Drilling a case hardened bolt

[Aerovette]

Need some help.

I'm putting a head gasket in my parent's car and the last "expert" that worked on it, broke a bolt off in the head. (Actually TWO bolts. One he managed to get a heli-coil in, but it's in crooked and a bolt only goes in a few turns).

Anyway I bought a titanium and two cobalt drill bits and they are barely scratching the bolt. I was told, and read, that cobalt it is. Best for a hardened bolt...but it's not doing shit.

I don't have a welder or I would weld a bolt to the broken bolt and back it out with a wrench.

What can I try next?

EDIT: It is an exhaust manifold bolt not a head bolt. I left that part out.

[Bill]

Try an ease-out?



Or, if you just can't get it out, use a little extra RTV sealant around that area of the gasket.

[Aerovette]

Originally Posted by bill_daniels

Try an ease-out?



Or, if you just can't get it out, use a little extra RTV sealant around that area of the gasket.

Well Bill, to use an EZ out....I GOTTA DRILL A HOLE

[the new me]

Originally Posted by bill_daniels

Try an ease-out?

I would guess the reason he is trying to drill the bolt is so he can use a screw extractor like the Drill Hog.

[Bill]

Originally Posted by aerovette

Well Bill, to use an EZ out....I GOTTA DRILL A HOLE

Try a smaller diameter drill bit to make a pilot hole first? And don't forget a little WD-40 or other lubricant to keep things from getting too hot.


Also, I'm more of a big picture guy, I don't get bogged down on details!

[Aerovette]

Originally Posted by bill_daniels

Try a smaller diameter drill bit to make a pilot hole first? And don't forget a little WD-40 or other lubricant to keep things from getting too hot.


Also, I'm more of a big picture guy, I don't get bogged down on details!

I did. I started with 1/8. Got nowhere.

[Bill]

Originally Posted by aerovette

I did. I started with 1/8. Got nowhere.

I don't know. Try a new titanium set like this. Drill at a slow speed, use oil.

https://www.amazon.com/DEWALT-DW1354...language=en_US

[BayouCountry]

Remove the two bolts holding the exhaust manifold to the tail pipe and pull the head with the manifold attached. See if the machine shop can remove the bolt when you take the head in for resurfacing.

[ZipZap]

Manifold bolts are the absolute worst when they get f'ed up. The heat, as well as someone who screwed up previous work, can make for a frustrating job.

Titanium bit. Oil. Compressed air to clean out crap as you're drilling.

The whole easy out thing might never work, so be ready to drill and tap for a new bolt.

Not a great way to spend Independence Day weekend!

[Rodnok1]

Is the Rodeo head aluminum or steel.
Use a quality bit with a pilot tip.

[Aerovette]

Originally Posted by Rodnok1

Is the Rodeo head aluminum or steel.
Use a quality bit with a pilot tip.

The head is aluminum.

[ratflinger]

Originally Posted by BayouCountry

Remove the two bolts holding the exhaust manifold to the tail pipe and pull the head with the manifold attached. See if the machine shop can remove the bolt when you take the head in for resurfacing.

You're pulling the head anyway, let the machine shop handle it. They should have all kinds of tools and knowledge for this. Then let them repair the 2 fked up bolt holes, properly.

[Mick]

One problem with steel bolts is that when you start drilling, you can't stop until you get done what you want, because the drill "cold works" the metal. Once the metal is cold worked, it reaches 9+ on the Moh's hardness scale, and becomes nearly impossible to penetrate with another drill bit.

Back when I used to do a lot of work on VWs, the exhaust manifold bolts would break off regularly. People found out I had successfully removed a few, and would ask me if I could try to get the broken bolt out for them. I would ask them "did you try to remove it yourself?" If they said "yes", I said "no".

[Aerovette]

What bit would a machine shop use? That's all I need. I know how to drill, I just can't find a mean enough bit to shred the bolt.

[ratflinger]

Originally Posted by aerovette

What bit would a machine shop use? That's all I need. I know how to drill, I just can't find a mean enough bit to shred the bolt.

There are specialty bits for things like this. Not available in HD, Lowes, or any other place you shop. There will be stores online that sell these. When I was still installing heavy medical equipment we used special cutting bits for rebar (when we hit it) in our Hilti hammer drills. These were well over $80 apiece 20 years ago, but they cut rebar like butter. Even the Hilti bits were almost that price, but they lasted 10x longer than any crap you could buy at the box stores.


Cliffs: Probably cheaper to let the machine shop do it than to buy the bits yourself.

[6spdC6]

Originally Posted by ratflinger

There are specialty bits for things like this. Not available in HD, Lowes, or any other place you shop. There will be stores online that sell these. When I was still installing heavy medical equipment we used special cutting bits for rebar (when we hit it) in our Hilti hammer drills. These were well over $80 apiece 20 years ago, but they cut rebar like butter. Even the Hilti bits were almost that price, but they lasted 10x longer than any crap you could buy at the box stores.


Cliffs: Probably cheaper to let the machine shop do it than to buy the bits yourself.

I have installed quite a few things myself, floors, walls ceilings and know what it is like to hit a rebar, and the anchor has to go right there. We cheated and got the job done. Drill as far as you could and then get a cutting torch an basically melt out the rebar that is in your way. Then continuing drilling and then install anchor. Course all that hot flame in the hole will make some interesting popping and shit flying. Just telling about rebar, this will not help out the OP!

Now retired but a steamfitter/ welder for 40+ years!

[The_Dude]

I would take it to the guy (machine shop).

[DAB]

(looks around)....it might be dead Jim, it might be dead.....

[JRD77VET]

Originally Posted by ratflinger

You're pulling the head anyway, let the machine shop handle it. They should have all kinds of tools and knowledge for this. Then let them repair the 2 fked up bolt holes, properly.

You want to pay extra for the repair? Keep messing with it. The more screwed up you make it, the more it's going to cost to fix it correctly.

The crooked helicoiled hole can be repaired with an insert.

A machine shop isn't going to use a hand held drill, they'll use a bridgeport or similar machine to CONTROL FEEDRATE and LOCATION.

I do helicoil repairs to the Kawasaki Triple oil pumps. First thread repair is $35 and $8 for each one after that. If somebody already installed a helicoil or similar "repair", price is $60 PER HOLE.

"Wanna be machinists" make my life difficult and they pay for the aggravation

Originally Posted by Mick

One problem with steel bolts is that when you start drilling, you can't stop until you get done what you want, because the drill "cold works" the metal. Once the metal is cold worked, it reaches 9+ on the Moh's hardness scale, and becomes nearly impossible to penetrate with another drill bit.

Back when I used to do a lot of work on VWs, the exhaust manifold bolts would break off regularly. People found out I had successfully removed a few, and would ask me if I could try to get the broken bolt out for them. I would ask them "did you try to remove it yourself?" If they said "yes", I said "no".

Work hardening

[Aerovette]

Interestingly, I saw a youtube video where they used a masonry bit.

It did well...until it didn't.

I am most likely going to put to together without that bolt. Tired of fkn with it and I don't know of any machine shops nearby that would do it.