Torque wrenches:Inch pounds or foot pounds

[3rdtimesthecharm]

I need to get a torque wrench for working on antique outboards.I hear they read in inch pounds or foot pounds and there is a formula for converting one to the other.Which is more common,inch or foot pounds?

 

[64osby]

Re: Torque wrenches:Inch pounds or foot pounds

10 ft lbs * 12 = 120 in lbs

You can work with either wrench, just make sure you get one that goes up to 50 ft lbs or 600 in lbs, 50's OMC flywheels torque spec is 45 ft lbs or 540 in lbs.

 

[Frank Acampora]

Re: Torque wrenches:Inch pounds or foot pounds

Neither is more common that the other. To convert, you simply divide by 12 (12 inches in a foot) to go from inch pounds to foot pounds.

It is handy to have both because small bolts like 1/4 X 20 take a max of 70 INCH pounds. That is only 5.8 foot pounds. Neither wrench is more or less accurate, but because of human inaccuracies the inch pound scale is more precise and better to use on small bolts.

 

[tpenfield]

Re: Torque wrenches:Inch pounds or foot pounds

I need to get a torque wrench for working on antique outboards.I hear they read in inch pounds or foot pounds and there is a formula for converting one to the other.Which is more common,inch or foot pounds?

I don't know why they bother to have inch-pounds on some of the bigger torque wrenches . . . but since there are 12 inches in a foot . . . your inch-pounds will be 12 times greater than your foot-pounds.

Of course there is always the 'newton-meters' that the torque wrenches also have for the metric stuff.

 

[3rdtimesthecharm]

Re: Torque wrenches:Inch pounds or foot pounds

Thank you for your replies, Gentlemen.

 

[F_R]

Re: Torque wrenches:Inch pounds or foot pounds

Any OMC 40hp or larger requires 100 foot pounts of torque or more on the flywheel nut. That totally eliminates any inch pound wrench for that use. On the other hand, small screws require torques in the 60 inch pound range. 60-80 is standard for a 1/4" screw. That's only 1-1/2 foot pounds leeway. A real high quality 150 foot pound torque wrench with factory fresh calibration may have an accuracy of a few foot pounds-----WAY too inacurate for that 1/4" screw. A typical spark plug torque is 12-12.5 foot pounds---still not available within the accuracy of a 150 pound torque wrench. Ever wonder why there are so many stripped spark plug holes?

Bottom line: You need two wrenches, at least. I have three.

 

[Sea Rider]

Re: Torque wrenches:Inch pounds or foot pounds

Personally preffer to use Newton Meters wrenches on Jap engines...

Happy Boating

 

[Chris1956]

Re: Torque wrenches:Inch pounds or foot pounds

Gee, I use an old crappy foot-pounds torque wrench (1/2" drive) for the bog bolts/nuts. I have a 3/8" drive inch pounds wrench for the small stuff.

 

[toolman99]

Re: Torque wrenches:Inch pounds or foot pounds

Ummm it doesn`t matter what the wrench is labeled, you convert the spec and torque away ie 1 ft/lb = 12 in/lb etc. you can find converters online for the tricky conversions to newton /mtrs etc

 

[SolingSailor]

Re: Torque wrenches:Inch pounds or foot pounds

Aside from the conversion between feet and inches, if the required torque is within its range, the inch-pound wrench will allow greater precision.

 

[cyclops2]

Re: Torque wrenches:Inch pounds or foot pounds

Later in life you develope calibrated arms. My 74 year old arms are very accurate.
So are my sparkplug & point gap setting eyeballs.
Bolt tightening patterns & locktite do a fantastic job.

 

[BillP]

Re: Torque wrenches:Inch pounds or foot pounds

Any OMC 40hp or larger requires 100 foot pounts of torque or more on the flywheel nut. That totally eliminates any inch pound wrench for that use. On the other hand, small screws require torques in the 60 inch pound range. 60-80 is standard for a 1/4" screw. That's only 1-1/2 foot pounds leeway. A real high quality 150 foot pound torque wrench with factory fresh calibration may have an accuracy of a few foot pounds-----WAY too inacurate for that 1/4" screw. A typical spark plug torque is 12-12.5 foot pounds---still not available within the accuracy of a 150 pound torque wrench. Ever wonder why there are so many stripped spark plug holes?

Bottom line: You need two wrenches, at least. I have three.

+1 on that. If I was buying only one it would be a inch lbs because small bolts in aluminum are way easy to strip. Big bolts have more margin of error.

Whatever you decide on beware that cheap clicker torque wrenches can be tricky. A friend of mine rebuilt his airplane engine with a craxxxman clicker and ended up landing on the hiway due to engine failure from loose bolts. Later on it was discovered his wrench was way out of calibration...it was a new wrench. Cheap bar types are way better if you don't want to spend big bucks ($300+) for a decent clicker. I check my cheap bar torque wrenches (Husky & Great Neck) against my pricey (Klein) clicker and they are spot on. The only difference is bars have to be used more carefully.

bp

 

[toolman99]

Re: Torque wrenches:Inch pounds or foot pounds

I think there's really 2 issues here, one is what scale ie inch/lb vs ft/lb vs newton/mtrs and the second is working range. You should always try to go with a tool working in the midrange of it's capacity vs one working at either extreme of it's working range. The same logic applies to what drive to use , ie. 3/4 inch drive to torque wheel bolts, 3/8 for plugs and 1/4 for small screws and bolts so, just as you should have 1/4, 3/8, 1/2, 3/4 and maybe even inch drive sockets, you really should have several q wrenches to cover several working ranges

 

[cyclops2]

Re: Torque wrenches:Inch pounds or foot pounds

I have a 150 lb spring scale I use to check & recalibrate my bar & my arms.

Assume the worst. & prepare for the worst.

You will not be dissapointed..........Cyclops quotation of wisdom.