I would like to take the sideplate off a 15-3 but don't know the proper bit size to remove. I just purchased a S&W specific set of 4 bits with handle from Brownells. The 120-1 is just a little loose, but the 150-3 does not seem to seat all the way. Don't want to mess up the screws. Any advise on removing will be greatly appreciated.

You can grind/file that 150-3 a bit to get a proper fit to the screw.

Mike

For goodness sake....use the right tool. I know you know what you are doing, or you would not be interested enough to ask, but I am in the midst of making a repair to the rear screw-hole on an Air-Lite on which the previous owner must have had the hands of Godzilla and used some glue to boot when he installed the side plate screws. He/she/it had made such a mess of the threads that I had to drill it out only to discover he/she/it had installed an oversize screw. I would be betting they had stripped the hole and installed the bigger screw. I am installing a threaded insert (of sorts) to fix it.

I am so skiddish about side plate screws, especially in the aluminum frames. Those threads were not designed to take a lot of ins-n-outs anyway.

markeb,

It may sound cliche', but the correct screwdriver is the one that fits the slots.

Over time S&W has made their screws with quite a variance in slot width, so it isn't possible to tell you that a certain bit number will fit, you just have to try them and use the largest that will fit the slots in your gun, or start with the next larger one and cut it to fit.

It is actually common to find slightly different width slots on the same gun!

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Gunsmithing since 1961

I concur with ALK8944. Over the years I have encountered Smiths (and other brands as well) with screw slot variations. That is exactly why I have the grinding stone that Brownells sells. There are times you have to modify an existing bit or make a bit from scratch. I will usually save older screwdrivers that have broken tips, and I will custom grind them to fit screws that I encounter over & over.

The older Smiths from the late 40's and early 50's have screws with the same threads, but their slots are thinner. The current bits available in the Brownells sets just do not fit then well, so I have modified and made up a few that fit just right.

Chief38

The 150-3 fits most of mine, including the new 34-1 that I got today. I have had the complete Brownell's bit set for many years and more recently acquired the LE driver set. I can always find one that fits, though more than a few have been modified over the years.

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-jwk-
US Army '72-'95

The newer Smith's seem have more consistent slots than older models. Browning Shotguns (specifically the A-5) have much narrower slots in their screws to begin with, but have variations within them as well. Because the slots are so thin to begin with............the bit must be a precise fit to work properly and to not snap during use. Ask me how I know! The bit grinding stone from Brownells has been a useful tool.

Regards,
Chief38

I bought this same set of bits from Brownells. I have several K frames and a J frame, and the 150 bit doesn't fit the side plate screws on any of them. The 120 is too small. I guess I'll be grinding the 150, but it's annoying, as I ordered these thinking they'd be "the right bits".

Some of my custom ground Gunsmithing screwdrivers........

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Well, about 45min of filing with an EZ-Lap medium while watching TV, and from time to time, wiping off the 150 bit and testing it in a model 15, I now have a bit that snugly fits the side plate screws on all my S&W's.

I have that exact same set, and the small bit edge is now "twisted sideways" from having to take out a side plate screw that someone must have locktighted. But the bit never slipped from the slot.

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H Richard
SWCA1967 SWHF244

I broke down and built one out of hex stock to use only in the drill press to get those stuck side plate screws out of police trade ins. seem like most of them never saw a drop of oil and are really stuck. Standard heads are about the easiest tool to build tool maker 101. Buy the stone from Brownells it's worth it or find a copy of the modern gunsmith by Howe and learn how to make them from scratch. Not that that's much help but with the various heads you're gonna see expect to grind and dress a bunch of heads. But that's part of the fun

I am not a gunsmith and I am not a machinist

But getting tired of screws that did not fit====

I started measuring screws slots and buying individual bits that fit

you have

the diameter

Then the width of the slot

hence 150-3 is .150 thous diameter and .03 width of slot (this is from memory and I am not at my bench---so cut me some slack if I am a bit off -------bit off---hey that is pretty funny).

I found that I had to order some bits to fit Smith's----but the Smith screws were not exactly so sized.

I think the screws I got had designatons like "445-5, or "450-43" or something like that----they work once your figure it out.