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PostPosted: Sun Apr 21, 2013 9:32 am 
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Joined: Thu Jul 26, 2012 1:31 pm
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Location: The Cave of Shame
I would say unlikely to be honest - of your current fleet most have dealings with or the frame was actually built in the Far East so standardised sizes and pitches are far more likely. If you are paranoid get a bag of standard randomly assorted M bolts (even screwhead will do) from eBay or your local DIY/screw fix as testers - then once doubly certain order the shiney and expensive ones.

PostPosted: Sun Apr 21, 2013 9:34 am 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
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Joined: Sat Jan 27, 2007 10:35 pm
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Location: The desolate flats of Cambridgeshire
You will not have any trouble. Unless you have anything particularly odd, all the threads will be standard (coarse) threads.

The 'M' incidentally signifies the bolt is metric, its not a 'special' value.

PostPosted: Sun Apr 21, 2013 10:25 am 
retrobike rider
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Location: Nth Somerset, UK
Good thing you are working on bikes from the 80's and 90's; when I used to work on British and Italian motorbikes from the 50's, 60's, 70's and 80's I used to come across all sorts of stuff, and have an eclectic mix of spanners, sockets, taps, dies and helicoil kits left over from that work.

PostPosted: Sun Apr 21, 2013 7:11 pm 
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Joined: Fri Jan 13, 2012 2:28 am
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Location: Near Gatwick
If your just working on your bike you will probably only find a few fine pitch bolts, all the other will be coarse, so you
simply ask for MX. I can only think of two fine pitch things, bottom bracket[M8x1.0mm] and derailleur hanger[M10x1.0mm].
Thinking about it shimano spindles are 1mm pitch as is the bolt holding the freehub on.
Metric thread standards generally have 4 pitches[I think there is 4 for most large sizes], like M10x1.5mm which is coarse, the fine pitches are 1.25mm, 1.0mm and .75mm.
I have only seen a few <M8 fine pitch threads on cars and bikes, they were on tubes in instruments and things like that.
So If you can assume any M6 is 1mm you have a 1mm thread gauge. so you check a M8 and if it's not 1mm[but is bigger]
it's 1.25 mm and so on, so you can check metric pitches with a few bolts. M8 and M10 fine I haven't ever seen less than 1mm pitch even though it is a standard.

If it's an imperial thread you want to check and you don't have a thread gauge, well lookey here I have picked three random bolts, I can recognise the threads in each case, but her's a simple way of checking them. rub an oily finger over the thread and roll it on a bit of paper and measure it! I have done the three threads and you can guess what thread they are.
OK it's a bit of a mess, you can see where I rolled the threads on the paper and to the left of the series of lines is the overall diameter. to the right, underneath the lines is the number and near that is the length[.0005inches was a bit optimistic] I didn't have my eagle eye lens glasses so wasn't as accurate as usual; it's surprising how close you can get.
At the bottom is what the threads are, no idea why the 6 of 16 looks like an 8;-)

The three random bolts were in fact recognisable, a bolt from a citroen caliper[M7], a rod bolt from a 429 ford engine[1/2 UNF]
and a Norton tappet adjuster[5/16 cycle].

if you want a PDF of the Zeus book pm me.

ramblings.jpg [ 22.55 KiB | Viewed 138 times ]
PostPosted: Sun Apr 21, 2013 10:37 pm 
Old School Hero

Joined: Thu Jun 10, 2010 4:46 pm
Posts: 159
Location: Salt Lake City Utah USA
This is a great resource.. ... fault.aspx

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