I had some 10mm diameter 416 Stainless heat treated to HRC35 left over from a previous job. Even though most of the time was spent converting it from round to square, overall it was not very hard. However, don’t underestimate the added complexity such small parts can add to fixturing.
Like with the rocker bases, when working with small parts in multiples, I like to keep as may together for as long as possible. Here I’ve cut off lengths of the stainless long enough to make two rockers per piece.
I could have spent more time and taken a light finish cut at a faster spindle speed and ended up with a better surface finish, but I have access to a surface grinder so that is what I’ll use to take them down to size.
I mounted the rotary table, indicated it in, and attached a scrap aluminum block. With the table on center and locked down at 0.00°, I milled a 0.1885″ groove about 0.1″ deep. I then fashioned a small clamp and was ready to start radiusing the ends of the rocker arms.
With both ends now radiused, the table is moved back to center in both X and Y and the rotary table locked again at 0.00°. One end of each rocker arm is then centerdrilled, drilled, and tapped #4-40 through for the valve adjuster.
See the log for the tappets for an explanation on why I’m making these a spherical bottomed hole and why they are only 0.070″ deep.
A few of the arms and pivot pins ready to go on the rocker bases.
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All material, including the CAD drawings, relating to the construction of the Hodgson Radial presented on this site is free to use any way you see fit. However, no guarantees are made regarding the accuracy or correctness of the material presented here.