A Boma

[DaveH]

(04-08-2015, 08:08 AM)f350ca Wrote: Dave, could you build a fire pit and heat it with wood. I know I think they're called a BOMA, ya build one of those then heat the stainless over it.

Now that's a good idea Greg - sometimes I just can't see the wood for the trees

DaveH

[DaveH]

(04-08-2015, 07:56 AM)Bill Gruby Wrote: Have you tried the heat yet Dave. If so, how did it go. Maybe making the scroll a little larger would help?

"Billy G"

No I haven't Bill - all I did was to try to heat about 6" of the end of the stainless flat bar. It didn't work too well, I could have built some 'fire bricks' around the flat bar to try to retain some of the heat. By this time scrolls were looking a bad idea Time to move on.

DaveH

[DaveH]

(04-08-2015, 06:57 AM)stevec Wrote: From the pic (how come it doesn't appear in the quote?) I'd be afraid of the "channel" just spreading open.

Steve

As it is drawn I also think the channel would open. It was just to show the idea my thoughts are to use two 25mm thick sides bolted together with two 30mm (or more) spacers.

DaveH

[DaveH]

I have bent a small length in the press brake it turned out fine  - quite easy   whether it will be quite so easy with a round die I'll have to try it and see.
It's not the end of the world Guys and I'll know in the future making scrolls from 3mm x 30mm stainless cold with my type of scroll maker is not the best plan.  

 
DaveH

[Bill Gruby]

Try heating just a part of the scroll. Bend that then heat some more and bend that. Sneak up on it so to speak. It will take more time but worth it in the end.

"Billy G"

[DaveH]

Bill, I think that might work, although it was suggested I should do it in one go.  Doing it piece meal always runs the risk of them all coming out different and I wouldn't like that very much. I know no one will notice but I will every time I look at it  

I'm just going to try using a round die in the press I've done similar things in the past and they have worked out fine - just not with flat bar stainless.
My main concern because the stainless I have is so springy that it doesn't fly out of the press and injury me - that would really tick me off.  

Heating it will reduce the springiness and is probably to safer way to go.
 
DaveH

[DaveH]

Knowing what I know now, I wouldn't use stainless I would use ordinary hot rolled steel and paint it.   
I'm not really geared up as a 'black smith shop'  

Strange really because I have turned and milled meters of stainless with little or no problems - just to say most of the stainless (99%) was 303.
Just goes to show cutting it is one thing bending it is an entirely different kettle of fish  
 
DaveH

[DaveH]

Had a quick go with the press break and using a 33mm dia die. The stainless flat bar was only a small piece (off cut) so I was a bit concerned it might fly out and hit me.  
Finished it off in the vice, over cooked it a little but with a little more practice should be fine.

   


DaveH

[DaveH]

Had another go. I though you might like to see the set up and how I did it. Even if you don't I'm still going to show you      
I have to say the set up does look a little on the dangerous side and it probably is


The initial set up, the hollow bar is 33 mm dia the spacing between the blocks is 48mm.
   

After a few operations of the jack handle.
   

It was at this stage I narrowed the gap between the blocks to 40 mm and after a few more pumps.
   

It was further squashed (carefully) in the vice and this is what I ended up with.
   

Not too bad

DaveH

[DaveH]

When I decided to make it out of stainless I had a look around to see what stainless steel Bomas there were - very few and I thought probably because of the cost. So I 'phoned a few guys up to ask what their thoughts were. Most thought is was a good idea (daft as me;  'birds of a feather'  ) and like me didn't really know an awful lot about 304 cold rolled stainless steel. However one guy knew some one (Mike) who did know about 304 cold rolled stainless steel.
Mike has just phoned me (very nice guy) and he has said the following:
Cold rolled 304 stainless is full of stress and when it is heated 'it distorts like crazy' (mike's words). This distortion will most likely crack the welds.
Mike's view to make it out of cold rolled stainless due to the distortion and cracked welds isn't a good idea - plain hot rolled mild steel would be much better.

Any one want to buy some 304 stainless  cold rolled 30mm x 3mm flat bar.

I'm seriously thinking of not using the stainless and just use hot rolled mild steel flat bar. 

 
DaveH