I'm looking at my Little Torch instruction book, which has a
table in the back and some words about nat. gas. The table says
you can use tips 3-7 with nat. gas and the text cautions that tip
3 may be hard to light. PSI for both oxygen and nat gas are
3psi with #3, 4psi with #4, 6psi with #5 and #6, 8 psi with #7.
There are part numbers listed of various regulators, and there
is one for LP gas with an asterisk that says LP= propane,
propylene, MAPP, H.P. or Flamex, but no specific mention of a
regulator for nat. gas. I would think you would need a regulator
to get the pressures right and that this H1954C-510 is what you
need. there is also a nte that you have to have at least 1 psi
of nat gas to use the torch at all. The inlet connection for
this regulator is CGA 510. Hope this info helps and I hope if
you do this you will let me know how it goes --- I hadn't thought
about it, but I am moving soon and will probably have nat gas at
the new place myself. HTH.