Grip screw dillema

[Munch]

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.

[RJay]

Or you could make a trip down to Tru Value and check out their metric screw selection.

[john323]

My guess is these are metric. Try :Metric Specialties Inc
622 South Flower Street, Burbank, CA 91502
(818) 848-6696

[Munch]

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.

[carver]

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.

[Hammerslagger]

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/me...ads-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.

[Munch]

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.

[JLA]

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.

[Munch]

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.

[Munch]

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.

[JLA]

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.

[Munch]

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?

[Hammerslagger]

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.

[JLA]

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.

[JLA]

Do these measure to yours Munch?

[Bill DeShivs]

The Starfire screws should work just fine.

[RJay]

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.

[Munch]

You're probably right on the money RJay. Then the torrent of obscenities will be unleashed.

[Munch]

[Munch]

[Munch]

[Munch]

[Munch]

The grips are nowhere near the quality of Woodnut's, but, it was my first attempt at it. Woodnut, THANK YOU, you inspired me to try something that I really had a lot of fun doing. I hope to someday be half as skilled as you.

[Munch]

Just messing around I measured the 3 remaining screws, The one posted above is a different length that the others. I'm thinking that someone may have replaced the screws at some point. The terminal end of the threads are NOT cut straight, is this normal?

[Bill DeShivs]

Depending on the depth of the holes in the grips, Star grip screws may have to be trimmed to keep them from dragging on the magazine.