Drilling hardened steel

[Timberwolf]

Upon closer inspection, that hole IS way off!!

.........
The blunt tip on the carbide masonry drill made it "walk" off the sweet spot..He needed a pilot hole, but the pilot drill would have probably walked off also......

[Cecil]

Thanks Peter.  I plan on using some old Rigid planner blades.  I will keep this in mind for a relatively cheap drilling solution.  Like you, it will be for an occasional project, so your method should work well for me too.

[Peter Tremblay]

Upon closer inspection, that hole IS way off!!

[Peter Tremblay]

.........
The blunt tip on the carbide masonry drill made it "walk" off the sweet spot..He needed a pilot hole, but the pilot drill would have probably walked off also......
 
 

Yup.

There is just a bit of walk.

The only solution that I can think of is a small divot made with a punch of some sort but I don't have a tool that is hard enough to divot this steel.

[AgGEM]

Yup.

There is just a bit of walk.

The only solution that I can think of is a small divot made with a punch of some sort but I don't have a tool that is hard enough to divot this steel.

Well, a carbide countersink would keep center for you. That is how it is done.
But they are pricey.
Ag

[Timberwolf]

Well, a carbide countersink would keep center for you. That is how it is done.
But they are pricey.
Ag

...............
I think a Dremel with the properly shaped diamond {or aluminum oxide} burr {like a round nose} would dimple it enough to keep the carbide bit on the mark...The hole could also be drilled with a bottom cutting carbide end mill if the piece could be clamped solidly in place.

[Peter Tremblay]

Thanks Jack,

I don't have a dremel tool but the diamond bits are very inexpensive. I'll get one and try.

I could chuck it in the drill press and use very light pressure to create a dimple. Then remove it and chuck the masonry bit without moving the X-Y vise.

I was thinking about a carbide end mill but I thought I'd try the $11 solution first.

[daddo]

Drill the hole in a softer metal plate then clamp that plate on top of the blade placing the hole where you want it, then drill it. Use a quick and deliberate start on the bit and it shouldn't wander much. The extra depth on the softer metal will allow you to fill it with oil.

[Peter Tremblay]

Drill the hole in a softer metal plate then clamp that plate on top of the blade placing the hole where you want it, then drill it. Use a quick and deliberate start on the bit and it shouldn't wander much. The extra depth on the softer metal will allow you to fill it with oil.

Great idea.

What thickness would you recommend for a minimum on the "guide" plate??

[CLETUS]

Thanks Jack,

I don't have a dremel tool but the diamond bits are very inexpensive. I'll get one and try.

I could chuck it in the drill press and use very light pressure to create a dimple. Then remove it and chuck the masonry bit without moving the X-Y vise.

I was thinking about a carbide end mill but I thought I'd try the $11 solution first.

Carbide ball end mill in a dremel to create the dimple will work. A carbide center drill would be the right tool. You're still limited by the slop in the quill.