Anyone can make mount a panel meter for me?

[Al (astral highway)]

Hi folks,

I want to make a neat job of mounting a little level meter (DC, 100uA), which will be in an RF detector/signal strength application.

It is tiny and light and a small rectangular profile, only about 1 cm x2cm. I just don't have the knowledge or tools or even place to attempt to cut out an appropriate hole in an alu case (which I haven't acquired yet, pending this thread).

I know I could try drilling a few holes and filing it to shape but I want it to be right first time and to look smart. So I wonder if anyone could do this and how much you'd like for the job.

it may seem ridiculous to those of you with workshops and machining skills, but I have neither and I know my limits. So my alternatives are to mount it on the circuit board and not encase it, or to encase it and do a good job.

This is just a finger in the air to see what folks think.

Thank you.

[mark_in_manc]

Well...I could mill a hole for you (on a fairly horrific Frankenstein home-brew milling machine ), and then file the corners to tight 90 deg angles if this is what you want. I guess you could just provide a template of the hole you want cutting, or mark up the box itself. If you're happy to pay postage both ways it wouldn't cost anything more. Someone closer to you may well be able to sort you out, in which case go for them, no problems. Someone might even have the right Q-max cutter.

One day soon-ish I might want to turn this tool into an automatic CNC gear-hobbing machine. My arduino-related pain might well be this forums to share, if mods are sympathetic!

[Ed_Dinning]

Hi Al, if the box is a light material there are several suppliers of what were called Q-max cutters in a range of sizes that cut a beautifully neat hole.

Ed

[Al (astral highway)]

Originally Posted by mark_in_manc

Well...I could mill a hole for you (on a fairly horrific Frankenstein home-brew milling machine ), and then file the corners to tight 90 deg angles if this is what you want. I guess you could just provide a template of the hole you want cutting, or mark up the box itself. If you're happy to pay postage both ways it wouldn't cost anything more.

Hey Mark,

That sounds great, very kind of you! I will now just need to source the box. Does it have to be sheet alu or can it be diecast? What's best from your viewpoint? It might be best if I send up the little meter with it once the box has arrived.

Cheers!

Al

[Radio Wrangler]

Aluminium and diecast boxes are nice easy stuff to file. Milling cutters are inevitably circular so the corners still need filing. For a small 20mm by 10mm hole, there may not be much to gain from using a mill.

Spending many hours spent communing with a file is an important part of any engineering education, otherwise trainees wouldn't be made to do so much of it. To be honest, it's a good skill to acquire. You can use it to do a lot. One day the brass hinge on the catch of my briefcase broke. I found a chunk of bras, drilled the holes it needed, marked it up and filed a replica. Took a coup'e of hours, but does he job and looks the part.

David

[Al (astral highway)]

Cheers, David!

I'm not afraid of a bit of graft but I just want it to look great! You've persuaded me, I'll have a go and if not happy, I will come back to you, Mark (in Manc) ...

[Nickthedentist]

Yes, do try it yourself.

Scribe the exact outline of the cutout onto the box, then drill a series of adjacent holes (about 2mm in diameter) so that their outside edges are just within the scribed line. It may help to use a centre punch first, supporting the back of the panel on a block of wood so it doesn't distort. Then, bash-out the piece of metal and neaten-up the hole with a large, flat file, noting that one edge of the file has no cutting teeth; this is useful if you want to cut in one direction only and don't want to affect the perpendicular edge of the hole.

Work in good light, blow away the swarf frequently, and take your time. You should be able to acheive a very professional result without too much effort.

Nick.

[kellys_eye]

You could make a cut-out to the best of your abilities then fit a bezel over it to tidy up the arrangement.

Laser-cut adhesive printouts aren't too expensive nor is a pcb routed with the appropriate hole.

If you also require an attractive front panel finish - lettered controls etc - then draft something and print as a pdf then send to the vinyl cutter people (there are some on high streets these days) - peel and stick!

[frankmcvey]

What Nick said. To which I'd add that I've often seen homebrew metalworking jobs - particularly in soft metals like brass or aluminium - spoiled by vice teeth-marks all over the work. So use a couple of slips of ply - even thick card will help - to protect the workpiece from the vice jaws.

Mount the workpiece in the vice so that the tops of the vice jaws are around 6mm (or less) below the line you're filing to. This holds the workpiece firmly so that it doesn't vibrate and chatter or make screeching noises as you file.

If you have the workpiece mounted in the vice at an angle, you'll find it hard to file accurately to the line, so mount the job so that the line you're filing to is parallel to the tops of the vice jaws - ie horizontal - then, as you're filing, all you have to do is concentrate on keeping your file horizontal.

