Long shot… grub screw size fan blower

Hi all
Does anyone happen to know the grub screw size which holds the fan on the smiths motor spindle on a Series 3 blower please? I’ve tried metric replacements but to no avail. Assume some form of imperial size.

Despite putting the grub screw in a very safe place and reminding myself numerous times not to lose it… I’ve only gone and forgotten where I put it

Thanks all as ever!
AK

No idea what size but it will be imperial.

Posting for future reference in case ever needed! Finally found the correct grub screw size:

10/32 x 1/4