Little Engines Air Pumps

[Pipescs]

So .... What happened here? Was anyone able to find a usable valve?

[Mike Walsh]

I finally managed to get ahold of Vernay and they sent me a sample pack also.

[Mike Walsh]

Getting ready to do some machining on mine in the next month.

I have been perusing the drawings.

For the valve head, I intend to purchase two 1-1/4"-12 taps from McMaster, the standard tap as well as a bottom tap.
I notice that the drawing shows a groove past the thread.

Is this critical to the design or can I get away with either the thread traversing the full length of the depth, or do I need to groove this for a reason that I cannot yet see?

I plan on starting a new thread, but I wanted to throw this out.

Thanks all.

Mike Walsh

[Kimball McGinley]

A groove at the end of an internal thread is usually called a "thread relief." Its function is to allow a lathe thread cutting tool to be stopped at the end of the bore, so it can be backed out and retracted. The machinist then will make more passes until the thread is to depth. This is called "single-pointing" a thread. I have attached an example. In this case, the relief is very narrow, however, I was short on space, and my parts will run on a CNC lathe, so it is just workable.

If using taps, a thread relief is not needed, providing that you check the thread depth required by the mating part. It should bottom on a shoulder, not the incomplete threads.

[Mike Walsh]

So....

Do we start a dedicated thread to build them?



If so I will drag out my castings to jump in.

I did -- check out the build forum.