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 Post Posted: Wed Oct 10, 2018 10:35 am 
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True Horneteer
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Ok - so this subject is a bit nerdy - but believe me - if you have ever snapped off an important bolt in an expensive component which then requires drilling out the bolt or replacing the component you will be keen to learn why this happened and avoid doing it again in the future.

It's very easy to gall the SS bolts that clamp the bars to the top yoke if too much torque is applied - I snapped a couple of these bolts last time I removed the clamp (probably due to a combination of over tightening when I previously installed a set of Renthals - and didn't use a torque wrench - and the specific galling problems with SS bolts described in the video).

SS Nylock nuts make the problem even worse (also covered in the video) - The engine bars I fitted to my bike come with SS studs and Nylok nuts which galled when I tried fitting them - the nut just stopped turning halfway up the thread on the bolt and then wouldn't undo either - it had galled on the threads. I had to junk the original stud and nuts and source a new stud and standard nuts off Ebay.

https://www.youtube.com/watch?v=HC4KiulYs68


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 Post Posted: Wed Oct 10, 2018 8:22 pm 
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Victor Meldrew
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Hmmm, not come across any problems using ss nuts and bolts, loads of them on both of my 175's.

Copper grease on the ones that go into alloy castings or into threaded holes in the steel frame.

I enjoyed going onto the CMNSL parts website, which has the sizes of all bolts and screws on the old Hondas, then using this info to order closest match sizes in stainless.

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 Post Posted: Wed Oct 10, 2018 9:05 pm 
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True Horneteer
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I thought it was worth sharing because it definitely chimes with my experience on the two occasions I described above - the ones to be really careful with are the four stainless steel bolts that clamp the handlebars to the yoke - I had two bolts stop dead due to galling and shear off as I was undoing them - possibly because I didn't follow the manual's tightening sequence when I previously installed a set of Renthals and didn't use a torque wrench - although I possibly could have got away with this admittedly sloppy technique if I had installed the Renthals with mild steel bolts and not stainless.

I'm also a bit wary of using copper grease on certain bolts these days (particularly ones that go into soft alloy parts) because you can get a false impression of the amount of torque you are applying (too much) with a spanner or wrench due to the slipperiness of the grease and end up with a stripped thread - greased bolts can also have the same effect on torque wrenches - even though the torque wrench is accurately calibrated you end up applying too much torque and might not even get a click out of the torque wrench because the bolt is slipping past it's optimum torque and damaging the thread due to the lubrication.


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 Post Posted: Thu Oct 11, 2018 8:54 am 
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Hornet Lord
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Bugger, I bought loads of stainless nuts & bolts for a kit that I've used on countless jobs. :(

Looks like plated steel would be the way to go instead, and is cheaper too.

Copper grease - Great on exhaust bolts but as a general anti-seize I would think a loctite product would be better. Even mild threadlock acts as an anti-seize if applied correctly.
I don't like introducing additional metals together in a joint as you can get galvanic corrosion, and copper is not nearly as inert as you might think. Keep all the metals the same and you shouldn't have an issue, apart from on engine casings as I wouldn't want an engine held together with cheeseainium alloy bolts. :angel

Greasing threads - I thought this was not a good practise in general but what surprised me is the wheel axle bolts on both my KTM's are alloy, there's an alloy tube as the spindle with a large alloy nut at the end. The rears are nipped up to 90Nm & the fronts to 45 Nm, and both have to be greased.
But generally speaking all torque settings are quoted for dry threads but for god's sake don't ever speak to an old mechanical engineer about that, you'll lose 2 good years of your life whilst you hear about all the various conditions that mean the torque needs to be de-rated, like if the bolt is not new (being re-used) then de-rated by 15%... or whatever, I don't really know TBH as a phased out, I'm an electronics guy you see. :lol


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 Post Posted: Thu Oct 11, 2018 11:50 am 
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True Horneteer
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Quote:
Bugger, I bought loads of stainless nuts & bolts for a kit that I've used on countless jobs.


