Wuzzat?

I needed to adjust a timing belt tensioner to 33 lb-ft and there was no way my torque wrench would fit into the space available so I got two stiff springs from HD.

Filling a 5 gal bucket with water (2 lbs for the bucket + [5 gals x 8.3 lbs/gal]) = 43.5 lbs and stretched the spring 1.09" from its rest length so the spring constant K = 40 lbs/inch.

The spring was anchored on the wrench handle 7" from the center of the 3/8" drive stub so 33 lb-ft would need a right angle force of 33x12/7 = 57 lbs.

As it turned out the posted max force on the spring was 61 lbs (no max length given) so it was close. I should have done this calc. before I bought the thing but it worked out.
And with two springs in a package for $4 I could in principle go to 66 lb-ft or so.

Next is to check the K for my weaker springs from the basement.

nealtw

like this?

oldognewtrick

Why don't you just go to the local parts store, most have tools they will rent or loan out.

Wuzzat?

It turns out that this wrench must have magical properties, because after I used it the car started and ran more smoothly than before.

Man, am I glad I can finally move this car out of the driveway!

I figure one hour round trip to the rental place, twice, so I calculate, "Can I make the part/tool/fixture in less time?"
This one was close.

nealtw

When I was young and couldn't afford such luxury as a torque wrench, I and all my back yard machanic friends had a fish scale in the tool box. If you notice a set of combination wrenches all have a different length. If you use one of these and give it a reasonable pull, you will be really close on the required torque for that size of bolt. The reason they give you a required torque is because an impact wrench can dammage aluminium parts you are bolting into.

Wuzzat?

Good idea.
http://www.nextag.com/scales-fishing/compare-html