Crowsfoot adapters for torque wrench

It seems like I need something like a crowsfoot adapter to be able to torque the aileron bellcrank nuts which sit behind a flange. AN4 nuts are 5/16" nuts which is not something in the common sets available around here.

Where did you pick yours up (for AN3 and AN4) or are there other solutions to torque things like the bellcranks?

Thanks.

I took a 5/16 open wrench, heated it and bent it 90*. Not exactly torqued to spec, but I'm sure it's close.

I bought a set of Craftsman crowsfeet from Sears.

Yep might as well bite the bullet and buy a set from Sears.

Sorry for the basic question, let me check sears. All the other places I checked have sets that start with 3/8" which is too large of course for the AN3/4 size.

Thanks

Even with a crowfoot that is a difficult place to get the wrench to. I ended up taping the end of the correct box wrench inside the jaws of the largest set crowfoot to make it a long crowfoot - then torquing that assembly. Weird and I have no pic but it works. There is a weird bending arm you have to avoid putting your force vector on the wrong direction to get it right.

I saw in Home Depot a few weeks ago a flexible socket shaft. The torque on a flex shaft is the same as a straight shaft and if I was doing it again I would probably use the flex shaft to make it easier and I'm sure it would work fine with either a crowfoot or a straight socket. Using that it would be socket->flex shaft->longer extension->wrench outside the hole. I've seen long debates about whether torque readings on a flex shaft are valid. But worry not, the torque is as read and the nut is giving everything back the wrench/socket gives it - or it would move. Now if you torque and change the amount of flex, then you bring inaccuracy. I think you minimize this by holding the rigid extension in fixed place while turning the torque wrench and by measuring the running torque in the same configuration.

JDBoston said:

Sorry for the basic question, let me check sears. All the other places I checked have sets that start with 3/8" which is too large of course for the AN3/4 size.

Thanks

Click to expand...

Huh? A 3/8" inch wrench/socket is the size for an AN3 (3/16") bolt / AN365-1032 nut. A 7/16" wrench/socket is the size for an AN4 (1/4") bolt/ AN365-428 nut.

Harbor Freight

Before you drop a ton of money on a set from Craftsman that you'll only use a couple of times, check out the cheap but adequate set from Harbor Freight.
The saved money will pay for some Avgas for you.

Buy a set of crowsfoot wrenches

Third vote for a set of Craftsman crowsfoot wrenches or similar. They will also come in handy to torque the flair fittings on fuel and brake lines as well.

Just remember when using a crowsfoot on the end of a torque wrench, it is necessary to compensate for the extra length (or not) depending on the position of the crowsfoot relative to the torque wrench. I have posted how to make the calculations at the following link:

http://www.dogaviation.com/2014/01/calculating-torque-values-for-fuel.html



Happy building,

Auburntsts said:

Huh? A 3/8" inch wrench/socket is the size for an AN3 (3/16") bolt / AN365-1032 nut. A 7/16" wrench/socket is the size for an AN4 (1/4") bolt/ AN365-428 nut.

Click to expand...

More specifically ms21042-4 which is what is called for (not an4 as I mentioned) is 5/16" for the nut.

This is pretty neat. Haven't seen it before, just stumbled on it:

https://store.snapon.com/Adjustable-inches-mm-Wrench-Crowfoot-Adjustable-3-8-drive-P644784.aspx

crows foot wrenches

Just bought a set (3/8" drive)from Lowes for $40. Good compromise between Harbor Freight and Sears (especially for the amount they will get used.)
Rick
#40956
Southampton, Ont

torque adapters

Torque adapters are another solution that I've found really useful in a lot of situations. They're basically 2" long versions of the crows foot with a fairly thin profile. Available from Snap-on, Matco, and a few other sources (search on ebay, etc.). Here's a link to the snap-on set

Very useful info

John-G said:

Third vote for a set of Craftsman crowsfoot wrenches or similar. They will also come in handy to torque the flair fittings on fuel and brake lines as well.

Just remember when using a crowsfoot on the end of a torque wrench, it is necessary to compensate for the extra length (or not) depending on the position of the crowsfoot relative to the torque wrench. I have posted how to make the calculations at the following link:

http://www.dogaviation.com/2014/01/calculating-torque-values-for-fuel.html



Happy building,

Click to expand...

That is a great link.
Thanks John

To bring this thread full circle at least in my case. First: Thanks everyone for the great ideas and links they will be invaluable when it comes time to use the crows foot.

After thinking about the location a bit more and getting a great pointer from someone building a 14 (thanks "E"!) it turns out that you can 'shove' the torque wrench behind the skin which avoids the need for the crows foot. I had not thought of that because it is a tight fit and was not clear right away at least to me.