I have a Speedway 125 Series flux wire welder.

The plastic liner is shot. It plugged it self up solid with shavings from the inside of itself. . .

I figure a steel liner won't have that problem.

Here is a photo of the critical parts from my welder/gun with all measurements that might be needed. The left two parts are what hold the liner in front of the feeder drive. The right two parts are from the gun.
(It wouldn't let me upload it to this site so here is a link.)

Problem is, steel liners are usually called out by P/N from a parts list so nobody cares to offer diameters and other dimensions for people doing what I am and it makes it hard. The road less traveled again. . .

Ie. The vendor has no need to provide dimensions on the diameter of the actual liner and the length and diameter of any compression nuts or terminators on the ends and so on.

Can anybody help with this?

What I really need is to be able to get a caliper on a couple different common liners and find the one that I can get to work without modifying my existing parts [too much].

I don't have TPI on the threads but I can get that data if needed.

The length of my current gun lead is a tad short of 11 feet.
The flux wire size is .030-.035.
I looked at the miller 194011. It looks like a good low friction liner. But I don't know the diameter. I have seen a pic that indicated the thread at the nut is 3/8 so it won't fit my existing thread but it doesn't really have to. It just has to sit there close in front of the feeder to keep the wire from pushing the liner out the front of the welder right?

What would be nice is if the liner can self tap into the threads of that ferule you see in the pic on the gun end of the liner. That is how the plastic liner was secured in the gun. This is where the actual O.D. of the steel/plastic coating on the liner come into play.

I should be safe from fire as there is a good plastic strain releif where the wires go out the front of the welder and the big brass hardware in the picture affixes to a plastic chassis in front of the wire feeder using the washers and nut seen on it in the picture.

Thanks for any help in advance.