Thread: Best tool for countersinking in aluminium?

I would use a three flute counter sink with metho has a lubricant followed by a little cone shape stone cutter dry aluminum is quite soft to cut
Bunnings or most tool shops will have what u need

For ally pretty much any countersink will work providing you have rigidity in both the work piece and the tooling; ie use a drill press with the ally clamped to the table and use the depth stop to maintain uniformity across the holes. If you use a drill/countersink combination bit you'll achieve perfectly concentric holes within the countersink.

Simplicity; I've not come across metho before as a lubricant; I would have thought it too volatile and would boil off at the interface between the tool edge and the chip? I was always taught to use paraffin, diesel or very light oil (WD40/Inox) on aluminium for all hand work and drilling.

I have always used this type of bit which leaves a nice clean finish.
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Originally Posted by Chief Tiff

Simplicity; I've not come across metho before as a lubricant; I would have thought it too volatile and would boil off at the interface between the tool edge and the chip? I was always taught to use paraffin, diesel or very light oil (WD40/Inox) on aluminium for all hand work and drilling.

CT, I got the metho lube tip a few years ago from my BIL who used to build ally boats up to 42 ft long (mostly by himself) - he did the lot: shell - engine - electrics - upholstery.
He used many wood working tools like circular saws and SCMS with negative rake teeth, and routers, and for these he would rub the teeth and the cutting line with hard wax, but for drilling and tapping he used metho.
The fact that metho evaporates is a good thing because the last thing you want on a boat shell is a layer of oil all over the place so the mess factor is much reduced.
Anyway I tried it and it really does work very well - I use a hand pumped trigger pack to squirt the workpiece and the tool and yep it does evaporate but is has a reasonable heat of evaporation so it really cools the tool well.
I have found one problem with it in that if too much is used it can give me a head ache but just turning on my exhaust fan fixes that.
Of course it is also a fire hazard so venting becomes even more important if large amounts are used.

Simplicity suggest a stone but I imagine that will gum up virtually on first contact.

Not sure when I heard of the metho trick.
But yes it does work as long has u don't push so hard to cause smoke! But we are talking aluminum here.
And because it is a drier (the metho ) well no mess and that's a bonus
Tho one point to remember is steal in contact with aluminum will react ie don't use steal screws use brass instead

Originally Posted by Simplicity

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Tho one point to remember is steal in contact with aluminum will react ie don't use steal screws use brass instead

Unless I'm mistaken I think you have the above back to front - brass and aluminium are not the best of friends - check out a dropped swivel in an ally boat which was not noticed until it is too late.

I am of course talking real brass here and not what you find in many cases today which is brass coloured screws, hinges, rods etc.

Well I just learned something new .
I wasn't a were that brass and aluminum react .
But yes steal and aluminum react .
I remember has a young panel beater ,having to paint ,strip a 1960s Bristol body car ,made in aluminum with paint striper ,we wearer only allowed to use plastic scrapers because a steal one would scratch the aluminum and react a few months later under the new paint job
Not want you want ?

Most wood screws are either galvanised or nickel plated, so there's no actual ally/steel contact. Is that still an issue?

I can't see gal or nickel being a problem
But then I'm not an industrial chemist either