Bar end shifters bolt problems help

[fr188]

Hi I've just wanted to try 9 speed Dura Ace bar end shifters on my vintage bike, which hasn't any leaver bosses on my Carlton Pro, I have a vintage Dura Ace band on clamp with bosses , but when I try and fit the barrel justing stops which can with the bar ends on to the clamp the 3 mm Allen screw is too tight and won't fit in the vintage band on clamp, I'm assuming that the the old clamp is old imperial measurements, what can I do? Can I tap out the old clamp with a 3 mm tap?

 

[Yellow Saddle]

Any screw has a known major and minor diameter corresponding to the peaks and valleys of the thread. The depth of these are defined by the type of thread - BSA, Metric, Metric Fine, Metric Coarse etc.

Conversely, the tapped hole has a major and minor diameter too. If you want to retap a hole to say a 3mm Metric tap, you must ensure that your current major diameter in the hole does not exceed the minor diameter of a 3mm metric screw. For that you need to know what type of thread you have in there to start off with.

Without the right tools you cannot say for sure. But, with experience and savvy you can make a good guess. The dimensions for the metric machine screw's thread you have are available online. Start there and work backwards.

 

[fr188]

Thanks for the reply, I just tryed it with and old Huret downtube band on and the barrel adjusters fit on & screw in quite well, so I don't know I I'll leave it like that or try and tap out the D/A band on

 

[fr188]

Went with The Huret band on fits fine, however there is now an annoying rattle on the right hand lever I think it's the plastic round bit were the sis & friction wording is printed on I'll have to figure out to eliminate it, apart from that it works fine in friction mode as I have a D/A 7402 rd