M2.5 bolt

[Jim77]

Hi all

I need to get hold of the following Y6R398050 bolt but it is longer supplied.

https://manualzz.com/doc/53867909/shima ... loded-view

However I have found that it is a m2.5 x 5.2mm bolt and want to buy a subsitute.

However, how do I measure the distance between threads of the “nut” and whether it coarse or fine thread?

Cheers


Jim

[531colin]

You can “thread” a sliver of wood into the hole and see if it gets marks from the screw thread.
Or you could probably scrounge a suitable bolt from your local bike shop scrap bin…..take them a couple of packets of chocolate biscuits!
Westfield fasteners only list one thread pitch for that diameter so it’s probably that one

[Jim77]

Thanks for your advice Colin.

[Jdsk]

There are two M2.5 pitches:
https://www.engineersedge.com/hardware/ ... e_vignette

How important is that unthreaded section under the head?

Jonathan

[colin54]

Hi all

I need to get hold of the following Y6R398050 bolt but it is longer supplied.

https://manualzz.com/doc/53867909/shima ... loded-view

However I have found that it is a m2.5 x 5.2mm bolt and want to buy a subsitute.

However, how do I measure the distance between threads of the “nut” and whether it coarse or fine thread?

Cheers


Jim

Hi Jim, where did you get the 2.5mm diameter figure from ?
The reason I ask is that I've just had a look at a couple of different Shimano shifters with similar though not identical covers and the outer diameter (OD) on both fixing screws is 2.9mm so likely nominal 3mm screws. It's hard for me to get precise measurements for a screw that small, but here's a picture of what I've got for what it's worth.

From the attached photo I count that as 13 threads (over a length of 6.8mm approx)) = .52mm pitch so likely M3 with a .5mm pitch thread would be the one that lines up from looking at the table linked by Jonathan above.
Hoping this helps and doesn't muddy the waters, good luck.
Edit M3, not M5 - altered in text in second paragraph.









edit

[Jim77]

Thanks for your reply Colin - I got the figures from this site: https://www.sjscycles.co.uk/gear-spares ... y8ae98010/

I also put some blue-tac in the “nut” and the diameter did measure 2.5mm.

[Brucey]

.................. how do I measure the distance between threads of the “nut” and whether it coarse or fine thread?

there should be an identical screw in the other shifter. So you can measure that.
IIRC the same thread dims may be used on one or both gear indicator screws, too. It is usually M3x0.5mm here, isn't it?

[Jim77]

That is great thinking Brucey. I just better not loose that one as well! I will be using a magnet and container I think to catch it if it falls out.

[SimonCelsa]

A quick eBay search gives :https://www.ebay.co.uk/itm/224909198717 ... R67_5qDOYw

doubtless there are many more sources. Quite cheap so go for a range of sizes maybe!

[colin54]

I've just tried a 3mm diameter dropout adjusting screw in one of mine, same thread.

[Jim77]

Ok I took Brucey’s advice and removed the other one and attach the picture. I shall do some measurements…

[Jim77]

I count 11 threads and the length is 5.2mm - so that gives about 0.4727. So that would suggest a coarse thread?

[colin54]

I count 11 threads and the length is 5.2mm - so that gives about 0.4727. So that would suggest a coarse thread?

Hi again Jim if it is 2.5mm OD and from your calculation it's likely to be the coarser of the ones in the table up thread (so a standard M2.5mm x 0.45mm pitch screw ).
Good luck

[Jim77]

Thanks Colin - the ones I can find the head diameter is about 1mm too wide. I guess if it doesn’t fit I will have to file it down slightly?

[531colin]

Got a pair of trigger shifters that some genius has left out in the rain for a few years.
Do we suppose the bolts are common to the various Shimano types? (I guess they are)
Do you want the bolts out of one shifter, and which one?
Scrub that, the bottom cover is common isn’t it?