Generally .370 for irons and .335 for woods these days.
Hosel is the the socket (or neck) in the head of a golf club into which the shaft is inserted.
hosel
The hosel is the part between the club face and ferrule.
The Hosel (one 's') is the socket or neck in the head of a golf club into which the shaft is inserted.
Shank
The socket is known as the hosel, it is where the head is connected to the shaft.
ho·seln.The socket or neck in the head of a golf club into which the shaft is inserted.Above retrieved from Answers.comViper1
What is the hosel size for Ben Hogan bh5 golf clubs? irons
All golf clubs are measured in inches. Just a shaft is simply measured top to bottom. When a golf club is assembled, with a head and grip, an iron is measured from the top butt end of the grip to the bottom of the hosel. When a wood is being measured it should be measured to the closest point of the sole to the hosel.
It varies from club to club. It is on one of these; the hosel of the golf club, on the shaft, on the shaft sticker, underneath the grip or somewhere on the head. It is quite easy to find. If you cannot find one, it may not be the original shaft or it simply may not have one.
This is the width of the bottom of the shaft, where it enters the hosel.
Use an abrasive on shaft and inside hosel, clean with acetone or alcohol, let dry, use 2 part epoxy on shaft and in hosel, join the 2 together, wipe off excess glue, allow to cure 24 hours before using.