Modern Vespa

Two parts to this...

One: Am I the only person who gets confused trying to sort through the workshop manual for the right torque for the right fastener? I think it's partly a translation issue. Does anyone have a list of torques for BV and GTS to share? I've started one, but well, see above.

Two: In a perfect world, at least to my understanding, torque wrenches should be calibrated every year, regardless of usage. That's clearly impractical and expensive for occasional use, IMO. Checking around here, the price is $40-50 per unit. Considering we're not in a super-precise world (and folks are using impact wrenches instead of torque wrenches...), any thoughts, recommendations for those of you that are or were professionals?

Dave,

I use a torque wrench for the variator and clutch nuts.

The others get “feels right” torque by hand.

I don’t do engine work, but if I did, I would be torquing those down to spec.

Because these are big nuts, I have a Craftsman 1/2” drive torque wrench. It is over 15 years old and has never been recalibrated.

So far, no issues.

As for torque specs, go to the Wiki above. Routine maintenance to workshop manuals. Then to wotmeworry for the service manual for your scooters.

Around 25 pages in are all of the torque values.

You can pull them up on your phone while working on the scoots.

Peace of mind.

Bill

Hi Dave,

I have several torque wrenches that I use for critical applications. One is a 1/2" drive the other a 3/8" drive. I also have a digital one that attaches to a standard ratchet that I got at Harbor Freight to carry on the Cannonball as part of my tool kit.

I think for all our applications, a torque wrench does not need to be calibrated yearly. When I was working in the nuclear industry the torque wrenches were calibrated yearly and I never remember any as found results that were significant.

Just remember is it is the click type versus torsion bar to store it in the zero position to release any tension in the wrench.

That would be a huge mistake. They are rated in the hundreds of Nm. Torque is force x distance,
You can measure a wrench and use a luggage scale.
https://www.engineeringtoolbox.com/torque-wrench-luggage-scale-d_1909.html

Probably the annual calibration check is best practice for the service person who uses their torque wrenches on a daily basis. My home wrenches rarely come out of their storage cases.

FWIW, in the past I had access to my employers torque wrench calibration equipment. After checking annually for a few years I concluded my beam and click wrenches stay in calibration and now I only check them if they are dropped. In my opinion the beam type torque wrench is the most reliable since there are no moving parts. So at home, I check my click wrenches against my beam wrench occasionally and if they read about the same I figure I am good to go.


Bill

Yeah, that crossed my mind....not that my beam wrench was anything fancy, but at least confirm approximate accuracy....unless, of course they're both messed up.

Friendly with my independent auto mechanic...thought about a quick torque wrench comparison...assuming his were checked recently.

Interestingly I'd read that calibration was recommended regardless of use...I think the criteria were 5,000 cycles or one year (kind of like oil...). I don't know enough about these things, but the implication is that these things can go out of spec sitting in a drawer?


Good point about removing tension, Barry. I've at least got that down!

Calibration in the industrial world is determined by the user. If they don’t use one for a year, if the Quality program says it must be calibrated, that’s what they do. Many will write this up as “if it’s used” it should be calibrated after 1 year. Many say they must be recalibrated after 3 years, used or not.

For the casual user, i would leave it for 3 years and then get a cal.

Make sure to store in its relaxed state.

buy a split beam. 3/8" will do practically all you would need.

they hardly ever need re-calibrated, and preform wonderfully. precision instruments makes a very nice piece for cheap and they are great.

wanna get down and dirty?

straight up harbor freight clickers are okay.

i worked in a dyno shop building engines all day. now i'm back to diesel horseshit (i'm a transmission and driveline specialist) you know what we have in our shop?

chicanery of harbor freight, precision and some cast offs from the land of misfit toys.

yeah i've got the johnny kick ass snap on shit. but you know what i use day to day? the PT or the harbor freight.

and you know what, when the guy comes by to calibrate them. the shit ass shit harbor freight ones are always within spec.

but yeah, if you needs, i's go PI first and then harbor freight

-g

Hi fledermaus, yeah, if professionally used click type should be recalibrated about every year. Beam type are good but can be more difficult to use and so are often not quite so accurate under some circumstances. This is simply because sometimes they are more difficult to view square on to get a completely accurate site of the gauge and read it off at that moment you reach the torque figure you want. This is particularly so if the work is on the vehicle high up or low down, instead of on the bench. And as said by someone above, all click type torque wrenches should be stored with the calibration wound down to near zero, BUT not beyond that. It messes with the calibration if you do that.

