Hi,

I need to make some brackets for a video camera rig from aluminium on a tight budget.

Essentially we are talking about some blocks of aluminium big enough to take 2 15mm holes spaced at 60mm. They will take 15mm diameter rods which support other camera gear and accessories. The plan is to make a cut at each end from the outer edges of the pieces and tap a hole for a thumb tightening bolt to secure the rods.

I am planning to source a cheap drill stand and twist vice. I am hoping I can get enough accuracy from this type of set up.

I am happy with tolerances of up to a millimetre, so I am not expecting CNC levels of accuracy. As long as things can be tightened rigidly, small inaccuracies can be adjusted for.

I can't afford to anodise, but anyway it's a bit overkill, so I'm going to go for spray finish. Any thoughts on the most cost effective spray which will offer at least some scratch resistance? Or maybe chemically dying the metal is better at hiding scratches?

Are any guidelines / links / tutorials which could be recommended for drilling largish holes in aluminium. Do I use a small pilot hole to centre the drill, and then go straight to the full 15mm? Or do I buy a set of progressively bigger drill bits and work up to 15mm? I'm planning to make quite a few of these, so purchasing guidelines on drill bits would be appreciated.

To make my lateral cuts, I was thinking buying a cheap jigsaw table to attach my cheap jigsaw to. This is just to make the cuts properly square and to be able to use a guide rail to get a straight cut.

Thanks in advance for your thoughts, and thanks for reading.

Cheers!

Tap the rods to 12mm and tap the plate to accept them. No bolts required.

Keeping to 12mm means no requirement for a reduced shank drill bit which would be needed with the usual cheap drill presses (max chuck capacity 13mm??).

Use a pre-made guideplate to get repeatability for hole drilling accuracy.

Metal surface preparation is the key to a good paint result and a simple primer/top coat will suffice if left long enough to dry hard.

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If you got lots to do a bench drill and stepper bit is the best plan.

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Thanks for the input. Unfortunately the rails have to be 15mm because there are other accessories that require this gauge. Also, the system needs to remain adjustable, so I can't tap the brackets.

I am going to have to use a reduced shank bit I think. Are there any disadvantages in using these?

I can't afford a bench drill right now unfortunately, and anyway I don't have anywhere permanent to mount one. Do you think a drill stand will present insurmountable problems?

I had never heard of stepper bits. Looks interesting. Is the idea that the hole can be drilled in one go? I.e; do I need to get one that tops out at 15mm? Or can I get one that goes to 22mm and use it to make a conical pilot hole?

I tried but I couldn't google too much info on these. When I say lots, I mean less than 10 (I'm making a rig for me and a friend), so I don't mind doing progressively bigger pilot holes. I'm just worried about the centre of the hole 'moving' as I go up in bit size.

Thanks!

If you google stepper drill you get taper bit, which would do the job if you got the right size.

A proper steeper drill is like a normal drill bit but it steps up to a larger size for example it can start at 12mm and step to 15mm. probably not worth the cost for 10 holes.

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Is it the case that a step or taper drill would be less appropriate for a larger depth? I thought I would do a diagram to make things clearer.

The outer dimensions are 25x25x90mm.

A stepper drill would be perfect but pricey.

A pilot and build up will be the cheapest way.

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I dont think a step drill will be of any use ther scruff, youd end up with a stepped hole. Theyre for sheet metal.

Reduced shank, or blacksmiths drill will be fine, as its only in aluminium, it wont be hard going.
Id start with a 4 or 5, then a 10, then the 15.


You should be able to do them acceptably with hand held drill.

The 6mm, id consider using a bolt rather than tap the aluminium, wouldnt take much for the thread to be pulled out. A shakeproof washer would give it enough grip for the head id imagine.

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Brilliant. This feels like very sound advice. Than you very much.

hardwood would give similar results

for your ally to clamp your tollerances would need to be so tight as ally wont bend to any extent your slot would also have to extend around 50mm beyond the rod to allow enough movement

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The one I'm thinking off Hitch would be perfect, I'm sure they are called step bits.

Normal drill bit with two sizes on the same shank.

For example starts at 12mm and finishes at 15mm.

Like this.

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Dont think ive ever seen step drills with only 2 sizes on, probably a special purpose one for something?

Im thinking one likethis

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I have seen both types.

The confusing bit is that they are both called step drills

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That looks like its for drilling counterbores for cap screws and the hole in one operation.

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Why isn't the number 11 pronounced onety one?