I think I will just continue to spend money lol
Good news!
If you do enough of this, eventually the bits can be transferred to a new frame and the old one sold on (or kept...can never have too many. n+1). Even if the new frame is for a Rohloff drivetrain, the other things can be swapped.
I have a number of bikes and they have now formed a sort of food chain. When I improve one, the "other children" get the hand-me-downs so in effect upgrading one upgrades the others as well.
So pleased to find you've got a bike to actually start playing with. It is grand learning experience in every sense, often as much fun as the actual riding!
I was wondering if it would be a good time to treat any rust
It is never too early to treat it. If left, it it can become too late.
Or to clean up the inside of the head tube ? Is that what is called? The bit the fork goes through
Yep. Much easier while the bike is apart.
Should I put any kind of oil or grease or wax inside this tube to protect it from future rust ?
I would. Automobile panel cavity spray (like Waxoyl) or bicycle-specific Framesaver are good. Or you could go old school and boil linseed oil and pour in the vent holes (horribly messy and can clog threads) or straighten a coat hanger and form a small loop to hold an oil-soaked rag you can swab up and down inside the main tubes. All worked back in the day but the modern sprays are much more convenient and ultimately more effective, requiring less retreatment.
Also I thought I read not to put any grease on the fork , well the bit that the stem attaches too as I could slip off and be dangerous ? Think I read that in Thorn literature a long time ago
Yes, that was the word. I sprayed on and wiped off some Boeshield and have had no problems and no rust on the paintless steerer to date. The current Thorn fork steerers have an ED treatment that prevents rust.
Best,
Dan.