I just engraved glass, shale, and a pebble from the seashore with 4 of these diamond point bits. Then I drilled a glass bottle as well. After all that, the bits still have a diamond coating although it's not quite as obvious and sparkly as it is on the unused bits. All bits fit perfectly into a Dremel 3000 with the standard collet. None wobbled. See photo to compare before/after shots of the ball point bit.

I just engraved glass, shale, and a pebble from the seashore with 4 of these diamond point bits. Then I drilled a glass bottle as well. After all that, the bits still have a diamond coating although it's not quite as obvious and sparkly as it is on the unused bits. All bits fit perfectly into a Dremel 3000 with the standard collet. None wobbled. See photo to compare before/after shots of the ball point bit.

I just engraved glass, shale, and a pebble from the seashore with 4 of these diamond point bits. Then I drilled a glass bottle as well. After all that, the bits still have a diamond coating although it's not quite as obvious and sparkly as it is on the unused bits. All bits fit perfectly into a Dremel 3000 with the standard collet. None wobbled. See photo to compare before/after shots of the ball point bit.

good one

good one

good one