M-gineering wrote:

Charles Ping wrote:

I can't find the definitive answer so if you'll forgive me.......

I have a frame with a 1 1/8" head tube (ID something like 33.8mm)
For now I would like to use some 1" threaded forks that are gathering
dust. What's the best sensibly priced conversion that uses a threaded
headset to get my 12 year old out and about?

two headset reducers and a 1" headset

Correct, but make sure the steerer is long enough and has sufficient
thread before splashing out. A good bike shop can cut extra thread if
needed, but it will cost. If the fork needs work, price up a 1 1/8"
carbon fork off eBay - normally about £60.