"Softness" of Impact Sockets

[The Critic]

Over the years, there have been several posts about Snap-On's impact sockets having poor wear characteristics due to the "softness" of the metal used.

Is there any advantage to using an unusually soft blend of Cr-Mo for impact sockets?

 

[dnschmidt]

Cr-Mo or Cr-V has little to do with it. Heat treatment is what determines the eventual hardness of a socket. This is always a balancing act. Too hard and they shatter, too soft and the drive ends deform under heavy use. Impact sockets typically are "softer" than chrome sockets due to the beating they take from the impact. I have no information as to whether Snap-On's impact sockets are any harder or softer than other major brands.

 

[Zewnten]

I have one set of SO impacts and yes they're soft, my one set of williams is the same. My proto's have held up great, barely show any wear. I actually have issues with the SO's wearing so much, it seems to be leaving bigger marks on hardware as they wear.

 

[ChefRex]

When they wear I hand them back, simple.

 

[Marlin]

The ASME/ANSI hardness spec for impact sockets has a max of 55 HRC, that's far from soft. The hardness spec for non-impact sockets is almost identical. So the whole hard vs. soft difference between impacts and chrome is a myth.

 

[bonneyman]

I always thought impacts were softer because they were tougher (being less brittle) compared to hand sockets that were chrome plated and harder (to last longer in use - you know, picky customers). It's why I was told don't use chrome sockets with impacts - they tend to break.

 

[WWheeler]

... It's why I was told don't use chrome sockets with impacts - they tend to break.

I've avoided ever using chrome sockets on impacts after twice myself breaking the hog ring on the impact's anvil when it wouldn't let go. Have seen several coworkers do the exact same and also seen them break the tip off flat head screwdrivers attempting to get the socket off. The hog ring can be VERY unforgiving letting go of a hand socket's four detent divots.

Impact sockets typically don't have any such detent divots, instead usually just 4 flat insides and a single hole for a detent pin style anvil, which can still make for getting the socket off of a hog-ring impact a little tough just by hand but nothing like a chrome socket's 4 divots.

 

[AdAstra]

The ASME/ANSI hardness spec for impact sockets has a max of 55 HRC, that's far from soft. The hardness spec for non-impact sockets is almost identical. So the whole hard vs. soft difference between impacts and chrome is a myth.

It's not quite that simple though...

ASME B107.100 calls for hardness in the range of 38 to 55 HRC for impact sockets, and 38 to 56 for hand sockets (of the most common drive sizes below 1/2" anyway)...

Buuut, ISO 1711 calls for 40 to 48 HRC for impact sockets, and a 39 HRC minimum and no specified maximum for hand sockets of the same common sizes.

The ASME spec covers a huge range of hardnesses, beyond just that which would be expected for manufacturing variation... it allows for different manufacturers to apply various design philosophies and use various materials that might have different toughness/fatigue properties vs hardness. So there's definitely room for some impacts to be softer than some hand sockets and all still meet the specs.

 

[Wrench97]

I always thought impacts were softer because they were tougher (being less brittle) compared to hand sockets that were chrome plated and harder (to last longer in use - you know, picky customers). It's why I was told don't use chrome sockets with impacts - they tend to break.

Softer so they do not crack and break apart while using on impact guns, they also do less wear to anvil on the impact gun.

 

[demarpaint]

I consider them wear items. My go to are HF, [flame suit on] which have been decent, when they're beaten up or appear to be worn out I take them back and get a replacement.

 

[Marlin]

It's not quite that simple though...

ASME B107.100 calls for hardness in the range of 38 to 55 HRC for impact sockets, and 38 to 56 for hand sockets (of the most common drive sizes below 1/2" anyway)...

Buuut, ISO 1711 calls for 40 to 48 HRC for impact sockets, and a 39 HRC minimum and no specified maximum for hand sockets of the same common sizes.

The ASME spec covers a huge range of hardnesses, beyond just that which would be expected for manufacturing variation... it allows for different manufacturers to apply various design philosophies and use various materials that might have different toughness/fatigue properties vs hardness. So there's definitely room for some impacts to be softer than some hand sockets and all still meet the specs.

You are correct and most impact sockets including SO are right at the top end of the ISO spec at 47-48 while chrome are in the low to mid 50s, so softer is accurate. It's just odd from an engineering perspective to hear steel at 48 HRC referred to as soft.

 

[2ndGearRubber]

The ASME/ANSI hardness spec for impact sockets has a max of 55 HRC, that's far from soft. The hardness spec for non-impact sockets is almost identical. So the whole hard vs. soft difference between impacts and chrome is a myth.

LOL I have a ton of wallowed out impacts. Chrome will typically crack before they get wildly oversized. Impacts can become unusable due to poor fit, from wear.

 

[dnschmidt]

I guess all of this can be summed up as a safety/liability issue. Nobody probably got hurt by a wallowed out drive end (Unless the dumb ******* was too lazy/cheap to replace a wallowed out impact socket and it flew off the impact) but you could certainly be hurt by having a socket shatter into shrapnel. THIS IS JUST MY GUESS. A post by Chris Pettit of Astro Pneumatic described one of his first days at work at Astro when he went to his boss Steve Fisher to report that some impact sockets that Astro were selling were too hard and were subject to shattering. Steve pulled all of these sockets immediately. Chris stated that this is how he knew he was now working at the right place.

