while the oil is burning.

Should a torch become clogged in the head or tubes, it may usually be
cleaned by removing the oxygen hose from the handle end, closing the
acetylene cock on the torch, placing the end of the oxygen hose over the
opening in the nozzle and turning on the oxygen under pressure to blow the
obstruction back through the passage that it has entered. By opening the
acetylene cock and closing the oxygen cock at the handle, the acetylene
passages may then be cleaned in the same way. Under no conditions should a
torch be taken apart any more than to remove the changeable nozzle, except
in the hands of those experienced in this work.

_Nozzle Sizes._--The size of opening through the nozzle is determined
according to the thickness and kind of metal being handled. The following
sizes are recommended for steel:

Davis-Bournonville. Oxweld Low
Thickness of Metal (Medium Pressure.) Pressure
1/32 Tip No. 1 Head No. 2
1/16 2
5/64 3
3/32 3 4
3/8 4 5
3/16 5 6
1/4 6 7
5/16 7
3/8 8 8
1/2 9 10
5/8 10 12
3/4 11 15