Mechanical tools: DRILL-HOLDING DEVICES

The types of drill holding devices

. name the types of dril holding devices

. state the features of drill chucks

.state the functions of driil sleeves

. state the function of drift

For driling holes on materials, the drills are to be held accurately and rigidly on the machines. The common drill holding devices are drill chucks and sleeves and sockets

Drill Chuck

Straight shank drills are held in drill chucks. For fixing and removing drills, the chucks are provided either with a pinion and key or a knurled ring. The drill chucks are held on the machine spindle by means of an arbor fitted on the drill chuck.

Taper sleeves and sockets

Taper shank drills have a morse taper. Sleeves and sockets are made with the same taper so that the taper shank of the drill, when engaged, will give a good wedging action. Due to this reason morse tapers are called self holding tapers. Drills are provided with five different sizes of morse tapers, and are numbered from MT1 to MT5.In order to make up the difference in sizes between the shanks of the drills and the type of machine spindles, sleeves of different sizes are used. When the drill taper shank is bigger than machine spindle, taper sockets are used.while fixing the drill in a socket or sleeve, the tang portion should align in the slot. This will facilitate the removal of drill or sleeve from the machine spindle.