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Allen key size problem

Posted By: vavavroom

Allen key size problem - 03/03/19 02:40 AM

I need to loosen M2 hex head screw. None of my Allen bits fits. 1.27mm is too small, 1.5mm is too big, I really don't feel like sanding a 1.5mm bit down to fit. I am not aware of any intermediate size.
Posted By: Chris142

Re: Allen key size problem - 03/03/19 02:50 AM

Have you tried an sae hex key?
Posted By: Langanobob

Re: Allen key size problem - 03/03/19 02:54 AM

Or try a Torx bit.
Posted By: spasm3

Re: Allen key size problem - 03/03/19 03:33 AM

If sae does not fit , hammer a robertson bit in.
Posted By: user52165

Re: Allen key size problem - 03/03/19 06:16 AM

Originally Posted by vavavroom
I need to loosen M2 hex head screw. None of my Allen bits fits. 1.27mm is too small, 1.5mm is too big, I really don't feel like sanding a 1.5mm bit down to fit. I am not aware of any intermediate size.


7/128 = 1.43mm Not sure that SAE is made.

This is where a high quality item made to tight tolerances is needed. I suspect yours is not, or the head, is buggered up. Probably 1.5. The other posts are good also.

Bondhus ball types are all I use.
Posted By: CR94

Re: Allen key size problem - 03/03/19 06:49 AM

Originally Posted by user52165
...or the head, is buggered up. Probably 1.5. The other posts are good also. ...
Exactly. Check for burrs at the entrance of the hole in the screw, or at the tip of your hex key.
Posted By: jhellwig

Re: Allen key size problem - 03/03/19 07:17 AM

If you are trying a ball end use a regular one. Ball ends don’t have as much grip area.
Posted By: gaijinnv

Re: Allen key size problem - 03/03/19 07:56 AM

M2 spec is 1.3mm. Many available: 1.3mm at Ace Hardware

HTH
Posted By: Imp4

Re: Allen key size problem - 03/03/19 01:27 PM

An M2 SHCS should accept a 1.5mm he Allen key per DIN 912 & ISO 4762.

Attached File
1-32.pdf  (24 downloads)
Posted By: gaijinnv

Re: Allen key size problem - 03/03/19 03:31 PM

Originally Posted by Imp4
An M2 SHCS should accept a 1.5mm he Allen key per DIN 912 & ISO 4762.



For a socket head screw you are correct, but OP does not have a socket head screw. Applicable standard is ISO 7380 which specifies 1.3mm for M2.

[Linked Image]

HTH
Posted By: Imp4

Re: Allen key size problem - 03/03/19 07:02 PM

Originally Posted by gaijinnv
Originally Posted by Imp4
An M2 SHCS should accept a 1.5mm he Allen key per DIN 912 & ISO 4762.


For a socket head screw you are correct, but OP does not have a socket head screw. Applicable standard is ISO 7380 which specifies 1.3mm for M2.
HTH

'ISO 7380- Hexagon socket button head screws' is button head screws just like you have illustrated.

OP states:
Originally Posted by vavavroom
I need to loosen M2 hex head screw.

He does not specify socket head or button head...
I guess we'll need OP to clarify exactly what he has/needs...
cheers
Posted By: red7404

Re: Allen key size problem - 03/04/19 05:44 AM

IMHO. this is where you buy the cheapest tools you can find. and mod them to your harts content
Posted By: gaijinnv

Re: Allen key size problem - 03/04/19 03:28 PM

'ISO 7380- Hexagon socket button head screws' is button head screws just like you have illustrated.

OP states:
Originally Posted by vavavroom
I need to loosen M2 hex head screw.

He does not specify socket head or button head...
I guess we'll need OP to clarify exactly what he has/needs...
cheers

I completely agree cheers
Posted By: lyle

Re: Allen key size problem - 03/04/19 07:09 PM

Lordy, oh lordy, he says he has a HEX HEAD SCREW. No wonder his Allen bits don't fit, he needs a box end or open end wrench.

Now if he had a hex socket screw that would be different, but he needs to specify head type.
Posted By: EdwardC

Re: Allen key size problem - 03/04/19 11:29 PM

We should probably check if his name is even Allen.
Posted By: Imp4

Re: Allen key size problem - 03/05/19 02:48 AM

Thanks everyone for the clarification. 🙄

Now if only OP would reappear from his cloud of smoke...
Posted By: vavavroom

Re: Allen key size problem - 03/08/19 11:19 PM

Sorry for the confusion and the late reply. I have been working so much overtime lately I haven't gotten around to posting. The screws in question have internal hex aka Allen heads. not hex heads. I hate posting using a mobile device. The auto-correction and auto-complete feature always mess something up that I surely miss. The heads are not buggered up as someone suggested. They are button head screws on sensitive commo equipment. So I won't be "hammering in" some other socket. It's not that I have a real problem getting them out - I can loosen them with small pliers by gripping the head, but I want to use the proper Allen key because there are more than a few of them. It looks like button head M2 require actually a 1.3 mm socket. This makes sense because the 1.27mm is just a little too small. I wasn't sure that the Allen keys advertised as nominal 1.3 were not actually 1.27mm. I'll get one and find out. As for whether I tried SAE Allen kes, no, I did not since they are nowhere near the required size. I measured all my Allen keys and the nominal size is always larger than the actual size:

1.2mm is actually, 1.17mm
1.5mm is actually 1.46mm
2.5mm is actually 2.35mm

[Linked Image]
Posted By: George Bynum

Re: Allen key size problem - 03/11/19 01:37 AM

The 1.27 mm probably really are that nominally ... because 0.050" is 1.27 mm and is a common electrical connector pitch. SAE hex sockets do exist in 0.050"

#0 SHCS, #1 and #2 flat and button head use a 0.050" hex key.

In the ANSI (A=American) dimension charts, there is a 0.9 mm and 1.3 mm, nothing between. I don't have a DIN reference but doubt there are non ANSI standard sizes.
Posted By: vavavroom

Re: Allen key size problem - 03/18/19 01:17 AM

As it turns out a 1.3mm Allen key fits. So there are 1.25mm, 1.27mm, and 1.3mm. None of my Allen key sets had the 1.3mm.
Posted By: gaijinnv

Re: Allen key size problem - 03/18/19 04:18 AM

Originally Posted by gaijinnv
M2 spec is 1.3mm. Many available: 1.3mm at Ace Hardware

HTH


Originally Posted by vavavroom
As it turns out a 1.3mm Allen key fits. So there are 1.25mm, 1.27mm, and 1.3mm. None of my Allen key sets had the 1.3mm.




gaijinnv for the win!

banana
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