Broken Tap Woes, Well kinda....

Had to look up what you were doing with the alum.

In the words of the wookie:
"Alum in the form of potassium aluminium sulphate or ammonium aluminium sulfate in a concentrated bath of hot water is regularly used by jewelers and machinists to dissolve hardened steel drill bits that have broken off in items made of aluminum, copper, brass, gold (any karat) and silver (both sterling and fine). This is because alum does not react chemically to any significant degree with any of these metals, but will corrode steel. When heat is applied to an alum mixture holding a piece of work that has a drill bit stuck in it, if the lost bit is small enough, it can sometimes be dissolved / removed within hours".

That's a relief. I thought, "no way is he rebuilding the aluminum wall of the hole by sticking it in some boiling alum" :confused 3:
 
Good job Doc! I've never heard of this process before so the old dog learns a new trick.

Couple of things on the original piece......why Delrin? Because of wash down on the meat saw? And if so, why was the sample piece so dirty? Or do I want to know......ewwww.
 
C-Bag said:
Good job Doc! I've never heard of this process before so the old dog learns a new trick.

Couple of things on the original piece......why Delrin? Because of wash down on the meat saw? And if so, why was the sample piece so dirty? Or do I want to know......ewwww.
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Hi C-Bag,
i'm happy i was able to share a trick!
i believe the piece was made of delrin for ease of manufacturing, and low cost- not for longevity.
the sample pieces were bouncing around in the back of my truck for a couple months.
in operation, the guide support is kept clean by scrupulous operators :grin:
 
Had to laugh when I saw "on this episode of how the 1/4-20 tap breaks, "

I could totally hear Don Pardo saying that. Then, "will the good doctor save the part? Is this a recipe for good or disaster......tune in tomorrow".

My adventure with 1/4-20 taps was more about getting schwangle in the hole doing it by hand than the wrong size hole. After going through the cluster of getting it out I decided that looking ahead at the many 1/4-20 I was going to tap it was a good investment to buy a manual tapping machine. Best $130 I ever spent and best of all no more broken taps(knocks on wooden head).
 
Cadillac said:
Question what does the peroxide do? Can you explain your process? Good luck with ur part.
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i'm sorry Cadillac, i was trying to make a witty joke, but failed miserably! :black eye:

here is the method i was taught years ago...
use a nonreactive vessel, like Pyrex or Stoneware (Alum will eat your steel pots and pans)
( i have not tried aluminum cookware for this process, but i imagine it would render the cookware useless for cooking food after)
the alum is added to hot/boiling point water until the alum precipitates from the solution.
(in my situation, i used a little over 100 grams of Alum for 32 Oz of water)
since you have a saturated solution, it will have the greatest effect on dissolving iron/steel.

i left my project submerged overnight and it was sufficient to dissolve the tap in about 12 hours

since aluminum is a major constituent in Alum, the aluminum is not harmed during the reaction
the alum/water acts as a corrosive agent, eating away at the steel.
there is a thin coating left on the part after treatment, but it polishes off easily with a stainless brush
 
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LOL!
i love tapmatic and the old tap magic with 1,1,1 TriChloroethyleyne , was the best.

as my eyes get older,
i'm finding that i can't tell a thousandth like i used to, so now i gotta be way more careful when i put my bits away! :rolleyes:
 
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