Here is my dilemna. I was drilling the steam holes in my new AFR heads and on the first head I made it through all of the holes and then on the last 30 degree hole, I broke off the bit. I have been completely unsuccessful at extracting this bit. In fear, on the second head, I only drilled the lower 3 holes. I read on this site that this was adequate and that this is how Edelbrock instructs to drill.

Questions:

Is drilling just the 3 lower holes really adequate?

Is the drill bit embedded in my head going to cause me heartache later on?

Any help is greatly appreciated!

I believe AFR recommends to drill the upper holes also.
IMHO, try to get rid of the broken drill bit.

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//Fred
11.58@116 N/A SBC

If the broken drill bit is still stuck in the hole then you don't really have a hole there, do you? Get it out and drill the top 3 holes. No simple answer but to do it.

I was afraid that that was going to be the answer. The bit is sitting down in the hole about 1/2". Any ideas on how to extract it?

Getting out a broken drill bit is a pain. I broke a bolt int he eluminium intake on my Tahoe, then while drilling I broke a bit off in there. Took me the whole day to repair it. http://www.nastyz28.com/ubb/frown.gif

Not only is there no simple answer but there is no answer for extracting the broken bit. I went through 4 new cobalt bits trying to get it out and they barely scratched it. I talked to a machinist about the problem and he had no solutions either. I guess that I will be running it and seeing what happens.

I snapped one while drilling my heads last month & was able to loosen it in the hole with a dental pic & then extract it with a rare earth magnet. It still took me about 2 hours.

Persistance is the only advice I can give you.

the easiest way to get a broken bit out i think... is to mount the head to a drill press bench ,get the angle right... use a 1/64 of an inch smaller bit than the one broke.. and drill it out at high speed but drill SLOWLY

a super stong bit IS needed.. and it must be sharp so pick up a couple of the bits if you dont have a bit sharpener


another way to do it if you have a drill press that works in reverse... do whatever you can to find a reverse rotation drillbit... alot of the time the reversing action of the drilling bit will catch on whatever is broken and back it out...

[This message has been edited by 1981coupe400ci (edited October 11, 2005).]

A regular drill bit isn't very hard. Soak that sucker in Aerokroil, and get a carbide drill bit to drill it out. You need all the steam holes. You will probably need a drill press so you can put good pressure on it. Either that, or EDM it out.

Using a propane torch melt paraffin wax on the hole.
Then using a drill press and left hand bit, drill in reverse to extract the old bit...

Thank you all for your help. I will let you know how it goes.

<font face="Arial,Verdana" size="2">Originally posted by jakeshoe:
Using a propane torch melt paraffin wax on the hole.
Then using a drill press and left hand bit, drill in reverse to extract the old bit...</font>

That works well also if the bit isn't shattered http://www.nastyz28.com/ubb/wink.gif If you have problems locating a left hand drill bit, let me know and I'll mail you one. What size are you using? 3/32, 1/8?

I have been using a 1/8th bit. Thanks! I have had some difficulty finding a reverse rotation bit.

I wouldnt recommend leaving the bit either.. thankfully, I haven't run into this problem..So I cant help you get it out. But, if for some reason, you cant get it out, and wind up leaving it in there.. I would bring it to a welder and have them just tack that bit so it stays there.. Never now.. some weird scientific shyt might happen,through expansion & contraction of the head while driving/racing, and that bit decides to vibrate loose.. wouldnt be good..

just a though.. but do what ever you can to get it out..

menards or lowes or home depot would have reverse rotation bits i would think...

if not ebay would definitly have something

the proper name is "left hand bit"

goto ebay type in "left hand bit"



[This message has been edited by 1981coupe400ci (edited October 16, 2005).]