Modern Vespa

Been using an impact wrench on wheel axel bolts and variator/clutch nuts.

It's great for the removal. One quick zzzzzt and nut is off. No special tool, banged knuckles, grunting or cursing involved.

But is it safe to use for putting the nuts/bolts back in place? The wrench has a max fastening torque of 345 ft lbs, way more than the 40-65 ft lbs required for the parts in question. There's no way to lower or control the torque. How does it not over tighten or strip the bolts/nuts?

Impacts for taking off, ratchets and torque wrenches for installation.

Click-type torque wrenches are now $11.99 at Harbor Freight with coupon.

Quite good enough for occasional Vespa wrenching.

you can get a digital torque meter adapter for your ratchet or breaker-bar for $25 from aliexpress.

So I gather it's risky/foolish to attach nuts and bolts via an impact wrench?

Did so a couple times without harm, maybe I was fortunate. Will use a torque wrench in the future.

Yes. Over torque and you will damage threads. Might get lucky and only damage the nut and not the threads on the shaft. Too low and assembly can loosen over time which will take out the splines. I've seen 2 crankshafts with the splines wiped out because the variator came loose.

your good just JAM the hell out of em. hammer them in call it good, all those good things like that, no worries, those piaggio engineers don't have a frickin clue on specs and what's needed.

tech tip: power tools make installing spark plugs much easier, just sayin.

And don't forget the loctite! You don't want that plug flying out at an inopportune moment now, do you?

You are a bad influence on the kids.

You CAN buy an interesting accessory set at Harbor Freight called "torque sticks." They're metal impact wrench extenders of various thicknesses and lengths that distort by twisting at a certain torque level, and don't pass the higher torque through to the fastener. They aren't terribly precise, but they're precise enough. Lots of interesting tests and demonstrations on YouTube.

But a torque wrench is cheaper and easier to use in MOST cases.

nope

nope

What confuses me is I hit the nuts w the impact wrench until they stopped turning. It was as though the wrench knew when to lay off.

super RED is the best.

Well sure, if you want to do a half arsed job. Get a welder if you want it done properly.

It laid off when it was done.
Not necessarily when the nut was done.
And that's the thing, isn't it?

nope

That's a good use of a torque stick. Get all 20 lugnuts onto the studs in the vicinity, then hit them all with the proper torque stick and not worry (much) about the actual torque wrench.

Am I going to hell for not rotating my tires? It's a pain to get all four off the ground at the same time, and for what I'd pay a shop to do a few times and be without the use of the car I can pay in replacing tires a little bit early.

The way I rotate tires on a car is, using the spare, change out one wheel to the spare, then move on to the next wheel. So a total of 5 tire changes to move all four tires.

Clever but I'm still not persuaded that it's worth the time. Even lifting the car one side at a time to do front-and-rear swaps seems futile to me. I seem to replace enough tires when they're worn 80% due to punctures, or because their opposing tire was punctured, and it's not worth paying the shop to patch it.

Maybe I'm missing something but if suboptimal-frequency tire replacement is costing me an unnecessary $75 a year because I'm not rotating my tires, I'm OK with it.

(Of course if I had a lift in my garage I'd be rotating my tires once a week and shaming anyone else who doesn't.)

(Hmmm….if a lift costs $2k then it only takes 27 years to justify at $75/year…but that does't count the opportunity cost of the capital…but wait there might be other intangible benefits…)

For the really big torque nuts a cheapo is fine, but for the small delicate bolts etc, I really like to use an accurate snapon, even though it is expensive, still cheaper than snapping off little bolts etc.

My Metabo impact has a power setting so if you do insist on using one to put nuts on you are only hitting it with approximately 50nm on the lowest setting rather than the full whack.
However I'd still prefer to use a properly calibrated torque wrench (ie not one from alibaba etc). I've got a set of ACDelco digital torque wrenches, they are really affordable and seem really well made.

I don't understand the fascination with digital readouts for analogue measurements. Just extra complexity, and not more accurate or precise.

I also like the simple torque wrenches. I find myself reaching for my 45 year old beam type torque wrench a lot of the time. Requires no setup at all.

What does an Impact wrench look like?

Something like this

Old skool pneumatic classic: Ingersoll-Rand 231C

The impact wrench is one of a handful of items I do not suggest ever sourcing from Harbor Freight.

See what you did there, click

Turns out they are actually called impact wrenches, at least by the makers. I thought they were impact drivers.

must be honest I have never been a fan of them "bolt unscrewing and screwing guns" I do not have the confidence of them knackering up the threads, I like finger tight first, then torque wrench, unless I worked in a tyre center that did it 100s of times a day, as time is money.

Actually anti seize paste is preferable for spark plugs.
If you get a spark plug broken off inside an aluminum engine head because it is frozen in there, you are in for a major engine job.
A properly snugged up plug will grip aluminum threads pretty securely.
Tight enough to crush the "crush" washer will do the job.