Not discounting the comments above, to fit a removable steering wheel is quite simple. I have one on my car which I can assure you Frank did not fit!
There are basically two popular designs in the uk. One is a hex shaped based system and the other more similar to a spline as you would see on a gearbox input shaft. The former cost me about ú45 and the latter ú95. There are two parts to each system. The slug which requires to be welded to the steering column and then the attachment to which your steering wheel bolts on to. With steering wheel makes having different bolt patterns you need to ensure you get the right adapter kit as part of your purchase. If you have a really odd ball steering wheel then you can turn up an adapter quite easily on a lathe. I did this on our Lotus 51. A bit more than 5 minutes this time!
On the GTD standard steering column the slug on the hex type adapter slips over the existing spline at the top of the steering column perfectly. Either remove the column or be extremely careful, but just weld the slug in place making sure the fore and aft positioning is how you want it and that a reasonable penetration of the column up the slug is used.
To make the steering wheel point ahead you have the spline at the foot of the column for adjustment. Or just be jolly clever in your initial marking and alignment of the slug.
Dave Parker has a spline style adapter on his R42. This car has indicator stalks etc. However that has not prevented him making his wheel clip on.
I have both types of adapters fitted to cars in my garage. The Hex style one is easier to use but has a fraction more play in it as it only has the six mating surfaces. The spline style is fancier but is more difficult to use but once on is more precise. Having used both I would say the spline style adapter is better overall.
Trans Autosport (TAS) make a version of the the hex adapter and SPA make the spline adapter.
There are other adapters out there but these are the most commonly used items I know of.
A brief aside but having a clip on steering wheel helped me at Loton Park as with my car out of action, I was offered Julians car to drive. I only fitted his car with my steering wheel attached as it was a slightly smaller diameter than his but we had the same adapters so could swap in seconds. Very handy.
Hope this is of help
try searches at www.tas.com www.spa-uk.co.uk www.demon-tweeks.co.uk
[ October 30, 2002: Message edited by: Malcolm M ]