Run in stand/dyno build.

[Terry Keeley]

Welcome back buddy!

 

[Terry Keeley]

Well i really thought I had this licked, pins were made of S7, 0.160" in diameter and heat-treated. Think I'll go to 5mm next and try a dowel pin as my buddy Rudy suggests.

 

[David Murany]

Well i really thought I had this licked, pins were made of S7, 0.160" in diameter and heat-treated. Think I'll go to 5mm next and try a dowel pin as my buddy Rudy suggests.

I think it's time for a small piece of flex shaft

 

[Terry Keeley]

I think it's time for a small piece of flex shaft

Lol! You might be right but I ain't done going down this road yet.

You know how stubborn (stupid?) I can be...

 

[David Murany]

Lol! You might be right but I ain't done going down this road yet.

You know how stubborn (stupid?) I can be...

Haha. Oh I know

 

[Ken Retallick]

I think it's time for a small piece of flex shaft

Shhhhh!!

 

[Buckshot]

Damn that got HOT!

Well i really thought I had this licked, pins were made of S7, 0.160" in diameter and heat-treated. Think I'll go to 5mm next and try a dowel pin as my buddy Rudy suggests.

 

[Terry Keeley]

Shhhhh!!

Ha! Don't want to diminish the "entertainment value"?

**** that got HOT!

Yup, that collet is pooched. When the pin broke it loosened up letting the shaft spin.

I think I'm gonna try some flats like the CMB unit Tyler posted to distribute the load, a dowel pin won't cut it tho as they're only case hard and the flats will end up being soft.

Maybe a larger S7 pin with flats?

Hey Ty, how big is that pin anyway? Not sure from the color what they used to heat treat them, nitriding maybe?

Might even try making it from unhardened 4140 or 4340. Made a lot of other high wear parts from that and they've held up well.

 

[Buckshot]

What’s your address and I’ll send you one.

 

[Terry Keeley]

Thanks for the great offer but no need, you gave me most of what I needed.

Do me another favor and run a file over it some where to give me an idea how hard it is (or isn't)?

 

[Ken Retallick]

Terry, Entertaining in that you are finding 100 ways that dont work!

I wonder if a piece of spring steel rod would absorb some shock loading instead of fracturing?

 

[Buckshot]

Thanks for the great offer but no need, you gave me most of what I needed.

Do me another favor and run a file over it some where to give me an idea how hard it is (or isn't)?

All three parts are hardened. File skates right off.
Also note that the ball and socket is a tight fit.

 

[RaceMechaniX]

Terry,
My pin has the same diameters as Buckshot. 5mm pin with 3.9mm across the flats. The pin is case hardened, but the ball and socket are not for the 35cc motor. I suspect the overall size of the coupler is larger on the 35cc compared to the 27cc.

-Tyler

 

[Terry Keeley]

Terry, Entertaining in that you are finding 100 ways that dont work!

I wonder if a piece of spring steel rod would absorb some shock loading instead of fracturing?

Ya, a bigger pin and more "forgiving" material might work. The S7 pins are through hard and possibly a little brittle?

Thanks Ty and Buck, that gives me some ideas. I might try some 4140 HTSR as is with flats...

 

[Brad Christy]

Terry,

I've got my doubts about 4140PHT. It will be 25-30Rc, and that won't get it. You can always have the parts gas nitrided, but, to get the case depth you want will be kinda spendy. The HT shop I use will nick your for about $260 for .011-.020" case depth. The S7, though hardened, is probably your best bet.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Terry Keeley]

Terry,

I've got my doubts about 4140PHT. It will be 25-30Rc, and that won't get it. You can always have the parts gas nitrided, but, to get the case depth you want will be kinda spendy. The HT shop I use will nick your for about $260 for .011-.020" case depth. The S7, though hardened, is probably your best bet.

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

Ya, I think you're right.

Looking at it again the heat-treated S7 is up around 300 ksi and 4140 is only about 130.

I'll go big with flats...

 

[Brad Christy]

Terry,

Yup. And there's nothing saying you have to stay with that 5mm pin diameter. You could always step it up to, say, 1/4" (or bigger), scale the flat dimensions to match and make a matching flywheel nut, all out of S7.

Just random thoughts....

Thanks. Brad.
Titan Racing Components
BlackJack Hydros
Model Machine and Precision LLC

 

[Terry Keeley]

Looks what I got off Craigslist today for a song.

Fan rubbed a bit and guy said it was for 220v.

Seated the fan properly on the shaft and re-wired it for 120, man does it blow (or suck?)

 

[Mike Bontoft]

Maybe it's time to build something like this. Without its inclusion into the Cosworth DFV, as Keith Duckworth put it, the Engine design would have been a dead duck! Due to continued gear breakage.

 

[dwilfong]