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Qbeam
November 18th, 2008, 03:20 AM
Gents,

I did a cursory search for torque values on scope mounts. No luck.

Here are the questions:

1. Is there a standard/general torque value (in-lbs or ft-lbs) for mounting rings to the rail?

2. Is there a standard/general torque value (in-lbs or ft-lbs) for the rings to the scope?

3. Is there a good torque wrench for this type of task? (I don't think we'll be using the monster/normal torque wrench for this.)

Any help on this would be greatly appreciated.

Thanks,

Q

alucard0822
November 18th, 2008, 07:28 AM
#6 screws get 17 in-lb, #8 screws get 35 in-lbs. I have a snap on 1/4" torque wrench and torque screwdriver I have from my days in the shop, but most any torquing screwdriver works from harbourfreight, brownells, or midway. You can also bed the rings and base. Use a thick coat of car wax as a release agent, and a thin coat of epoxy on the rings, and underside of the base, torque to 10in-lbs, remove excess, let dry, release the scope, clean off the wax, then then torque to spec.

E.Shell
November 18th, 2008, 07:51 AM
To add to Alucard0822's post:

I torque the #6 screws that hold the base to the rifle to 15 INCH pounds.

For the scope cap screws, I use the same value, 15 INCH pounds.

Screws in any given assembly should always be tightened down in several stages, bringing all screws down together to ensure that they are all equally tensioned.

On tactical style setups, I torque the ring crossbolts to at least 45 INCH pounds and sometimes go to 65, depending on whose rings and what sort of hardware they use.

I use a 1-75 Seekonk, like this one: http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=18221

Screws torqued as described will not come loose, and I do not use LockTite on scope hardware.

Qbeam
November 18th, 2008, 01:53 PM
Thanks for the info gents, now the follow-up question is with regard to #6 and #8 screws. Are these standard sizes (6/32s, 8/32s, or metric)

I've looked in my Machinery's Handbook 28th edition, and have gotten eye strain with the fastener section. I would assume that #6 and #8 are screw IDs, and they are probably US units versus Metric. Other than that information, I would assume the torque values vary based on the screws used?

alucard0822
November 18th, 2008, 02:11 PM
Thanks for the info gents, now the follow-up question is with regard to #6 and #8 screws. Are these standard sizes (6/32s, 8/32s, or metric)

I've looked in my Machinery's Handbook 28th edition, and have gotten eye strain with the fastener section. I would assume that #6 and #8 are screw IDs, and they are probably US units versus Metric. Other than that information, I would assume the torque values vary based on the screws used?

normally #6-48 and #8-40 are what is encountered most, they are SAE sizes, but not fractional. #10 and 3/16" screws normally found on tactical setups, I torque to 50in-lbs. I run the screws down until the cap or base meets metal, make sure there is the same gap on both sides, then alternate turning opposing screws 1/4 turn each until the desired torque is achieved on both. Its refreshing to see that Ed does it mostly the same way I have been torquing scopes, good to know I am doing something right for a change:D

this is a screw # chart SAE chart (http://www.boltdepot.com/Fastener-Information/Wood-Screws/Wood-Screw-Diameter.aspx)

Qbeam
November 18th, 2008, 02:14 PM
thanks for the info, Alucard:thumbsup:

Qbeam
November 23rd, 2008, 02:06 AM
Gents,

I have picked up the torque wrench E.Shell recommended from Brownells, and have found out that the Warne Quick Detach rings come with Torx T-15 screws.

I have torqued the ring to scope screws (4/ring) down to 15 in-lbs, and the ring to upper/base (1/ring) to 30 in-lbs. I didn't want to go further due to the possibility of stripping the the screw.

Should I change these values, or stick with them.

Thanks,

Q

E.Shell
November 23rd, 2008, 10:51 AM
Those torques values should be fine Qbeam. I'm sure the scope ring caps are GTG as is. Not sure what the thumbnut should go to, but 30 inch pounds seems sufficient.

alucard0822
November 23rd, 2008, 11:20 AM
Gents,

I have picked up the torque wrench E.Shell recommended from Brownells, and have found out that the Warne Quick Detach rings come with Torx T-15 screws.

