Thread Insanity. (Someone please explain)

[Sheepdog]

Ok so moving through some fabrication, I have come across at least 2 threads I didn't know existed. Someone help me understand the madness. My background is in automotive fab. M10-1.25,.1.5. 1.75, 3/8-24, 5/16-20. All the common stuff is no big deal.

So I guess my question is what in the world is the utility in 15/32-32 and the danm bizzar spyder asa thresds I can't recall at the moment...

Thanks all.

Sheepdog

[moving_target]

proprietary bull would be my guess. picking a thread that was "yours" moreso than any good reason for it.

who knows, somebody with actual knowledge might have a real reason and chime in LOL

[SuperActionMan]

In what specific usage did you find the odd threads?

Non-standard ones are often to keep parts proprietary or for some special purpose like an adjuster screw that has to have very fine movement. Sometimes it's just an old holdover "tradition" like threaded bottom brackets for bicycles. 1.370-24tpi.

15/32-32 is also very close to M12x0.8.

[Sheepdog]

Autococker 3 way to front block is the most pressing one at the moment.

[XEMON]

A lot of it came down to what tools who ever designed the gun had on hand at the time (phantom barrel threads are a good example of that) the rest was more of what thin threads fit in the space we have without making parts too thin ...

As always, there were those who wanted to be special ...

PS: the asa threading is a older co2 tank standard

[Sheepdog]

Sorry. Not ASA. My bad. Spyder drop forward/ trigger frame bolts.

[Euphie]

The Spyder bottomline screws are so small probably because that was the solution they came up with to still allow a hole in the middle of the bottomline so you could get your M-16 grips on and off. None of my Spyders have a .45 frame not sure when they started that but as soon as they did they should have just swapped to 10-32 but that would have broke compatibility with old ones so IDK.

It isn’t impossible to do 10-32 though I have a Taso m16 bottomline adaptor that has both long and short standard bottomline spacing and I still have enough room to get the m16 grip off

[DocsMachine]

The original 'Cocker 3-ways were off-the-shelf switches, I can't recall from either Clippard or Humphries. I don't know if Bud had to thread them, or if they were already threaded, but either way, they were about 1/2" in diameter, and needed a shallow thread to fit them into the front block.

A standard 1/2" thread, like 1/2"-20, would have cut too deep into the 3-way body. You needed a finer thread so the thread depth was considerably shallower.

15/32-32 is an obscure but not unique thread. Why not 1/2"-32, which is another thread that exists? Probably because that slight OD reduction allows for a thin "shoulder" keeping the user from screwing the switch into the block too far. (Then again, the threads simply ending should do that, too.)

Most likely happenstance? The switches were probably already threaded, off the shelf. Bud simply bought those, ordered a tap, and went from there. Why reinvent the wheel?

Doc.

[k_obeastly]

You'll also find 15/32 32 on the threads by the adjustment knob on the clippard LPRs and some of their other stuff. They used them for mounting their components.
TV-3SP by CLIPPARD - Buy Or Repair - Radwell.com The non 1/8 NPT end is 15/32 32

It is also the threads used on the end of the barrel of walther p22s.

[DocsMachine]

Oooh, I think Beasts is on to something. I never even considered that, but yeah, those little knurled nuts that go to toggle switches, are often 15/32-32.

Pneumatic switches like you linked to, are meant to mount in the same panel as electrical switches- that would make sense that the spool switches/3-ways would have a similar thread. So my blind guess that the original 3-ways that Bud used were already threaded, was almost certainly correct.

And THAT makes me wonder why no one's used one of those little knurled nuts off a toggle switch, as a sort of "lock nut" to tighten a 3-way into the block at the correct angle.

Doc.

[Jordan]

I have, but only because I happen to have some of those nuts from tinkering with pneumatic switches.

IIRC, Craig Palmer said the early WGP switches were a direct copy of the Humphreys 4ppx switch (used on early PPS semis) with the ports rearranged to accommodate the front block. Humphreys 4ppx valves are threaded 15/32-32 for mounting, so it stands to reason that Bud copied it, likely for those reasons you mentioned.

[Sheepdog]

Interesting. Not sure how i feel about it...

[SuperActionMan]

Before even reading the rest of the replies, as soon as I saw mention of an Autococker three-way I went on Clippard's site and found that thread size on their other small three-way valves.

The only alternative is to make your own front block and three-way with some common thread. It will then very ironically make the assembly entirely non-standard for Autocockers.

[Jordan]

Before even reading the rest of the replies, as soon as I saw mention of an Autococker three-way I went on Clippard's site and found that thread size on their other small three-way valves.

The only alternative is to make your own front block and three-way with some common thread. It will then very ironically make the assembly entirely non-standard for Autocockers.

Keep in mind that industry parlance for what we call a "threeway" is actually a four way valve - two outputs and two exhausts make it a 4way, with two control paths.

Three way valves, like the SMAV3 that Clippard makes, only have one control path - either normally closed (NC) or normally open (NO) - which means you can only use them on single-action cylinders/rams, unlike a 4way that can be used on double-action rams like what is used on a Cocker.

Maybe that's common knowledge now - if so I'll apologize in advance for the redundancy.

[flyweightnate]

Hmmm... a single acting ram would solve that whole pinching paint thing. Use the spring to move the bolt closed, but the gas to cock the hammer.

Surely someone has tried it.

[Brokeass_baller]

flyweightnate Somebody did that to a Trilogy years ago on PbN. It was pretty interesting. Plugged the 3-way hole (er, 4-way. Whatever.)

[Sheepdog]

All good stuff. Got a 15/32-32 tap on the way!