Torquing Up Your Gear

Discussion in 'General Sako Discussions' started by antsa, Jan 27, 2021.

  1. antsa

    antsa Member

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    Torque values for actions and scope mounts on our Sakos have always been a subject for discussion. In the manual that came with my 85 Hunter about 10 years ago the only mention of action screws is in the "Maintenance Before Use" section. Here it says "Check the tightness of the fastening screws 1 and 2 (Fig 1) with Nr 25 Torx key included with the rifle". That's it!.
    I was recently browsing through the latest version of the owner's manual I had downloaded off Sako's website. This edition covers the 85, the S20, the Quad and the Finnfire II. Under the heading "Disassembly and Assembly of the Rifle Components" it states:

    BARRELED RECEIVER

    Remove the barreled receiver from the stock as follows (fig. 13):

    1. Make sure that the rifle is not loaded with ammunition.
    2. Remove the bolt and the magazine.
    3. Remove the two receiver fastening screws (A) using a Torx T25 driver.
    4. Remove the trigger guard by pulling it downwards.
    5. Carefully pull the barreled receiver upwards out of the rifle. On the Sako 85 Bavarian Carbine lift the back of the barreled receiver upwards and pull backwards (fig. 23).
    Installation is carried out in reverse order. Tighten the receiver screws to a torque of 7 Nm (62 in-lb). Make sure to put metallic recoil block (B) in place into stock and pull barreled receiver backwards before tightening the receiver screws in order to remove the slack from the recoil lug.


    See here! A specific value for a tightening torque. Note that no distinction is made for different stock materials.

    A read through the updated and improved Optilock mounting instructions also now provide specific torque values for rings and bases.

    Discuss!

    Cheers
     

  2. P04R

    P04R Well-Known Member

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    7 Nm is fine for synthetic stocks and metallic bottom metals. With something like Quad with wood stock and polymer bottom "metal" I would be more cautious.

    If one has an adjustable torque wrench, the best way IMO is to snug up the screws by hand to tightness that feels good/right and adjust the torque wrench to match it, then make a note of the value and use it in the future.
     
  3. paulsonconstruction

    paulsonconstruction Sako-addicted

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    Please tell me how one single torque wrench setting is applicable to "every" rifle with different stock materials under varying environmental conditions. The "Torque" thing is just the latest fad that the OCD crowd is trying to get the rest of us to be concerned about. Sako is just responding to this latest silliness by posting a "value" so these obsessed people will stop asking them & to calm their nerves. Because you know, if I tighten my action screws 2 in/lbs above or below the "setting" my rifle won't hit the target. Waste of time & money, IMHO. But then again, I know how to assemble my rifle without guidance & assistance from others. How in the heck did are ancestors ever hit anything without a access to a FAT wrench?
     
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  4. South Pender

    South Pender Well-Known Member

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    In my opinion, 62 in.-lbs. is far too much torque to put on the action screws, especially for any wood-stocked rifle. A Beretta support document updated a year or so ago (link at the bottom) suggests 25-30 in.-lbs. "for all Sako and Tikka action screws." I've also seen 36 in.-lbs. suggested on several internet sites. I had researched this very issue about a year ago and found suggestions re Sako action-screw torque all over the map. An important variable that must be taken into account in the discussion is whether the screws are dry or lightly lubricated.

    Perhaps more important than the actual torque value is consistency. If you've torqued the screws to 30 in-lbs. on a wood stocked rifle, and accuracy is good, I'd return to that value in the future after atmospheric conditions have perhaps changed the screw tightness through shrinkage or swelling of the stock wood. For those who like to work by "feel" rather than a numerical torque value, I might add that when torquing the action screws on my 85 to 30 in.-lbs., they feel very snug. Of course, one person's snugness may be very different from that of another--hence the advantage of working with numerical torque values and a decent torque screwdriver. As for the latter, I use the CDI model (https://www.protorquetools.com/1-4-dr-5-40-in-lbs-cdi-micro-adjustable-torque-screwdriver-401sm/).

    This support document states the following important point, which, I think, puts the 62 in.-lbs. value in the right context:

    "The torque values published in the manual [presumably the 62 in.-lbs.] are listed as the factory setting. Achieving this setting without stripping the threads requires industrial grade equipment that is not commercially available, as well as installation by a trained technician. Use of commercially available gauges and tools requires a far lower torque value than offered in official documentation from Sako and Tikka." (bolding mine)

    The same document suggests the following:

    1. Optilock scope ring cap screws: 17-22 in.-lbs.

    2. Optilock base to scope ring stud screw & base to dovetail clamp screw: 25 in.-lbs.

    3. Tikka T3 aluminum scope ring cap screws: 12-14 in.-lbs.

    4. Tikka/Sako A7 screw-on bases: (a) 10-12 in.-lbs. (less than six threads of engagement in receiver thread)
    (b) 15-17 in.-lbs. (more than six threads of engagement in the receiver thread)

    This document also cautions against torquing down a screw dry. It suggests applying a drop of oil to the underside of the head of the screw and the threads and then wiping 'dry' (which will leave enough residual oil to allow the screw to seat properly) if not using a thread locker. It also suggests using a thread locker only for scope base screws.

    https://berettausa.custhelp.com/app/answers/detail/a_id/795/kw/action screw torque specifications/session/L3RpbWUvMTYxMTc4NDU3Ni9zaWQvZ3UxeHk4MnA=
     
    Last edited: Jan 28, 2021

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