neonwarhead Posted December 4, 2009 Report Share Posted December 4, 2009 Having removed the pillion footpegs and hangers on my KTM I'd like to plug the holes with dome headed bolts to keep the threads clean and look a bit more "finished". Is there an easy way of working out what size bolt/thread I need other than trial and error? Link to comment Share on other sites More sharing options...
speedy sie Posted December 4, 2009 Report Share Posted December 4, 2009 go and buy a thred guage,onlt 50p/£1 verey handy and cover most threds from m4 to m14 fine and course thred. Link to comment Share on other sites More sharing options...
eddie Posted December 4, 2009 Report Share Posted December 4, 2009 Measure them? Link to comment Share on other sites More sharing options...
neonwarhead Posted December 4, 2009 Author Report Share Posted December 4, 2009 Measure it, of course, why didn't I think of that! Measure what dimension exactly? The outside of the threaded part seems to be 7.8mm according to the vernier guage, does that make it an M8? What about thread pitch? I'm liking your suggestion speedy, hadn't realised there was such a thing. Link to comment Share on other sites More sharing options...
will#224 Posted December 4, 2009 Report Share Posted December 4, 2009 Measure the distance between the sharp part of 2 threads. The KTMs i've worked on before were fine threads. Link to comment Share on other sites More sharing options...
lorenzo Posted December 5, 2009 Report Share Posted December 5, 2009 If the outside of the thread is 7.8 then it's an M8. Of course, there's probably 2 different thread pitches for m8, a normal and either a coarse or a fine (some go bigger, others go smaller). A thread guage is a great little tool, like a pen-knife of comby things. Bet you only ever use the 1mm and 1.25, with the occasional 1.5mm on really big stuff. Still, they're cheap enough. Link to comment Share on other sites More sharing options...
jaycee Posted December 5, 2009 Report Share Posted December 5, 2009 go and buy a thred guage,onlt 50p/£1 verey handy and cover most threds from m4 to m14 fine and course thred. +1, got 2, metric an d imperail Link to comment Share on other sites More sharing options...
eddie Posted December 5, 2009 Report Share Posted December 5, 2009 If the od of the bolt measures 7.8mm, it will be an M8 bolt. The iso (std) pitch for a n M8 bolt is 1.25mm. The japs (on their bikes), generally use a finer pitch thread for M10 and above (as mentioned previously), however, MOST, not ALL, M8 threads on jap bikes are 1.25mm pitch. Using your vernier, measure the distance between 2 of the "points" of the threads. It is easier to measure over a greater number of threads (points),for example 10 threads/points. Divide this measurement, by the number of threads (points- in this case 10), this calculation will equal the pitch of the thread. Or buy a thread gauge. Hope this is more useful than my last reply! Paul Link to comment Share on other sites More sharing options...
speedy sie Posted December 5, 2009 Report Share Posted December 5, 2009 i work with fucking bolts of all size from, m4 to m30 yarp m30 and i alway carry thred guadge in pocket they are like a set of felia gauges andout as big as a box small matches...bloody esesial.. Link to comment Share on other sites More sharing options...
neonwarhead Posted December 5, 2009 Author Report Share Posted December 5, 2009 If the od of the bolt measures 7.8mm, it will be an M8 bolt. The iso (std) pitch for a n M8 bolt is 1.25mm. The japs (on their bikes), generally use a finer pitch thread for M10 and above (as mentioned previously), however, MOST, not ALL, M8 threads on jap bikes are 1.25mm pitch. Using your vernier, measure the distance between 2 of the "points" of the threads. It is easier to measure over a greater number of threads (points),for example 10 threads/points. Divide this measurement, by the number of threads (points- in this case 10), this calculation will equal the pitch of the thread. Or buy a thread gauge. Hope this is more useful than my last reply! Paul Cheers!!! Link to comment Share on other sites More sharing options...
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