Need Reccomendation for gunsmithing thread gage set

[Texasflyboy]

I would like to buy a quality (starrett or equal) thread gage set for my gun smithing use. I have several old guns I am working on, and my el cheapo thread gage set is not helping me decipher what threads I am dealing with.

Can anyone recommend a quality thread gage set that will help me deciper the most common thread sizes used in US Martial arms?

Thanks in advance..

Tom in NC

[sturf]

Brownell's sells both English and Metric gauges. been using them 30 years.

[JIMinPHX]

A lot of screw threads on guns are specials. Like the barrel threads on S&W revolvers. I think that the “nominal” major diameter is like .560” or something like that. It’s not 1/2". It’s not quite 9/16”. It’s something strange like .560”. Guns use strange screw pitches too. There is a #6 extra fine that is commonly used in guns that you will not find in the hardware store. The metric guns are like that too. Pietta uses a 6mm extra fine thread on their cap & ball revolver nipples. Even grip screws on a 1911 are a screwey special thread.

If you’re going to be measuring gun screws & you really want to know what you are actually looking at, you should get a set of thread wires & a micrometer so that you can measure the pitch diameter. You will then need a copy of the Machinery’s Handbook, so that you can decipher what the pitch diameter info really means. I get that kind of stuff from MSC. I think that their website is something like mscdirect(dot)com. I usually buy out of their catalog, so I don’t have their web reference handy.

[Buckshot]

..............One of the reasons gunscrews can be tough is that lots of times they're used in (going into) relatively thin sections and so require fine threads. It can be VERY tough to figure them out too because some can be so short. One of the first oddities I ever ran into, and this was a long time ago was the 1903 Springfield action screws which are 1/4-27. An explaination I got for this was because it was metric. I never bothered to check it out.

More recently needing a couple I merely single pointed a couple 1/4-28's (my QC box not having 27 tpi) . Once to full depth I loosened the tool and moved it forward (not depth) a thousandth, tightened it down and made a final full depth pass. This in effect put in enough 'slop' that it would thread into the Springfield action and securely tighten.

As an aside, a couple years ago I bought a 37 tooth gear for the stud position on my lathe. This gave me 27 tpi and a whole slew of usefull 'in betweens'.

You're right to think of getting a Starrett thread gage. First one I bought was made by PEC and it was a *** :-) and about useless.

...................Buckshot

[Morgan Astorbilt]

The large Starret thread gage, one in English and one in metric, will cover almost all thread pitches, and you can then "mike" the diameter. Another handy item, is a "Screw Check'r". These are hardened steel plates with smooth and threaded holes covering most sizes. They also come in English and metric. Brownells carries them (with their name added) as do Enco and MSC.
Morgan

[Texasflyboy]

Thanks for all the replies. I purchased a Starrett 427 along with another set from eBay (Browne & Sharpe).

Tom in NC (T minus 7 days)