Center Drill Bits

[John S]

Forget centre drills, they are a throwback to earlier days and were designed for putting in the support holes for centres on lathes, hence the name.

No commercial CNC shop would dream of using centre drills today, instead using what are called NC spotting drills.

These are very stiff short fluted drills that will start a hole off without wander and not break like the flimsy centre drills.

Nearly the same results can be obtained using a good quality stub drill.

John S.

[Robin Hewitt]

Forget centre drills,

And avoid "UK Drills" on ebay.

I bought £30 worth of cheap Jobbers bits, the first two I tried broke almost instantaneously, the rest followed them quickly in to the bin

Hi Kip

My Z axis is delayed. First I'm remaking my standoffs for the milling table. The previous set was too clever, interchangeable bolt holes in different sizes. I soon lost precision.

This time I'm making 20 in 5 different threads, all cut from the same 3/4" thick steel bar and all 3/4" thick

Robin

[Hogout]

Forget centre drills, they are a throwback to earlier days...... instead using what are called NC spotting drills.

John,

I have looked at the webpages of the usual suspects but none mention 'spotting drills' only centre drills. Do you have a source?

Cheers.