Although many designs of quick-set tool holder have been produced probably the best known and most widely used is that originally manufactured by Dickson in the UK. The units are made from high quality steel hardened and ground and produced in a variety of sizes to suit lathes from 89mm (3.5-inch) to 381mm  (15-inch) centre height. Ordinary and extra-long toolholders to take standard, parting, boring and Morse taper bits are available and, once mounted in place on the central block, can be quickly adjusted in height until the best cutting effect is found and the setting locked. This completely obviates the need to fiddle with packing pieces and, if kept together, the holder and tool can now be guaranteed to drop back into exactly the same position every time they are used. It is strongly recommended that, in order to get the best from the assembly, a selection of extra holders is acquired so that each commonly-used tool can be given its own and left in place.
Whilst the larger sizes are largely immune to heavy handling the three smallest models should be treated with care: it is not necessary to brutally yank up the adjustment and retaining screws; instead, just firm hand pressure will lock the units securely against the heaviest work. Full details of the Models and their measurements can  be found below.
Spares for these units are available.

S1