Thread cutting oil?

Timco

Got my new very old threader working great. Didn’t have cutting oil at my shop. What’s the worst that can happen using motor oil mixed with some cutting oil?

ChrisJ

From what I've seen working in a machine shop, almost any oil will work fairly good when cutting metal.

For example, even WD40 is 100X better than dry. Motor oil will probably cut threads 80-90% as good as proper cutting oil.

That said, I would still get some good cutting oil and clean the thing out.

Pumpguy

Back when I was a teenager, my dad and I installed a hot water heating system in our house. Sears designed the whole system and sold the whole kit; boiler, copper tubing, circ pump, baseboard rads, expansion tank, etc. Kit even included use of pipe vice, threading dies, and cutting oil. Back then the cutting oil was lard oil.

Today, you can get better cutting oil at any hardware store, although in a pinch melted lard or bacon grease would work okay.

Keep in mind that black pipe can be pretty nasty stuff to thread, compared to many steels that a machinist would see. Good quality cutting oil frequently contains sulfur and/or other compounds to help improve the machinability needed to get decent threads

ChrisJ

> @Pumpguy said:
> Back when I was a teenager, my dad and I installed a hot water heating system in our house. Sears designed the whole system and sold the whole kit; boiler, copper tubing, circ pump, baseboard rads, expansion tank, etc. Kit even included use of pipe vice, threading dies, and cutting oil. Back then the cutting oil was lard oil.
>
> Today, you can get better cutting oil at any hardware store, although in a pinch melted lard or bacon grease would work okay.
>
> Keep in mind that black pipe can be pretty nasty stuff to thread, compared to many steels that a machinist would see. Good quality cutting oil frequently contains sulfur and/or other compounds to help improve the machinability needed to get decent threads

Black pipe is a joy to thread compared to 304 and 316 stainless. Unfortunately I get to work mostly with stainless.

EBEBRATT-Ed

I used to swear by the "dark" cutting oil like Hercules. But lately our shop buys the Ridgid Clear. I used to have bad luck with this stuff but it seems to work really well for me now. Maybe they changed the formula.

Cutting oil works the best but in a pinch when I ran out I have used motor oil, wd40 etc with mixed results

Timco

Every time.

Headed for real cutting oil and dies if I can find them. The seem sharp as hell but I’ll start over. When it bogs down I know it’s doing this.

SeanBeans

We’ve had bad batches of 1 1/2 pipe before. every time it would do this.. picked up a new piece and everything cut fine

ChrisJ

> @SeanBeans said:
> We’ve had bad batches of 1 1/2 pipe before. every time it would do this.. picked up a new piece and everything cut fine

That's what I was thinking when I saw it. I had some that it kept ripping the threads off randomly

Timco

Lol. It’s the fluid. Motor oil just does not do it. Used actual dark cutting oil and it works great.

ChrisJ

> @Timco said:
> Lol. It’s the fluid. Motor oil just does not do it. Used actual dark cutting oil and it works great.

Did you use the same dies?

ChrisJ

Joe's only guess was it's because an EG40 and EG45 are identical except the 40 has one less burner tube and a modified and baffled draft hood. I converted mine down to a 40 so I had the parts from the 45 here.

His guess was it was just pulling to much air though the block / burners because it's actually laid out and designed for another burner tube.

I don't know.... I just thought it was odd no one actually knew what the issue was. We did exactly what Tim and Jim said to do.

Timco

Yes

ChrisJ said:

> @Timco said:

> Lol. It’s the fluid. Motor oil just does not do it. Used actual dark cutting oil and it works great.



Did you use the same dies?

nibs

Crisj,
The key to cutting stainless is to keep it cool, if you are drilling it, drill at slow speed, with lots of pressure, try not to drill pilot holes unless absolutely necessary, then drill a very small pilot hole. Avoid using abrasive cutting discs, as they heat the stainless.
If you are cutting threads, try to work slowly and use a lot of pressure, try to avoid making two passes, some people use water just to keep the material cool, which is more important than lubrication.
Stainless is very soft (like cheese) unless you allow it to work harden, then it crystallizes, and becomes hard as hades.

ChrisJ

> @nibs said:
> Crisj,
> The key to cutting stainless is to keep it cool, if you are drilling it, drill at slow speed, with lots of pressure, try not to drill pilot holes unless absolutely necessary, then drill a very small pilot hole. Avoid using abrasive cutting discs, as they heat the stainless.
> If you are cutting threads, try to work slowly and use a lot of pressure, try to avoid making two passes, some people use water just to keep the material cool, which is more important than lubrication.
> Stainless is very soft (like cheese) unless you allow it to work harden, then it crystallizes, and becomes hard as hades.


For threading stainless I've switched to form threading recently as long as the customer allowes it. So far, I like it.

Work hardening is something that took me a while to learn about and a lot of pain.

EBEBRATT-Ed

@nibs is correct about stainless which is a P I T A. The slowest speed possible. I burned up a few drill bits and hole saws drilling on SS electrical disconnects before I figured it out

ChrisJ

> @EBEBRATT-Ed said:
> @nibs is correct about stainless which is a P I T A. The slowest speed possible. I burned up a few drill bits and hole saws drilling on SS electrical disconnects before I figured it out

Drilling stainless is easy.
I spend most of my time milling it.

The real fun comes when you snap a tap off in it.

nibs

Jim Webb, an owner of Keypower Hydraulics in Richmond BC told me how to work stainless, in the mid '70's. I will always be grateful.