cross-posted from: https://jorts.horse/users/fathermcgruder/statuses/110789232582943740
What’s a good torque wrench to get?
I want to replace the spark plugs in my car and I’m apparently going to have to torque them to 30Nm. #diy #tools
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Maybe an unpopular opinion; but if you want a budget torque wrench (less than $100usd), get a beam style. I’ve personally used this one to assemble dozens of engines. I’ve got a $400 Snap-On digital that is great for torque to yield fasteners where you have to tighten to a specific degree. But if it’s just something like spark plugs, I’ll grab the beam torque wrench every time. I wouldn’t recommend the micrometer/click style for a novice. It’s too easy to get the setting off by a turn and unless you know what that amount of torque is supposed to fell like, you put your trust into listening for the click and end up causing much bigger problems for yourself.
Any questions, feel free to PM/DM. I’m having mechanic advice withdrawals after leaving reddit.
I’m a novice mechanic and I never had any issue with click torque wrenches.
Admittedly, I have a science degree and I have a great deal of experience with measurement equipment, vernier scales, etc. But I don’t think the setting on a click wrench is very challenging, even for a novice. Just watch a couple YT videos.
If you’re familiar with mic adjustments, you’re golden. The problem shows up when someone isn’t familiar and is operating at the low end of the adjustment range. You can accidentally end up below the threshold where it makes an audible click. If you don’t have a frame of reference what 30Nm should feel like, you don’t realize somethings wrong until you’ve cranked down way too hard. Beam wrenches are simpler (and quicker).
Thank you, I hadn’t considered that style. All the YouTube videos use the mechanical click type, but you’ve got me thinking that the simpler beam style might be better for my situation.
A beam style torque wrench will work if you can see the dial from straight ahead, ensuring there’s no parallax error in your sight. However, it won’t work so well if you can’t see the dial. If you’re working on replacing the spark plugs in an FRS for example, where they’re down low and against the chassis, a click-type torque wrench might be the only way to do it. Also, keep in mind that torque values change if the threads have any kind of lubrication on them such as grease or anti-seize.
Oh man, how do I account for anti-seize lube?
In general, if you put any kind of lube on the threads, the torque spec should drop a bit because the lube makes it easier to spin the parts. Over-spinning the parts can stretch the threads to the point of damaging them. If you don’t compensate for the lube, you could end up over-torqueing things. For example, if wheel lug nuts should be torqued to 100 lb-ft dry, it may drop down to 90 lb-ft with anti-seize. As for spark plugs, I don’t know how much it should be reduced, if at all. It also depends on if the torque spec is already tuned for anti-seize. If the official procedure calls for anti-seize, then it’s probably ok to assume that the torque spec already compensates for it.
What would be a good beam style wrench on the inch pound scale?
It depends how precise you need to be. If a 10-15% margin of error is acceptable*, then most of the budget brands (Presa, Titan, Neiko, ect) will be fine. If you need <5% margin of error, start looking at the major brands (snap-on, blue point, matco, mac, cornwell) that come with calibration certificates.
How many inch pounds you are working with will determine the size you need.
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1-100in/lb - 1/4" torque wrench
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100-1000in/lb - 3/8" torque wrench
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1000+in/lb - We really should be using a different unit at this point, but 1/2" torque wrench.
*For most shadetree repairs 10-15% is more than sufficient.
Edit: tried to fix formatting
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Split beam torque wrenches are where it’s at, especially for home use where it’s going to sit for long periods of time. Split beam is easier to set, and you don’t have to leave it at 0 when not in use. I have ruined many traditional clickers because I forgot to set it back to 0 for storage, then it sits like that for months.
They aren’t as cheap as a traditional clicker, but they are so much better.
