Drill bit types

[Goran HosinskyParticipant @goranhosinsky61367]

[Goran HosinskyParticipant @goranhosinsky61367]

There seems to be two basic HSS drill bit types, the rolled one and the ground one, the second being somewhat more expensive. What is the difference in use?

Goran
Canary Islands

[Speedy Builder5Participant @speedybuilder5]

Never come accross a rolled drill bit, just plain machined, and machined with clearance lands right the way up the drill on the edges of the spiral.

[Goran HosinskyParticipant @goranhosinsky61367]

Perhaps I am using the wrong terms but what I seen in the catalogues are

Rolled high speed, straight shank HSS drill bit

 respective

HSS fully ground drill bits,

Goran

[JasonBModerator @jasonb]

The rolled ones are a cheap basic form of manufacture, OK for a bit of DIY around the house but they are not as good as fully ground bits being more likely to wander, fracture of cut over/under size.

 

The main flute pattern is rolled and then the edges ground whereas a fully ground bit has the flutes and edges ground

 

Jason

[larry PhelanParticipant @larryphelan54019]

I have some rolled drill bits and never have any problem with them.

[Clive HartlandParticipant @clivehartland94829]

There was a programme on Discovery about drills being manufactured and they showed the flutes being milled both at the same time. The profiles of the flutes ground into the special cutters.

Clive

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