Restoring Sako Ring Screws

Discussion in 'General Sako Discussions' started by icebear, Oct 9, 2020.

  1. icebear

    icebear Sako-addicted

    Messages:
    1,550
    Likes Received:
    789
    Country Flag:
    USA
    State/Region:
    US Arizona
    One of the biggest problems for Sako collectors is the unfortunate fact that a very high percentage of original Sako rings have badly buggered screws. This comes from previous owners (and even guys who call themselves gunsmiths) using improper screwdrivers. The Sako ring screws must be turned with a parallel blade screwdriver, such as the one-piece drivers made by Grace or the interchangeable bit systems offered by Brownells and many others. A driver with a tapered blade will inevitably turn out of the slot and damage it.

    Original screws are unobtainable, and the repros offered by a certain dealer of dubious reputation are expensive at 30 bucks a set. With careful effort, screw heads can be semi-restored to the point where they will be at least unobtrusive. You can't make a messed-up screw head look like new, but you can make a major improvement that will eliminate it as a distraction.

    The tools for this are the correct screwdriver, a pin vise to hold the screw, a screw-slot file plus other files to your taste, a fine sear stone (I like the triangular variety), 320 or 400 wet/dry sandpaper, fine bronze wool, a buffing wheel or a buff on a Dremel tool, denatured alcohol, and your favorite cold blue. I've found that Van's Instant Gun Blue is easy to work with and delivers a reasonable approximation of the color of Sako bluing.

    The first step is to clean the screw with denatured alcohol. Then chuck the screw in the pin vise. Next, using the screw slot file, clean up the slot on the buggered screw. This is critical. You have to square up the slot and get rid of burrs, including at the ends of the slot. Next you need to get rid of the ridges along the top of the slot created by the incorrect driver rotating out of the slot. This can be quite difficult. One tip is to use your fingernail to feel for the ridge. Often you will be able to feel a ridge of metal that you can't actually see. The stone can be quite useful at this stage. Then you need to file and hone the head to a correct shape. This is relatively easy with the earlier style rings with the horizontal joint between top and bottom. These use cheese head screws and you just have to file them flat. The late style rings with the angled joint use Fillister head screws, which are slightly domed. It's quite a bit harder to restore these to a semi-original shape. Once you have the shape done to your satisfaction, polish it with some 320 or 400 wet/dry sandpaper and finish up on a buffing wheel or a Dremel with a hard buff. I actually do the polishing in two stages - first I use a hard felt buff impregnated with valve grinding compound (left over from another project), then I use a softer buff with Dremel polishing compound, which is basically jewelers' rouge. Finally, you need to clean the piece with denatured alcohol. Be sure to clean the threads as well, to get out any dirt or leftover locking compound.

    The final step is cold bluing. You can pour out some bluing liquid in a bottle cap or other small container and immerse the screws in it, or you can apply the bluing with a Q-tip. Let the bluing work for several minutes, then immerse in cold water to stop the action. Card with fine bronze wool and repeat as many times as necessary to get the finish you want. (Safety note: All bluing salts are toxic, most are acidic, and they are not good for your skin. Whatever you do, don't touch lips or eyes while you're using cold blue. Manufacturers recommend using rubber gloves. Van's Instant Gun Blue seems to be pretty mild on the skin and I don't bother with gloves, but I do make a point of washing my hands immediately after using the stuff.)

    Here's a photo of a recent restoration with Fillister head screws. I did them four at a time to keep from having to reorient the scope. The screw on the right is restored; the one on the left is as found (i.e. buggered). The restored screw looks better in real life than it does in the photo. The strobe on the camera has made the reblued surface look much lighter than it appears to the eye. Since the ring screws are buried in the counterbore of the upper ring half, they are in shadow and minor flaws are not visible. The camera exaggerates the flaws.


    Ring Screws 1.JPG
     
    Last edited: Oct 9, 2020
    dgeesaman, lord frith and waterwolf like this.

  2. kevinlg

    kevinlg Well-Known Member

    Messages:
    633
    Likes Received:
    102
    Country Flag:
    USA
    State/Region:
    US Texas
    Also......over the years, I've used a small polished cross-pane hammer. While holding a screw in a pin-vise I can "reform" the screw head.....before the use of any small files or blueing.

    Hope this helps.
     
    icebear likes this.
  3. icebear

    icebear Sako-addicted

    Messages:
    1,550
    Likes Received:
    789
    Country Flag:
    USA
    State/Region:
    US Arizona
    Thanks for the ideas. I don't know why I haven't been using a pin vise for this job but I will from now on. I have edited my original post to include the pin vise.

