How to cut a hob extractor "chimney"?

dunroving

I've purchased a Bosch hob extractor, and the "chimney" is too long, which is quite strange (my ceilings are standard height - 2.30m).

So ... need to trim about 15cm off the chimney.

Hacksaw won't work because it is too wobbly. Metal shears won't work because it will leave a crimp in the metal.

I'm struggling to even think of what to search for on Google. A sheet metal cutting company? Problem is, it's made out of sheet metal, but is no longer a flat sheet (has been moulded into the right-angled chimney).

I'm a bit stumped!

Will2208

I used an angle grinder with a thin blade. I clamped chimney to a workbench, marked up where I wanted to cut and then very carefully and slowly cut with an angle grinder.

dunroving

Just an update, after further research.

I found one thread that suggested trying metal fabrication companies (of which there are a number, as I'm in Birmingham!). Everyone I called said they just do industrial work, so am running out of luck.

FYI, the cut will be on show, and there are no other options (can't cut the bottom, as it has attachment points on it). So it has to look good.

Any help greatly appreciated!

EssexExile

As above, angle grinder & hide the cut with some trim.

FreeBear

dunroving wrote: »

Hacksaw won't work because it is too wobbly.

Clamp the metal between two sheets of plywood or MDF, then use a hacksaw (or a jigsaw with a suitable metal cutting blade). Don't bother with an angle grinder as it will leave a real nasty burr and discolour the metal around the cut.

Jackmydad

How does the manufacturer suggest it's cut?

Stainless is pretty horrible stuff to cut.
The only viable alternatives I can think of for a shaped piece, is either an angle grinder, or possibly a jigsaw, although the metal is probably going to be too thin for that.

Stainless will cut with a plasma cutter as well. Stainless fabricator for that I suspect, and you've tried them.

So angle grinder, disc that will cut stainless steel, (Screwfix have them) and appropriate PPE?

Can't you take the duct through the ceiling and make it off there?

Jackmydad

FreeBear wrote: »

Clamp the metal between two sheets of plywood or MDF, then use a hacksaw (or a jigsaw with a suitable metal cutting blade). Don't bother with an angle grinder as it will leave a real nasty burr and discolour the metal around the cut.

I agree about the burr and so on, but if it's a shaped piece like a "chimney" or duct, you can't really clamp it between pieces of wood easily.

As EssexExile says some trim will hide any mess from the cut.

ianto11

Use some of these in a 115mm angle grinder, small burr, dress with smooth file and any discolouration of stainless you can clean perfectly with one of these (note has to be a stainless wire brush )

Or could you not fit it lower as long as it satisfies the minimum distance requirement form the hob ?

Flugelhorn

I go one cut by a metal workshop in industrial bit of Yorkshire - they were very helpful, very neat job

beaker141

Usually the chimneys are in 2 pieces that interlock and slide together a bit to adjust for height - is yours not able to do that ?

dunroving

beaker141 wrote: »

Usually the chimneys are in 2 pieces that interlock and slide together a bit to adjust for height - is yours not able to do that ?

No, it's the bottom bit alone that is too long - so I can't even fit that to the wall, never mind the additional telescopic bit.