Machinist question?

[Capt. Dave]

How do you get a broken cobalt drill bit tip out of a piece of titanium rod? I had a pilot hole, so I thought I could punch it out from the other side. Nope, broke the punch. Thanks for any input.

 

[fla kid]

I think I remember they useto make a remover bit for some sizes

 

[ls1_guru]

Well, in a perfect world an EDM would get it.

We don't have one in the shop so what we do is really small diameter round end mill on the Bridgeport at high speed in the center of the bit and basically mill it out.

Takes time and pucker factor x1000

 

[Zeroed in]

A Carbide drill bit can cut thru a Cobalt bit.

 

[Capt. Dave]

So drill a new hole is the best option?

 

[ls1_guru]

Not a new hole, trying to get the broken one out.

A Carbide drill bit can cut thru a Cobalt bit.

Same reason we use a carbide round end mill, but with a hand drill you don't get the RPM or stability needed so it's sketchy..

 

[lil'skeet]

Whew, that is 2 hard materials there. Was thinking heat on the titanium to help expand it a little but sounds like you have the other end plugged up.
What is the size of the drill bit?
Keep us updated on how you make out.
ls1_guru sounds like the one to help you on that.

 

[Zeroed in]

So drill a new hole is the best option?

Probably the only option left. Maybe drill out the pilot hole on the opposite side up to the cobalt, then try and punch it thru?

 

[Capt. Dave]

It’s a very small hole. 7/64. It’s not an important hole, so a new one seems to be the best option. It’s on a small marlin spike I’m making. I can cover the broken hole with knot work.

 

[ls1_guru]

Yea if you can get around it with a new hole that would be the best option.

 

[Zeroed in]

I've busted many cobalts mostly in SS. I bought those Spyder Blue HS bits at lowes to cut the cobalt. It was working great until the spyder caught a bind and snapped (easy to do with small diameter bits). But I eventually drilled around them and got it done.
g/l

 

[ls1_guru]

That is something I learned with SS, the harder cutters are not the key with that stuff, they break. HSS at the right speed seems to last the longest.

Still takes a long time tho.

 

[Capt. Dave]

Here’s what I got. Nothing important,just a project. But yea two very hard metals leave few options.

 

[ls1_guru]

Has that been heat treated?

I know how I would punch a hole through that, with the water jet haha..

 

[Zeroed in]

True, but I was using a handheld drill, variable speed. And you know how that goes, start out slow to medium and before too long, you're wondering why the bit isn't cutting any longer, then you realize you're running max speed on the hand drill.

 

[ls1_guru]

True, but I was using a handheld drill, variable speed. And you know how that goes, start out slow to medium and before too long, you're wondering why the bit isn't cutting any longer, then you realize you're running max speed on the hand drill.

Yup, smaller diameter likes that RPM's, and some of them will definitely let you know if you're not in the sweet spot.

 

[Zeroed in]

Can you cut the hole a little bigger, then try and tap it out?
Then fill the hole with jb weld marine, then re-drill the hole 180 degrees. Would that work?

 

[Zeroed in]

* Not 180 degrees, but 90 degrees

 

[ls1_guru]

Same thing I was thinking, just a matter of how far in the broken bit is

 

[stage20]

If you have a welder, weld a nut to it. Even if it's down in the hole, hit it with some wire till it builds up and grabs the nut. Spin it all out then.