CR-MO and CR-V impact sockets revisitied

I emailed a representative form JET (the company that made my impact wrench) asking if it's true that the wrong type of socket can actually damage the hammer. Ignore the sales pitch


Thank you for your inquiry. Chrome molybdenum actually contains vanadium as one of it's
components, the addition of molybdenum is an enhancement. Chrome Molybdenum steel is used on the
best grade impact sockets as it is more malleable than chrome vanadium. This allows more precise
heat treatment (JET sockets are heat treated in 9 stages) and helps to absorb some of the impact.
Chrome vanadium is a harder steel and when used with impact tools tends to shatter when
overloaded. Chrome vanadium steel is more suited to hand tools such as wrenches, sockets, pliers,
and screwdrivers.

You will find most industrial suppliers such as Westward, Gray, Proto, etc. use chrome molybdenum.
Ultra Pro is primarily an automotive brand. JET tools are designed to be economical enough for
the automotive trades but tough enough for the heaviest duty user. Those selling CR-V impact
sockets probably will tell you something different. CR-V sockets are usually less expensive than
CR-MO. You should get reasonable performance from your CR-V impact sockets, but you would have
longer life with CR-MO.

I have not heard of any type of socket putting undue stress on the impact wrench. Most stress on
the wrench will be the result of over-tightening of fasteners. Whether the socket is CR-V or
CR-MO, the socket should fail before the wrench is damaged. In the case of a Magnesium series
impact wrench, I would recommend using the best quality sockets you can afford. It should be noted
there are several grades of CR-MO steel available, and JET uses the very best for it's impact
sockets.

Regards

Jeff Segal
Product Manager

I was right?? lol

Like I said, I havent had 1st hand experience with damaging the hammer, but I have heard the rumor so I will continue to use only impacts until its actually disproved... know what i mean?

Thanks for posting this.... and yup, typical sales pitch lol

Jim

Weeellll....not entirely right
CR-V are harder, yes, but they are MORE likely to break because they can shatter. And supposedly they don't stress the hammer. Which makes sense since the hammers are way harder than any socket or bolt you would use.... otherwise they would wear out real fast right?

In the guys defense, they make some pretty good tools for a good price. And most of it isn't offshore AFAIK.

Huh! Interesting. Where do you find JET impact sockets? I know that Gray Pneumatic is Cr-Mo also. I think Sunex is too... but all mine are Cr-V. But, hell, by the time I wear mine out, I'll have definitely gotten my moneys worth and will have an excuse to buy more tools!

eschoendorff said:

Huh! Interesting. Where do you find JET impact sockets?

Click to expand...

http://www.jetequipment.com/en/category.php?pageno=1&pcid=26&catid=5

Jet Equipment is a Canadian brand, with tools mostly made in Taiwan. I see them sold in auto parts stores and industrial supply dealers, at much cheaper prices than Proto, et al. I don't have any so can't comment on quality, but I've been to small garages with several mechanics using them as their primary tool brand. I've only seen them sold in Canada, probably because of the name. Jet Equipment is not Jet Tools USA which makes top quality wood working equipment.

eschoendorff eschoendorff is offline
Director of Bands

Last Activity: 06-22-2009 09:59 AM

In my personal experience CR-V sockets over time actually round out the anvil on an impact gun, I have seen this with my boss' dewalt cordless impact after years of use without ever putting an actual impact socket on it, and also with an IR thunder gun that he also used chrome sockets on. I never saw the hammers but the anvil itself was damaged from the long time use of chrome sockets.

4x4gearhead said:

In my personal experience CR-V sockets over time actually round out the anvil on an impact gun, I have seen this with my boss' dewalt cordless impact after years of use without ever putting an actual impact socket on it, and also with an IR thunder gun that he also used chrome sockets on. I never saw the hammers but the anvil itself was damaged from the long time use of chrome sockets.

Click to expand...

Did you mean CR-V impact sockets or thinner chrome plated ones?

MAD said:

eschoendorff eschoendorff is offline
Director of Bands

Last Activity: 06-22-2009 09:59 AM

Click to expand...

Sheesh. I guess I should look at the date of posts more carefully

I did a search for Gray tools and this thread came up. It taught me something I didn't know though.

Very interesting I learned something new todaythat you can have different grades of chrome moly steel)! I always thought it was just one grade called Cr-Mo.

Thanks for sharing this information.

Just bumped into this thread by accident while looking for something else... so sorry for resurrecting an old horse...

When it comes to impact sockets, CrMo sockets are more malleable than CrV and their lifespan is shorter. They are cheaper to produce, molybdenum is about half the price of vanadium. The composition was introduced by the Asian forges. On the test bench they compare very favourably to CrV but as mentioned, don't last as long due to the plasticity. The plasticity has nothing to do with safety by the way. An appropriately rated socket for the job is the key...

I sell both types. I sell more CrMo because they wear out. FWIW, it is not so much a question of composition but type of use, application and match with an appropriate impact hammer and torque setting. The suggestion that CrV wear out an impact wrench quicker is a myth. It is all about energy transfer.

CrV sockets will be better for the fastener and more effective - one of the points of the impact is to break the molecular bond between the fastener and the CrV will do it better as less energy is lost in the socket.

In the end, all impact sockets will wear - you may find the CrV, unless used in a manufacturing or constant use application, will last a lifetime. The CrMo won't.

Congrats you get the reward for the day of bringing back the oldest thread. Just giving you a hard time.

I do have a question......you said that you sell more CrMo because they wear out. Are the sockets you sell lifetime warranty and I assume wearing a socket out is not covered under said warranty? Thanks