Opening a Philips coil can

[Radio Fixer]

Alas I have to do this as two coils in the bandpass filter are open.

The cans have a rolled over edge securing the Bakelite flange of the coil former in place. Many just use a screwdriver or such to lever this back but it makes for a messy looking can.

This is a can from a scrap radio chassis and not the real thing.

I came up with the setup in the first picture which works if not ideally. The tool is an old Radio Spares right angle screwdriver. I rounded off the edges but it still acts a little like a lathe tool rather than just rolling the turned over lip back. To use it the coil can is rotated, by hand from underneath. The back Jubilee clip is tightened progressively.

   

But the second picture shows it leaves the can still looking neat.

   

The third picture show a close up looking into the can. There is still some lip there and I could always use some Araldite as well. Now has anyone got any ideas how to neatly roll the lip back in place?

   

And for that matter a better way of opening the can in the first place.

Note: I don't have the use of a lathe.

thanks Gary

[pwdrive]

How stiff is the aluminium? hows about a hand roller made from an old brass tuning drive pulley, you could file the desired "fold over" profile curve in the pulleys groove using a cordless drill and a small diameter file.

Lawrence.

[Radio Fixer]

Yes! a good thought Lawrence.

I was thinking about an L bracket, with a tapped hole for a screw. This would be mounted on the above jig and the screw would allow a piece of curved wood to gradually squeeze the can lip inwards as the can was rotated. Then I would need something to bend the edge over. Something like you roller.

thanks Gary

[Refugee]

I agree Put the pulley in a drill and file one side into a flat flange with a flat file to fit the step and leave the other side original and it should roll the lip over again.
You should be able to hold the can in the rig you have already made up.

[Radio Fixer]

Had another go today at putting the coil back and it came out none too bad.
Annealed the end and then pushed the can in with the screw and wood block, revolving the can by hand. That was fine then peaned the edge over using a flat ended round punch and a hammer.

It is actually good enough, not perfect but with the can fitted to the chassis I dont think anyone could tell. The main thing is what you see still looks fine. I may do better if I can come up with a way of opening without belling out so much.

   
   

Boy! its damp cold in that garage. Even with a fan heater going I didnt want to stay out there long. I'm sure it kills some creativity. So next attempts, after the holiday I will have to put thermals on and a couple of
coats

Gary

[pwdrive]

Looks good enough to me Gary.

Brrrr, yep, cold, was down the woods this morning with my hands in the cold pond water.

Regarding aluminium cans, not the same as yours but the old trick with the narrow capacitor cans (chassis mounted) in the R1155 etc was to start and push the edges over just part way (a few degrees) towards the center then fit back in the chassis hole and screw up the bottom fixing nut, that used to pull the flange back as was.

Lawrence.

[Radio Fixer]

Like the R1155 trick.

Gary

[pwdrive]

Some of the larger pepper can HT filter caps had bottom nut fixing too.

Get them thermals on, I've managed without so far this year but I'm having second thoughts.

Lawrence.

[pwdrive]

Here's an easy and good way to re stuff this type of capacitor can, I've used this in the past, very good results.

Lawrence. EDIT: Whoops I've drawn it wrong, in a rush, will amend later.

[Radio Fixer]

Is it this way that a friend used on a Murphy PSU?

   

Pretty self explanatory. Cut, restuff, bell one end slightly and the other filed and rolled in a little. Put together with super glue.

Gary