Goofed, broken drill into workpiece :-((

Steve · 2008-03-22T18:22:04+00:00

I've managed, through nothing but carelessness, to break a 1.5mm drill bit in the cylinder head of the little glow motor I'm (still) making. Only one hole left to complete and I broke the soddin' bit into the head. I've been dripping sulphuric acid into the hole for the past couple of days, without seemingly much progress.Any better ideas for getting the broken bit out? Is there anything better than H2SO4 to do this job?I can bodge it , but rather not without trying.Steve

Mar 22, 2008 31 Replies

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David Littlewood 18 years ago

In article , Dave Baker writes

Aluminium potassium sulphate, K2SO4.Al2(SO4)3.12H2O. Fairly common chemical. Only advantage I can think of is that it's less likely to eat your flesh.

[Actually, for the terminally curious, there is a whole family of "alums" of general formula K2SO4.M2(SO4)3.xH2O, where M is a trivalent metal ion. Fe3+ and Cr3+ are probably the best known, termed iron alum and chrome alum. But the aluminium version is by far the commonest, and usually just referred to as "alum". Makes sense, as the others don't actually have any aluminium in them....]

They are easy to grow into nice big pretty crystals, especially the Cr version, which is a nice red colour. Getting a bit OT here though.

David

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Peter Fairbrother 18 years ago

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£3.99 plus £2.25 postage for 250 g.

Used for dyeing, as a mordant, and so on.

-- Peter Fairbrother

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Steve R. 18 years ago

Jewellers supply firms usually sell a nitric acid paste. This is used by watch and clock repairers to remove broken screws. Mine is a white paste. Just put a dab on the end of the offending object, and warm over a flame. Repeat as needed. Not sure how effective it is with HSS though.

Steve R.

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Steve R. 18 years ago

some windscreen washer winter additives are 100 percent isopropyl

so dont go wasteing your money at the chemist .when 1 litre of the stuff can be bought for £1.29

all the best.mark

Interesting! Here in British Columbia, isopropyl alcohol is available off the shelf in most drug stores (chemists). I find all sorts of uses for it.

Steve R.

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Donald 18 years ago

I have some alum somewhere. Take a deer or sheep skin, spread it out and apply a solution of alum and it will cure it to make you a rug. Don't worry about the animal rights people, sheep are bred to give you lamb and the deer have to be culled. Venison is a fat free supply of protein. Donald, South Uist

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Wes 18 years ago

Making pickles a bit more cruchy.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

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