OK, Time for a bit of an essay
as mentioned above – last week wasn’t the best for progress …
The fork threads were slightly damaged from the tab washer on the headset (5mm either side of the tab washer groove). The bike shop that my friend works at didn’t have the die to repair it (quite a new shop and no need for a 1” thread die) so this was the only bike build job that I couldn’t borrow the tools for and do myself
I took the forks to a long standing family bike shop that’s quite local to me. It’s a husband / wife business and very ‘old skool’ – just what ‘I thought’ I wanted. "Yes no problem we can do that for you while you wait. It will only clean the treads up" Great, so I thought … 10 mins later (and a lot of banging from the workshop) the forks reappear, covered in grease. "Done – we do that job FOC" Sorted I thought, bought some stuff from the shop as a thank you, wrapped the forks in a rag and left. Got home to clean the grease off to find that the threads wiped off with the grease and the nice new plastic lining had suffered from hammer rash !
About 2 hours with the 2000’s wet and dry removed all the hammer rash apart from one knock that was a bit deep and had gone down to the primer. Luckily this is within the ‘cable rub’ area so will be covered with the protective pads – a great testament to the powder coat as it A) stood up very well in the first place and B) was thick enough to flat down and look like new again.
The treads were OK for about the top 10mm, bad for about the next 10mm (where the cup sits) and then OK again further down.
The threads that were damaged were stripped around two thirds of the diameter leaving just the base of the thread and a jagged surface
I have been building the threads back up with Devcon titanium putty (which I can borrow from work) with the aid of an old headset cup. I degreased everything, screwed the cup to the base of the thread, coated the thread in putty, let it go slightly tacky and then unscrewed the cup off the fork to reform the damaged threads.
I wasn’t hopeful at first but after a few goes it has actually worked really well and looks / feels pretty good providing a nice tight thread
My plan is to now clean the thread properly with the correct tool to ensure it is square and then (if needed) repeat the putty treatment until perfectly formed / square.
I don’t plan on using the damaged area of the thread to lock the cup onto as per normal 1” threaded design, I will use the good part on the top of the steerer for that. That’s why I am looking for the headlock style of locknut i.e. the locknut should provide the support and locking for the top cup, time will tell …
The rethreading tool has now been sourced through my friend. Their shop is in a chain and one of the shops far up north had one in the workshop. Hopefully that should arrive via their internal delivery system some time today
Second thing that went a little wrong was the anodising. DISCLAIMER !!!
– Don’t think I am having a pop at anyone with an old ally bike and or parts !!! but never has it been so apparent to me, the potential weaknesses that may be in old aluminum that has been left unprotected and / or with damaged anodizing
The parts that were either natural ally or had scratched anodising had all been flatted down and buffed up a little before they went. I normally send stuff in this finish and it comes back great, note that these components would have polished up well and ‘looked
’ good. Unfortunately (should that be fortunately ?) the etch part of the anodizing process has shown up what I can only describe as micro corrosion as it cleans the surface. This is quite concerning for me as even some parts (my seat post for one) that only had a few small scratches on have actually suffered quite badly and enough for me to be concerned about putting by overweight arse on it (just on the back / bottom of the post where it clamps / gets scratched and were crud can find its way in). The anodisers had seen it before and think it’s to do with age and salt attack. I suppose other then using a dye penetrant on stuff there was no way of guessing beforehand that the parts would have this reaction. The mind boggles in what surprises there may be in old ally frames / parts that have been (and are still) used hard and left damp with road salt etc…
What did cheer me up a little though was that all the new and ‘undamaged’ anodized parts in the same batch all came out great
Hopefully the next update will have pictures of the repaired forks and machined XT thumbies – sourced via Canada from RockiMtn
Then I can finally start building the thing …