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1/4 or 3/8-inch torque wrench?

rv12iS-builder

Well Known Member
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I want to buy a 20–150 inch-pound CDI torque wrench. They are available with either a 1/4-inch drive or a 3/8-inch drive. Is one drive size better than the other for working on aircraft and torquing AN4 bolts? I own sockets in both sizes, so that's not an issue, and both wrenches are the same length and diameter.

Thanks!
 
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If you own sockets in both sizes I would say it doesn't matter. I have 1/4" CDI that I like and it is sometimes a pain to go back and forth between the 1/4" and 3/8" wrench set I have.
 
Both eventually

The 1/4? 20-150 in lb will do the job for about 90% of the build. However, at some point you will need a Ft Lb wrench for a few items. At which point a 3/8 ft lb torque wrench is a good option.

Adapters for 1/4 to 3/8 and 3/8 to 1/4 come in very handy.

A couple of things that need greater than 150 in lb are spark plugs and exhaust manifold nuts.
 
I use a little Park Tools beam style 1/4" drive for AN3 and AN4. It's simple, easy to use, and compact enough to fin most places. And not terribly expensive.
 
I use a little Park Tools beam style 1/4" drive for AN3 and AN4. It's simple, easy to use, and compact enough to fin most places. And not terribly expensive.

I have that same wrench and use it for AN-3 bolts. Since it maxes out at 60 inch pounds, I've never used it for AN4s.
 
I use a little Park Tools beam style 1/4" drive for AN3 and AN4. It's simple, easy to use, and compact enough to fin most places. And not terribly expensive.

I don't think those beam wrenches are still available.
 
Also recommend the 1/4" beam style. In addition to its normal function, it allows you to measure running torque, which you need to add to the specified torque to get the torque you use for installation.

Dave
 
Thanks, Marc, but I'm not sure a typical torque wrench from Harbor Freight is up to aircraft standards. That said, Harbor Freight has a high-end line of torque wrenches called Icon. I thought this video was interesting. It compares an Icon torque wrench to a similar wrench from Snap-On.

https://www.harborfreight.com/38-in...nch-64065.html?_br_psugg_q=icon+torque+wrench

I understand, no problem. I bought the HF wrench as I needed to torque something while I was waiting for my ordered Snap-On to arrive. I feel it's just as good, just not quite as easy to use.

-Marc
 
+1 for both

Mark - u been building long enough that u should have both. ;)
No more delays. Get that done & flying.

@ OSH 2019 also
 
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