Landeron 248

[GeorgeClarkson]

Bye the part number you wrote is wrong, the correct part number is 8350.

[chadders1966]

46 minutes ago, GeorgeClarkson said:

Bye the part number you wrote is wrong, the correct part number is 8350.

Thanks, I did mean to post the correct number - IPad jumbling I think. Too late to edit now unfortunately.

Edited January 15, 2017 by chadders1966

[RyMoeller]

7 hours ago, Marc said:

@chadders1966

whilst searching for a replacement, just for fun why not try and make one.

You need some decent springy high carbon steel of about the right thickness, slightly thicker is good, something like an old (but decent quality) hacksaw blade for instance or a piece of old clock main spring. Heat it to a bright cherry red and then let it cool slowly to anneal it so that it can be worked.

Next get it to the right thickness by working it on 400 grit wet/dry paper on a sheet of glass using an old champagne cork to hold it flat and keep your fingers out of the way. Work both sides and check the thickness often.

Then drill the holes, one for the screw and two for locating dowels.

Now superglue the broken pieces to the stock so that the locating dowels are in the holes and the screw hole lines up. Using this template you can cut and file to shape.

Once you're happy, remove the template and carefully tidy up the finish, apply any chamfering or counter sinking. It might also be wise to test fit at this stage too although you don't have any locating dowels.

Now bind the whole thing in soft iron wire in preparation for hardening. This helps to keep the heating even and reduces the risk of warping. Heat to a bright cherry red again but this time cool it quickly by quenching it in vegetable oil (some people also use brine).

Unwrap it and check that it hasn't distorted. Also test it for hardness using a file, it should be glass hard at this stage. If all is well then clean at least one side to a bright finish so that you can see the tempering colours.

Now temper it by placing it on a piece of brass sheet (the thicker it is the more evenly it will heat) over a spirit lamp and watch closely for the tempering colours to appear. The colours start with a very pale straw colour which gradually darkens and then goes to a light blue which then darkens. You want to make sure that the process happens evenly over the whole surface and you are aiming for a mid to dark blue. Once you have got that, quench the part in water.

You can now polish the part back to bright, or even leave it blue depending on the aesthetic effect you want.

For the locating dowels find yourself a sewing needle of the right diameter. Anneal it as above, and cut two pieces, slightly longer than you need. Install in the dowel holes in the spring and rivet in place. Now carefully grind to the correct length.

Install the spring in the movement, sit back, and admire your handiwork over a glass of something suitable.

Just a thought...

Ah thank you for this Marc- this is why it pays so handsomely to peruse these forums!  I've made many a part out of brass stock but when it comes to working with steel I didn't have a very good understanding of annealing and hardening.  I'm going to have to try this out now.