Much is made by many of using impact wrenches to put stuff back together again. Well, that's a whole story in itself. Essentially they are indeed a no no when putting stuff back together in any reputable workshop especially working on bike engines. Any of my techs or apprentices would have been seriously disciplined for using one. They can do much damage. Fine for undoing stuff, but not great for doing up stuff and just so inaccurate unless it's one of these very very high end jobs. Most impact wrenches cannot accommodate proper settings for pinning stuff back together again anyway. But for those that can the problem is they wear very quickly and get chucked about in the workshop too much making them inaccurate very quickly. Where torque is not a critical thing, yeah they are fine.

Greasy makes a valid point concerning cheap torque wrenches. You don't need to spend much money to get a great one. But learn how to use it. Many folks who diy don't use them properly. With the click type, you must stop torquing as soon as the ratchet clicks. DON'T give it an extra push on the handle afterwards "just to make sure!". That can move the work just the smallest almost imperceptible amount further, but adds another 10-20nm or more without you knowing, and stretching the threads or worse. Read the instructions meticulously.

click, roll off, click again.

done.

that's it.

-g

Yeah, that may be the way you do it greasy and for you that's most likely ok because you are really experienced and careful. But it's not the way any torque wrench company will tell you to use it (read your instructions) and it's not the way we teach apprentices or anyone else over here. There is no purpose to the double click. There is a danger of over torquing.

There are multiple professional videos online showing how it should be done. I certainly wouldn't encourage a newbie to double click. Only one click needed ever, unless torquing is required in multiple stages.

My question on this would be where do you get the luggage scale calibrated?

During the 29 years I spent in dealerships (about 20 as a general line tech, heavy powertrain specialist, electronics specialist and shop foreman) I sent one torque wrench out one time for both an overhaul and calibration. It was tired and they refreshed it (to a degree). Clicker wrenches when brand new are accurate to +/- 4% on average, with the best production clickers running about 3%. So they have to drift quite a bit for it to really matter. For example, if the spec for a fastener is 25 - 30 lb ft and you set your torque wrench for the middle of the spec at 27-28, the torque wrench has to be off by 10% before it starts to matter.

You cannot check the accuracy of a torque wrench against another torque wrench. It takes specialized equipment to get an accurate reading. You also cannot torque a bolt to 30 lb ft with one wrench and then see if the other wrench clicks when set to the same setting. There is tightening torque, and there is breakaway torque. Breakaway torque is always higher than tightening torque. So if wrench #1 torques a bolt to 30 lb ft, it might take 40 lb ft for wrench #2 to make it start moving again.

Glad to see this discussion though, at least some people use torque wrenches!

Excellent points Bueller.

And another point is to remember virtually all torque values you see in a manual are DRY torque values. NO anti-seize, no thread lock, and definitely no grease or oil. Only apply any of those things if the manual states you must use them and use the WET torque value mentioned in the manual for that work item. Adding any of those things alters the amount of torque you must use if added to a DRY value. If you use any of those things without altering the torque value, you can strip the threads by over torquing. Seek specialist advise on that if you need to because it's normal to reduce the amount of torque before pinning the work together.

All correct, if I may say it ... but ...
The need to recalibrate a "professional" torque wrench is essential for how many times you have used the tool; if you use it continuously and you have a workshop where you open and close motors and more, that's fine but if you make an occasional "do it yourself" use it will take a long time to recalibrate.
Besides the speech you are making, on correctness of use and calibration, we need the right tables with torque values.
I shudder when I read of users applying values ​​read here and there in internet discussions. Another little considered thing is the state of the bolt head on which the final part of the tool acts, if it is damaged it can distort the application of the correct torque.
And again, as soon as you buy one, you have to charge it to the maximum and then you have to trigger it a dozen times, never forget to reset it before putting a torque wrench in its case. This way you will reduce the chances of it being damaged over time. Bringing the spring to zero, in fact, is very important to ensure that it does not lose its calibration.

I use torque wrenches professionally. Snap-On and Cleco brands never fail. They get calibrated annually. If a manufacturer tells you to use a torque wrench, there is a good reason for it.

Thanks for all the input. I definitely know more now than when starting the thread..or at minimum confirmed my suspicions.

Maybe a bit late, but I finished torquing everything I needed to on my Beverly, and, well, did do a bit of second-clicking. I'll be more careful next time!

Good man! Well done.

A torque wrench can be absolutely accurate. But due to numerous variables, the clamping force of the fastener can vary substantially. So no need to obsess.

Unless the beam is damaged on a bending-beam wrench, the accuracy does not change. Just make sure the pointer points to zero.

Mostly the point of a torque wrench is to keep you from tightening the fastener 'a half a turn past stripped'.

If you are torqueing numerous fasteners, sometimes a good idea to have a marking pen, and marking each fastener as you torque it, so a visual inspection is easier.

That's a great idea. +1

Many mechanics also mark a bolt or nut and the part underneath them to detect a fastener unloosening over time.