I have torqued the ring to scope screws (4/ring) down to 15 in-lbs, and the ring to upper/base (1/ring) to 30 in-lbs. I didn't want to go further due to the possibility of stripping the the screw.

Should I change these values, or stick with them.

Thanks,

Q

Doesn't really matter what the screw head diameter is, it's the shank diameter that is improtant in determining the torque needed, if in doubt yo can measure the screw with a mic or calipers, look at the chart I linked to, and determine what sized screw it is, or if metric, what it is closest to. Then torque it accordingly. Sometimes the base might have #8 screws, the rings might have 3.5mm screws (roughly equivalent to #6), or vice versa, or they could all have the same size, some with allen heads, some with torx. What torquing does is set the clamping force to a specific value, and keeps the stress on the screw and part threads down below mechanical limits, often times overtightened screwa actually come lose because the screw streaches, and the threads can be compressed, and strip easier. The engineers figure if they want the ring caps to hold with say 50lbs of force, then torquing a pair of screws with 48 threads per inch to 15 in-lbs will accomplish that, while staying well below damaging the screws. Screws are basically wedges wrapped around a shank, with a set mechanical advantage. If the screw has 20 threads per inch, and you turn it with a force of 1 in-lb, without factoring in friction it will lift a 20lb weight with 1 lb of effort, effectively the same thing mechanically as pushing the same weight up a ramp 20" long, and 1" high. So basically Clamping force is the actual spec you are trying to achieve, what diameter the screw's shank is, gives you an idea of what the torque should be, and what clamping force the engineer that designed it desired.

Qbeam
November 23rd, 2008, 12:15 PM
Guys,

Thanks for the info. Has anyone had good or bad experiences with Warne Rings? Any info on them would be appreciated. It's what the shop had, so if necessary, I can upgrade them if necessary.

Thanks,
Q

wilcam47
November 23rd, 2008, 12:33 PM
also dont forget to put a little thread lock on the screws...it will prevent the screws from vibrating loose over time...

E.Shell
November 23rd, 2008, 02:23 PM
also dont forget to put a little thread lock on the screws...it will prevent the screws from vibrating loose over time...Lots of people say to LocTite scope screws, but I think that is an outdated practice left over from the days of slotted head screws and a general lack of torque wrenches. To each his own, and YMMV and all that, but IMHO, LocTite is not only not needed, but even a liability here. If the screws are properly torqued, they simply will not loosen up.

There is not one drop of LockTite on the scope mount/rings screws on any of these rifles, nothing has EVER moved, and some are on their second barrel:

http://www.pillicustomhomes.com/eshell/213/PrecisionHerd01s.jpg

kerplooey
November 24th, 2008, 06:56 PM
Funny you should post this...I just read an article today on torques. The guy recommended 20-25 lb in. on the mount itself, and 17 lb in. on the rings. He also stated to use some threadlocker, but didn't specify what strength in the article.

alucard0822
November 24th, 2008, 07:14 PM
Lots of people say to LocTite scope screws, but I think that is an outdated practice left over from the days of slotted head screws and a general lack of torque wrenches. To each his own, and YMMV and all that, but IMHO, LocTite is not only not needed, but even a liability here. If the screws are properly torqued, they simply will not loosen up.

There is not one drop of LockTite on the scope mount/rings screws on any of these rifles, nothing has EVER moved, and some are on their second barrel:

http://www.pillicustomhomes.com/eshell/213/PrecisionHerd01s.jpg

Do you bed the bases and rings? I never use loc-tite on mounting hardware, and only a base or two on hard kickin stuff worked loose a little bit, then I bedded the rings and bases, still didn't use loc-tite, and it has stayed put ever since, All torque values were the same both times I installed them. I think the epoxy mates the surface better, applies the pressure more evenly, and may have some mild dampening properties. The scopes also seem to hold 0 better between outings.

