Machining aluminium at the space

[Nick Johnson]

I need to drill some holes in a number (40, specifically) of die-cast aluminium enclosures like this one: http://www.hammondmfg.com/pdf/1550Q.pdf . Three holes on the bottom, and one on one side. They need to be relatively precisely placed, at least relative to each other.

I'm pretty much a novice at this sort of machining by hand. Is this the sort of thing that's practical with equipment at the 'space - perhaps the 3 in 1? Is anyone able to offer advice or training? I'm happy to make a donation to the space / beer fund / beer for you in return for time and training.

-Nick

[SamLR]

Assuming the drill press is working you probably want to use that. With such a large run it might be worth making a jig from some scrap wood that you can use to align the holes correctly.

The 3-in-1 is not the right tool for this :p

S

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[Paddy Duncan]

But the 3 in 1 is the best and only accurate drill press we have :)

[cepm...@yahoo.co.uk]

Make a suitable template to mark the boxes accurately and use a small
(3mm) drill to drill a pilot before opening out to the final size. This
technique has worked well in the past for me.

The pillar drill should be adequate for this. Otherwise either of the
other two machines will do the job in drill mode.

If you are around tomorrow (Sat) afternoon I would be happy to show you
how it is done.

Phil




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" et cognoscetis veritatem et veritas liberabit vos. "

[Henry Sands]

the drill press is plenty accurate if you clamp down your work properly, the ideal tool for the job would be a mill press, which is basically a drill press with a precision adjustable clamping base.

[Paddy Duncan]

er, you mean the 3 in 1 then :)

[chrisbob12]

+1 for drill press. It might help to counter punch the centres before putting the pilot holes in (so you can wiggle the work piece under the (stationary) drill bit for a positive location). In the past, I've printed or photocopied the hole and centre locations, then taped them to the workpiece, then punched in the centres, but then I've never run off forty. The jig sounds attractive :)

[Billy]

Make a jig and use the mill.

Chrisbob's suggestion about printing a piece of paper with copies of
the layout, and using that as a template, is a good one, but because
you're doing 40, i'd go farther.

Make a wood/metal enclosure, that will hold one of the boxes, with
holes to match your layout. Clamp it in a drill vice, and clamp the
vice to the mill bed. use Chrisbob's suggestion of counter-punching an
initial mark. Then use a small drill bit to make a pilot hole, and use
that as a guide for a larger drill bit.

Make sure that the drill bit's are sharp before you start, and have
the mill set at a reasonably high speed.

I suggest the milling machine, as it has a movable bed, that's the
most precise of the one's we've got.

Remember aluminium is soft, and the boxes you're drilling are
relatively thin, so it'll drill through quite quickly, so you won't
need to apply much pressure.

[Peter "Sci" Turpin]

Use a jig. Just a corner made of wood and clamped in a fixed position
relative to the drill.
Position it on the table so a box placed in it will have the hole
drilled in the first place. Drill the first hole then place the box in a
separate pile. Drill ALL the boxes with the 1st hole only. Then
reposition the jig for drilling the 2nd hole, etc, etc..

It may seem counter-intuitive to do so many "partial" jobs, but it will
save you a tonne of time as long as you do one *position* at a time and
keep the piles separate. You will fly through them like this and as long
as the jig is firm and clamped right, all of them will be identical.
Place box in jig, pull down drill, make hole, put box aside, place box
in jig.. You'll get through all 40's first pass in about 3minutes. Whole
job should take 30-60min including realigning the jig for each hole.

[Aaron Sokoloski]

On Fri, May 24, 2013 at 1:35 PM, Peter "Sci" Turpin <s...@sci-fi-fox.com> wrote:

Use a jig. Just a corner made of wood and clamped in a fixed position relative to the drill.
Position it on the table so a box placed in it will have the hole drilled in the first place. Drill the first hole then place the box in a separate pile. Drill ALL the boxes with the 1st hole only. Then reposition the jig for drilling the 2nd hole, etc, etc..

It may seem counter-intuitive to do so many "partial" jobs, but it will save you a tonne of time as long as you do one *position* at a time and keep the piles separate. You will fly through them like this and as long as the jig is firm and clamped right, all of them will be identical. Place box in jig, pull down drill, make hole, put box aside, place box in jig.. You'll get through all 40's first pass in about 3minutes. Whole job should take 30-60min including realigning the jig for each hole.

Heh, but don't forget Hofstader's law: http://en.wikipedia.org/wiki/Hofstadter%27s_law

I'd allocate at least a couple hours, maybe a day for this, if you include making the jig.  It looks like he'll need an angled jig in order to make the side of the box level, since the sides are sloped.  Also, Nick, you probably want to use a spotting drill or centre drill (the short, thick kind -- http://en.wikipedia.org/wiki/Drill_bit#Center_and_spotting_drill_bits) to make the starting hole in order to keep the normal drill from walking all over the place.  The hackspace definitely has some.

See this video, starting from about 29m50s: http://techtv.mit.edu/videos/142-machine-shop-1

Finally, it's probably worth trying the whole routine once or twice through first, to make sure you haven't made any mistakes in the process.  I'm sure you've got the sense to do that, but I thought I'd mention it anyway :)

[Ndlovu (aka) Dean]

really really simple 

The pillar drill is exactlly the tool you need 

create template through which you can centre punch holes (probabily some sheet that you have maked with a scribe and drilled the attached a shoulder on that forms a 90 degree edge

drill pilot holes I would go anywhere between 1.5mm and 3mm

then finish off 

when drilling clamp box in drill vice 

[Dirk-Willem van Gulik]

Op 24 mei 2013, om 13:09 heeft Nick Johnson <arac...@notdot.net> het volgende geschreven:

I need to drill some holes in a number (40, specifically) of die-cast aluminium enclosures like this one: http://www.hammondmfg.com/pdf/1550Q.pdf . Three holes on the bottom, and one on one side. They need to be relatively precisely placed, at least relative to each other.

I'm pretty much a novice at this sort of machining by hand. Is this the sort of thing that's practical with equipment at the 'space - perhaps the 3 in 1? Is anyone able to offer advice or training? I'm happy to make a donation to the space / beer fund / beer for you in return for time and training.

With pretty much any drill (and ideally a drill press) you can do this accurately (assuming holes < M12) with relative ease by first making an accurate dent in exactly the right spot. See:

http://www.youtube.com/watch?v=VGd8XatdNdw

A centerpunch is ideal - but a nail will do on aliminium just fine too. 

Given that you have to do 4x40=160 of them - consider making a a few 'jig's or templates. 

I.e. drill some small holes accurately in a piece of scrap wood or metal and use that to put your centerpunches quickly in exactly the right places. Sometimes it is easy to use an old (plastic/wooden) box for this - you then push the enclosure in one corner of the box - and get repeatable alignment on the three sides. You then turn the enclosure around - and do the same in an other corner of this box - as to get the locations on the other side.

Dw.

[Jo]

Hi Nick, et al,


I was going to start a new thread but instead thought I'd reply to this as I am also interested in machining some aluminium. I think for my purposes I will need to use the milling machine, but have never done this kind of work before - would anyone be willing to give me a beginners' demo? (donation to the space/beer offered in exchange, in accordance with the custom :) )

many thanks,

Jo

[Blobface]

+1. An intro to the milling machine (or especially 3 + 1) would be much appreciated, also the wiki mentions that the 3 in 1 can only be turned on by keyholders. Also can both machines work on steel as well in terms of power? (provided one has the correct bits)