Metric Hex Key Sizes Smaller than 1.5mm for Tool Kit?

[Gwhite]

I help coach the MIT collegiate team, and we have an amazing collection of various .22's and air pistols from almost every manufacturer, past & present.

I'm trying to make sure we have all of the tools necessary for adjustments & repairs in our shop and in the "Coach's Kit", which is a case we take on away matches. Many of the tool kits that came with the various pistols are long gone or incomplete.

I have a set of T-handle hex ("Allen") wrenches that go down to 2 mm. I know I've run across repairs/adjustments that required 1.5 mm keys, and many pistols require that size for trigger adjustments. In terms of even smaller standard metric sizes, there are also 0.7 mm, 0.9 mm, and 1.3 mm.

I've checked my own pistols, and the smallest size I've found in any of the factory kits is the 1.5mm wrench. That covers both .22's and air pistols from Morini, Steyr, Pardini and Benelli. I've also checked the manuals for the Hammerli 160 & Toz free pistols, which list the tools supplied.

So, does anyone know of any pistols that require any of the three smallest sizes of wrench? They are cheap and small enough that I can just get some anyway, but if they aren't needed, there's no point in making it harder to find the 1.5mm keys in with the others.

Thanks!

[Gerard]

My Pardini K10 came with a set of Allen keys and a star key for one a couple of the trigger bolts. The smallest Allen (or hex) key measures 1.3mm according to my caliper. The only use for it is the 4 locking bolts retaining the rear sight blades - one has to loosen each of these just a bit to allow the larger Allen recessed in the left side of the sight to do anything. It'll turn without unlocking the blades but the notch won't change. I'm guessing it's got a spring in there, but haven't dismantled the sight to figure out how it works. Anyway, nothing smaller externally on the K10. Perhaps there's something inside? But I've had no need to work on the guts of mine.

[David Levene]

Don't hold me to it but, from memory, the rear sight blade on later FAS pistols and the allen screw in the hammer box of FAS cartridge pistols need a key smaller than 1.5mm.

[plutone]

My Pardini K10 came with a set of Allen keys and a star key for one a couple of the trigger bolts. The smallest Allen (or hex) key measures 1.3mm according to my caliper.

WOW, so I discover I'm missing that key! :-( The smallest one in my set is that for the trigger's weight settings.

...
The only use for it is the 4 locking bolts retaining the rear sight blades - one has to loosen each of these just a bit to allow the larger Allen recessed in the left side of the sight to do anything. It'll turn without unlocking the blades but the notch won't change.

No need at all! You can set the width of notch just inserting and turn the same key for trigger setting... at least on my K10.

[Gerard]

No need at all! You can set the width of notch just inserting and turn the same key for trigger setting... at least on my K10.

Two possible explanations arise. One is that your K10 has the 4 small locking bolts slightly loosened, compared to mine which are tight. The other would be that there is some difference between the way yours works and mine. That would seem unlikely... but who knows? All I know is that one time I was playing with gap width and realised after a couple of adjustments that nothing in my sight picture had changed. Then I remembered that I hadn't first loosened the 4 small bolts. Once I did that, the gap was adjustable. Go figure.

[jliston48]

Don't hold me to it but, from memory, the rear sight blade on later FAS pistols and the allen screw in the hammer box of FAS cartridge pistols need a key smaller than 1.5mm.

I just found this post.
The free play and the first stage of trigger pull weight on the FAS-603 trigger are both about 1mm - certainly much smaller than 1.5mm. These screws are located in a recess at the top of the trigger.

[Tycho]

The screw that adjusts the microswitch on the Morini 162 (on top of the e-unit) is also smaller than 1.5mm.

[Gwhite]

Sounds like I should lay in a stock of at least 1.3mm and maybe 0.9mm.

Thanks for all the feedback!

[RobinC]

Top trump?

The trigger reach adjustment screw on a W. Hart 2 0z trigger is under 0.9 mm, 32 thou of an inch, I'm presuming its imperial as Hart is (was?) from Nescopeck PA. USA.

It needs a magnifying glass to see its not round!

And I found one in a local services company here in the UK local to me!

And he had more in stock in a dusty bin!

[David M]

Hex key standard sizes

Hex keys are measured across-flats (AF), which is the distance between two opposite (parallel) flat sides of the key. Standard metric sizes are defined in ISO 2936:2001 "Assembly tools for screws and nuts—Hexagon socket screw keys", also known as DIN 911, and, measured in millimeters (mm) are:

0.7, 0.9, 1.0, 1.25, 1.3, 1.5
2 to 6 in 0.5 mm increments
7 to 22 in 1 mm increments
24, 25, 27, 30, 32, 36, 42 and 46 mm.

[FredB]

I always learn something useful when David M posts.

Thank you!

[Tycho]

Of course, when you have Italian screws and Italian keys, everything is relative.

[Gwhite]

Hex key standard sizes
<snip>
0.7, 0.9, 1.0, 1.25, 1.3, 1.5
2 to 6 in 0.5 mm increments
7 to 22 in 1 mm increments
24, 25, 27, 30, 32, 36, 42 and 46 mm.

Interesting. I wondered about 1.0mm, but the best dealer I know of for such things in the US (McMaster Carr) doesn't list it, or a number of the other sizes. They may well exist, but at least McMaster doesn't seem to think they are particularly common. There are also a lot of N.5 sizes that don't appear to be in regular use. 3.5mm, 4.5mm, and 5.5mm are all not readily available.