The Steamboating Forum

marinesteam wrote:I've contacted Dave and now I am on the list to get my very own Navy K valve when he gets the next batch of castings. Yeah!!!!!

Ken

Yup, me too.

- Bart

I love boat jewelry but a screw to hold a cotter pin? Maybe just a teeny bit over the top.

Like isn't the point of a bent pin that it prevents something from unscrewing?

This is envy talking.

Lopez Mike wrote:I love boat jewelry but a screw to hold a cotter pin? Maybe just a teeny bit over the top.

Like isn't the point of a bent pin that it prevents something from unscrewing?

This is envy talking.

The screw is optional... Given my habit of dropping things into inaccessible areas, I'll use safety wire and keep a roll on the boat .

- Bart

Dave said that this detail was copied from a similar fixing on the clevis' from the York engine.

Yes it isn't the normal installation for a spit pin but I think the intent is to prevent the pin from rotating and wearing the hole in the clevis. This is a pretty elegant solution to that problem. The other end of the pivot pin is flush with the clevis and the screw & split pin also prevent the pivot pin from moving sideways out of the clevis. The part count is the same as with a split pin on both ends of the pivot pin and the part count is the same. I think this makes for a cleaner installation aesthetically.


Ken

Ken,
All very well and makes sense but it does violate the principle behind a cotter pin and/or safety wire which arrangements cannot vibrate loose. It wouldn't be allowed on and airplane or a race car or racing motorcycle.
I think it's elegant but on an aesthetic level only. If it were in a high vibration and control critical location, it wouldn't be a good idea.
I have this fun cartoon idea where the cotter pin has it's screw which has it's own cotter pin which has it's screw . . . . . . .

Mike

Surely better for the clevis to rotate, and even out the wear. I've seen many stepped ones in my day, where they didn't rotate.

Ah, I think that if you wear out a clevis pin on your throttle that you are fiddling with your throttle toooo much! This ain't no sprint car.

This from a guy who is working on a Model A Ford's brake linkage where EVERY pin is toast.

Mike

Good engineering principals still apply Mike.

When I went through (mostly) Otter's 120 year old engine, I found the holes for the eccentric rod clevises well worn in the bronze Stephenson link casting... and the pins were completely shot. I bored the holes in the link out to 1/2" and turned and inserted Delrin bushings and made hardened pins to fit. The clevis ends completely hide the Delrin, and there's not even a hint of play or sound.

- Bart

Mike,

I think that you're over thinking it. Not meant for safety, just another way to retain a pin in a clevis.

Ken