I expect your bolts will be fine - maybe a tiny bit of lubrication to avoid any potential galling? I think it happens in very specific scenarios - particularly when you have SS bolt going into a softer alloy like the handlebar clamp or where very high torque is being applied - rather than being a guaranteed problem.

Quote:
ooks like plated steel would be the way to go instead, and is cheaper too.


Yeah - good call.

Quote:
I don't like introducing additional metals together in a joint as you can get galvanic corrosion, and copper is not nearly as inert as you might think. Keep all the metals the same and you shouldn't have an issue


Yeah - I've heard of this in relation to header studs and the like.

Quote:
Greasing threads - I thought this was not a good practise in general but what surprised me is the wheel axle bolts on both my KTM's are alloy, there's an alloy tube as the spindle with a large alloy nut at the end. The rears are nipped up to 90Nm & the fronts to 45 Nm, and both have to be greased.


I guess KTM factored this in when they established the correct torque rating.

Quote:
But generally speaking all torque settings are quoted for dry threads but for god's sake don't ever speak to an old mechanical engineer about that, you'll lose 2 good years of your life whilst you hear about all the various conditions that mean the torque needs to be de-rated, like if the bolt is not new (being re-used) then de-rated by 15%...


lol :angel I must be turning into an old git - about ten years ago I would have been bored rigid by conversations like that - these days I find them guite interesting . . . :help

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I'm an electronics guy you see.


Seems like you will be perfectly set up for the future when we will all be working on electric vehicles controlled by complex microprocessors then :D


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 Post Posted: Thu Oct 11, 2018 8:36 pm 
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Victor Meldrew
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I wouldn't grease any thread that had a critical torque setting, I was thinking more of stainless screws into alloy engine cases, or stainless screws into holes tapped in steel frame parts. For the latter, I use moly grease, same stuff as found in CV joints. In alloy, to avoid corrosion, in steel to avoid rust ( same difference ).

I don't use a torque wrench on such bolts, just tighten by feel and experience. In fact, these days pretty much the only bolts that I use a torque wrench on are the cylinder head bolts on my 175 and 200 engines, anything else I just do up tight, including the axle bolts on my Hornet. Similarly, I wouldn't go anywhere near my sump plugs with a torque wrench, or, from bitter experience, the caliper bolts on my Hornet.

I kitted my Hornet out with stainless cap head screws for the engine cases more than 15 years ago, installed using copper grease, as per instructions with kit. No problems with those, still undo freely. I wouldn't use cap head screws thes days foe aesthetic reasons, prefer proper hex heads or JIS pattern as OEM fitments.

And my Hornets Renthals are held on with stainless cap head screws, never had any problems with those either. :lol

In this old photo, pretty much all the bolts and screws visible are stainless, except for the fork clamps and tops. Brief experiment with Renthal Low bars, before reverting back to Ultralows.

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Ten years have got behind you
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 Post Posted: Thu Oct 11, 2018 8:56 pm 
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True Horneteer
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Quote:
I was thinking more of stainless screws into alloy engine cases, or stainless screws into holes tapped in steel frame parts. For the latter, I use moly grease, same stuff as found in CV joints. In alloy, to avoid corrosion, in steel to avoid rust ( same difference ).


Good advice on the Moly - I'll remember that :D

Quote:
I don't use a torque wrench on such bolts, just tighten by feel and experience. In fact, these days pretty much the only bolts that I use a torque wrench on are the cylinder head bolts on my 175 and 200 engines, anything else I just do up tight, including the axle bolts on my Hornet. Similarly, I wouldn't go anywhere near my sump plugs with a torque wrench, or, from bitter experience, the caliper bolts on my Hornet.


Yeah totally agree - although I'm going to use a torque wrench to re-install the cam-holder bolts after the shim change that's coming up - I bought a Norbar 0-20Nm torque wrench specifically for this job - I heard that properly calibrated torque wrenches tend to be most accurate about half way into their range - so the little Norbar should hopefully do a good job on the 12Nm (I think) cam-holder bolts.

