Constructing the Josslin Hudson

[Bill Shields]

Some of my soldering setups make yours look like NASA fixturing n comparison.

End result important

[Carrdo]

The upper brackets silver soldering operation.

I have always claimed that preparation is 90 % of silver soldering successfully. See the first photo. I used everything in the photo at some point in the soldering operation. Even so, one bracket only silver soldered successfully on the third attempt. I think the problem was there wasn't enough heat for long enough and/or the fixture holding the two parts together needs to leave about a 0.002" wide gap for the the silver solder to flow completely through the joint by capillary action. This was hard to determine and I was also afraid that the boiling flux would move or misalign the parts slightly. This operation doesn't have to look pretty but it must be structurally sound.

A couple of observations. With propane, one really has to sock the heat to the parts to be joined. I need them to be a bright orange all over to have the silver solder which I use to flow freely. Secondly, what ever flux is used (white or black), the right consistency needed is that of fresh toothpaste. Deviate from that, either too dry or too runny, and I have found problems. And both fluxes will dry out with age even when tightly sealed.

The first three brackets successfully silver soldered. The toothpicks seen in the photo are used to place the flux only on those surfaces where it is needed. Placement of the flux and keeping it there gets more difficult as the part size decreases. And it is difficult to put stop off with any precision on these small pieces.

[Bill Shields]

Only 90% ?

Looks good

[Carrdo]

Moving on to finish the entire spring hanger brackets.

These are of a built up construction and just require care to keep the parts square or rectangular and to the print size. Even though they are simple, they all take time to make including all of the custom made fasteners.

[Carrdo]

Further rotary milling on the spring hangers to produce the end bosses. Machining these spring hangers involved a lot more machining than I ever anticipated.

To produce the end bosses alone involved 16 individual rotary milling operations. Plus an additional 8 full end rounding operations.

With the end bosses, the entire setup had to be torn down several times and then set up again as I needed to closely control the depth of the curved end slots to a final 1/16" wall thickness on the side frames as per the Josslin print. I did this by taking trial rotary cuts, then tearing the setup down, measure the resultant side frame thickness and adjust the depth again as needed as nothing could be accessed or measured in place.

[Carrdo]

Finishing all of the spring hangers by milling down the centre sections.

Some delicate clamping is required here as the centre section finished thickness is only 1/16". Use a sharp end mill and take only light finishing cuts.

[NP317]

That answered my question from seeing your posted photo #946.
RussN

[Asteamhead]

Carrdo,
Precision work, nice to watch your progress!
Asteamhead