Cutting neat notches in a stainless steel cooker hood chimney

[happysteve]

Eh up

Is it possible to cut a neat notch - say arch shaped, with the arch diameter about 25mm - in a stainless steel cooker hood chimney, without either making a mess of the chimney, or breaking/burning out tools, or both?

Special hole saw - or maybe regular holesaw used for steel - and cutting compound, on low speed? Jigsaw for the straight bits - is there a special blade? Speed setting? Compound? Clamp the steel either side with offcuts of timber, or it doesn't bend/flap about too much?

There will be 20mm galv conduit running horizontally behind the chimney (which recirculates filtered air back to the room, so a small gap around the conduit will be fine).

Advice on good cutting techniques appreciated.

Cheers!

 

[SagaCU29]

Eh up

Is it possible to cut a neat notch - say arch shaped, with the arch diameter about 25mm - in a stainless steel cooker hood chimney, without either making a mess of the chimney, or breaking/burning out tools, or both?

Special hole saw - or maybe regular holesaw used for steel - and cutting compound, on low speed? Jigsaw for the straight bits - is there a special blade? Speed setting? Compound? Clamp the steel either side with offcuts of timber, or it doesn't bend/flap about too much?

There will be 20mm galv conduit running horizontally behind the chimney (which recirculates filtered air back to the room, so a small gap around the conduit will be fine).

Advice on good cutting techniques appreciated.

Cheers!

Yes, mark it up take it off and find a sheet metal workshop that will do stainless.

 

[telectrix]

maybe a 25mm hole punch would be appropriate. then trim the straight bits with a multitool fitted with a metal cutter. burn ther cutter out, it's only a few squid.

 

[snowhead]

Step drill for the hole.
Tin snips / Aviation snips for the slot.

 

[telectrix]

Step drill for the hole.
Tin snips / Aviation snips for the slot.

good luck with step drill on stainless. hole punch will go through it like a knife through butter and not bend it (much),

 

[buzzlightyear]

I remember doing it once with a angle grinder boy it looked bad the only way off cutting steel is with a plasmer torch cutter.

 

[Strima]

Available in various shapes and sizes.

50124790 | Greenlee Punch and Die Tool | RS Components - https://uk.rs-online.com/web/p/punch-die-kits/4778779?cm_mmc=UK-PLA-DS3A-_-google-_-PLA_UK_EN_Hand_Tools_Whoop-_-Punch+&+Die+Combinations_Whoop+(2)-_-4778779&matchtype=&pla-341424870708&gclid=Cj0KCQjw0rr4BRCtARIsAB0_48MUoG6LXz4_tephGOpaRXKMKABYI_dTcWCY4gwqHYJzwZIi39Zba0MaAsC6EALw_wcB&gclsrc=aw.ds

 

[nicebutdim]

Nibbler.

Bit pricey to buy for a one off job though.

 

[happysteve]

A punch is a good shout, thanks Should have thought of that... in a former life I used one to make XLR patch panels (albeit on mild steel).

I've found an offcut of 1mm stainless sheet in the shed, I will tentatively experiment before unleashing my destructive powers on a client's kitchen furniture

Any further advice appreciated.

Thanks folks!

 

[telectrix]

taken from the RS description:

Legislation and Compliance
RoHS Status: Not Applicable
Statement of conformity
COO (Country of Origin): DE
Product Details
Special Size Hole Punches
Special size hole punches used to punch burr-free holes for switches and instruments in enclosures. Punch up to 3.0mm mild steel and up to 1.5mm stainless steel. (punching stainless steel reduces lifetime of punches)

 

[Scintillam]

A punch is a good shout, thanks Should have thought of that... in a former life I used one to make XLR patch panels (albeit on mild steel).

I've found an offcut of 1mm stainless sheet in the shed, I will tentatively experiment before unleashing my destructive powers on a client's kitchen furniture

Any further advice appreciated.

Thanks folks!

If you decide against using a punch have look at the other holesaws that are available now as there’s better options for stainless than bi metal hole saws. Starett website has the other options
[automerge]1594845712[/automerge]
Is the Galv conduit already in place? If not should it not also be stainless?

enough room to get a grinder in to cut the slot out?

 

[happysteve]

If you decide against using a punch have look at the other holesaws that are available now as there’s better options for stainless than bi metal hole saws. Starett website has the other options
[automerge]1594845712[/automerge]
Is the Galv conduit already in place? If not should it not also be stainless?

enough room to get a grinder in to cut the slot out?

Thanks

The client likes the look of galv steel, and has already purchased some "distressed" look metal-clad sockets.

 

[davesparks]

Thanks

The client likes the look of galv steel, and has already purchased some "distressed" look metal-clad sockets.

I like the look of a nice galv install too, but I wouldn't have it in my kitchen!

I feel I have to ask, what is a 'distressed look' socket? I can't help but wonder if it's just the rusty old crap I've been ripping out recently someone has dug out of the skip?

 

[happysteve]

I like the look of a nice galv install too, but I wouldn't have it in my kitchen!

I feel I have to ask, what is a 'distressed look' socket? I can't help but wonder if it's just the rusty old crap I've been ripping out recently someone has dug out of the skip?

I also love a good galv job

I would never criticise a client's choice of fittings on a public forum, but I can see where you're coming from

It looks a bit like someone's applied emery paper and given them a matt, dull, slightly uneven finish...

I don't know how much they paid for them, but I could have achieved a similar effect by taking the usual ones I supply out of their protective packaging, and letting them roll around the back of the van for a couple of weeks!

 

[happysteve]

Did some trials on an offcut of 1mm stainless steel sheet.

The 25mm punch worked really well, very neat. Drilled a 4mm pilot hole, then widened to 6mm then 10mm (for the punch bolt), nice and slow, with a bit of water to cool things down.

Tried tin snips to cut: made a nice neat cut, but bent the metal (furthest cut away from the camera on the arch in the picture below).

Tried a jigsaw with very fine tooth blade, on slowest setting, again with a bit of water (nearest cut on the picture below). I learned that the underside of the jigsaw base plate can scratch the stainless steel, so tried another cut elsewhere after putting masking tape on the stainless steel to protect it - that came out fine. A bit of deburring with a file, nice neat finish.

Obviously I made the arch a bit high, but you get the general idea.

Gives me confidence to do it on the client's cooker hood chimney.

Thanks for the advice in the earlier posts, I'll post pictures once the job's done* (in a few weeks)

* unless it goes embarrassingly badly, in which case I'll post pictures in the Arms