By always placing your workpiece so that your file is always horizontal, you'll help your muscle memory and skill-of-hand to develop more quickly.

Don't take the first side of your hole all the way down to the line in one go - leave about 1/2 mm to go, then rotate the workpiece 90 degrees and work on the second side of the hole, and so on until all the sides are filed to within a fraction of the line. Then work carefully round the hole again with a fine file, taking each side precisely down to the line.

This technique helps you to avoid marring a finely finished side when you're rough filing the next side. Any accidental file marks from the unsafe side of the file will be taken out on your finishing pass.

Put on some nice music, take your time and enjoy the work. You'll surprise yourself at what you can do with a little practice.

Cheers,

Frank

[mark_in_manc]

Have fun, Al. Is it you that works on the balcony of some flats? Maybe you can find a vice to clamp to the balustrade - if I did that I'd drop it (or the work, or a file...) on someone's head Maybe you have a workmate for home DIY stuff, which would do you.

If you get fed up with it, do PM me.

cheers
Mark

Give it a go on a scrap piece of metal, when it come to removing the bulk of the metal after drilling a pair of wire cutters is good for the job. The 'secret' is (are) take it easy, use a good quality file with a safe edge i.e. one of the sides has no teeth so you can go into a corner one way only, use the largest file (with small teeth) you can, it is straight (should be!).

Make the hole a bit too small (20 thou or so) to start with but square and then nibble away until it fits. Another trick is to make the hole tapered (big side to the inside) and then you only have a weeny bit to remove for that super fit.

Warding files are quite useful, a half way house twixt needle and ordinary.

It is a bit of a skill, but soon learnt.

[Karen O]

There's something satisfying about filing rectangular apertures. It requires patience. I cover the work in fablon, partly to protect, partly to provide a surface to mark out the edges of the hole.

I file in phases. I start with a rough file and progress to needle files as I work closer and closer to the lines. In the last stage I only move the file in the direction of the metal as that leaves a nice finish.

I think its an important part of the creative process to do what you can by hand - I rarely use power tools. That's just as well because I often work in the middle of the night!

[Mike Phelan]

For rectangular holes I use one of these:
http://www.mytoolshed.co.uk/p16693/E...llKxoCl0bw_wcB
A few on EBay as well.

[Al (astral highway)]

Looks great for larger holes, Mike? Any good for 3 by 1 cm? A factor for me is that my space is limited so if I buy a tool, it has to be one that I'll use all the time. Thanks for sharing this, though !

[Mike Phelan]

Would be pushing it a bit on such a small hole, Al, but I do have another gadget whose name I cannot remember that will cut square holes approx 5mm square and is powered by a drill.

[Ed_Dinning]

Hi Mike, basically a nibbler, when drill powered is a bit more like a broach.
I have also seen a hand powered version, but you would need a grip like a gorilla for even 1mm material.

Ed

[Radio Wrangler]

Apply a self-adhesive paper label so you have something to write on, and it gives the surface a bit of protection if you hit it with the file handle.

Mark out the aperture very carefully, and mark the places for three holes to start drilling. You're going to put a pilot drill through first and then an 8mm drill. So you need one hole positions dead centre and two 10mm to either side.

If it goes wong at this stage, peel off the label and apply another.

You can always mark the label up before sticking it on if you trust yourself to get it located just where you want the meter.

Use a centre punch on the pencil marked hole positions.

Drill the pilot holes very carefully.

Follow up with progressively larger drills, but don't go over the marked outline.

So now you have three holes and a marked outline. File the holes together with a small file until you have room to get a bigger one in.

Only have the file in contact with the work when pushing to make a cut. Raise it off thework when drawing it back, or else the file will rag the edge of the paper and you'll lose your outline marking.

Communing with a file is an important aspect of an apprenticeship and the engineering gods will smile on you. Dragging a file backwards across the work as you return for the next cutting stroke will set them scowling. Lift off on the return stroke and they will happily shower bounty upon you. Take fairly long strokes, use most of the length of your file if you can. If you reciprocate quickly in tiny short strokes, any real engineer within earshot will walk over and give you a right clip round the lug 'ole. It's tradition and part of our heritage. Said engineer will also give you in advice in a traditional ancient language.

David

[Karen O]

And provided you die with your soldering iron in your hand, you can enter Valve Halla

[Radio Wrangler]

That's true.

The guardian of Valve Halla can then tell if you're a real engineer and fit to enter....



... by which end of the soldering iron you are holding

David

[Herald1360]

If it's the wrong end, you may well smell the problem before you feel it

An old Adcola leaves interesting brown striations........