Belling out thin mild steel

[nigel_bytes]

Hey chaps i need a little help with my MR2 i have just ordered some astra mk1 sills (they do fit but have a crease in them) thats not my problem though

Under the sills to the rear are some kind of mild steel strengthening plates (well past the sell by date) with holes which i understand are for strengh.

They are belled out ?
So my question is, After cutting out the holes just how do you bell them out ? Is there an easy way of doing this or is it to buy expensive tools to do this.
Help please.

 

[breezer]

THere is an expensive tool to do tis, not sure how you do it without one.

This is the sort of thing (and average price as far as I know)

http://www.motorsport-tools.com/index.php?main_page=product_info&cPath=18_246&products_id=822

They are supposed to be very good - but the tool only does one size so if you wanted to do more than one size you would need to buy more than one

 

[Tigman]

cant you drill your hole then find a piece of tube slightly bigger place under the hole and beat the metal into the tube , if its a plate thats not seen it wont matter too much about appearance !

 

[shenion]

As Tigman says, use a pipe with larger inner diameter. Then pound through a tapered hardwood dowel to form the flange.

 

[nigel_bytes]

this is my problem replacing this plate here,

 

[nigel_bytes]

What i want to make here (from another forum)

 

[hotrodder]

As said, can form 'em (the round ones at least) with a hammer and a couple of formers of suitable radius (old sockets, bits of pipe etc). For non round holes (or when surface finish is important) easiest way involves some hardwood, a router and a hammer (ideally a bossing mallet)...

Cut out the shape (not that important here but often have to remember to allow for the metals thickness), radius/rebate the edges with the router and you have the former. Cut out the blank sheet of metal (allowing extrea material for the swage/bell), clamp to the wooden former and methodically work the edges down against the former

With a lathe it's easy enough to make belling dies like the one's in the link. Just need to remember to allow for the metals thickness

Edit, hardwood formers work okay for maybe half a dozen of parts with 20swg CR4, maybe a dozen with 16swg aluminium. For more parts aluminium formers last longer and can be cut, shaped and routed like wood. Steel formers will last for ages/indefinately but obviously a lot more work to make