Dear Bob and all,
Not being a machinist, and being easily confused by "hybrid" (Metric + SAE specs) sizing on threadings like 10MM x 26 TPI, I am lost when Bob mentions a "full roll" tap. A brief Google search gave me some not-quite-applicable machinist references, plus listings for Spinal Tap (definitely OFF-topic) and other distractions.
Are there any good basic (simple enough for a home bike mechanic to comprehend) references about taps and threadings (mostly Metric in my case) that would not go too far into the "weeds" of production machining, CNC, etc.?
For example, is there an all-metric sizing equivalent of 10 MM x 26 TPI?
sleep-deprived as all get-out but enjoying the Tour de France none the less every morning at 5ish for the duration in Alameda, CA USA
Message: 1 Date: Sat, 17 Jul 2010 12:08:21 -0700 From: Bob Freitas <firstname.lastname@example.org> Subject: Re: [CR] Derailleur hanger threads To: CLASSIC RENDEZVOUS <email@example.com> Message-ID: <4C41FFA5.firstname.lastname@example.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
The size is 10mm x 26tpi but a 10 x 1.0 tap is close enough (25.4) I recall the official Tap (Campagnolo?) was $25 back in the day but you could find a 10mm spark plug tap at most any hardware store etc for just a couple bucks and that will work fine. Downside of any 'thread cutting' tap is just that it cuts the thread so in multiple use situations you will end up with less that was there before. Notching a tool or even a 10 x 1.0 bolt might be better but best would be a 'full roll ' tap which reshapes and does not remove any material. This would be for damaged threads if you were converting an non threaded dropout a thread cutting tap would be required. I have seen thread files with a threaded end to repair inside threads but have never seen anything adjustable like we see for outside threads. Anyone who has knowledge of such an item I would like to see it
Sunny MILL VALLEY, CA USA