

[guntech]

Just push the mount towards the muzzle end of the slot and snug it up with the small wrench be it Allan headed or Torx... if you need an actual value 25 inch pounds is sufficient.

 

[FatCatsDad]

Just push the mount towards the muzzle end of the slot and snug it up with the small wrench be it Allan headed or Torx... if you need an actual value 25 inch pounds is sufficient.

Thank you Sir.
I did however use a final value below 25 inch pounds.
It started feeling tight at 12, I should have stopped.
The fastener snapped at 17 inch pounds.
Luckily there are 2 mounts in the box, low and high so I had a spare.
After some quick Google work I found a few charts with metric fastener torque specs.
3mm fastener recommended torque is 11.5 inch pounds.
I installed it using 11.

I'll boresite at 50 yards in the backyard when the sun goes in. I can't see the laser in the bright sun.

I'll shoot some slugs in the morning and make the final adjustments.

 

[guntech]

That doesn't say much about the quality of that screw... glad you had a spare. At any rate snug with a small wrench is always good... what did the manufacturers instructions state?

 

[bdb.hunting]

That doesn't say much about the quality of that screw... glad you had a spare. At any rate snug with a small wrench is always good... what did the manufacturers instructions state?

Just looked at the manual out of curiosity and it didn’t state a value.

B

 

[Butcherbill]

The trs25 instructions say to tighten it snug and then give it a 1/4 turn, something similar will work I would expect

 

[guntech]

I have always felt as tight as your thumb and finger can do it on the short end of the wrench and then a little more works fine.

 

[cosmic]

FCD - This effort should give you the opportunity to develop a "feel" for an appropriate torque value for a fastener. You should bear in mind that fastener load vs applied torque varies substantially with factors such as thread pitch, wet vs dry threads, thread/collar damage, manufacturing tolerance, etc. For this reason, I tend to avoid using quoted numbers and a torque wrench. Havent broke a fastener yet....

 

[FatCatsDad]

FCD - This effort should give you the opportunity to develop a "feel" for an appropriate torque value for a fastener. You should bear in mind that fastener load vs applied torque varies substantially with factors such as thread pitch, wet vs dry threads, thread/collar damage, manufacturing tolerance, etc. For this reason, I tend to avoid using quoted numbers and a torque wrench. Havent broke a fastener yet....

I did find charts for fastener torque specs, with various columns for pitch, wet threads(loctite) etc.

If a company has spent money on R&D to develop installation specifications that yield the best performance and equipment life then I follow it.

After some deep Vortex Googling I found the torque value for this specific fastener is 15" pounds.

The 11 I used as a value felt very tight and after the first snapped, I chickened out and stopped before 15.

It's funny but on the Vortex Canada site in the reviews for this red dot, there are complaints of this cross slot bolt breaking and the threads from the mount also stripping out.

They should change the materials or change the specs.

I have followed up with an email to the customer service address requesting a new screw be sent.

I'll see how that goes..

I shot some slugs out back after coffee this morning and it is super nice to use.

It's my first ever red dot and really don't know much about them.

Lots of pros and cons on mounting height and even mounting location on the rail.

I'll find out how it is in the real world on these in the back field in a couple of months.

 

[cosmic]

Well - The cross bolt is taking the recoil load directly in shear. Its ability to secure the optic is relatively unaffected by fastener preload. However, the combination of excessive axial stress from the fastener and shear stress can cause the cross bolt to fail upon firing. Its worth noting that many crossbolt systems utilize "coin slots" for tightening, which effectively limit the torque applied. I would say this is a good example of too little being better than too much.

 

[FatCatsDad]

That doesn't say much about the quality of that screw... glad you had a spare. At any rate snug with a small wrench is always good... what did the manufacturers instructions state?

Purolator dropped off a package from VORTEX today.
They sent at no charge a complete high mount, a complete low mount, 8 mounting screws and a Torx key.

 

[guntech]

Their service is excellent.

 

[FatCatsDad]

Their service is excellent.

I agree with this statement.
It would however be better to not need to make warranty claims at all .
Is the warranty generous due to inferior products , low prices and high volumes of sales.
Seems I see Vortex more than any brand these days .

It just so happens I have my eye on a rangefinder at Cabelas on sale this week, reg 279, sale 189 and free shipping.
I can see why Vortex are popular.

 

[kamlooky]

With no Canadian Bushnell warranty, Vortex profits should increase as well as the other brands.

Good thread Faddycatzs.