Tig break test.

[deereman75]

how the heck do you know so much about the lincoln tomb stones?

 

[rankrank1]

how the heck do you know so much about the lincoln tomb stones?

Love to read and pretty much have a photographic memory. If the subject interests me - read it once and its there for life.

I only wish my actual welding skills matched what was inside my head - LOL.

 

[deereman75]

I only wish my actual welding skills matched what was inside my head - LOL.

So do I.

 

[slowzuki]

I was told the other reason for the circle at 75 amps is the pipe thawing setting was 75 amps. That would make sense if it is also the 100% duty cycle setting.

I've got both the old tombstone and a Miller of the same era, I've never had leads to spark the miller up. Both weigh a metric buttload and I avoid dragging them around if possible.

If the windings are aluminum, I'd hate to see what the copper units weigh.

While I agree with you that the older ones are better in most cases it has nothing to do with copper at least on the Lincoln AC-225. Every Lincoln AC-225 ever built was with an aluminum wound transformer. The duty cycle on every Lincoln AC-225 ever built is only 20% at every setting except 75 amps which is 100% duty cycle on 75 amp setting only (reason it is circled on your faceplate). The 75 amp setting utilizes the primary windings inside the transformer only so it is capable of 100%. Settings below 75 amps revert back to 20% duty cycle since the smaller secondary's inside the transformer are utilized on every other welder setting. That said many people have welded with these old Linclon's with total disregard to duty cycle and never hurt them.

Lincoln AC-180 were copper wound transformers and lack a cooling fan (otherwise they look almost identical to an AC-225).

Miller Thunderbolt's were copper wound in beginning and switched to aluminum somewhere along the line (maybe when they went from top crank to front crank models????). The duty cycles are different on the Miller Thunderbolt (and Hobart Stickmate clones). While only 20% at wide open, as you decrease amps the duty cycle does continually increase. In essence anything under about 100 amps is 100% duty cycle on the Miller Thunderbolt.

Lastly, not saying the Miller is better. I own both a vintage top crank AC/DC Thunderbolt and a vintage AC-225. I think the Lincoln is stronger on AC than the Miller is on AC. I can not compare DC capability as my Lincoln lacks that option.