 

[bonneyman]

Softer so they do not crack and break apart while using on impact guns, they also do less wear to anvil on the impact gun.

Oh, so they save wear on the tool. Never thought of that angle - I only considered the broached ends.

Learn something new just about every day!

 

[CGarage]

I guess all of this can be summed up as a safety/liability issue. Nobody probably got hurt by a wallowed out drive end (Unless the dumb ******* was too lazy/cheap to replace a wallowed out impact socket and it flew off the impact) but you could certainly be hurt by having a socket shatter into shrapnel. THIS IS JUST MY GUESS. A post by Chris Pettit of Astro Pneumatic described one of his first days at work at Astro when he went to his boss Steve Fisher to report that some impact sockets that Astro were selling were too hard and were subject to shattering. Steve pulled all of these sockets immediately. Chris stated that this is how he knew he was now working at the right place.

Awesome. Respect to Astro.

 

[Marlin]

You are correct and most impact sockets including SO are right at the top end of the ISO spec at 47-48 while chrome are in the low to mid 50s, so softer is accurate. It's just odd from an engineering perspective to hear steel at 48 HRC referred to as soft.

Actually, I was incorrect on the hardness of the chrome sockets. I just checked 3 well known brands and they are all in the 46 to 48 HRC range, pretty much identical in hardness to the impacts.

 

[finn]

LOL I have a ton of wallowed out impacts. Chrome will typically crack before they get wildly oversized. Impacts can become unusable due to poor fit, from wear.

Chrome sockets likely crack because the crack initiated in the chrome layer plated on top of the base metal. It then propagates into the base metal. Once the crack extends into the base metal, the cross section of the socket reduces rapidly and the socket shatters in short order.

Highly stressed components like chrome plated piston rings (remember them?) and wave washers in certain fuel injection equipment use what is called “high crack content chrome”, which features a plated surface with multiple tiny micro cracks instead of a lower number of larger cracks. The micro cracks self relieve without propagating into the base metal. Before you ask, all plating has cracks. Big ones propagate under stress, small ones resist propagation.

 

[Mr_B]

I guess all of this can be summed up as a safety/liability issue. Nobody probably got hurt by a wallowed out drive end (Unless the dumb ******* was too lazy/cheap to replace a wallowed out impact socket and it flew off the impact) but you could certainly be hurt by having a socket shatter into shrapnel. THIS IS JUST MY GUESS. A post by Chris Pettit of Astro Pneumatic described one of his first days at work at Astro when he went to his boss Steve Fisher to report that some impact sockets that Astro were selling were too hard and were subject to shattering. Steve pulled all of these sockets immediately. Chris stated that this is how he knew he was now working at the right place.

This is exactly what my MAC dealer stated regarding more big brand current manufacture impacts wallowing out fast.
2 of the criteria's possibly resulting in softer impact socket manufacture is liability risk in modern world of legal action and safety and increased performance of impacting tools, I guess it better the sockets deform rather than the anvil .
My MAC sockets got returned and all my newer impact sockets up to 1/2" drive and 48mm are non usa made, mostly crv, pretty cheap with good usable design & hold up well enough to daily workshop abuse and have acceptable working life with no catastrophic failures to date .

 

[CGarage]

This is exactly what my MAC dealer stated regarding more big brand current manufacture impacts wallowing out fast.
2 of the criteria's possibly resulting in softer impact socket manufacture is liability risk in modern world of legal action and safety and increased performance of impacting tools, I guess it better the sockets deform rather than the anvil .
My MAC sockets got returned and all my newer impact sockets up to 1/2" drive and 48mm are non usa made, mostly crv, pretty cheap with good usable design & hold up well enough to daily workshop abuse and have acceptable working life with no catastrophic failures to date .

Heard the same thing from a mate in UK.
He recommended Halfords and Laser (both made in Taiwan) impacts and says he is far happier with these compared to big tool truck brands…..

 

[Mr_B]

Heard the same thing from a mate in UK.
He recommended Halfords and Laser (both made in Taiwan) impacts and says he is far happier with these compared to big tool truck brands…..

Laser use to sell Taiwan made crv sockets branded Japan Style that very good quality/design and great value for prices could find sets online .
Those sockets done great for me, nicer design than most of the big common impact brands & lasting way better than moderm MAC set and some snapon I returned .
I do think people in profesional use with modern high perform air and battery tools plus the abuse scenarios of torch hammer and press use impacts can get you got realise they got a limited working life .

 

[CGarage]

I think the Laser stuff is still all made in Taiwan.

 

[Mr_B]

I think the Laser stuff is still all made in Taiwan.

Most of it might be, hard tell with UK retailers/brands as no legal obligation on specifying COO, they seem procure various sets from different manufacturers looking at the range they offer .
Sets I got via a independent tool truck was Japan Style branded on sockets, newer stock appears a little different .