... in a tight place.

Have to torque a nut to 47 ft/lbs or thereabouts which cannot be reached by a standard socket because there is only about 5/8" between the end of the bolt and an obstacle which cannot be moved, you have to come in from the side with an open end wrench or at best come over the top with the box end. I see these socket wrench adapters for a 3/8" drive which would give enough room to come in below or above the obstacle but with this offset mounting it looks like you wouldn't get a true reading since it looks like the torque you'd apply is basically just trying to round out the drive hole.

So, would something like this work or is there another tool I don't know about that could do this job. AFAIK there is no such thing as an open end torque wrench or at least Amazon doesn't show one, just these adapters. The other option is an open/box end wrench and a cheater bar with a "TFAR" (that feels about right) measurement.

This setup would come in below the obstacle, you just can't come in straight over the top of the nut given the thickness of a ratchet drive and socket combined.



Something like these would at least be better since they'd grab the nut on more than just two sides.

Those are perfectly acceptable and normal for getting a tq wrench on a nut when you cannot use a socket. Care must be taken (if you care about accurate torque) to keep the open end of the wrench at a 90 degree angle to the head of a torque wrench, If it is at 0 degrees, as in the top picture, you are increasing the moment arm of the wrench. If it is at 180 degrees, you are decreasing the moment arm (see how the open part of the wrench is forward of the pivot ie:extension?)

Sets like these (except by snap-on) is what I used when turning wrenches on aircraft... https://www.amazon.com/Stanley-Proto-J5100-Torque-Adapter/dp/B001HWEAAG

We always called those crow foot sockets. Unfortunately, I don't remember how to adjust torque for the small amount of offset.

Depending what the nut was doing....I would figure out a way to guess the approximate torque of 47ft lbs and just use an appropriate wrench, 47 ft lbs isn't that much imo.

Thanks. Those Stanley adapters are like the crow foot ones but basically act as a box end so it would apply pressure more uniformly around the nut. In addition to being tight and hard to reach, the nut isn't particularly hard. I used my largest adjustable wrench which only touches two sides to start to loosen it and the leading edges where the force was applied started to deform slightly.

I'm thinking that 47 ft/lbs is not critical but a reasonable or suggested amount of tightness, the nut and bolt aren't parts that are going to break at 50 or come loose at 45.

They will work with no problem.

The technical term for adjustable wrench is "Swedish Nut Lathe" The are very effective at making a bolt head or nut nearly perfectly round.


With either crows feet, or torque adapters, just remember to keep them at 90 degrees from the torque wrench head to keep the torque accurate.

Crowfoot set, with enough of an extension that you can hold the extension to keep it plumb, is as good as you'll get. If your techniques under normal circumstances are good (and yes, there is a technique) then you'll be within a couple percent.

I will quibble with setting angle, however. When possible, I've usually gone with 180 degrees (open toward the handle), with just an extra nudge past the click. (We have Snap On dial wrenches) Never had an issue with that method -- and by the way, we use "Cat Come" thread gloop on EVERYTHING so we can get it apart next time. Permatex works just fine as well.

I'd suggest maybe you EXPERIMENT with an accessible fastener of similar size, try all three, and carefully note the rotational stop point, then re torque to see which angle comes closest to the real value you want. Remember, the ratchet head has a zillion positions.... Might not even be 90, 180, or zero. Might be 25 from zero either way.

The axis line of the extension is only maybe one inch further away from the axis line of the center of the nut on that 3/8 drive setup looking at the picture. I’d bet you’re not even .5 ft/lb difference than when being directly over the nut.

Get the box end crowfoot adapters, so you’ll be grabbing more surface area of the nut, and put it on 47, and click it. Done.

If it's on anything critical use the crow's foot at a 90 and find a dyno to test it on.

If you use a torque wrench very much you should dyno it frequently anyway.

Evnin gang, I don't recall a formula for the offset, but if you use an extension you loose 1lb for every 12in of extension. I think, it's been to long??? You'll be fine, use the line wrench, with the box end if ya can get them but even a line wrench will work. The plain open end may slip??? Like someone already said it won't break at fifty or come loose at thirty eight. Bill out. 👣🐾👣🐾🇨🇦 It may not even be needed, I swear some engineers do chit to pizz of mechanics 🤡

in this case it was inscrutable Japanese motorcycle engineers who decided to put a muffler right next to the axle nut which you need to loosen to adjust the chain tension. I could remove the muffler but that adds a whole 'nuther level of PITA to what should be routine maintenance.

And of course it's a 19mm nut and my current set of metric wrenches only goes up to 18mm. I might try to find a single 19mm box end wrench, the longer the better and just TFAR it. What's the standard torque equivalent for "farmer tight"?

But seriously, I'll go ahead and get the right tools and then I'll have them. Thanks to all for the info, this helped a lot.

"Snug plus 1/6 turn" (one flat of the nut) will put you in the ballpark on a nut that size. BTW, 19MM and 3/4" are so close to the same size it takes a micrometer to measure the difference. I use whichever wrench or socket is handy, both ways.
Jerry

tighten till you think it might twist off.

Dad always said, "Tight is tight; once more than tight is broke."

At those levels I just tighten when it feels right.

Yeah. Just tighten the crap out of it.




Happy Trails


Bob

Oh, the Japanese have a way. Loctite. Oops, has a lock nut already.... 47 is only half farmer tight and you don't want it to be too tight binding your chit. .

The crowfoot acts like a lever, no? And levers multiply torque by trading distance. Draw yourself a schematic using levers and do the math. Guessing you'll be about right if you stal at the lower end of torque spec givrn tolerances and the crowfoot making a small lever. (but I don't knowe that.)

Now see, that is information worth remembering.

Thank you for that.

So a johnson bar multiplies torque by magic? Note I said it wouldst amount to much with a crow foot, just use some caution not to go too far and break it. Changing the anger of the wrench shifts some of the force from radial to axial and so reduces accuracy of the torque wrench. (Don't know about you but a little explanation helps me understand and remember.)

on a single nut or bolt it wont matter.. if it is a head bolt on an engine then use the same method on all the head bolts so they will all be the same...or anything that has multiple bolts...I was a auto mechanic for 30 years. (GM) trained.

I think we
re talking past one another, I'm not disagreeing with your last post.

LoadClear had it correct in the first reply...

Phil

And now we both have another post.



Happy Trails


Bob

And in case it's not perfectly clear yet...

Go to 0:13 to skip the annoying opening music.

In other news, I posted this question to a forum specifically for this motorcycle and the answer there is "we don't need no stinkin' torque wrenches" - TFAR! Or just plain "TIGHT" in capital letters.

It’s fine, 90 degrees is correct so the moment arm increase is minimized.

The truth is torque isn’t really that accurate of a way to consistently tension bolts. Use some thread locker or lube and your bolt tension goes way up for the same torque reading.

Torque is used for mechanical design all the time, for structural bolting we require other methods as torque is pretty inaccurate/inconsistent unless calibrated by testing.

Yup. Bolt stretch is key to holding tension on the fastener, generally speaking index angle gets you there. Torque is just a quick and dirty way to get you in the ballpark.