| Nordic |
Hey, been looking at cases for my 5.1 channel gainclone amp, but quite frankly the prices just don't justify the material costs over here... and then you still need a heatsink.
So I picked up the phone and phoned an aluminium sheetcutting place localy (well at the time I only asked for a price for a 10cm x 30cm x 2cm piece of Alu... to use as heatsink), turns out its quite a bit cheaper than I thought (about $10).
So now I am thinking that I could reasonably afford to have all panels cut and make the case myself.
<<<The real question is, >>>
Would I be able to make my own screw holes or do I need to ask someone to put it in with some kind of machine or something?
If you can point me in the right direction or give me a google search term that's actualy usefull I would be very gratefull.
I's going to be one heavy amp, the trafo is just shy of 9kgs, and I still need another smaller one for a preamp to go in there too, so I don't think wood is an option.. |
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| Nordic |
Ahh so thats what those funny drillbit thingies are for....
My dad had a litle box with things like those, think it had little round rings it fits to and i think there is some kind of handle thing which you stuck through it... but how do I know if the thread is the same as the screw's?
Think I should ask the sheetcutting place if they can do this for me... looks very daunting |
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| Emiel |
| quote: | Originally posted by Nordic
(well at the time I only asked for a price for a 10cm x 30cm x 2cm piece of Alu... to use as heatsink)
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Please keep in mind that the amount of heat a block of aluminium can dissipate is lots and lots smaller than an actual heatsink with fins and stuff!
If you have the right tools (especially a drill and the right drills to make holes and taps for tapping threads), a good design and the patience it's not that hard to make your own case!
Good luck!
Kind regards, Emiel |
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| Nordic |
| Will definatly try my hand at it with some PC heatsinks for practice (lol will have to avoid the copper core by the sounds of it). |
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| AndrewT |
Hi,
a counterbore for the bolt heads looks really neat.
Even if the plate is not thick enough to get the bolt head at or below the surface, it is worth doing. Black screws on black plate are O.K. but gold or silver on black plate is something else.
You can grind a flat ended drill to get your own counterboring tool, but you have to start your drill turning after inserting the drill into the predrilled hole or else the drill corners will chew up the plate edge if you do not centre it correctly. Practice on some scrap. |
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| AuroraB |
Peter..
How much do you use helicoils ( or similar )..?
In my work ( sounding rockets), - helicoils are used everywhere in alu structures, - not a problem as such for hobby work, except for the money..... |
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| Emiel |
Hi!
I believe helicoils are used in aluminium if the bolts have to be tightened with high torque and/or tightened and loosened often. Normally they are used in plastics.
Ciao,
Emiel |
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| Peter Daniel |
| When I was working on aircrafts, helicoils were used only to repair damaged threads (pending engineering approval). Otherwise, special nutplates have been used, whenever screws where applied in aluminum: http://airbolt.com/nutplates.htm |
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| Emiel |
Or find someone with a (CNC) mill and other tools :D |
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| AuroraB |
Well-- we do both... partly high torque - and repeated dismantling...
threads in alu are rather soft and are easily destroyed.....
I can not do without the torque drivers at final assembly though.. I am far too strong on my own...;) |
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| Peter Daniel |
| quote: | Originally posted by Emiel
Or find someone with a (CNC) mill and other tools :D |
It is still a hassle. While I uses professional fabrication house, with all sort of CNC mills, I find working at home at my own pace the most satisfying for short production runs, or protoypes, using basic tools only;) |
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| Peter M. |
I just drill the holes slightly smaller than the screw, apply some lube(oil, beer, coffe allmost anything works), and let the screw make its own threads.
Do it verrry carefully as it is easy to break the screw, take a few turns back and forth as it goes in...
Try it on scrap pieces first! It may not work with all alloys.
Regards,
Peter |
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| dnsey |
What are those threaded insert things which are fitted rather like pop rivets?
I've seen them demonstrated, and come across a few in commercial gear, but can't remember what they're called. They seem ideal for our purposes. |
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| Christer |
| quote: | Originally posted by Peter M.
I just drill the holes slightly smaller than the screw, apply some lube(oil, beer, coffe allmost anything works), and let the screw make its own threads.
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AFAIK the industry use methanol based spirits when machining aluminium. I have learnt to do so from people working in the aircraft industry. Other things may work, but the people I know who supposedly know this say that spirits is what one should use, and it has worked well for me on the few occasions I have worked with aluminium. |
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| Nordic |
| quote: | | I work as a sheet metal and structure technician contractor for Aviation |
No wonder you have no fear... |
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| AuroraB |
| quote: | Originally posted by dnsey
What are those threaded insert things which are fitted rather like pop rivets?
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We use some of those .. we call them pop nuts.....
only snag is you need the special tool....
:mad: |
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