WT Borrow 21mm sheet metal punch

[Impy]

Hi guys, does anyone have a 21mm sheet metal punch I can borrow? Just need to do a couple of 1/2" bsp holes in a stainless pot and would rather borrow than buy new.

I'm in Croydon Park, NSW.

Cheers

 

[Meddo]

Not that size sorry, if no-one can help with a lend they can be had pretty cheap here - about $20 shipped:

http://stores.ebay.com.au/Big-Red-T...&submit=Search&LH_TitleDesc=1&_sid=1085143381

$20.49 to be exact:

http://www.ebay.com.au/itm/Q-Max-Sheet-Metal-Punch-21mm-/171843437950?hash=item2802aac57e

 

[flocculated]

Are these a better option than a drill bit/hole saw?

 

[Meddo]

Most reviewers seem to suggest that they are. I'm no metalworker but I was able to get much cleaner holes using a punch than normal drill bits in 1.2mm SS, and slightly cleaner than using the Keg King hole saws which were pretty good themselves. I found that the punches are completely stress-free to use - they just work. I haven't tried stepped bits.

 

[Impy]

I've been wrestling with step bits. With thin pots, step bits make an absolute mess as you have to push quite hard to get them to bite.

By reviews i've been looking into the sheet metal punches seem to be a sure thing that make perfectly sized holes.

 

[Mardoo]

Sheet metal punches are awesome, but there are definite limits on the thickness of stainless you can get through. I've managed to use them on plenty of stainless pots and modern kegs, but the reason I can't loan you my 21mm is that I destroyed it trying to get through one of the old Mytton Rodd 18 gallon kegs. Total fan of punches, I've built all sorts of stuff using them, but if you want to go thicker than 2mm or so SS, use a hole saw of some sort.

 

[mofox1]

If you use a punch - make sure the threads are lubed. Either machine oil, or wd-40... Mine worked great initially, sat in the shed for months (years?) before I used them again and it was squealing like hell & then couldn't budge the thing. Belatedly worked out the thing was dry and after a lube it went thru the sheet metal like butter again.

As Mardoo mentioned - this was with <1mm sheet metal. YMMV.

 

[Mardoo]

Lots of lube will get your punch through! (Usually...)

 

[Matplat]

Yeah punches are specifically meant for thin sheet, where the metal would rather deform, than allow itself to be drilled.

Using conventional metal cutting hole saws on a curved surface is a bad idea anyway, because you don't break through the entire surface at the same time, the teeth then start catching on the 'open' edge.

Fucks shit up real nice.