Metric Sockets - double black band

[aeromechanix]

Greetings...I am new to the forum.

I am interested in learning more about the Snap-on metric socket series that incorporated a unique double black band. I purchased my first set of these sockets off the truck in 1972 while working at a Chevy dealership. At the time, very few mechanics in the shop owned metric tools, but I had an interest in British cars which incorporated SAE, Whitworth and metric fasteners and thus began collecting all three standards.

When was this series introduced and when was it discontinued? Is the banding composed of black oxide or some other type of coating? How was the banding applied in manufacturing? Before or after chrome plating? Thank you for sharing your knowledge.

[J.A.F.E.]

I can not answer run dates but they seem to be early 70's to early 80's. The black bands are black oxide so grinding the plating off and adding the BO finish had to be expensive. All the metric sockets of the era were like that. I bought a set of 1/4 drive 6 point shallow and 3/8 drive 6 point shallow black band new off the truck mid 70's and I still use them. They do turn up in the swaps every now and again but usually just single odd sockets or small groups. I like the design quite a bit.

[aeromechanix]

Thank you for responding J.A.F.E.

I suspected that the manufacturing process must be relatively complex to add the black oxide bands. Perhaps that is why they were discontinued in later years. Like yourself, I find them distrinctive and continue to use my 3/8" and 1/2" sets on a routine basis.

I wish I had purchased several 10mm and 12mm - 14mm spare sockets many years ago. I use these sizes frequently and they have become worn and loose fitting. Do you have any thoughts on how I might "refresh" the black oxide on the bands? The coating has worn off on many of my more heavily used sockets.

On a related note, is there anyone on this forum that was employeed at the Kenosha plant back in the 70's. If so, I would be very interested to learn more technical details of how these sockets were manufactured.

Thanks again for sharing your knowledge.

[J.A.F.E.]

There are some cold BO methods I have read about but have no personal experience. Most of the ones that turn up around here the BO is worn or rusty.

I suspect cost was the reason they were discontinued but I really like the distinctive look.

[Ian UK]

Great bit of info that. I have had one double band metric socket in my box for ages and often wondered where its usual metrice knurling had gone