On Jun 14, 5:37*am, "Chas" wrote:
"Vernon Tuck" wrote in message

...
On Jun 12, 11:46 pm, Ned Simmons wrote:





On Sat, 12 Jun 2010 18:13:36 -0700 (PDT), Vernon Tuck

wrote:

I'm not a machinist and I don't have any measuring tools. So I'm not
sure about the diameter of these holes but I'm pretty sure they're
M20x1.5 or M21x1.5. I have found European sources for blind plugs in
these dimensions but have not yet found a source in the USA.

These seem to be intended for use as conduit fittings, but the threads
are
right:http://www.sealconusa.com/strainreli..._npt.htmlhttp:...

McMaster has some as well, but a quick look showed only very expensive
high pressure SS fittings there.

4822T45
Extreme-Pressure SS Threaded Fitting M20 X 1.5 Male X 1/2" NPT Female
Adapter, 5000 PSI
In stock at $46.63 Each

--
Ned Simmons

I found the M20-1.5 drain plug in an auto parts store. *They were kind
enough to let me try it on the tank. *It was too small. *They also had
a drain plug in M22-1.5. *I now know that is the correct diameter and
thread pitch. *However, the shape and mass of that drain plug were
unsuitable. *At $12 a pop (and I need 3 of 'em) it turned out to be
too expensive, also.

After going back to google again and again I think I have correctly
surmised that PRESSURE WASHER HOSE FITTINGS will work. *They're the
right diameter but I'm not sure they're the right thread although from
the picture it looks about right. *So I bought 3 fittings for $3.00
each. *Not only are they pressure rated they're also made of brass.
That strikes me as a good thing so they won't get frozen by rust
developing between the fitting and the tank.

The fittings I ordered are both male, 22mm at one end and 3/8" at the
other. *I am hopeful, but probably delusional, that the smaller thread
will fit a standard air hose quick disconnect.

I have learned that 22mm bolts, when available, are ridiculously
expensive. *So if these fittings don't work I will probably launch the
tank into near earth orbit.

Thanks,

V
You might like to try 1/2 inch BSP (British Standard Pipe) fittings which
are 14 TPI 55 degree thread and 21.3mm or 27/32 in OD. *BSP is used in many
countries including Germany, but USA is not one of them. If this is the
size, you may be able to find a suitable BSP-NPT adapter or else retap the
holes to 1/2in NTP which is 14TPI 60 degree thread and a slightly larger OD
IIRC.
--
Regards,

Chas.

(To email me, replace "xxx" with letters tango papa golf.)

I am delighted to report that I found the perfect fittings at northern
tool. These are brass fittings apparently intended to be threaded
into the ends of pressure washer hoses. Both ends are male, one
being M22-1.5 and the other, 3/8 NPT. Thus, I am able to screw them
into the tank and thread a standard female quick disconnect air hose
fitting onto the smaller end. I will be able to charge the tank and
purge/drain it by simply plugging hoses into it.

Isn't google great?

V