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Evan
02-21-2005, 02:26 PM
Well, yesterday I broke a $12 tap off in the work while power tapping. That is the bad news. First tap I have broken in years.

The good news became apparent when I tried to remove it with the couple of threads worth still sticking out of the hole. It turned out that I had laid out and drilled the hole 1/4" away from the proper position. It also turns out that the hole with tap in it will be completely hidden in the final assembly. So, I took the angle grinder and ground the remains flush.

As it turns out what I actually acomplished was to drill a hole in the wrong place and then plug it with a tap http://bbs.homeshopmachinist.net//biggrin.gif After that I decided to watch TV while my luck was still holding...

Rustybolt
02-21-2005, 04:56 PM
I'm laughing really hard, because it's happened to me too.

precisionworks
02-21-2005, 05:23 PM
Technically speaking, these are known as "extra" threaded retainer fastening cavities. I always put in two or three of these, just to be on the safe side. <LOL>

[This message has been edited by precisionworks (edited 02-21-2005).]

Spin Doctor
02-21-2005, 05:59 PM
I can actually speak from experience that I have never broken a tap. Had few wear out quite rapidly though http://bbs.homeshopmachinist.net//rolleyes.gif

Daminer
02-21-2005, 08:39 PM
There are two kinds of people who use taps:

1 Those who have broken a tap

2 Those who will

Thrud
02-22-2005, 04:38 AM
Evan:
Lazy Bastich! Remove the evidence, lest rust give it away (It was in Aluminum, right?)

If you want good taps Evan look for "Norseman" brand they are made in Minniapolis, MN. They also have superb drills. Lower in price than those dormers you like and these little buggers will draw blood. That of look for Yamawa (Japanese), or OSG (Clarkson/Osborn - G.B.) Merlins or blue Wizards.

rsanter
02-22-2005, 12:30 PM
I can honestly say I have never broken a tap....where I wanted to.

bob

SGW
02-22-2005, 12:59 PM
Clearly, it's a security measure to prevent cutting or drilling of the finished product.
http://bbs.homeshopmachinist.net//biggrin.gif

debequem
02-22-2005, 05:17 PM
Great idea! I was wondering what I should do with all of my broken taps. I was tossing them out.

Now I know to bury them in a blind hole in my work.

Great tip!

Rich Carlstedt
02-22-2005, 10:47 PM
OK, this HINT is for only those guys who break taps.
Take a tap and grind a ring groove around it above the flute area by about 1/4 inch. make the groove no deeper than the depth of the flute grooves.
Now when you break the tap, it will fail at the ring, and not in the hole, and you can still get it out.
We did this in Crankshaft sumps years ago when removing broken studs. a broken tap meant a 10K to 20 K bill for repairs.
Also all Allen Capscrews ( 5/8 and 3/4) had a 1/16 or 3/32 hole drilled through most of it before it was used in the sump. That way, if the screw broke, we had a center hole to guide a drill /easyout