Model Engine Maker

Help! => Mistakes, muckups, and dangerous behaviour => Topic started by: Danny M2Z on September 17, 2013, 02:09:08 AM

Title: Dodgy Hex Key
Post by: Danny M2Z on September 17, 2013, 02:09:08 AM
G'day.

I found a set of long T handled metric hex-keys at a well known Australian hardware store.

Just what I needed for fiddly screws as they had a ball end. Now at the price I did not expect fantastic quality, but I did expect them to fit a socket head screw.

The first screw I needed to tighten had a 4mm socket, but the key just spun in the hole.

Out with the measuring gear. Oop's, somebody at the factory in China must have a red face!

* Danny M *



Title: Re: Dodgy Hex Key
Post by: tel on September 17, 2013, 04:02:02 AM
Yeah, you do need to check stuff from Mr. B's Emporium - mostly OK, but now and then .....
Title: Re: Dodgy Hex Key
Post by: sshire on September 17, 2013, 04:49:25 AM
It's correct. Their tolerance is +- 2mm.
Title: Re: Dodgy Hex Key
Post by: derekwarner on September 17, 2013, 07:32:29 AM
Something is not KOSHA here  :ShakeHead: ....according to ISO
...an M5 SHCS has an inhex  AF or W dimension of 4 mm......
...an M4 SHCS has an inhex  AF or W dimension of 3 mm....so a measurement of 2.98mm for the corresponding hex driver key size is acceptable

When one purchases a hex key set.... :Director: are they not based on the AF sizing?........which has little to do with the thread sizing designation :facepalm: .....Derek
Title: Re: Dodgy Hex Key
Post by: tel on September 17, 2013, 07:40:28 AM
Yes. Allen keys are designated by the a/f size - here we have an acceptable 3mm key branded as a 4mm, which is clearly not acceptable.
Title: Re: Dodgy Hex Key
Post by: mcostello on September 17, 2013, 04:51:11 PM
I doubt anyone in China has a red face over anything they do. They figure We are foolish enough to buy their stuff. (Got my share also.) :'(
Title: Re: Dodgy Hex Key
Post by: tel on September 17, 2013, 09:26:30 PM
... more likely having a quiet chuckle over it in a corner somewhere.  ;)
Title: Re: Dodgy Hex Key
Post by: Noitoen on September 17, 2013, 09:29:16 PM
You have it wrong. 4mm on the handle means it's for 4mm screws :cheers:
Title: Re: Dodgy Hex Key
Post by: tel on September 17, 2013, 09:34:29 PM
I've never seen allen keys designated that way - for starters while the 3mm key will fit an M4 cap screw, it won't fit an M4 c/s screw.
Title: Re: Dodgy Hex Key
Post by: Noitoen on September 17, 2013, 09:51:47 PM
Just kidding ;)