Quote:
And my Hornets Renthals are held on with stainless cap head screws, never had any problems with those either. :lol


Probably because you installed yours properly in the first place (unlike me :Bang )


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 Post Posted: Fri Oct 12, 2018 7:51 am 
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Hornet Lord
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I bought a 3/8" torque wrench for dealing with all the intermediate level bolts, like brake calipers.
I also bought a digital luggage weight scale and set about checking the calibration on this new 3/8" and my old 1/2" torque wrenches. The new one seemed pretty much spot on, my big (cheap) 1/2" one... not so much... not very linear... but at least it was generally reading low.
That one only gets used at 2 settings anyway so I have made a note of where to set the wrench in order to achieve that torque.


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 Post Posted: Fri Oct 12, 2018 1:33 pm 
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Victor Meldrew
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I quite fancy getting one of those digital torque wrench adaptor things, converts a 3/8" ratchet handle into a digital torque wrench.

At the moment, I just have a 3/8" and 1/2" Clarke mechanical torque wrenches, which click when setting is reached, no idea how accurate these are.

I also have a moving beam 1/2" drive wrench, which has a scale and a pointer showing torque reached. I bought that some time ago, when setting up a cam belt on a car engine. Useful when used on oily threads, you can 'see' as well as 'feel' how tight the fastening is becoming.

Quote:
I bought a Norbar 0-20Nm torque wrench specifically for this job


Excellent plan, Norbar are a well regarded make, different league to the Machine Mart stuff.

_________________
And then one day you find
Ten years have got behind you
No one told you when to run
You missed the starting gun


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 Post Posted: Mon Oct 15, 2018 11:08 pm 
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True Horneteer
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Quote:
I also bought a digital luggage weight scale and set about checking the calibration


Yeah, I got one of these for this purpose but haven't checked calibration yet.

Quote:
That one only gets used at 2 settings anyway so I have made a note of where to set the wrench in order to achieve that torque.


Sounds a bit like the non-adjustable preset torque wrenches they use on assembly lines where the technician can grab a specific wrench for a specific bolt and know that it's calibrated for that particular operation.

Quote:
I quite fancy getting one of those digital torque wrench adaptor things, converts a 3/8" ratchet handle into a digital torque wrench.


Yeah, I've heard good things about them - but if I was going to go digital I'd prefer to get a dedicated digital wrench.

Quote:
At the moment, I just have a 3/8" and 1/2" Clarke mechanical torque wrenches, which click when setting is reached, no idea how accurate these are.


You can buy a digital scale as mentioned above and calibrate with that - you can check out how to do it on YouTube.

I replaced a couple of old torque wrenches I've had for 20 years with a couple of Norbar conventional click wrenches - the little 0-20Nm I mentioned and a 20 to 100Nm wrench for stuff like remounting brake disc bolts etc where I want consistency across 6 bolts etc - but for calipers and axle bolts etc I tend to go by feel and experience - plus as you say torque wrenches are not magic - it's possible to over tighten even with a properly calibrated wrench if the bolt or thread is lubricated in some way like a sump bolt.

Quote:
I also have a moving beam 1/2" drive wrench, which has a scale and a pointer showing torque reached. I bought that some time ago, when setting up a cam belt on a car engine. Useful when used on oily threads, you can 'see' as well as 'feel' how tight the fastening is becoming.


Yeah - first time I ever saw one of them I couldn't work out what it was even for. :D

Quote:
Excellent plan, Norbar are a well regarded make, different league to the Machine Mart stuff.


Yeah - I did a bit of research and as you say it turns out that they are well regarded - I didn't want to spend the kind of really silly money you can spend on these things - the kind of tools they bolt together satellites with :lol - but the Norbar comes with a signed calibration certificate so hopefully they will prove to be up to snuff.


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