E.Shell
November 24th, 2008, 08:19 PM
Do you bed the bases and rings? I never use loc-tite on mounting hardware, and only a base or two on hard kickin stuff worked loose a little bit, then I bedded the rings and bases, still didn't use loc-tite, and it has stayed put ever since, All torque values were the same both times I installed them. I think the epoxy mates the surface better, applies the pressure more evenly, and may have some mild dampening properties. The scopes also seem to hold 0 better between outings.
Just MHO:

I always lap scope rings, and torque those screws with just enough oil residue to prevent corrosion. With good quality rings, application of the proper torque, and improved contact provided by lapping, nothing will move. I had a Loopy 6.5-20x50 on my .50 MBG for awhile (200 +/- shots) and it stayed put.

I have bedded bases in the past. I used to do my BR guns and would take great pains to align the scope to be on target while at the mechanical center of it's adjustments, which I accomplished by egging out the base holes (lateral) and building up a layer of Devcon (vertical). I also bedded bases on a few heavy recoiling rifles, but have done the same guns w/o bedding with no ill effects. I think bedding is a good idea, if one feels like putting forth the additional efforts required, which I do not. This is mostly due to time constraints, but also due to it being a PIA both ways, on and off.

I will still shim them if contact is not within about .001". If there is perceptible movement as I test tighten the base screws, I will shim the base to eliminate all flexing. Once shimmed to remove any flex, and correctly torqued, I have never had a base screw come loose and all of my rifles do a good job of holding zero. I had not noticed a damping effect with bedding, and ideally, it would provide a "hard" interface, with the main benefit of removing the twist and flex so often present.

My 1k bench gun, a 30" Hart barreled 6.5-300 Wby Mag in a Shehane Tracker stock, shot 1/4 MOA groups with a bedded Davidson bases and Kelbly rings, then shot the same 1/4 MOA with a shimmed Farrell Base with Farrell rings.

http://www.pillicustomhomes.com/eshell/213/range-s.jpg


Bedding the rings to be stress-free may be more desirable than lapping, and I lap rings for the same reason I shim bases: expedience both ways. The requirement for either bedding or lapping rings is reduced by stress-free installation of the base. With the compound twist that is the norm with the top of factory actions and misaligned base screw holes, something must be done at the ring/scope interface level or the scope will either be placed under stress or actually damaged.

When I install the rings to the base, I use my clean lapping bar as a mandrel to provide preliminary alignment, and to pre-stress the rings. I'll position the rings and lightly tighten the ring/base fasteners, then snug the ring caps down on the lapping bar. Once everything is roughly aligned and the ring caps snug, I loosen, then re-tighten the ring/base screws to full torque, while the lapping bar is keeping everything as closely aligned as possible. When I loosen the ring caps, any minor misalignment inherent to the system will return, and at that point, lapping, a la "line bore" will clean up alignement and improve contact surface area.

I don't use LocTite anymore for scope hardware at all, mostly due to the terrible mess it makes, taken with the dubious value. I have had to apply heat to get the screws to move w/o risk of breakage. Cleaning previously LocTited will take longer than the mounting job itself, and I usually just run a tap into the receiver holes to chase that crap out of the threads. The small amount that squeezes out under the base can be difficult to remove without marring the finish, but will interfere with base fit if allowed to remain.

I think that the original need for LocTite was more imagined than real, but can understand the use, due to the widespread use of slotted head screws that would not withstand the torque of the fastener shank itself. With the inability to fully tighten the fastener, no wonder it would come loose, and no wonder LocTite was all the rage. With the introduction of Allen head cap screws to scope hardware in the 80's, things got better. With the now common use of Torx driven fasteners, it is quite easy to achieve specified torque and with that, LocTite became unnecessary.

E.Shell
November 24th, 2008, 08:48 PM
. . . The guy recommended 20-25 lb in. on the mount itself. . .
A little heavy for #6-48s, sounds like he may be using #8-40 screws, which are a common upgrade and/or used to straighten misaligned OEM #6 holes by milling to the next size up.