What is a #2 center drill

[Pontiac787]

I have been looking at some 115 piece drill bit sets and noticed that a few come in a case with an open hole in the center. The hole is labeled "For a #2 Center bit". Now after learning that a spotting bit is used to start a hole and a Center bit is actually used when working with a lathe I would think the open spot would be for a spotting bit but spotting bits don't seem to come in numerical sizes. What's going on here?

 

[rlitman]

It is for a lathe, but you can use a centering bit as a spotting bit.

 

[JKady]

It's a size #2 center drill

http://www.mscdirect.com/product/details/01031327

 

[astroracer]

A centering drill is used in the lathe to put a "center hole" in the ends of a long piece of stock that will be turned between centers. it can also be used as a spotting drill for drilling holes, as mentioned.
Mark

 

[larry_g]

I have been looking at some 115 piece drill bit sets and noticed that a few come in a case with an open hole in the center. The hole is labeled "For a #2 Center bit". Now after learning that a spotting bit is used to start a hole and a Center bit is actually used when working with a lathe I would think the open spot would be for a spotting bit but spotting bits don't seem to come in numerical sizes. What's going on here?

I think that your looking at bit sets for lathe use. You need to find sets for a drill press. They should have a place for a spotting bit....

lg
no neat sig line

 

[hautpot]

Center drills are to be used in conjunction with live centers.

 

[sk farmer]

Center drills are to be used in conjunction with live centers.

or dead centers...............

 

[bmxdad]

Wow ...

Center drills are very short shanked with a larger dia. body. They're only made to go down .100 or so. They are basically pre-drills. Picture below is a center drill. Tip goes in and the larger body leaves a small chamfer to center the full size drill. Otherwise the split center could walk the drill. They are mostly used on cnc mills. They are used on lathes too, but a turning part will self center. Hole might be bigger, but still on center. A turning tool can walk. If you don't have center drill, a good center punch will work too.

They are not made to drill actual holes ....

 

[larry_g]

Wow ...

Center drills are very short shanked with a larger dia. body. They're only made to go down .100 or so. They are basically pre-drills. Picture below is a center drill. Tip goes in and the larger body leaves a small chamfer to center the full size drill. Otherwise the split center could walk the drill. They are mostly used on cnc mills. They are used on lathes too, but a turning part will self center. Hole might be bigger, but still on center. A turning tool can walk. If you don't have center drill, a good center punch will work too.

They are not made to drill actual holes ....

I'm going to disagree with you here. As said in posts 6&7 they are for putting a center point in a piece to be turned on a lathe between 'centers'. They are designed to drill to full depth of the 60* angle on the end, not just .100". It so happens that they make a fairly good spotting drill, but that is not their intended use.

lg
no neat sig line

 

[bmxdad]

Yes, they are used to put in a center mark for a lathe center, but they do more than that.

Tomatoe ... Tomotoe