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Discussion Starter #1
Problems...

So I went ahead with the drilling and tapping. I followed the advice of you guys and modified some of it for my own purposes as I saw fit. I drilled the hole perfect and strait. Used the starter housing as a guide, got a brass sleve and a 5/16 bit and it came out perfect. I was going to use Harley's method but it turns out the chuck on the drill hits the bellhousing and I couldn't get close enough to use all the bits (25/64,3/8,5/16) as planned. I found a 5/16 bit that was long enough to reach the whole way and used that. I was very careful and very pleased with the results.

However, this is where the problem comes in, I broke the tap off in the hole. Shoot!! I had the perfect hole and then crack it broke. I tried a bunch of things to get out the 3/4" that it went in, but had no luck.

I was told that if I give the tap a good wack with a center punch it will shatter. Will this work? Any other suggestions?

And yes I was using oil and backing it out ever so often to clean it out. Oh well, thats the way it goes sometimes.

Thanks again

Dave "I never give up" Nafarrete
 

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Go to a local machine supply house and get a tap extractor (or remover, I forget what they are called). It has long hardened tings that fit between the flutes of the tap and a handle. See, your not the only one to do this. There's even a tool for removing them
. I haven't had any luck trying to shatter a tap to get it out. In my business we tap parts everyday, but since the materials are inexpensive and labor isn't, we scrap the part. Not an option, in your case.

I take it you are taping a 3/8 hole. I guess you can't grab any of it with vise-grips. When I hand tap I turn 1/4 in and 1/2-3/4 turn back out. What is it you are tapping? And how deep do you need the hole?

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street
 

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Discussion Starter #3
Tap extractor? I saw what they called a tap extractor at the parts store. It looked like a twisted candy cane that was tappered. Is that what you mean. It didn't have any edges that could grip as far as I could tell. The guy said put it in a drill and somehow it works. I don't think that guy knew what he was talking about.

I am tapping the hole for my starter on the bottom of the block. It's the inboard hole.
 

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David,
The tool Pat is talking about has "fingers" that go down between the flutes or "grooves" of the broken tap. And also, yes, taps are hard and brittle enough that they can be broken. The few that I have broken in the past, I had to chip and dig a little at a time. Once you get it out, and you will, with patience, be sure and run a new tap a little deeper if you have the depth. If worse comes to absolute worse and you destroy the threads (and you won't) you can always drill out the hole and helicoil it. Who knows, if you get a good tap extractor, it may back right out. Let us know.

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Tom Parsons
 

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I don't think you want to use a drill. Best to go by hand. It's too hard to control the speed and torque of a drill in a delicate operation like removing a tap. Also, use lots-a-oil.

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street
 

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Dave,
The 'twisted candy cane' thing you saw at the parts store is used for extracting broken off bolts. The idea is that you drill a small hole in the center of the broken bolt, then lightly tap this tapered extractor into the small hole, and turn it CCW. The tool is designed so that it bites into the bolt when turning it CCW. With the situation you're in, it would be the wrong tool for the job.
My experience with these is that they are practically worthless. If a person has broken off a bolt, it's almost certain that you have some seriously locked up threads. The odds that this little tool (usually about 1/2 the diameter of the bolt you're trying to remove) is going have the strength necessary to overcome stripped/rusted/damaged threads are slim at best.
You'll have to be very careful (and a little lucky, too) when using the tap extractor that Pat and Tom are referring to, but it can be done!! Good luck.
 

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Dave, When you find a tap extractor,make sure you get one specific to your tap ie 3/8 and # of flutes you have on your tap. You may need to buy a box of replacement fingers in case you bust up the ones that came with the extractor. Keep the collar up against the block and as mentioned go to a good machining supply house to get a top qual. ext. Rob
 

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Remember the post the first time around about buying a good (expensive) tap ? This is why.
I've never had good luck "chipping" a tap out.

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Gotta have a Chevy !In Durham N.C.
Make it look the way you like it, forget what the other guys say!
 
