Any sheet metalworkers here ?

Emp_Fab

I'm looking for the best way to make holes, about 7mm, in thin sheet steel - a large can specifically (for a funky lampshade).  Drilling them results in a shitload of burrs on the underside of the holes which is a pain to remove.  I thought about maybe using an arbor press with a hole punch on the end ?  How can I make holes in thin steel without burrs ?

fastonebaz

You seem to have alot of free time on your hands @Emp_Fab .  What is the deal? 

Bellycaster

It'll be pretty thin steel if it's akin to the sheet steel thickness of a "Can". So, you'd have to drill small at first and work up to 7mm diameter hole in stages of say 2mm each time.

Some support (that also gets drilled into....don't use your fingers) on the inner surface of the "Can" will prevent the burrs pretty well, probably enough that you will be able to de-burr them with some sand paper.

That's the Enginering theory anyway, but seeing as I'm assuming it's a curved surface, you'll have to be a bit inventive in how you do it.

Edit: My point is.........Rigidity is the key aspect in achieving your very lightly burred hole 

p90fool

I always use a step drill bit, then just touch it with the next step up to deburr it on the other side. 

They don't grab like a normal bit. 

Emp_Fab

fastonebaz said:

You seem to have alot of free time on your hands @Emp_Fab .  What is the deal? 

That’s an odd question!  How much free time do you think it takes to drill some holes ?  

Corvus

Just need a scrap backing board, ply or pine or whatever. And a decent sharp drill bit.

Jonathangus

So if I'm understanding correctly, you want it to end up looking similar to this?

https://www.ikea.com/gb/en/p/ordning-kitchen-utensil-rack-stainless-steel-30131716/

Gassage

Just buy one you bloody tight arse!

EricTheWeary

You don’t want a sheet metalworker you want a good one. 

De nada.

ESBlonde

When making holes to mount Speakons or XLR sockets we use this type of thing. Drill a small hole for the bolt in the centre of where you want the hole. Clamp the device about the bolt and tighten away. Cuts a clean hole in sheet metal. Not stunningly fast, but neat and tidy while being decent cost for the (small) job. Not sure where to get a 7mm version. Sometimes know as a greenlee punch.

https://uk.farnell.com/ruko/109220/punch-hole-round-22mm/dp/4700818?gclid=EAIaIQobChMIyO2s4JaX5gIVTbTtCh2rqAMAEAQYAyABEgK1IPD_BwE&gross_price=true&mckv=09bUwDQ8_dc|pcrid|78108295629|&CMP=KNC-GUK-GEN-SHOPPING-4700818

ROOG

Jonathangus said:

So if I'm understanding correctly, you want it to end up looking similar to this?

https://www.ikea.com/gb/en/p/ordning-kitchen-utensil-rack-stainless-steel-30131716/

@Jonathangus That would make a reasonable lamp shade, albeit a small one.

Funkfingers

Emp_Fab said:
make holes ... in thin sheet steel large can ... for a funky lampshade. 

Sounds suspiciously like part of a Ned Kelly fancy dress costume. 

Emp_Fab said:

press with a hole punch on the end.

That would be the most efficient method. It will still leave burred edges. (Mostly on the inner surface of the lampshade.)

Emp_Fab said:

How can I make holes in thin steel without burrs?

Tricky. Not even a plasma cutter is likely to manage that. 

PolarityMan

Funkfingers said:

Emp_Fab said:

How can I make holes in thin steel without burrs?

Tricky. Not even a plasma cutter is likely to manage that. 

Hmmm...so Chuck Norris?

Sesh

Q max cutter? Depends on how thin the steel is. Otherwise I'd clamp wood or aluminium either side and drill.