- Location
- 54°52'56"N 112°10'7"W Alpha Bravo
So why do they say to return it to the lowest setting after use?
:confused: Broke my LMT - MRP Locking Bolt!!!
- Thread starter Adamg_55
- Start date
So why do they say to return it to the lowest setting after use?
Only for Click style torque wrenches which have the screw style adjustment. Beam style (needle along the length of the wrench) have no requirement as such as they auto "zero".
Has to do with backlash/takeup in the adjuster.
You can still overtorque with a torque wrench. The Click means you arrived at the designated torque value, but you can still keep turning....
If you want consistency, you start from a lower point and stop at the desired setting. If you pass the setting, you should back it off a fair amount and then re-ajdust to the desired torque level. The reason for backing it off has more to do with If you have to back off the setting you will have some play prior to the actual adjustment.
Think of a delayed reaction. Happens alot in really cheap machining (aka made in china cheap) equipment where backlash can be several thousandths of an inch.
Doesnt the click just mean that its time to really give 'er pig and crank the sucker down?
Someone is going to listen to this and not be too happy with the result.
Considering the number of posts in this thread, they probably should include torque wrench instructions. Hold on they are probably included with the included torque wrench
Quote:
Originally Posted by beltfed
I'd recommend a decent quality torque wrench - give it the proper torque, not 'snugged up'. You shouldn't have to stop every 100 rounds or so to see if your bolt has loosened off ala Robarms stuff....
My point was that 'snugging up' means something different from person to person, and very few can read into what torque they are applying with different tools. Having a bolt or screw back out would be bad juju as well.
There just isn't a good excuse not to use a proper torque wrench when changing out one of the LMT barrels. -imho.
Originally Posted by beltfed
I'd recommend a decent quality torque wrench - give it the proper torque, not 'snugged up'. You shouldn't have to stop every 100 rounds or so to see if your bolt has loosened off ala Robarms stuff....
My point was that 'snugging up' means something different from person to person, and very few can read into what torque they are applying with different tools. Having a bolt or screw back out would be bad juju as well.
There just isn't a good excuse not to use a proper torque wrench when changing out one of the LMT barrels. -imho.
mine neither.. I saw all the stories of loose bolts on the xcr's so when I got mine i put on my rocket scientist hat, grabbed the allen wrenches, brake clean and lock tite. I wish I had more down the hole but at about 1000rounds shes as tight as a ......... The only reason to lose a bolt from an xcr is pure ignorance, everyone knows they seem to leave the factory loose, big deal tighten them. I wouldnt fire ANY new gun without checking it over first. PS last I checked 99.99% of rifle scopes and accessories are attached via a threaded mechanism. None of my gizmo's have come loose, if they did I could blame nothing but myself.
LOL - sounds like LMT needs to include torque wrench instructions with their rifles as well
If you cant work a torque wrench, should you even be changing bolts on a gun? BTW I have one of the earlier MRPs and got no stinking torque wrench..
Given that LMT doesn't specify a lubed or dry torque value, I'd torque dry to be conservative and just check for tightness after a few hundred rounds.
If you are worried about seizing/corrosion in the mated threads, then you can use a lube with a surfactant like G96 that will wick up into the threads after you torque.
FYI, here is a table with wet and dry torque values. See how much difference there is between the two for the same fastener of the same grade (yes, it is for metric threads, but you get the idea):
http://www.cncexpo.com/MetricBoltTorque.aspx
If you are worried about seizing/corrosion in the mated threads, then you can use a lube with a surfactant like G96 that will wick up into the threads after you torque.
FYI, here is a table with wet and dry torque values. See how much difference there is between the two for the same fastener of the same grade (yes, it is for metric threads, but you get the idea):
http://www.cncexpo.com/MetricBoltTorque.aspx
- Location
- 54°52'56"N 112°10'7"W Alpha Bravo
LOL - sounds like LMT needs to include torque wrench instructions with their rifles as well
In all fairness though, some of these chinese torque wrenches have been the ####s, mine included. When I bought my good one it was super smooth, night and day difference.
Doesnt the click just mean that its time to really give 'er pig and crank the sucker down?
I was always taught, tighten the bolt in until it starts to get easy to turn again, then back it off a quarter turn.
Did you know that it is good practice to exercise your torque wrench before first use of the day?
I've always used some kind of thread lubricant, usually moly grease, synthetic oil or neverseez. I always triple check the final torque on every fastener to ensure they are all equally to torque.
I was always taught, tighten the bolt in until it starts to get easy to turn again, then back it off a quarter turn.
Just kidding. For those not realizing this is a joke, if it starts getting easier to turn again, you have plastically deformed the fastener in tension and are close to getting torsional shear. In other words, the fastener has for all intents and purposes FAILED and will not retain its design strength.
Throttle_monkey1
CGN Ultra frequent flyer
Im gonna troll this thread a bit. I find it funny that you are one of the biggest bashers of the XCR for bolts supposedly backing out all the time, but here you are defending the broken bolt on an LMT.
- Location
- 54°52'56"N 112°10'7"W Alpha Bravo
1. Never bashed the XCR just because of bolts falling off, there are other reasons.
2. The LMT bolts in question were designed to fail in order to prevent damage. They do not fall off on there own, like said XCR.
3.The LMT bolts break because of being over tightened by user error, they don't just break on there own.
apples and oranges my friend,
- Location
- 54°52'56"N 112°10'7"W Alpha Bravo
That's what I just said!
I said XCR bolts fall out on there own, not break on there own.
Again it's apples and oranges, the LMT bolts don't fall out on there own, like said XCR.
They don't fall out of the xcr on their own either, it's still a case of user error as everone on the planet knows they sometimes leave the factory loose, so if an xcr owner looses a bolt it's because they're a potato head. I think it's safe practice to assume everything you buy may have a loose nut, screw or bolt and should get a thorough inspection before use. You look down the barrel before you shoot a new gun don't you? Why not check the bolts and screws? I know when I buy motorcycles, dirtbikes, trikes, sleds, cars and trucks I give them a good once over before I go mashing gears up the highway or hitting single track deep in the wild.
