[406chevelle]

I was all stressed out about drilling the steam holes in my AFR heads, so I did a ton of research and even made a tool to make sure I had the right alignment, bought high quality drill bits and started drill the holes one after the other,




I’m think hey this isn’t so bad, it’s actually pretty easy when out of the blue the drill bit breaks, not good, 1 ½ inches of drill bit stuck about ¼ of an inch down in the head.

I’m feeling pretty $crewed right now.

Any ideas on how I might be able to get the drill bit out?????

Any help is appreciated.

406chevelle

[Ghetto Jet]

This is not an expert opinion but it might help. Go to the hardware store and get whats called left handed drill bits, as you drill with those they will pull your broken bit out. Or you can try using drill bit thats a size or two smaller and try to drill through the broken bit.

Mike

[TurboS10]

If you broke a good bit, you will never drill it with another one. If it is 1.5 inches in I think I can assume it is all the way through. I would probably try to see if there is enough room in the water jackets to just push it on through and shake it out. If not, you could probably make some kind of tool that would slip in the flutes of the bit and unscrew it out of the hole. It would take some good material and some time with a dremel, but the bit should back out fairly easily if you can just get a hold on it.

Chris

[Frisco]

Take it to a good machine shop (not an automotive machine shop) and have it removed by EDM.

You can not drill out a broken drillbit with another drillbit.

If there is a small portion of the broken drillbit above the surface of the head; you might be able to grab it with a pair of pliers and then turn it counterclockwise to back it out. Actually, turn it slightly in both directions to break the chips loose from the flutes of the drillbit while pulling up. If there are any chips that can be removed with air, a pick, tweezers, etc. try to remove them first.

Good luck!

[406chevelle]

Thanks for the replies Guys.
There is no way to drill this out, it is down in the hole about a ¼ of an inch, and had about ½ an inch before it come through the other side, I don’t think I could have messed it up any worse then I did, well lets wait and see what happens when I try and get it out, maybe I can make it worse.
I cleaned out the loose chips the best I could and tonight I’m going to pick up a very small pair of needle nose pliers to try and reach down in and turn it out.

Frisco, I may have to take it to a machine shop, I was trying to picture how they would get it out with out harming the head, I feel stupid trying to do it myself, but last time I had machine work done, they drilled a hole through the side of my crank, so I was leery about having very precise holes drilled in the heads, the machine shop has a very good reputation, but good help is hard to find and the owner has a few flunky’s working for him.

MED electrical discharge machining, I looked around on the web a little bit but could not find anything explaining this method of machining in any detail, can you explain how they might use this method to machine out a drill bit??

I was thinking about just sending it to 4 Jaw Chuck, I know he has nothing better to do, and my heads would come back perfect. LOL, JK 4 Jaw, but you are the man.

Thanks again for the replies,

406chevelle

[Frisco]

Originally posted by 406chevelle

MED electrical discharge machining, I looked around on the web a little bit but could not find anything explaining this method of machining in any detail, can you explain how they might use this method to machine out a drill bit??

Thanks again for the replies,

406chevelle

EDM is not a method to drill out the material. It uses an electrode (usually carbon or copper) to burn out the material. The electrode in your case should be the same size as the drillbit. It should also be set at the same angle as you were drilling. Most automotive machine shops don't even know what EDM is. This is why I suggested going to a good machine shop.

Side note: It looks like you were drilling the holes without any cutting agent in the photo you posted. That is more than likely the reason the chips jammed up the drillbit and broke it off. The chips also look powdery. This may be to your advantage. Since no apparent cutting fluid was used, the chips may be able to be picked out and blown free of the hole. This would then "free up" the broken drillbit. Do not use a Dremel tool. It will just make the situation worse.

[406chevelle]

Side note: It looks like you were drilling the holes without any cutting agent in the photo you posted. That is more than likely the reason the chips jammed up the drillbit and broke it off. The chips also look powdery. This may be to your advantage. Since no apparent cutting fluid was used, the chips may be able to be picked out and blown free of the hole. This would then "free up" the broken drillbit. Do not use a Dremel tool. It will just make the situation worse.

Frisco,
I did not have any cutting oil, so I use a little white lithium grease that is in a spray can, kinda like WD40, I guess that didn't work to well.
I did take your advice and cleaned out as much of the chips as I could, got me a very small set of needle nose pliers and worked it till it started to move and slowly managed to work it out, I am pretty damn lucky.



OK now call me stupid, but when I bought the needle nose pliers I also bought some new drill bits to finish the job, I am bound and determined to drill these steam holes myself.

Thanks for the help Frisco, by the way EDM sounds very interesting, I am going to check it out just for personal knowledge.

406chevelle

[Frisco]

Excellent!!!

Use a cutting oil for aluminum when drilling. Kerosene, Alumatap (brand name) , even bacon grease. White lead works excellent but has been banned.

Do not try to drill the complete depth at one time! Drill in some and remove the drill to clear the chips. Blow out the hole before drilling some more. Since you are using a hand held drill motor, don't apply too much pressure or the drillbit will bend and then break. Let the bit do the work.

ENJOY!!!

[k2mooch]

I used a buddy's drill press at VERY low rpm and tranny fluid. Had to back off every 3 seconds to cool the titanium bit. This was through a 1/4 in thick cast iron alternator bracket so I could run a heater hose through it rather than change out my alternator and bracket to fit my engine application.

Not to sound like a **********, but why and where do you drill steam holes in a head anyway? I'm guessing it's for better cooling, but how does it work? I'm just curious.


MoocH

[406chevelle]

K2mooch

Here is a bit of infomatiom that I gathered off the web.

On a factory assembled 400SBC there are holes in BOTH the block deck and cylinder head surface.

This was done so that the steam pocket that would otherwise be created between the low side of the outer cylinder walls and underside of the block deck has an escape path.

On ANY other SBC there is a gap between cylinders, but because of the 400's "siamesed bores" there is solid metal there.

Steam inside an engine is bad since steam is going to be generated getting rid of it as quickly as possible is a good thing.

Steam acts as an insulator, prevents cooling water from getting to that pocket and creates a hot spot in the engine.

The critical steam holes on the 400 are the lower ones, because they release steam that becomes trapped in the pockets between the outer cylinder walls and the underside of the block deck.

On a SBC (and most engines for that matter) coolant flow in the block is nominally rearwards, then up to the heads, then forward. Allowing any steam bubbles to "cut the corner" through small bleeder holes in the block deck gets them to the radiator that much faster.

406chevelle