oxy-acetylene regulator pressures?

[wagin]

It's been a long time since I've had to do a lot of burning on heavy steel. I"m probally wrong but I remember setting acty, regulator on 7psi and the oxy regulator on twenty psi. I am burning 1/4 inch, maybe a litte thicker, and am having trouble. Are my settings correct, or should I use different pressures. Oh yeh, I'm using a Harris tourch with a #3 tip. Anyone have advice? Thanks, Wesley(Wagin)

[Craig in Denver]

Originally Posted by wagin

It's been a long time since I've had to do a lot of burning on heavy steel. I"m probally wrong but I remember setting acty, regulator on 7psi and the oxy regulator on twenty psi. I am burning 1/4 inch, maybe a litte thicker, and am having trouble. Are my settings correct, or should I use different pressures. Oh yeh, I'm using a Harris tourch with a #3 tip. Anyone have advice? Thanks, Wesley(Wagin)

1/4" is a load for O/A (maybe a little thicker) and a #3 Harris is too small. The Harris chart shows you should be using a #7 tip with 7psi on both sides.

[Tensaiteki]

Assuming you are cutting and not welding:

Your pressure setting look about right for the metal thickness. However, they seem to be way off for the tip size and the tip size is way off for the material thickness.

A #3 Harris tip is meant for cutting 2-3" thick steel. For cutting 1/4" the recommended tip size is a 00.

Here is a chart for material thickness, tip size, and recommended pressures (it's actually a Victor chart, but the sizes etc. pretty much match with Harris tips):

[Craig in Denver]

Uh-oh. Are we cutting or welding?

[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.
.

[wagin]

thank ya'll for the advice. Got a #1 tip today,(was the smallest available), and it performed much better. After pondering this cutting problem, and the great info, I recalled that I used a #00 tipp for most everything during my construction and fab. days. thanks again.

[farmersamm]

I've always had a Harris, and a lot of guys have suggested that a Victor might be better. I've never run one so I don't know.

It's sometimes a nuisance running the Harris because the preheat flame is so short. You have to pretty darn near touch the iron with it. Tip needs cleaning more often too. I guess that's because of the short preheat.

Try to stick with genuine Harris tips if your supplier can get them. I've tried other brands which are supposed to work on the Harris but they never seem to work right.

A 2/0 tip works great on 3/16 to 1/4, 3/8 if you slow down. Generally I like a 0 tip for 3/8 to 1/2. I seldom cut much thicker stuff.

Don't drop any iron on yer tootsies.

[Hammack_Welding]

Originally Posted by farmersamm

I've always had a Harris, and a lot of guys have suggested that a Victor might be better. I've never run one so I don't know.

It's sometimes a nuisance running the Harris because the preheat flame is so short. You have to pretty darn near touch the iron with it. Tip needs cleaning more often too. I guess that's because of the short preheat.

Try to stick with genuine Harris tips if your supplier can get them. I've tried other brands which are supposed to work on the Harris but they never seem to work right.

A 2/0 tip works great on 3/16 to 1/4, 3/8 if you slow down. Generally I like a 0 tip for 3/8 to 1/2. I seldom cut much thicker stuff.

Don't drop any iron on yer tootsies.

I've never seen much difference in actual cut quality from torch to torch and I use them all in my shop, and service rigs. If you are having trouble preheating then step up a tip size. However I do agree with others that a #3 tip is way to large for 1/4" material. I generally run a #2 on all of my torches, and the majority of what I cut is from 3/8"" to 2" material.