HPA /ASA Thread problem

[cadams]

I have a 3A 4500/92CUI HPA tank that doesn't seem to want to thread all the way into my new drop forward ASA. It will screw into my original ASA that came with my 68 Classic, but not this new one (Empire).

I had a simplar problem when I tried using my HPA tank on a friends tippy a-5; it wouldn't even start to thread in the tippy.

After close examination of the threads on a std CO2 tank and my HPA, they are a little different. Heres my best ASCII representation:

CO2:
<>
<>

HPA:
/ \
/ \

Make sense? This is exaggerated of course, they are actually very very similar, but not quite. To add to my confusion, my original ASA works fine with my HPA AND std CO2 tank.

So, are there different thread patterns on certain HPA tanks / CO2 tanks? Any adapters?

[michbich]

My co2 and hpa threads look the same, the <> type.

[druid]

It's entirely possible that the asa is cut wrong...let me explain.

Like cutting the rifling into a gun barrel, taps are used to cut the lands and grooves. Typically for steel though, the bits are made from carbide but for aluminum, they can be of chromed stainless steel. Over time, the bits will wear down which alters the original "thread" pattern because as the bit wears down, the grooves become more shallow and the tool itself won't get as deep into the project piece. This might be the case in your asa.

I would suggest sending it back for a replacement, explaining the problem in detail. Take pictures to show what you are trying to tell them.