How crazy do you have to be.....

[goodfellow]

... to do what I just did?

This is an old 1970's vintage Sears moisture trap, and while working on the car the other day, the bottom end blew out with a loud bang.





Turns out that the plastic drain fitting had deteriorated and cracked wide open, thereby blowing the NPT moisture drain valve right out of the bottom.





To some this would be a time to say "got my money's worth, let's buy a replacement!". You can get these things for about $30-$40. Well in my case, this little unit has a special place in my heart. Every car I've painted in my life (and there's been a few), I've used this trap to attach my paint gun air hoses. For close to 50 years it's done the job; hence I was loathe to part with it.

No big deal I thought. I can make a new fitting out of aluminum, then thread for the lock nut and tap a new 1/8" NPT hole in no time.    -- I thought!!

It was quick work to machine the overall dimensions of the fitting, but when I needed to thread the 5/8"-18 lock nut/collar threads, I realized that I was missing a 24 tooth change gear for my manual lathe. So I spent all of yesterday afternoon machining a new 24 tooth change gear for the sole purpose of threading that stupid fitting. This morning I used that gear to make the 5/8"-18 threads and then tapped the fitting for 1/8" NPT for the drain valve. If I figure my time on a low-end $$ basis, this thing cost me close to $600.

Back in working order and ready for another 50 years -- of course I replaced all the bowl seals as well.



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Retirement does have its upside, but I pray doing crazy crap like this won't become a habit. --- LOL 

[john k]

If you didnt have to go to town for parts,  didnt spend cash, didnt spend you needed doing something else, then you are still ahead of the game.  Driving all over to look at things that arent what you want, wasting gas money, being around folk that might be sick, would be a lot crazier, in my book

[oldnslo]

If my memory serves me correctly, that happened to my vintage Sharpe version some time ago. I recall the replacement part was a bit less tho, and it was repaired and got me up and running quickly.

I see we share the same odd-sized Acme air fittings that are getting harder and harder to find (within reasonable costs). I'm down the road too far to change fittings now with my miles of air hose, and connected tools. Folks nowdays have fewer choices for fittings (thankfully) than in years past.

[goodfellow]

If my memory serves me correctly, that happened to my vintage Sharpe version some time ago. I recall the replacement part was a bit less tho, and it was repaired and got me up and running quickly.

I see we share the same odd-sized Acme air fittings that are getting harder and harder to find (within reasonable costs). I'm down the road too far to change fittings now with my miles of air hose, and connected tools. Folks nowdays have fewer choices for fittings (thankfully) than in years past.

ACME it is -- good call OnS! These air fittings are early 70s as well. My dad and I went in on a big lot at Montgomery Ward when they were selling them for pennies on the dollar. I recall him saying at the time "we won't need to buy another fitting for the rest of our lives". I believe he was correct in that prediction -- LOL

[Matt_T]

Hate to armchair QB you after an ordeal like that. But maybe it'll help the next guy.

Do you have a 5/8"-18 die? Easier, faster, and generally does a better job, compared to screw cutting.

Would modifying a 5/8"-18 screw work? Stainless would be best for that if you could get one.

Lastly pretty much any 5/8" thread would leave enough meat for the 1/8" NPT drain. Using a pitch you could cut, and making a new locknut, would be a lot faster than making a new change gear.

[goodfellow]

Good points all Matt. I’m ashamed to say that I don’t have an SAE tap/die set above 1/2”. In metric I have large sizes, but not standard. I did call the local ACE and they didn’t have an individual die in stock.

The bolt Idea is good and practical, but the fitting required two indexing slots; hence I chose to do the whole job in soft aluminum vs. steel.

Like I said, roughing the fitting in alu was  a breeze, but at that point it hadn’t occurred to me that I didn’t have a required change gear. The lathe came with one, but it must have been lost during the last move. By making the gear I killed “two birds” because that 18 pitch is pretty common, and I needed it anyway.

But, you’re absolutely correct, a proper die would have been the way to go. Since I hardly use SAE fasteners anymore - I neglected the larger sizes in my kit.


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[Matt_T]

Glad you found my criticism constructive

In metric I have large sizes, but not standard.

M16 would probably work. IIRC it's only about 0.005" larger than 5/8".

[muddy]

Goodfella saves another oldie but goodie tool! Nice work Ray!

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