Weird Snap-on GM-70-M Rachet

[Chromdome35]

I have a Snap-on GM-70-M 1/4" Rachet I purchased at a flea market.

It has a very strange problem...no 1/4" socket that I have will fit on the post. It seems to be slightly too large.

Anyone ever run into this before?

 

[colin39]

Sounds like an 1/8 ratchet, post a picture
This thead is worthl.......... You get the idea

 

[colin39]

Couldnt help myself

 

[ken w.]

9/32" drive ?

 

[drtyler]

Measure it...

If the post is larger, it may be a 9/32" drive.

 

[T45]

Yes that is common, snap on made this in many ways and there are 9/32 not 8/32 (1/4 inch) square drives built to suit slightly different sockets with 9/32 broachings.

If you want to use the ratchet, they can be upgraded to 1/4 drive with a new kit. Some people really like those little ratchets.

 

[Chromdome35]

Measure it...

If the post is larger, it may be a 9/32" drive.

Just measured it, it is 9/32". I didn't know such a thing existed.

Can someone who is much more knowledgeable than me tell me about 9/32" drives. Why does something so non standard exist? What was it used for?

 

[T45]

Your tool is like 70 years old, from the 1940 ish time period. Back then they were trying to build smaller ratchets. 1/2 drive was standard. 3/8 drive was more nimble (ferret). And below that they went from the 10/32 to 9/32 stage before getting 8/32. The 9/32 was stronger and they probably did't get to 8/32 fully adopted they got the metalurgy correct. In the WW2 era there were lots of advances in tech but also lots of issues with directing the best resources to the war effort. Today those 8/32 square drives can take 50-100NM, but back in the day it was 9/32 giving a bit more confidence in the smaller tool. 1/4 drive ultimatey allows for thinner lighter sockets.

 

[Chromdome35]

Your tool is like 70 years old, from the 1940 ish time period. Back then they were trying to build smaller ratchets. 1/2 drive was standard. 3/8 drive was more nimble (ferret). And below that they went from the 10/32 to 9/32 stage before getting 8/32. The 9/32 was stronger and they probably did't get to 8/32 fully adopted they got the metalurgy correct. In the WW2 era there were lots of advances in tech but also lots of issues with directing the best resources to the war effort. Today those 8/32 square drives can take 50-100NM, but back in the day it was 9/32 giving a bit more confidence in the smaller tool. 1/4 drive ultimatey allows for thinner lighter sockets.

Awesome info, thank you very much!

 

[ssdave]

I have two of those midget ratchets, but in 1/4" drive. One made in 1942. It is my favorite small ratchet, and gets a lot of use, even though I own newer dual 80 technology 1/4" ratchets.

I don't think that it is substantially weaker than the newer ratchets, it's plenty strong enough to turn small sockets and occasionally even breaks a bolt if I'm not careful with it.

 

[snapmom]

The GM70M was made as a 1/4 dr.