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Author Topic: Mid- Engine Modified Sports  (Read 422120 times)

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Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1740 on: October 05, 2019, 05:10:18 PM »
The swing arms I made were a little too flexible so I cut some 1/2" square steel tubing and inserted two , one inside each edge, and riveted them in place. This stiffened the assembly considerably and the shift motion feels good now.

Regards, Neil  Tucson, AZ

Well, after a number of shift cycles, that approach was not satisfactory after all- the steel arms were too thin and even after being reinforced it started to flex. Back to the drawing board- or the stash of surplus stuff.  :-)

With my little hobby bandsaw, I cut two new swing arms out of 1/2" 6061-T6 aluminum plate, made a 3/4" hole in one and a 5/8" (nearest to 14mm) hole in the other using aircraft counterbores. They cut a nice clean hole that is also pretty accurate. I drilled and tapped two 1/4-28 holes in each to act as set screws. On the opposite end of each swing arm I drilled a 3/8" hole for the link bearings.

From somewhere I had bought a few odd tube ends that had ball bearings staked in one end and the other end was bored 3/8"- a perfect fit for a 3/8" spherical rod end bearing that I had. Clean both the made threads and the inside of the hole, apply some good ol' JB Weld epoxy and Voila!- a nice link for connecting the swing arms.

The G50 shift rod moves in and out as well as rotates and the rotation is opposite to the normal shift pattern, necessitating the link monkey motion. The G50 end swing arm needs to be able to rotate but be stiff when pushed & pulled. Since the G50 shift rod and the long shift rod are not parallel, there needs to be a bearing on the other swing arm that can accommodate rotation in two axes but also be stiff when pushed & pulled. A spherical rod end bearing does this nicely. I ground a two small divots in the end of the long shift rod to prevent the set screws from slipping on the 3/4" Thompson ground & polished shaft. It has a hard 60C surface so set screws would not be able to bite into the surface otherwise.
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1741 on: October 05, 2019, 05:14:01 PM »
Here are the latest shift linkage photos. I think this approach will be OK.
Regards, Neil  Tucson, AZ

Offline floydjer

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Re: Mid- Engine Modified Sports
« Reply #1742 on: November 04, 2019, 08:37:52 AM »
very nice work Neil. Carry on.
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.