Swaging tool for copper tubes

[pendlesteamer]

I have seen articles in ME recommending that a shoulder of about 10 thou be swaged on tube ends to prevent them sliding through tubeplate when silver soldering (eg Emma Victoria by Henry Wood 18/04/2014)
Apparently a suitable tool has been described in ME a number of times, can anyone advise which issues these were?

Many thanks

[ejparrott]

'friad I can't, but my method is to bead the tube with a roller.

Turn a mandrel in the lathe to be a loose fit up the tube. At a distance from the turned shoulder back towards the tailstock, equal to the distance you want the bead, neck each side with a parting too about 1/16" deep ISH! and then form this into a rounded 'hump'. Reduce each side of it to its core diameter

something roughly like this:

|
|_____n_____

|-------u-------
|

Then make a roller to fit your knurling tool which has a groove in it equal to the thickness of the tube plus the hump on the mandrel. Anneal the tubes, pickle them to clean, then hold the end over the mandrel up to the shoulder, rotate and press the roller against the tube with the cross slide...instant bead. Oil helps, but remember to clean and pickle again before soldering.

[gwr14xx]

You could try a method I used to enlarge the ends of the tubes for a Hielan Lassie boiler. All you need is an Allen screw with a head small enough to go inside the tube (preferably with some plain shank), a nut and 2 stout washers (a neat fit in the tube), a spacer and a short piece of rubber tube that fits neatly on the Allen screw and in the bore of the tube. Put one washer on the Allen screw, then the short piece of rubber tube (say 10mm long), then the 2nd washer, spacer and nut. With the tubes annealed and inserted in the tubeplate, insert the assembly into each tube in turn and tighten the nut. Compressing the rubber forces it outward and swells the tube either side of the tubeplate.

 I found this method very effective - and cheap!

  Eddie.

[pendlesteamer]

Thanks for that ejparrott. Knocked up the bits this afternoon and trialled on some tube offcuts. Works a treat, now to do the actual tubes.