Pipe threads - threading tips anyone ?

[David Morrow]

I'm always looking for air compressor fitting so I finally just bought 1/4", 3/8", and 1/2" dies ( I already had the taps ). Now I can make just about anything that I want. Using the taps & dies really takes more effort and care than normal taps & dies because they are tapered. I have made fitting from brass and aluminum. I have tried various lubricants but, it's more of a struggle than I would have expected. I do get the job done eventually completed with a liberal dose of physical and verbal exercise.

Does anyone have any tricks or tips in this regard ( other than broadening my vocabulary )

 

[mklotz]

There's a very good reason why professional pipe threading machines stink of sulfurized cutting oil.

 

[sunworksco]

I second that!
Sulfur threading oil is the key.

 

[doc1955]

On tough materiel I like using Moly-Dee it makes things go easier but the stuff is messy.

This stuff works well on stainless steel.

 

[Maryak]

Buy a small bottle of Hypoid gear oil to API GL5 spec, preferably SAE 140 weight. This has a fair whack of sulphur in it and compared to sulphurised cutting oil its cheap and readily available.

Hope this helps

Best Regards
Bob

 

[Blogwitch]

For steel pipe threading in the UK, they used to use a product called tallow, and now not readily available, but a web search usually comes up with a result, but there is a good substitute, in the UK it is called lard, I think the same product in the US is called shortening, as used in cooking.

For other metals (and steel as well), as everyone else has suggested, a good hi pressure cutting oil or solidified paint on lube.


John

 

[Mainer]

I assume you got the best quality taps and dies (i.e. the most expensive) you could find. If you didn't, that is step #1. I became a believer when, several years ago now, I bought a 1/4-27 pipe tap for something like $25. It was worth it, because it worked.

Assuming you have quality taps and dies, other things you can do are step-drill holes and taper shafts before using a tap or die. No matter what you do though, a tapered pipe thread takes effort to cut because it has to cut the full length of the taper, all at once.

And, of course, good lubricant helps.

 

[Stan]

Just to clarify John's suggestion. In North American grocery stores, lard is animal fat. It used to be rendered out with heat but now is just squeezed out in an extruder. Shortening is made from vegetable oils from multiple sources and is usually hydrogenated.

As an aside: Tallow is made from beef fat.

 

[lordedmond]

try Trefolex its green and yes it STINKS but works well


used it a lot to thread conduit 3/4 , 1 inch and 2 inch when I worked as a sparks


Stuart

 

[n4zou]

Before starting a die on the end of pipe I put it in the lathe and cut a slight taper matching the taper of the threads on the end of the pipe. It helps getting the die started straight and there is slightly less material it must cut. You must be careful not to remove too much metal and end up with shallow threads on the end of the pipe. As others have said use a good thread cutting oil too.

 

[David Morrow]

I have some hypoid 90 which I use for the final drive in my bike. Next time around, I'll give that a try.

The dies I have are new and are very good quality; the knees on my Visa card got a bit wobbly when I paid for them.

 

[dsquire]

the knees on my Visa card got a bit wobbly when I paid for them.

David

Now I know how to tell if something is expensive. :bow: :bow:

Cheers

Don

 

[rake60]

I avoid pipe thread dies unless that is no other way.
If I have to use a pipe die, I use TAPFREE Excel.
It cost about $10 USD for 6 fluid ounces so I use it sparingly.

Pipe thread tapping can be made easy. I use spiral flute pipe taps.

Again, they are not cheap.
A good 1/4-18NPT pipe tap averages $50 USD but you will only ever need to buy one.
They are not recommended for use in hand tapping but they work fine for me with a T-Handle
tap wrench.

Rick

 

[MachineTom]

The standard taper is 3/4" foot all sizes. I set my T/A the angle, take a cut then thread, easier, but not easy. you will be surprised how much is removed at that shallow taper.

 

[my65pan]

On tough materiel I like using Moly-Dee it makes things go easier but the stuff is messy.

This stuff works well on stainless steel.

I second the Moly-Dee. It's hard to get the stink off of your hands after using it, but it is by far the best stuff I've run across.

 

[kvom]

The standard taper is 3/4" foot all sizes. I set my T/A the angle, take a cut then thread, easier, but not easy. you will be surprised how much is removed at that shallow taper.

Can I assume that, using a taper attachment and the same setting, I could single point external pipe thread (at least enough to make the die cut easier)?

 

[MachineTom]

That is what I did, cut the taper, run a few passes single point using the T/A for the threading as well, then cleanup with a Ridgid pipe threading die, quicker than trying to crank the threader from my wheelchair. A lathe chuck will not hold a pipe from slipping when using a single pass die, no how no way, okay maybe a 18" 4 jaw could, but nothing 8" or smaller.

 

[kvom]

My 10ee spindle lock needs one hand to hold the knob in, so even small dies take some effort.

 

[purpleknif]

Chamfer the hole 1st. It'll help a lot !

 

[MachineTom]

Kvom, is your lock pin broken, mine push and 1/4 turn to latch the button?

No hole to Chamfer PK, its external threads we are talking about.