Chuck size determines the size of shaft which can be driven by the drill. The common chuck sizes are 3/8 and 1/2 inch (10 and 13 mm).
- 3/8 inch (10mm) - light duty, suitable for most 'every day' tasks - appropriate for all Jiffy mixers EXCEPT the PS-1 and PS-2
- 1/2 inch (13mm) - heavy duty, will accept up to 1/2 inch shaft - only required for the PS-1 and PS-2 Jiffy Mixers