Torque Wrench Question

[Top_Ramen]

Aren't these considered more reliable than the click types?

[JayG]

Originally Posted by arthrodriver

Hmmm, With regard to drain plugs...I never really thought about it before, but a steel drain plug fitting a steel pan is ?3/4" or ?14mm, or ?9/16" hex head? Anyway, the shank is acutally quite large. But I would not look on a torque table for a setting as I think it might overkill. If most plugs take crush washers it would seem the "first"application would flatten the copper washer and subsequent ones would apply more torque to mate the work hardened washer to the pan. Perhaps (my bad) I do keep using the same flattened washer so the snug torque is higher than any manual callout which may require "always replace." I have had more problem with others' overtightened sump plugs than any of my moderately tightened ones. The motor mounts inhibit vibration loosening. I guess stay with any callout you find in a manual, otherwise experience and judgement. I have found the H Frt "fish tackle box" of copper washers to work well if they fit as drain washers and also brake line/caliper washers.

Uh, the oil drain washer is a buck or less, you reuse it?

[arthrodriver]

To prove the 19 ft lbs try it with a new copper washer. Then undo it and see if the washer has deformed itself (expected). The next try with the same washer will take a little more. I don't think 19 foot lbs is excessive and may even be a little light. This situation is somewhat like a spark plug torque. These typically take 15-20 ft lbs in an aluminum head, and also rely upon a crush washer. IMO

Jay, Please know I am an old seasoned home hobbyist and some things I do may not be to the letter. For instance, yes, I confess to reusing the same sump plug gasket on my cars for years. I use the drip test. If no drip it's ok. When first starting out it is probably good to heed the warnings in factory manuals about "discard and use only new parts" until you get some wrench time. As noted, however, you will work harden the copper washer each time you reuse it and chase slightly the torque you sense you need (or measure). Without too much cynicism some of guidelines are really ridiculous IMO. Case in point. A tapered steel diff or trans plug (like a pipe thread) will go on indefinitely. Just keep everything clean and do use a torque wrench on these. The friendly Mercedes dealer wants $7 a pop for such a rugged, reusuable plug.

[jakeru]

I have both beam and "clicker" type torque wrenches (several clickers in 1/2"-3/8" drive, and one beam in 1/2" drive). I tend to use the beam on any application where torque accuracy is extremely important. As stated here, the clickers have moving parts which can fail or get out of whack and this affects accuracy. (Good practice to store clicker wrench laying flat on the back side, with the torque setting untwisted to relieve spring tension).

I've been able to make the torque setting scale of the beam wrench readable in some "off viewing angle" applications by marking with a sharpie a reference line on the back side. For speed, the clicker the wrench can be desirable. For example, quick tire change.

Another way to speed things up, of course, is to not use a torque wrench. Be mindful that lubricants on the threads can dramatically affect things. If you are not using a torque wrench, you will be more likely to notice when plastic deformation starts. (Which is for many not frequently replaced fasteners, where the torque setting is optimized anyway).

[arthrodriver]

Perhaps we should demystify "deformation" and the effects of lubrication on torque for those who are new to the game. Fasteners are supposed to stretch in order to exert holding power. The tensile strength and diameter of the fastener play into the proper torque. Fasteners which do not have girlie configuration , know as "waisted" can be torqued to the universal tables, SAE and metric. The TTY fasters (waisted, not wasted) typically take torque plus additional rotation. Lubrication of fasteners is tricky. Spark plugs, for instance, in galvanize are already lubricated via the coating in dry state. Many still put a thin "dry"oil film on plugs (I wipe the threads after a tiny drop of oil). Lubrication can cause excess torque to be applied. There are guides to how much apparent torque should be reduced when using a specific lubricant. I hope this is well received and does not irritate experienced folk. Just tell me to STFU if so.