0

Often in install or specification manuals you will see something like:

Tighten X turns past finger tight

Example install instruction of powers sleeve anchor

This has always bothered me as it seems ambiguous. I've always taken this to mean a "turn of the hand". Depending on flexibility, seems like this would be a little less than 180 degrees?

However, it could also easily be interpreted as a full rotation (360 degrees)....

I'm honestly surprised that the lawyers allow this in technical specs like the example above (why not just give torque?).

Improve this question
9
  • good follow up question: What is the torque of "hand-tight"?
    – NSjonas
    May 8 '19 at 17:44
  • A: en.wiktionary.org/wiki/finger_tight
    – NSjonas
    May 8 '19 at 17:51
  • Well those instructions are rather vague...
    – Lee Sam
    May 8 '19 at 17:54
  • surprisingly so for something that could potentially be supporting 1000s of lb. In the chart above they have Max Bolt Torque, Tmax (ft-lbs)... however, it's MAX, so I'm not sure if that's the ideal installation torque or the point of failure
    – NSjonas
    May 8 '19 at 17:56
  • I always read instructions like that then allow an adjustment for the materials I am working with...
    – Solar Mike
    May 8 '19 at 18:04
8

A turn is 360 degrees.

You are expected to put a mark on the thing you are turning, so you can observe its rotation.

They have no way of knowing which kind of wrench you are using, what your wrenching style is, or what amount of swing angle local clearances will afford you.

"Hand/finger tight" is the point at which all free lash/slop has been removed, further turning actually loads the fastener, and torque becomes measurable.

In a fastener in tension, how much strain a "turn" amounts to depends an awful lot on the length of the fastener subject to tension. Getting from "strain" to "torque" then involves a lot of other stuff.

In the case of the anchor in your link, it has little to do with tension. It is intentionally deforming the anchor to make it engage the hole you just drilled.

Improve this answer
7
  • well... In that case I've been doing this correctly for a long time (luckily not for this particular use case). Wish they had just said 1080-1440 degrees...
    – NSjonas
    May 8 '19 at 18:01
  • 1
    When I tighten something hand tight, my friends have to find a spanner to get it undone... Mind you, serious tech to "put a mark on the thing you are turning" ...
    – Solar Mike
    May 8 '19 at 18:02
  • also, I assume then that the Max Bolt Torque, Tmax (ft-lbs) in the above spec, would indicate the rated torque of the bolt (not to be exceeded) and has nothing to do with installation torque (except that you should not exceed it when installing)
    – NSjonas
    May 8 '19 at 18:05
  • @NSjonas, you can't expect the average person to have any idea what 1440 degrees is or even how to figure that out.
    – JPhi1618
    May 8 '19 at 19:50
  • @JPhi1618 Really...because I passed the 3rd grade.
    – Lee Sam
    May 8 '19 at 19:57
1

Finger tight will engage the wedge against the sleeve. You need 3-4 full 360 degree turns to lift the wedge 3-4 full threads and apply the intended lateral force against the sides of the drilled hole.

Many plumbing fittings with rubber gaskets or cone washers will say something like "1/4 turn past finger tight". It means the same thing.

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.