What is this drill bit for?

[Ali]

????

Got a few of them.

Special application?

Made by Guhring but the part numbers etched in give me nothing on google.

 

[mechman]

Seen them with 4 flutes and were called core drills, they were mainly used for drilling rough casting bores etc.

 

[Paul.]

Three flute drill, used for drilling hard stuff, also useful for opening out existing holes without them going a funny shape

 

[northwest]

I will buy them if you are selling?

Great on sheet metal and plastics.

Edit: And keeping holes round as ^^^^

 

[fizzy]

I used something similar for phosphor bronze. Normal bits would snag.

 

[Ali]

Thanks. I think they’re all 7.5mm or 8.5mm so I can’t see myself reaching for them too often. Not sure how many I have, if more than 5 I might sell the rest. I’ll have to try them out on a few bits.

 

[Seadog]

+1 for core drill.

 

[whm_fab]

theyre great for drillinng perspex / lexan etc

 

[outofthefire]

I used to grind a steeper angle for drilling stainless and 8.5 is drill size for tapping 10mm x1.5 so a useful drill to have in your box.

 

[Morrisman]

Seen them with 4 flutes and were called core drills, they were mainly used for drilling rough casting bores etc.

Yes, usually used in a jig to open up holes in castings without deflecting too much.