DIY shift coupler pic

[jasonq]

so i go into the machine shop at work intending to make some brass bushings for my coupler. then i see this nice aluminum rod...and a mere 5 hours later, i emerge with an complete custom made universal joint style coupler. Its dead solid, no play at all. hope it works well...

jason

[3.2 CAB]

Looks great, are you going to spline the shaft? Keep us posted on how well it works, and if any problems come up. Do you know what grade aluminum it was? Again, WAY TO GO.

[RoninLB]

I gotta respect the effort.

[smestas]

Very nice work Jason!

Now figure out how you can make them cheap for the rest of us.

[kach22i]

Porsche................more than a car..............more than a hobby.....................it's your life now.

Nice work, but now eveyones going to want one.

[kstylianos]

Slick!!

Very nicely done.

[azasadny]

Great job! You're very skilled!

[youngkang]

Nice job. Now, I want one.

[Tim Hancock]

Anyone can buy a car, but not everyone can build one. Good job!

(those pivot pins look a little small and you may end up with some play over time due to a lack of suface brg area but who knows it may hold up just fine and if not it looks like you surely have the skills to tweak the design a little)

The satisfaction acquired by doing it yourself cannot be denied!

[Nathan]

Excellent work, bet you can get some precise shifts with that.

Nathan

[jasonq]

I got the coupler installed tonite and took a quick drive.

I replaced 30 yr old oblong bushings with new round hole bushings in the stock couple about 750 miles ago., so i have recent history.

here's my rating so people can get a feel for the relative improvement:
ratty old worn out oval bushings=5/10
new round bushings=8.5/10
new universal joint=10/10

where 10=the best i have felt my 150k transmission shift, your milage may vary.

It feels similar in precision to the round plastic bushings when it comes to finding the gear, but it is smoother engaging the syncros. This is probably because all the shifter force is transmitted strainght thru the 2 degree of freedom universial joing without fighting like the overconstrained 1 degree of freedom stock couple with round bushings.

another factor is shift coupler adjustment, and i seem to get better at it every time. So some of the improvement could be from that too.

Answers to some questions:
the aluminum I used was 6061-T6, aka "aircraft grade" in advertizements. It is basically standard issue aluminum.

I didn't spline it since aluminum on steel is pretty sticky. I did use a rounded cutter on the lathe on my last pass to add a sort of spiral raised surface. only about .005 high. oh, and the engineer shop at work doesn't have a knurling jib had something to do with the decision too.

the pins are 5mm dia hardened steel dowel pins. they are pressed into the aluminum and run thru 5mm+.001" reamed holes in a brass cube. they rotate against the brass. No releative motion against the aluminum. the aluminum arms are .22" thick on each side (.44" total bearing length), and the brass cube is .75" on each side (.75" bearing length).

If it fails on me, i put the OEM version in my repair kit, so that pretty much ensures it won't fail.

All in all, i'm happy. If i had thought about the design first, i would have made it a little different. mostly from a machining secquence point of view. A couple times i had to really think about how i could clamp the parts in the mill. I nearly machined myself into a corner. While the first took 5 hours, to do it again would be more like 2.5 hours.

I have a feeling i might try making a simplified version in the future. I got seat brackets, a telescope mount, and a kayak rack for my girlfriend's mini's factory roof rack to make first.

jason

[Speedy1]

hope you got enough of all of us!!!!