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I have had luck in the past extracting broken taps by using a screwdriver and a hammer to back out the tap (by lightly tapping the tap with the screwdriver CCW to loosen the tap). Then I use good set of small needle-nosed pliers in the flutes to continue back out the tap. Return to the screwdriver/hammer if the tap gets 'stuck' along the way. This doesn't always work, but has more times than it hasn't. As said above, use A LOT of OIL. Good luck. David
 

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I have been a machinist for 17 yrs and I can tell you one thing.Be careful and wear eye protection.When I have tapped cast iron,I never use oil as this causes the metal to log the tap very badly.Now that it is broke,
,blow as much of the loose metal out of the hole as you can.In this instance(trying to back out a broken tap) use oil(very light oil).If you getr a extractor,wiggle the broken tap back and forth and clean often.If you're careful an patient,it will come out.Believe me,I've been there,but at work you're on the clock and you do what you have to.
If you have access to a dremel tool with a small enough stone,you might be able to grind the center of the tap out and the rest should fall out.

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John 67SS
ACES #2887
Team Chevelle Gold #127
Bassett,VA




[This message has been edited by 67ss (edited 12-14-99).]
 

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Discussion Starter #11
OK, I understand the need to buy quality stuff. But I don't know what quality is. I bought my taps from a store and they said they were good. Company is "Hanson", heck I don't know for sure. That is all I can find anyway. I went to 4 different stores and that is all they carried(other than the taiwan stuff).

Where can I find the proper extractor? I never noticed anything like you decribe at any of the places I have been.

Dave
 

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Dave, Not sure how big of a city you are in or what you have available to you for tool stores. What I would recommend is to go to the largest car dealer near you and talk to the service manager. Ask him for the name and number of the local Snap On or Mac Tool guy. They will help you and you will know you have quality parts/tools. Bill
 

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Dave, The difference between "automotive" tools and Machine production tools is night and day. A "Hanson" tap wouldn't last 5 minutes in a machine shop.
Get out the old phone book and look for a machinist supply house. They will have the "finger" type extractor mentioned.Some times they work and sometimes they don't.If you find one and get it installed properly, take a torch and heat up the area around the tap. Cast iron expands more than tool steel and it will increase the odds of getting the tap out.
There are still alturnitives try this one and if it doesn't work we'll go to the next. one.

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Harley
69 461 El Camino Nitrous Model, 69 Chevelle coupe
70 El Camino,71 SS Camaro
79 Corvette
Kerrville,Tx.
 

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Hey David .. you did good picking the Hanson tap&die set ,, its not a cheap set, I have one that I have been useing for over 10 years ,, in fact my Snap-On set has the exact same case {except Snap-On logo on it}there may be better sets out there but Hanson is far from being junk .. instead of useing oil you mite want to use WD-40 as its no a heavy oil and its easy to use and cleans out the hole good ,, the broken tap extractor probly would be best found on a tool truck ,,Snap-On/ Mac Tools ,, if all else fials and the hole is not to your likeing ,, just Helli-Coil it

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John
Catapiller Mechanic
Salinas,Ca
70SS 454 Clone {in construction}
 

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If I was in your predicament, I'd try to call Harley or at least pay very close attention to what he has said/is saying.

Good Luck
 

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I hate when taps break. Hand tapping is like
cracking a safe. SLOW and easy 1/4 turn back out and a Feel not to exert much force.
It was said to use OIL. IMHO this is a last resort option. for the ever day guy wd40 is ok. but a product called TAP FREE is best
it can be bought at the samr place the tap extractor can be found. Machine/tool supply house. take your time you'll get it out.
Wayne Kline
ACES TC
PS I have in a pinch used two small nail set punches inserted in two flutes and a vise grip to secure the pair ,then used a rod/screwdriver inserted inbetween and turn ccw !
 

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David, I know you are located in SoCal. There are lots of "machine shop supplies" supply houses in the area. You can look up Rutland's (Whitter and other towns), KBC (Fullerton), DoAll (Glendale), IPS (El Monte), Enco (I forget where), not to mention the many smaller independents around. Just tell them you broke a tap, and they can help. I'd stay away from Rutland's though, it usually take a couple hours wait to get anything there.

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street
 

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Dave,
Here's the deal...go to the parts store...order a starter for a 69 Camaro with a 327 motor and TH350 trans. This is the cast iron nose, diagonal bolt pattern, 153 tooth flywheel starter. End of problem !

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100
 
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