Broken Tap in aluminum

[sparkness]

I was power taping a part 1/4-20 tap, did not clear the chips as this is a deep hole, and a hand style tap - broke it in the part, any recomendations using alum and sulfuric acid for removal?

 

[rancherbill]

put 2 old hex keys into the material beside the broken tap and then grab with pliers and twist. This is the pro. version. You can do the same with hex keys.

https://www.waltontools.com/products/extractr.htm

While looking for pics I found this technique and it's the same but different. I have never seen this one. Very cool.

http://ace240z.com/Broken Tap.html

 

[humber2]

Very good, will work with 2, 3 or 4 tang taps.

 

[shawhite]

Must have been one dull or cheap tap. I’ve had moderate luck with the Walton like tools. Where you power taping with a hand drill/impact?

 

[solo machinist]

Solid carbide left hand drill. This is my go to when all else fails.

 

[Walkers]

You can always use the old reliable weld a nut on top method.

 

[PCustoms]

I've broken them out with a punch before.

Not sure I'd want to mess with acid or alum?

 

[neophyte]

Must have been one dull or cheap tap. I’ve had moderate luck with the Walton like tools. Where you power taping with a hand drill/impact?

Aluminum can vary from very soft, to hard and strong as hell, depending on the alloy, and whether the alloy was heat treated and hardened.
Also,
Aluminum is known for “galling” issues, which only get worse the more the tool is used once the molecular bonding happens.
This is one of the reasons titanium nitrate, and certain other coatings are recommended for tooling when working aluminum.
The coatings help prevent galling.
Kerosene is also the “cheap” recommended tool lubricant for working aluminum.

 

[theoldwizard1]

I was power taping a part 1/4-20 tap the other day and broke it in the part, any recomendations using alum and sulfuric acid for removal?

Alum works but it will take a few days.

 

[BillK]

Remove Broken Taps with Walton Tap Extractors

You can remove broken taps in three easy steps with Walton's Tap Extractors -- without drilling, lasers, damaged threads, scrapped parts or repair inserts.

www.waltontools.com

 

[DIYNY]

i'd try to stick needle nose pliers into gaps. if that doesn't work then comes out dremel with a carbide bit.

 

[dutchgray]

If the part can be put in a milling machine I will drill the tap out with a centre cutting carbide end mill, use a fairly well used one as it will probably not survive, the usually shatter when the last bit of the tap comes loose.
This is if the easy hand removal methods don't budge it.
Never tried any of the chemical tap dissolving methods.

 

[F-22]

Solid carbide left hand drill. This is my go to when all else fails.

Can this be used with a hand drill? Solid carbide drills are very expensive and I've only ever used one with a milling machine (but they come with normal spiral flutes, the straight one must be for very brittle materials?).

If I remember right, a ~10mm solid carbide drill bit costs 100€+, I doubt I'd ever strap it into a hand drill cause it's way more brittle than a HSS drill bit...

 

[PCustoms]

Can this be used with a hand drill? Solid carbide drills are very expensive and I've only ever used one with a milling machine (but they come with normal spiral flutes, the straight one must be for very brittle materials?).

No.

Carbide drills are too brittle and a hand drill too wobbly. You'll shatter the bit very quickly.

 

[RoninB4]

No.

Carbide drills are too brittle and a hand drill too wobbly. You'll shatter the bit very quickly.

+1 for the above reply. Shatter a carbide drill in a hole and now you've got real problems only an EDM will correct.

 

[steel 35]

Last broken tap I removed was with Oxy / Act
not in Aluminum but I’d be tempted cause it was so cool, and instant.

 

[neophyte]

Can this be used with a hand drill? Solid carbide drills are very expensive and I've only ever used one with a milling machine (but they come with normal spiral flutes, the straight one must be for very brittle materials?).

If I remember right, a ~10mm solid carbide drill bit costs 100€+, I doubt I'd ever strap it into a hand drill cause it's way more brittle than a HSS drill bit...

That type of drill bit is usually made for drilling hardened steel plate, such as that used for armoring vehicles.
Those bits should only be used in a drill press, and for drilling solidly placed materials.
Also, those bits tend to be expensive.

 

[dnschmidt]

I'd try heat first. Aluminum has a much higher thermal expansion coefficient than tool steel. Heat up the aluminum and see if that makes a difference.

 

[sparkness]

OK here is what I did, I put the aluminum drum in a glass jar of water, 10% battery acid, 4 oz of Alum(aluminum potassium sulfate), heated for 6 hours - completely dissolved the tap, the drum will get cleaned up back on the lathe.

 

[shawhite]

That is a pretty cool science experiment.

 

[sparkness]

not so much an experiment, I did not want to remake the part and buy new material, I was too aggressive with the tap in deep cut - duh! my cost was $7.00 for the Alum, $6.00 for the glass jar, I had all other materials. the **** buildup on the aluminum is the iron from the dissolved tap.