Constructing the Josslin Hudson

Carrdo · Post by **Carrdo** » Fri Aug 05, 2022 10:33 am

Some of the misc. parts associated with the side rods which needed to be made. These are all "straightforward" lathe turning operations.

I put the term "straightforward" in quotation marks as the bronze bushings were anything but that. The bushing ID had to be drilled and then precision bored to a dead close running fit (tenths) on the steel crankpin while the bushing OD had to be a press fit in the rod (more tenths). As well, the surface finish and geometry on the ID and the OD of the bushings had to be dead smooth and straight. Everything on these bushings has to be turned at one setting. Lose one's concentration for a second and you can start over again.

Carrdo · Post by **Carrdo** » Sun Aug 07, 2022 9:01 pm

Continuing with the front side rods where I left off 4 years ago. I previously described how I got to this point.

The first operation was to rough down the tongue ends of these rods. It is very important that the tongue of the front side rod does not end up being canted with the rest of the rod (it has to be square, parallel and closely on size but it is also offset) so the setup to make and keep it this way has to right. I don't claim to have the perfect setup but with care, the one shown in the first photo worked. I don't need to repeat that it is very important to have all of the rod blanks as rectangular as possible to start with as this and all of the other rod setups depend upon this initial machining being correct.

But first numerous measurements and a lot of calculations (see the last photo - ignore the numbers as it is the methodology which is important) are needed here as with the rear side rods, the front side rod ends are also offset 1/32" from each other and the rods are asymmetrical about their centre lines.

One has to first establish where the two centre lines are on the rod blank and then work from there. Also, in my case, the layout process included marking the rods LH and RH as well as the inside face and the outside face and the top and the bottom of the rod blanks.

As with the rear side rods, I feared that I had not left enough blank thickness on the front side rods to achieve the above (as I came to the realization that the rod ends were offset 1/32" quite late). The first calculations indicated nearly .030" to the good on one blank but only .007" with the second blank so I escaped again this time.

Carrdo · Post by **Carrdo** » Wed Aug 10, 2022 7:41 pm

Some quick and dirty ways I scribe all of the partial intersecting arcs and half round ends, etc. on the front rod blanks prior to generating them with the rotary table setup(s).

Just to make things interesting, every partial arc on these Hudson rods has a different radius.