1/4-inch torque wrenches


#1

right to the question: are 1/4-inch torque wrenches worth it - compared to 3/8-inch and up?

1/4-inch torque wrenches cover the lower end of fastener tightness, to the point of being even less than “finger-tight”. 3/8-inch torque wrenches, however, get past that stage, into where you would be shooting in the dark as to the strength of the fasteners.


#2

1/4 torque wrenches are for low torque applications. Like pan bolts or carbs.


#3

I’ve never used one, always depended on my ‘feel’ for what is tight, and I’ve never had a problem. The fasteners I’ve broken were frozen, and I twisted them off while trying to remove them. Many such fasteners don’t have specs listed, anyway.


#4

Who are you and what do you plan to do with that torque wrench? Are you planning on rebuilding your transmission or preloading your differential pinion bearing? For the average DIYer doing routine maintenance I don’t think you’ll need an inch-pound wrench. Just use your mechanical intuition and some common sense.


#5

I can’t see where a 1/4" drive torque wrench would be used in an automotive application.

Every automotive application I’ve come across where in/lbs were spec’d out, a 3/8" drive torque wrench sufficed.

Tester


#6

I’ve never even SEEN a 1/4" drive torque wrench. My 3/8" drive works for anything small I’ve ever done. Do you have some tool salesman trying to sell you one?


#7

Is it “worth it”?
Nope. Not until that one time when you find yourself in a situation where you need one and nothing else will do…and it’s late and the stores are all closed. In short, for the small cost involved it’s nice to have one in the toolbox.

In the interest of full disclosure, I have to admit that I don’t have one. But when I finally get to that aforementioned situation, man, will I be pissed at myself.


#8

This is where experience really counts.

Most of us need to have a 1/2" drive to handle the heavy stuff - like cylinder head bolts. I’ll bet no one can really do that without that wrench.

Smaller things like spark plugs? I used the 3/8" to get a feel as to how much was too much. I rarely use it now.

I’m struggling with the 1/4" thing. I will hand tighten certain things - small bolts, but I guess over the years I’ve developed that feel for what’s too much. I could see it as a tool for situations like MountainBike said - or learning what it is supposed to feel like.


#9

I guess the 1/4 inch torque wrench falls within the realm of “left handed” monkey wrenches. They probably exist but I have never looked for one and I would never buy one.


#10

I have a 1/2 inch and have adapators for smaller size bolts. Torque is torque, no matter what size the drive is. Buying a 1/4 inch drive is silly since you then need to buy a larger one as well.


#11

The only time I ever used a 1/4 inch torque wrench is to set bearing preload to rebuild a differential. Of course you need a 1/4 to 3/8 adapter and a 3/8 to 1/2 adapter to fit the big socket you need to turn the pinion nut. Never needed it for anything else.


#12

“Every automotive application I’ve come across where in/lbs were spec’d out, a 3/8” drive torque wrench sufficed."
“I’ve never even SEEN a 1/4” drive torque wrench. My 3/8" drive works for anything small I’ve ever done. Do you have some tool salesman trying to sell you one?"

Many things on a car have torque specs in inch/lbs rather than the ft/lbs found on 3/8 drive wrenches. For these things we use 1/4’’ torque wrenches. Pinion bearing preload, maybe 30 inch/lbs. Transmission bands and valve bodies, anywhere from 40 to 100 in/lbs. Sure you can convert inches to feet, but a 3/8" torque wrench won’t even measure that low for most applications.


#13

Quoting @asemaster “Sure you can convert inches to feet, but a 3/8” torque wrench won’t even measure that low for most applications."

My 3/8" drive torque wrench is calibrated in inch pounds. The lowest setting is 10 in/lb. I loaned it to my neighbor a while back. He works for an aerospace manufacturer, and had something he needed it briefly for. He took it to their tool calibration department which certified it as accurate within 1% to 2%. Not bad for an old Proto I picked up at a garage sale for $10 probably 30 years ago.


#14

To have a torque wrench calibrated/certified these days is $80.00/wrench.

In the aerospace industy you will need a 1/4" drive torque wrench. But in the automotive industry?

Nope!

Tester


#15

@MG McAnick, it’s unusual for automotive tools to have a 3/8 torque wrench in inch pounds. Usually it’s the 1/4 drive that’s in in/lbs, since we’re using smaller sockets for transmissions, small items, etc.

@Tester, you must have one too. You may not need a 1/4" torque wrench, but you need a torque wrench capable of measuring down to 20 in/lbs or so.


#16

I usually drove Chrysler products and used a 1/4 torque wrench on the bands of the Powerflite and Torqueflite transmissions. I recall some of those adjustments being as low as 7 inch pounds.


#17

I’ve used one to adjust the bands on a Dodge automatic transmission. The 3/8" wouldn’t measure such low values.


#18

I’ve got a 1/4" torque wrench and used it primarly on transmission internals; usually manual transmissions and on shift fork bolts, detent bolts, bearing retainer plates, and so on.


#19

interesting comments, thanks everyone. my open-ended question was something out of exasperation - “is it worth it” - as I figured, it depends.

of course, I can imagine there are fasteners etc. that require specific, low torque, but I was clearly ignorant of them.

@asemaster said “Who are you?”

I take this to actually mean “what” and not “who”. As might be clear, I am a DIY/learner - not a pro.

I am working on a Porsche 944. The shop manual has plenty of low-torque numbers in there. One that has come into my sphere of interest is a small cover on the tranny which needs some low torque value I don’t know off-hand. Another is a bolt on the rear of the engine on a cover that I just tightened without a TW and it seems OK - no leaks, but not too tight. Also the TW might not fit in there.

also, Harbor Freight has some wrenches for twelve bucks on sale, so in fact I got one after I posted the question to try it out. Sears doesn’t have a 1/4-inch AFAIK. I am trying to find out if I should really save up for a Snap-On - or if an imprecise torque for these covers will suffice. Even a relative torque would be better than free-form tightening. From comments, seems so. but if doing more complex things like rebuilding tranny, no.

there is some confusion about my use of the term “1/4-inch”. As many comments suggest, I used this term assuming that small-size wrenches cover the low end of torque values, while larger wrenches cover the higher end - e.g. 1/2-inch TW for wheel nuts around say 100 Nm. This thread is not to deal with the “sweet-spot” of any particular wrench, or whether e.g. a 3/8-inch wrench actually suffices for some torque values that a 1/4-inch might cover. Of course low-end torque values have importance, but at the end of the day we need to buy a wrench, and 1/4-inch is the lowest there is, and the torque values are such as can be achieved by finger-tightening. compare with wheel nuts, where that is not the case.


#20

Doc, I would argue that in applications requiring inch ounces rather than foot pounds a 1/2 inch would not do. Those applications are rare on cars, but as I said before, when I ultimately come up against one I’ll be pissed at myself for not stocking a 1/4" torque wrench.