[Oldiron2]

Cutting tip #3, series 2490 or 6290 is for 2 to 3" thick material.
Welding tip #3 in series 23-A-90, 1390 or 5090 is for 1/16" thickness.

For an equal pressure torch using those above tips:

For cutting, you need a size 00 with 5 to 10 psi acetylene, 20 to 30 psi O2.

For welding, you need #7 tip with 7 psi of each gas.

This data is from an old Harris catalog (No.746), undated but probably from mid 70's.
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