Grip screw dillema

Discussion in 'Technical Questions & Information' started by Munch, Jun 11, 2012.

  1. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    I was unlucky enough to lose a grip screw for my Star model ss. 380. The problem I'm running into is that noone has these little buggers. I've checked every supplier out there that I can think of with no luck. Bobs has them for other models but I'm unsure if they will fit the ss. I'm wondering if anyone has ever drilled and tapped for new grip screws? Is there any disadvantage to doing this? I'm thinking of threading it to a common sae size so that I don't run into this again. Any suggestions for the size I should tap for? I'm thinking of 6/32, but would like to know if there is a better size to use.
  2. RJay

    RJay Well-Known Member

    Joined:
    Feb 22, 2004
    Messages:
    4,325
    Location:
    Goodyear, Arizona
    Or you could make a trip down to Tru Value and check out their metric screw selection.:)
  3. john323

    john323 Member

    Joined:
    Jun 1, 2011
    Messages:
    47
    Location:
    Monterey Park ,CA
    My guess is these are metric. Try :Metric Specialties Inc
    622 South Flower Street, Burbank, CA 91502
    (818) 848-6696
  4. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    RJay, I've dug through the metric screws at 4 of the hardware chains around here and have found close, but not anything that matches up. I did read somewhere that these were made a half step between normal metric screws. Instead of being a 4/70 it is a 4.5/75, so very proprietary... in the posting I read though the OP was not able to give the exact measurement and thread count.
  5. carver

    carver Moderator

    Joined:
    Jul 28, 2008
    Messages:
    15,992
    Location:
    DAV, Deep in the Pineywoods of East Texas, just we
    In Shreveport, LA there is a factory that makes screws, and fasteners. If you can find such a shop in your neighborhood that would be the place to look. If they don't have it, they could possibily adapt something already in stock for a small fee.
  6. Hammerslagger

    Hammerslagger New Member

    Joined:
    Jul 30, 2009
    Messages:
    1,097
    I infer that you lost only one screw, and have at least one other screw. These screws will almost certainly be a metric diameter and pitch. You need to find the answers to the nominal diameter and pitch.

    Such is easily accomplished with an electronic caliper set to metric mode. {Actually any readable caliper will do, if you are familiar with its use.}

    Getting the nominal diameter should require no explanation. Typically, your reading will be slightly under theoretical size, and you will round up to the next whole or half mm. To get the thread pitch you will likely need a engraver/watchmaker loupe (eyepiece) or similar magnifier. You use the points of the caliper's inside diameter jaws to "bracket" the crests of as many threads as possible, up to about 7 threads. {That is where the eye loupe comes in handy.} Next, you count the number of threads bracketed. Next, you read the distance shown on the caliper. Finally, you divide the distance by the number of threads bracketed less one thread, to get the pitch or distance between threads.

    A common metric thread for things like grip screws is 3.0 mm diameter x 0.5 mm or 3.0 mm x 0.35 thread spacing (aka pitch). Thus the shaft would likely measure about 2.88 mm and 7 threads bracketed would measure about 3.00 mm for 0.5 spacing or 2.10 mm for 0.35 mm spacing or pitch.

    {You count the first thread crest at the caliper point as # 0 and count up to 6 more crests, and read the distance to which you will divide the number of crests counted into to get the nominal pitch.

    Armed with the above info, you should be able to find a threaded fastener that will work or can be easily modified to work. If you find a correct shaft with a head too big, you can easily reduce the head diameter with a file and a electric drill.

    Hope some of this helps. Here is a possibly useful link: http://www.engineeringtoolbox.com/metric-threads-d_777.html Here is another: http://contrails.free.fr/article_machine_screw_en.php

    Sometimes you can find something close enough in the English system to work in the metric system, and vice versa. Such is not good practice; but I served my apprentice ship at "Slipshod Tool & Die". Sometimes its just better to get something fixed, less than perfect, than to leave it broken.

    P.S. Bob's, in Royal, AK, only wants $3.00 plus shipping for screws that might likely be the right thread size.
    Last edited: Jun 11, 2012
  7. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    Thanks for that incredible advice and information Hammerslagger! I saw those screws on Bobs gun parts I was unsure of the thread patterns being close to the same between models. Now that I know how to figure the pitch and diameter it, in theory at least, should make my search a lot more productive. If all else fails locally I'll order the screws from Bobs and hope for the best.