    How big a hammer are you using on the screw heads? You can actually hammer the metal back where it came from? Please post a photo of the hammer you use for this. Thanks.
     
    Last edited: Oct 9, 2020
  4. kevinlg

    kevinlg Well-Known Member

    Messages:
    633
    Likes Received:
    102
    Country Flag:
    USA
    State/Region:
    US Texas
    IceMan.......

    Sorry for the delay.......

    I got it about 40 years ago.....and it's really a small 4 ounce ballpeen that I polished to an almost mirror finish. Brownell's still lists them....except mine is branded "New Britain". My old crosspane hammer's surface was not hard enough to retain a polished finish.

    Yep.....I try to reform the screwhead surface, and then break-out the needle files.

    Hope this helps.
     
  5. icebear

    icebear Sako-addicted

    Messages:
    1,550
    Likes Received:
    789
    Country Flag:
    USA
    State/Region:
    US Arizona
    Thanks. I've got a couple of small hammer that I can use. I'll give it a try next time I have to do a batch or screws - I finished the batch I was working on . I'm a bit confused though - you are using a ball-peen hammer or a crosspane (aka crosspeen, crosspein)?
     
  6. kevinlg

    kevinlg Well-Known Member

    Messages:
    633
    Likes Received:
    102
    Country Flag:
    USA
    State/Region:
    US Texas
    Back when I bought mine, the ball-peen and cross-pane were two different hammers. The cross-pane is slimmer, with a smaller diameter face.
     
  7. Chris H Crawford

    Chris H Crawford Member

    Messages:
    17
    Likes Received:
    7
    Country Flag:
    USA
    State/Region:
    US Arkansas
    I know I'm late to the gaem but there are new Sako replacement screws on eBay right now.
     
  8. icebear

    icebear Sako-addicted

    Messages:
    1,550
    Likes Received:
    789
    Country Flag:
    USA
    State/Region:
    US Arizona
    Are you talking about the repros at $29.95 a set? Kind of pricey for generic 3.5mm cheese head or fillister head screws (unfortunately, those types of M3.5 screws are all but impossible to find in North America). There are also some so-called "Ruger/Sako" ring screws, which are actually Ruger screws that will screw into Sako rings but they are the wrong thread and don't hold properly. If you've found something other than those two, please post more details.
     
    L61R likes this.
  9. Chris H Crawford

    Chris H Crawford Member

    Messages:
    17
    Likes Received:
    7
    Country Flag:
    USA
    State/Region:
    US Arkansas
    The repros are what I was referring to.
     
  10. L61R

    L61R SCC President Forum Owner SCC Board Member

    Messages:
    1,285
    Likes Received:
    231
    Country Flag:
    Sweden
    State/Region:
    SE Ostergotland
    Old post but I have researched this quite a bit.
    And a generic 3,5x0,6 won’t fit in the Sako mounts. The Sako heads have a smaller diameter than on generic M3,5x0,6 so they fit properly. Generics won’t.

    I’ve tried various companies but none has fit properly.

    Jim
     
    icebear likes this.
  11. icebear

    icebear Sako-addicted

    Messages:
    1,550
    Likes Received:
    789
    Country Flag:
    USA
    State/Region:
    US Arizona
    Interesting. I have been unable to find either cheese head or fillister head M3.5 screws on this side of the Atlantic, except in stainless. Note that the two variations of the original Sako rings have different ring screws. The older version (flat) uses a cheese head screw. The newer version (rounded shape) uses a fillister head screw with a noticeably smaller diameter head. I have found that some M3.5 Allen head screws will fit the older type rings but not the newer. I don't recall the exact head diameters but I'll mike them when I have time to get to my shop. I have seen listings for both fillister and cheese head screws with small diameter heads, but not in M3.5. That is a very hard size to find in the USA. I don't know if it's a standard size in Europe or if it's mainly used in guns. I have found quite a few M3.5 screws in European guns.

    Custom Shop makes repro screws for both kinds of rings. The older style screws are cheese head, and indistinguishable from the originals. The newer style screws show up in their photos as fillister head, but the set I ordered turned out to be actually cheese head. They were, however, the correct diameter to fit the new style rings.

    Newer style rings. The screws in the QD pair are the repros. You can see that the top of the screw is flat, rather than domed like a fillister head.
    Late High Ring QD 2.JPG Late Medium Rings 1.JPG

    Older style rings with original cheese head screws.
    Original Sako Medium Rings 2.JPG
     
    paulsonconstruction and L61R like this.

Share This Page