Those look like nice sockets.. Personally I would only use them if regular ones wont work for the location.
What's a good cordless 3/8" impact that isn't real expensive?
there really arent many. They make them but they arent any more powerful than 1/4" drive
Dewalt has a 150 lb-ft model for example in 3/8" drive
I'd go 1/2" drive some are more compact than others.
You might want both a high power model and a smaller compact model depending on your work.
Do you normally use extensions with universal impact sockets or do you often use them without extensions?
While a short impact rated extension is ok.. they can rob some of the impact force.
Disclaimer: I dont do this for a living. You will probably want to hear from people who do this everyday.
I used to work in a manufacturing facility that went though tons of Milwaukee 18v 3/8 and 1/4 hex impact drivers. At they time they were running two 10 hour shifts, but they often turned into 11.5 hour shifts, so the guns were used round the clock by people who didnt own them.
The advantage of the 3/8" 18V class li-ion impact over a equivalent 1/4 drive one is:
1) You dont break the 1/4 hex -> 3/8 or 1/2 drive adapters. I bought a 1/4 drive for my personal use because its what was in stock but I keep two of each adapter type on hand because even the "impact rated" ones shatter eventually.
2)After a lot of use, the 1/4 hex drive on the gun itself has a tendency to explode, rendering the whole thing garbage. I saw half a dozen or so guns experience this failure, just in the areas that I worked in, so it wasnt uncommon. I never saw any of the 3/8 drive guns experience a similar failure. They ran until they were totally clapped out.
They are basically the same gun, but the 3/8 drive one is way more sturdy for long term or hard use.
They have plenty of torque. At full go, you can easily snap 1/4 Grade 8 bolts, and ruin Grade 8 5/16 or 3/8 bolts, and mushroom flat washers. They are just about perfect for 7/16 and 1/2 bolts.
Now that Im working as a tech repairing the same sort of machinery I used to assemble, I love my Milwaukee impact. Buzz a dozen bolts out of something quickly, with no airline to drag around and get hung up on everything. The only thing is I dislike going though the expensive 3/8 and 1/2 drive adapters, and I know the 1/4 hex on the gun is gonna explode someday, but Ill buy another, and just wait the couple days to get a proper 3/8 drive one.