M10 1.25

michipons

michipons

Hero member
Location
Palma de Mallorca
Hi!

I was reading Chez thread as it was recovered from the past when I wasn?t on the forum yet... hopefully grandson brings happiness to the family, and all the best if you read that.

(I didn?t want to ask my stupid question in that thread)

Regarding the metric thread issue, Piet has mentioned that the rear engine support screws are M10 1.25 and should be changed for the same, well as I wanted to change them, on that same length I just found with 1.50 thread instead of the standard 1.75 for M10, is that enough or it really has to be 1.25?? I found M10 1.25 but they were longer, and I wanted to avoid cutting them for later corrosion problems...

Miguel
 
Hi Miguel,
Standard pitch for M10 is 1.5, with 1.25 being fine pitch.  M12 is 1.75 and 1.5.
Sometimes it can be hard to fine just the right length bolts but keep looking or alternatively, I now regularly get the original bolts re-zinc plated rather than replacing.  If you have no original bolt or it is damaged and you really can't find the correct length, an option is to shorten and then re-zinc plate them.  Can even be done at home if you have no local friendly platers.  A bit of a hassle but all part of the fun!
Cheers
Steve
 
Hi, Miguel.
The rear support bolts on 750s are M12x1,25x70 (19mm spanner)and OCT stocks them, as well
as the self-locking nuts. Don't cost a fortune.

Ernesto
 
Ernesto said:
Hi, Miguel.
The rear support bolts on 750s are M12x1,25x70 (19mm spanner)and OCT stocks them, as well
as the self-locking nuts. Don't cost a fortune.

Ernesto
Click to expand...

Now that is an odd pitch for 12mm.

Yes, I read Chez thread too. Locally, 10X1.25 is available in many lengths, no probs. But that 12, it's an oddball.
Where I had a problem recently was rebuilding an RC30 engine. Ex race unit, unknown history but rough....very rough.
The head bolts on them are 9 X 1.25 socket head capscrews. Socket head because they're tightened through holes in the lower cam carriers - and yes, you have to put the bolts in before you assemble the bloody heads...Then the valves as they trap the lower cam carrier on the head....Honda......
There's an outfit in the UK who've commissioned new bolts - but hell they're expensive. Anyway, an extensive internet search found late Fiat 500 head bolts. 9 MM and the correct length too. Socket head - but a larger OD Torx type key needed. $NZ100 for enough for a set and a couple spare. Freight free - and in NZ.
Just had to open up the access holes in the cam carriers. They're under rolling bearings when it's all together so no problems there.

Living at this end of the world, you've got to think outside the box sometimes.
 
Triples use M10x1.25, twins M12x1.25(except on the through studs at the head, these are M10x1.5/M12x1.75).

Fine thread should be used as it achieves a higher tension for a given torque and is less prone to loosening.  I find lots of regular-thread bolts in there, often in stainless, mostly loose.  Owners often complain about excessive vibrations... ::)

piet
 
breganzane said:
Hi Miguel,
Standard pitch for M10 is 1.5, with 1.25 being fine pitch.  M12 is 1.75 and 1.5.
Sometimes it can be hard to fine just the right length bolts but keep looking or alternatively, I now regularly get the original bolts re-zinc plated rather than replacing.  If you have no original bolt or it is damaged and you really can't find the correct length, an option is to shorten and then re-zinc plate them.  Can even be done at home if you have no local friendly platers.  A bit of a hassle but all part of the fun!
Cheers
Steve
Click to expand...

I spoke M10 by mistake, true, M12 1.25 being standard 1.75
I have the originals, will think about Zinc them, my problem is that in Mallkrca nobody does it, only chrome, which is too shiny.

Would be great to know the home process to do it, Breganzane! Never heard about it!

Miguel
 
I think I found something very interesting... any experience with them?

Miguel

https://classic-plating.co.uk/

https://www.youtube.com/watch?v=CU3gEf58Mvk&list=PLZv5lJpkaktsRMn8M7ESZ7y-kXXubhC7y&index=1&t=1s
 
I was looking far and wide for stainless 8x1.00 cap screws for my bling light clutch kits 9clutch cable adjuster thread pitch). I found them in the UK - seemed to be the only place anywhere on the planet that had them. They also had M12x1.25 hex head stainless bolts the same length as std SF engine bolts so i bought some - I'll see how they go. Any probs and I'll toss them. I think I've got two of the std ones spare so can cover half of the 2nd motor. Need to source four nuts to suit, so maybe OCT and 'un sacco di soldi' in freight!
 
michipons said:
I spoke M10 by mistake, true, M12 1.25 being standard 1.75
I have the originals, will think about Zinc them, my problem is that in Mallkrca nobody does it, only chrome, which is too shiny.
Would be great to know the home process to do it, Breganzane! Never heard about it!
Miguel
Click to expand...

Hi Miguel,
OK, makes sense now.  M12x1.25 is not all that common but is a standard ISO extra-fine thread.  If you have the original bolts, that is perfect they are the best and also you will not be arrested by the "originality police".  :D
I have not personally done the home zinc plating as I have a friendly plater right on my way to work who rides old Indians and does a great job for a modest cost.  But I have a "youtube doctorate" on it and with the confidence of a millennial I therefore believe it is pretty easy.
Here is a video on it which I saw a while back, the guy has a very dry sense of humour but I think the info is more or less correct.  Maybe test on some hardware store bolts to start with!
Let us know how you get on.
Cheers
Steve
[youtube]https://youtu.be/Wy6u2kikAA4[/youtube]
 
Hi Miguel,
plating the original screws is the best solution.
If you want to buy them, you'll find them here: https://www.wegertseder.com/DIN-960-Sechskantschrauben-mit-Schaft-FEIN-Gewinde-STAHL-8-8-verzinkt
Ciao, Gert
 
lavgert said:
Hi Miguel,
plating the original screws is the best solution.
If you want to buy them, you'll find them here: https://www.wegertseder.com/DIN-960-Sechskantschrauben-mit-Schaft-FEIN-Gewinde-STAHL-8-8-verzinkt
Ciao, Gert
Click to expand...
Hi Gert!
thank you! website looks great! I will initially buy some, and then when I have a box full of screws, I will send them for plating, otherwise is a waste of money...
Servus!
Miguel
 
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