Machining Aluminium to a fine finish?.

[tony sayer]

Anyone here got any experience of milling Ally?

Bit odd this one but i have to make up quite a few machined ally cases had a quote in from a couple of people, lot of money suspect they don't want the job.

Can't afford a proper mill but i once used a Trend router to trim up some ally with a wood bit and it produced a very good edge finish. We have acquired a decent stand holder for a spare Trend router, a Wolf drill stand and a X-Y compound table and the whole works very well and stable for what it cost.

However using a fluted end mill with helical cutters on the edge machining the face as it were its fine, a good finish. However if we now try to put a machined edge on say a lump of ally flat 100 mm square around 7 mm thick the edge finish is rather more akin to a barstard file:(

Using yet again a wood bit a very much better finish is obtained but there is still a light ripple difficult to measure it but if you hold that edge to the the light with an engineers set square the variations were very small in that they'll only show a very small amount of light show thru. the metal is square and all that but just spoilt by the slight ripple. I'm taking light cuts at around 20,000 RPM with a lubricant tried a few faster slower, left to right and right to left cuts much the same result.

Its just about good enough for what is needed but anyone any suggestions on what bit might be used to get it flatter and smoother?.

These ones have been used but they put a very rough edge on the metal compared to the straight flute wood bits!

Cheers..

[DerbyBorn]

The cutting edge angles on carbide tools is usually wrong for aluminium.

[newshound]

Are you using a cutting fluid? Soluble oil or mineral oil is usually recommended for milling and turning, you might get away with paraffin or WD40.

[Dave Plowman (News)]

My Makita sliding saw produces an excellent edge on ally plate. Just take it gently. With the standard wood blade.

[newshound]

Similarly the Evolution, with it's multi use blade. But this doesn't help the OP.

[Bill]

In message <5nmNnCBwWZEcFw+ [e-mail]>, tony sayer [e-mail]> writes

I have a milling machine, but have never used it for ally, so can't help directly.

However, I think I may have asked here about my son and his need for ally frames for some device he was making, which needed accurate, clean

45 degree cuts to form the corners. I suggested sign makers as many years ago I had used one locally to produce large, accurately cut sheets of ally to form new top decks for some tape machines (Revox A77's that all had that bizarre raised front section that hindered editing).

However, when I went round the current sign makers, only one said they would take on the job and he couldn't guarantee the finish or the price. In the end, I went to a manufacturer of aluminium frontages for buildings who said they never had anyone walking in asking for tiny jobs like that. The production manager was very friendly and arranged to have the cuts made.

Unfortunately, it all ended in disaster, as they managed to cut things in the wrong order, producing one 4 sided frame and one with 3 sides and a gap. The basic frame material, from IKEA, turned out to be no longer available, no cash changed hands, my son turned his nose up at having non matching frames, so I've ended up with 1 3/4 frames in the enormous "might come in useful" pile in the garage.

I seem to be having a run of bad luck with tasks recently.

[tony sayer]

In article <XnsA9B769220B915TrainJPlantntlworldc@81.171.92.236>, DerbyBorn [e-mail] scribeth thus

OK then do you know of what's better?.

[tony sayer]

Yes WD40 has been tried as well as Machine Marts cutting fluid no difference in either case!..

[Dave Plowman (News)]

A sliding saw to cut 100mm of 7mm ally ain't going to cost much. And will get plenty other use. ;-)

My problem was the smaller ones weren't big enough for my sort of use. Hence ending up with the current one.

[tony sayer]

In article [e-mail]>, Dave Plowman (News) [e-mail]> scribeth thus

Its not cutting as such Dave its finishing the cut edge to a finer square level finish!..

[The Natural Philosopher]

tungsten carbide peramagrit tool

[Dave Plowman (News)]

Which is exactly what my saw does, Tony. Far better than I could achieve with the finest file.

[Bob Minchin]

Strikes me you are going far far too fast. Try somewhere in the region of 20 metres per minute tip cutting speed. Paraffin, diesel or wd40 are suitable lubricants.

[tony sayer]

Tried that and very little difference at all! In fact the faster it goes the better, this has been borne out by a Youtube video.

Phoned Trend support their consensus was that if a wood bit works then use it!

In fact i found another Youtube bid demo'ing that very thing!

The actual surface ripple will do, an engineers square up against it shows almost no light coming thru and i did try a quick rub across a bit of 300 ish grit wet and dry paper and its as good as i think its going to get so i think we'll leave it there it's good enough for the purpose i need it for:)

cheers..