Punch and then thread

[Tink]

Hi,
I'm starting to make more prototypes at home rather than sending off to have them made by a metalwork company.. however for one offs that always seem to need changes it seems prototyping myself is the best way forward..

However I've hit a snag.. how would I go about doing the technique of punching a hole into 1.5mm aluminium.. leaving a lip the other side and then being able to thread it.

Is there anyway I can achieve this at a basic home setup?

Thanks in advance for any help!

 

[Swifty]

Basic information here https://books.google.com.au/books?i...epage&q=extruding holes for threading&f=false, page 59 onwards.

Done this many times in press tools, including tapping in the press on the down stroke. You need to be able to accurately locate the punch and die.

Paul.

 

[gus]

Hi Paul,

The fins for the Howell V-4 Radiator. Would be a good idea to have the radiator fins stamped with with extruded lip to space out the fins equally just like the condenser coils. Have not seen any HMEM Members build Engine Radiators with such fins.

 

[Swifty]

Hi Gus, just too much of a pain to do for the hobbiest, although that type of work was always cropping up when I made press tools.

Paul.

 

[Tink]

Thanks for the link. Yes that makes it clearer in my mind now. I was hoping there would be some sort of small tool I could use..

Am I right in thinking that this is something that I wouldn't be capable of as a someone with no experience of punching? Currently I don't have any punches so would be looking to purchase something..

Perhaps I'm better off just tapping the M3 holes in 1.5mm sheet metal. Spreading the load over many screws and if it's secure enough then it'll be even more so when I get it done with extrusion from the competent metalworkers!

Or is there a middle ground that I would be capable of?

 

[Tin Falcon]

Or is there a middle ground that I would be capable of?

Sounds like a good application for aluminum rivnuts to me.
search the web there are a variety of riv nuts and tool's to install them.
they can be installed without the special tools but a bit awkward for more than a couple.
rivet nut or rivnut tools will bring up lots of hits many variety's to choose from
these are used to install threaded holes on bicycle frames automotive applications ect.
Tin

 

[Herbiev]

I totally agree with Tin. Rivnuts are the way to go. Just pop in the rivnut and you've got a neat threaded hole

 

[Swifty]

As Tin Falcon and Herbie have said, rivet nuts are ideal. I have used them in the past on sheet metal. There is another type of fastener that I have used on aluminium, a hole is drilled in the sheet and the fastener located in the hole and pressed in to clinch it. Very low profile using these types of fasteners.

I just checked Google, they are called clinch nuts.

Paul.

 

[bazmak]

Hi Herbie we also used weld nuts.Same thing but you spot weld them in
Now you have a spotwelder ?????.As for mthe punches they are simple to make
For say M5 you drill 3 dia male punch is stepped 3 to 4.2 (tapping size).Bottom
die is drilled 3mm for location and stepped to 7.2 ( 4.2 = sx matle thickness
Hit with a hammer and bingo.Cheap and simple 1 set per thread size
alignment is no problem just mark out drill the holes and punch

 

[Herbiev]

Hi Baz. Will have to give the weld nuts a try.

 

[bazmak]

Does it work on aluminium ?

 

[Herbiev]

Good question Baz. Will try today.

 

[Swifty]

Here's another option that I came across [ame]https://m.youtube.com/watch?v=NhkWINPRK3A[/ame]
Called flow drilling or thermdrilling.

Paul.

 

[Tin Falcon]

Swifty interesting that is one process I had not seen before.

The more I learn the more i realize how much there is to learn.
Tin

 

[Herbiev]

Love it Swifty. Looks like a drill I sharpened myself

 

[Swifty]

I did recall seeing this sometime in the past, H & F in Australia have started selling the required parts. Looks like the main holder has a very large aluminium heat dissipating ring attached to it. http://www.machineryhouse.com.au/Thermdrill. Of course, aimed for the manufacturing sector, but interesting none the less.

Paul.

 

[mcostello]

Left hand drill bit in a right hand drill press for a start?