Miguel

True except that when unscrewing the bolt makes a complete turn and stops at the mark.

I always use a Craftsman model 1019 Laboratory edition, signature series torque wrench. The kind used by Cal Tech High Energy physicists, and NASA engineers. A split second before I use it, it has to be calibrated by top members of the state and federal Departments of Weights and Measures, to be dead-on balls accurate.

fyi: dead-on balls accurate is an industry term.

What do the low energy physicists use?

Asking for a friend.

When I worked all of our torque wrenches were calibrated and we used many from 0.5nm all the way up to 75 ft lbs. in various ranges and sizes - other areas used much larger wrenches also calibrated.
I could never tell if they were in or out of calibration but we couldn’t use them unless they were certified and stickered.
But as far as I could tell the only reason we had them certified and calibrated so stringently was to keep our ISO rating I would be surprised if any of them were out of calibration by very much. They were checked every six months and it was a challenge to have them rotated in and out for calibration.

I have at times wondered if the beam might change over time, work hardening or loosing strength. Like when you bend a paperclip several times and it breaks. Of course the beam is not being bent that much but it may change over time.

Same as the valve springs in an engine. But the loss of tension there might be caused by sitting in the compressed state. Like when engine stops with rocker on the top point of the cam lobe after the last ride in the fall!

Ferrous metal generally has what’s referred to as a memory. As long as it is not bent past a certain point (which varies depending on composition and manufacturing techniques) it will return to the original form. This is the reason why you don’t have to replace that valve spring that sat compressed all winter. Likewise with beam torque wrenches. They do not get bent beyond the point where they would return to the original at rest form.

What he says.../\ /\

Torque Tips

The torque setting is determined by the diameter of the bolt, thread pitch & material, should you have any question, do a search with the above criteria
Any fastener that threads in aluminum or plastic requires special care
Using the appropriate sized tool, goes a long way towards avoiding disaster
There are very few large diameter bolts on scooters
Wheels, motor mounts, cvt...

Do the final snug down with regular combo wrenches which are about the right length to keep you out of trouble

I use a small electric impact screwgun,
1/4-1/2 trigger & a couple impacts of the hammer, is generally enough, better to finish it off with a wrench or a similar sized ratchet
When I take stuff I make note of how much trigger & how hard the hammer of the impact works

When using a torque wrench try putting your fingers about the same distance from the bolt as it is on a wrench or ratchet which will help you increase your ability to work by feel especially on all the smaller stuff 6-10mm

Interesting thread!

I asked my local bike shop where they got theirs calibrated, as I was concerned my 40 + year old ex USN lb/ft wrench might need it.

They looked at me as if I were mad ...

If you don't have a place you can conveniently take your torque wrench to be calibrated, and if you don't want to spend $$$$ to buy the calibration equipment here is a quick and dirty method you can use. I do not claim this to be the most accurate method, but it will get you in the ball park:

https://www.wikihow.com/Calibrate-a-Torque-Wrench

Probably not vastly different from what they do when you send it in to be calibrated. Although I would expect them to calibrate at several points along the torque scale, rather than at a single point.

While torque specifications are never given with a tolerance figure (at least that I've seen), I suspect anything within +/- 20 % is probably going to be OK, with the preference on +. That's likely within the accuracy of all tools except those that have been damaged.

Well might not be said as a +/- % but I always felt that was what was meant by the way most spec's are written:

Or this chart for some totally not Vespa Company:

Most manuals I have show a single specific torque value. Period.

Oh how I wanted to make a whole torque value post...

But guess y’all done did figured it out. Awesome.

Besides head gasket, clutch and vario? Tight? Snug plus one maybe?

That’s probably it.

-g

It just depends on the materials and what the work is Jim. But you prolly know that. Many manuals will show a single figure, but more and more manuals seem to show the maximum torque range, such as in our Vespa/Piaggio manuals. When I designed engines we always showed the maximum torque range. And to be clear, there is a maximum torque range for almost everything in or on an engine to allow for minor errors with torque wrenches, even on engine where they show only one figure.

Wow! You are all so technically savvy ... it's a pleasure to read you and there is always so much to learn.
PS: what is the "snug" (aderenza) mentioned by the greasy 125? Maybe i understand but the technical translation into italian is ambiguous.

well this pic is wrong.

first if they are to use a scale set up like this then they are using crescent wrench in the wrong direction, never torque against the adjustable side of the wrench.

Yes ... the arrow must be rotated 180 degrees to the left on the figure and placed on the handle of the tool...The moment is given by strength per arm.

With all this talk about proper torque if you really want to get into some arguments try taking to some people about the merits of the "Torque-Turn" method! That will cause a major rabbit hole on some forums!