DIY Home Improvement, Remodeling & Repair Forum

DIY Home Improvement, Remodeling & Repair Forum (
-   Tools (
-   -   Any wrench = a torque wrench (

Wuzzat? 12-05-2012 11:38 AM

Any wrench = a torque wrench
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 12-05-2012 12:42 PM

1 Attachment(s)
like this?

oldognewtrick 12-05-2012 05:16 PM

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

Wuzzat? 12-06-2012 01:26 PM


Originally Posted by oldog/newtrick (Post 80798)
Why don't you. . .

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

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

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 12-06-2012 02:15 PM

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? 12-07-2012 10:08 AM

Good idea.

All times are GMT -6. The time now is 08:48 AM.