    I have the caliper on my reloading bench about 15 feet from here, so I will be figuring this out shortly. Thanks again for your instructions.
  8. JLA

    JLA Well-Known Member

    Joined:
    Feb 26, 2007
    Messages:
    18,268
    Location:
    Heart Of Texas
    Or you could just PM me your address Munch. I have a set of grip screws that came out of my Llama 111a .380 that should be the exact same as the Star SS .380 grip screws, as they are both mini 1911 clones. I converted my 111a to 1911 grip screw bushings and made a set of corian grips for it so I wont be needing the factory grip screws anymore.
  9. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    I figured out the diameter and pitch for the Star screws to be 3.5mm and .8275. I then contacted the local screw makers, only two that I've heard of at least, and neither had anything in 3.5mm. So, I went back to Bob's gun parts and ordered 2 of the starfire .380 grip screws and in trying to make the $10.00 minimum order, I happened upon the closeout bin. They had unslotted grip screws for foreign pistols for 20 for a buck. Needless to say I grabbed some of those, and GI rifle bags at 5 for 10. great deal for a long term storage and moving bags. Thanks again for everyones tips! I really didn't want to tap out the holes, but i've just made some wood grips for this and I really want to take her out for a test with the new furniture.
  10. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    Thats very generous of you JLA. Thank you for that. If the offer stands, I will take you up on that in the event that the ordered parts do not work. Thanks again, I hope I can extend that same generosity to you or another member here in the future.
  11. JLA

    JLA Well-Known Member

    Joined:
    Feb 26, 2007
    Messages:
    18,268
    Location:
    Heart Of Texas
    It stands as long as you need it to. They have been stuck to my magnetic parts try for 2 months now and are in no hurry of wandering off. ;)
  12. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    On a side note, I'd love to know how you did that conversion on the Llama. Could this be accomplished on the Star also?
  13. Hammerslagger

    Hammerslagger New Member

    Joined:
    Jul 30, 2009
    Messages:
    1,097
    Relative to post #9, 3.5 x .8 mm (".8275" as stated by Munch) would be a very coarse and non standard pitch, but is possible.

    Let me restate the pitch procedure, which usually needs the help of magnification to count threads.

    You adjust your caliper (set to read in metric; or if not possible, which you can later convert to metric) so that the two sharp points of the inside diameter jaws are directly over the crests of two threads parallel to the length axis of the threaded shaft. You then count the total number of thread crests bracketed by the jaw points, and subtract one crest. Then you divide that number into the reading on your caliper in mm (or if decimal inch, which has been converted to mm). {For example 7 crests total count, minus 1 = 6 threads from origin point. Caliper reading is or has been converted to say 3.05 mm, divided by 6 = .5083. The closest thread count in any metric thread table is 0.5, which is you pitch.}

    There are special thread pitch measuring tools. However they are expensive and often not in ones possession when one has access to a caliper and needs to figure out what the threaded part is.

    Hope this clarifies.
    Last edited: Jun 11, 2012
  14. JLA

    JLA Well-Known Member

    Joined:
    Feb 26, 2007
    Messages:
    18,268
    Location:
    Heart Of Texas
    I have a thread pitch gauge. plus I made a screw gauge from a scrap piece of aluminum. I took both of my gunsmithing tap sets both metric and standard and D/T each and every hole in the scrap. when i need to determine a thread pitch i just try holes until it fits one.
  15. JLA

    JLA Well-Known Member

    Joined:
    Feb 26, 2007
    Messages:
    18,268
    Location:
    Heart Of Texas
    Do these measure to yours Munch?

    Attached Files:

  16. Bill DeShivs

    Bill DeShivs Well-Known Member

    Joined:
    Apr 7, 2006
    Messages:
    1,710
    The Starfire screws should work just fine.
  17. RJay

    RJay Well-Known Member

    Joined:
    Feb 22, 2004
    Messages:
    4,325
    Location:
    Goodyear, Arizona
    And just for info, with in a very short time of solving the problem, you will drop a tool on the floor, when you bend over to retrieve it, you will the missing screw up against the wall, laughing at you. Never fails.:D
  18. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    You're probably right on the money RJay. Then the torrent of obscenities will be unleashed.
  19. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
    [​IMG][​IMG]
    Last edited: Jun 12, 2012
  20. Munch

    Munch Member

    Joined:
    May 31, 2011
    Messages:
    352
    Location:
    Puyallup, WA.
Similar Threads
Forum Title Date
Technical Questions & Information Does anyone know the grip screw thread size for the P238? Mar 17, 2012
Technical Questions & Information Handgrip screws keep loosening on me Dec 8, 2008
Technical Questions & Information Winchester Model 88/100 grip end cap Feb 9, 2014
Technical Questions & Information Hawes .22 SA Grips update Oct 19, 2013
Technical Questions & Information Customizing Stocks and Grips Info?? Oct 10, 2013

Share This Page