125) A hole is drilled in a lathe by using a Dia 10 mm straight shank drill held in a drill chuck. After a short distance of the drill travel, it rotates along with the work. Which one of the following is the cause for this defect ?

Chips getting clogged

Centre not aligned

Spotting at the centre not done

Feeding by tailstock hand wheel is too slow

Answer is:

Chips getting clogged

The positioning of the taper turning attachment is not correct

The tool setting is not to the centre height

Play between the sliding units

Workpiece is not rigidly held

Answer is:

Boring tool springs its travel

Coolant is not applied with force

Tool set below centre

No secondary clearance ground on the front cutting edge

Answer is:

support the tool rigidly to avoid chatter during operation

support long shafts that are being threaded for their full length

support workpiece during facing large diameter workpieces with short length

support long workpiece held in chuck, to perform operations at the overhanging end

Answer is:

The angle of chamfering is not correct

The chamfering tool not set square to the work axis

The work face not running true

The overhang of the tool is too much

Answer is: