Is The Smith AT61 'Threaded Tip Tube' Detachable From The Mixer?

[Ahmdo Molah]

I've read on Miller's welding forum that the Smith AW1A torch compatible AW201 tip(for acetylene) for example, has a mixer with 1/4"-28 TPI internal(female) threads that mate with the copper tip.

As Smith mixers seem to be mostly identical other than the number of fuel inlet holes, I'm wondering if most of the Smith tip mixers 'share' the 1/4"-28 TPI internal(female) threading for the various copper tips and threaded tip tubes.

[ Questions ]
1. Among those that use a Smith AW1A torch with an AT61 'Threaded Tip Tube' (for LP gases), has anyone ever 'unscrewed' the copper 'Threaded Tip Tube', detaching the copper tube from the mixer?

2. Regarding the Smith AT61, can anyone confirm if the mixer's internal(female) threads (or the threading on the copper tube that mates with the mixer side female threads) are 1/4"-28 TPI?
* Note: I'm aware that the flame-side male threading on the tube is 1/4"-32 TPI. I'm trying to find out the type of threads inside the mixer that mate with the copper 'tips' & 'tubes'.

Thanks...
Jihoon Jo

[Ahmdo Molah]

A 'Senior Member' of the Miller forum who goes by 'tackit', offered help by calling Miller, talking to 'the girl there' who got 'Engineering' to send 'tackit' the following information about the AT61 'Threaded Tip Tube';

"... the mixer inside threads are 1/4X28, the nozzle threads inside the Mixer are 10X32."
Note
1. The "mixer inside threads" (1/4" x 28 TPI) of course refers to the copper tip/tube mating with the mixer.
2. The bonus info of "the nozzle threads inside the Mixer" (10 x 32 TPI) must refer to the internal threading that runs from about the fuel inlet holes to the end of the mixer(torch side) which mates the 'connical tipped insert' Miller Engineering calls "nozzle", at the central oxygen inlet / torch-side mixer-end (very bottom of the image marked "In-Tip Mix").

Smith Tip & Mixer Assembly.jpg

Again, many thanks to 'tackit' at the Miller forum. Cheers!

* Refer to thread 'Finding the best torch handle and tips to work with propane' for more information in a broader context.
https://www.velocipedesalon.com/foru...ane-45711.html


- Jihoon Jo

[Ahmdo Molah]

Just a reassuring update directly from Miller Electric (Smith)...

"Hello
You can unscrew the tube. You do not want to heat the mixer area at all.
Karen"

The other day I wrote to Miller asking if the Smith AT61 Threaded Tip Tube's copper elbow is screwed into the mixer with thread locker and if any heating would be necessary to soften it (if present) for unscrewing the copper elbow. I added that I would remove the rubber o-rings prior to any heating.

This time, instead of being redirected to a regional sales representative that was puzzled by my questions, I got the reply directly from perhaps the same lady 'tackit' referred to as 'the girl there'.

In hindsight, it seems possible that heating the mixer or elbow could anneal and/or distort them causing seal/mating issues.