Joined: Jun 2022 Posts: 1 Threads: 1
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0
Location: Yorkshire
Car type: Austin 7 1929 two seater sports
Hello. Ive foolishly started fixing my fathers chummy and the problem is that the starter dog nut won’t go into the threads on the end of the crank. The reason this has happened is because the threads removed themselves from the nut and have welded themselves into the end of the crank. I have since found the correct taps but they don’t seem to be taking to the cranks. Is this because I have a phoenix crank that has been hardened? Do I need HSS taps? Is the hole now to small? Oo forgot to mention, it’s a mag engine. Any help would be appreciated. Cheers.
Joined: Aug 2017 Posts: 142 Threads: 29
Reputation:
2
Location: New Forest
Car type: 27 Chummy
Hello Wilfred
To the best of my knowledge the thread is a non standard 5/8 x 16 Whitform so not BSF. If you have the correct tap it should clean out the thread of a hardened crank.
However, I have had a Phoenix crank in the past that had an under size thread in the nose. I had to screwcut the starter dog under size to get it to fit.
Hope that helps.
Adrian.
Joined: Mar 2015 Posts: 5,443 Threads: 231
Reputation:
67
Location: Scotchland
Mag starter dogs need to be altered to fit into a Phoenix crankshaft.
You need to waste the threads nearest the front.
Joined: May 2018 Posts: 2,955 Threads: 558
Reputation:
20
Location: Peak District, Derbyshire
Car type: 1929 Chummy, 1930 Chummy, 1930 Ulster Replica, 1934 Ruby
A perfect explanation with all the essential pictures. Thanks you for taking the time and trouble to post.
