Center Drills

[elevator joe]

Has anyone ever used a center drill from a milling machine in a cordless drill?
I have a small project coming up and thought it might work well instead of a drill bit and a countersink.

 

[rbgearz]

Use them all the time. They work great.

 

[elevator joe]

Do you use high speed steel or carbide, how long do they last on steel? Thanks: Joe

 

[rbgearz]

I just use the HSS. They last a long time if you're careful with them.

 

[Trucky]

Never use carbide out of a machine. HSS in a drill is sketchy but it'll work okay...

 

[dockterj]

Center drill or spotting drill? I wouldn't use a center drill in a hand drill motor - very likely to snap off the tip.

 

[rbgearz]

I use them alot in hand drills and I have snapped the tips off. Like I said...be careful.

 

[cmandp]

Never use carbide out of a machine. HSS in a drill is sketchy but it'll work okay...

This. You could break off the bit in the hole or very likely chip the heck out of the flutes and/ or cutting edges. I learned by mistake. Ruined a bit and still didn't get the set screw out.

 

[BFalfa]

where is a good place to buy center drills?

 

[jsaw]

I use them alot in hand drills and I have snapped the tips off. Like I said...be careful.

That has been my experience also

 

[bobadame]

They work very well for drilling sheet metal. For drilling stainless steel sheet, a cordless drill turning slow with Molybdenum Sulfide ( molly-d) as a lubricant is the way to go.

 

[lilscorpion]

They do make step drills that has a chamfer edge on the step for this specific purpose. The difference is you can make an accurate countersink for the size fastener you intend to use with the correct center hole for the machine screw. I've used them in plastic and aluminum before but they'd work in steel just as well. I get decent life out of them on the mill but it's easy to control the perpendicularity to the material and the feed rate. The biggest challenge you'll have in a hand drill is managing those given they're all really up to the operator. Being able to do so will certainly improve cutter life. Regardless, check out step drills, I think they're what you're looking for and the shank will be easier to chuck in your drill.

Here's an example of one: Countersink Step Drill

 

[saabman]

I use spotting drills (simple 90 degree cutting face, no step tip) all the time in my cordless drills hand drills.