#3-48 die

[Spell]

Hi,

Where can you buy a quality #3-48 die capable of cutting threads in stainless?

I have tried some Chinese wich were absolute crap, a KS brand made in Japan, it was no good either.

Regards Russell

 

[Buchanan]

You really need a s Coventry die head in a lathe to get a good thread as well as a good cutting oil. Dies don't cut good threads. They do cut acceptable threads though. ot get somebody to machine them on a CNC lathe.

 

[Spell]

i only have eight rods to put #3-48 threads on and may not ever use that thread size again.
have just learnt about something new, re. Coventry Die head, will keep this in mind for other jobs.

 

[Mechanicboy]

There is not really problem with die. The stainless steel is not easy to tread up with die. Use a treading tool of HSS who are sharp (do not use carbide tool) + cutting fluid. Tread up the stainless steel with small cut each time when you are rotate the chuck (do not use lathe motor) then you has full control under work. Results will be fine treads on rod. If the length of treads is long, use rotating center to prevent the rod is flexing under work.

 

[DJP]

Chromatap fluid and a new HSS die works for me when threading stainless. Galling is the big issue.

I have seen dies that are split and expandable with a set screw. I think the idea was to make multiple passes.

 

[Wizard69]

Check with MSC, Travers or the like. This assumes you are in the USA.

As for cutting the threads what exactly is the problem? For that matter what is the alloy?

When doing stainless you want to be right on with dimensions especially OD. OD is critical and i highly suggest referencing a hand book to determine the major diameter for the class of fit you are after. Once that is resolved use plenty of oil during the cutting process. Depending upon the alloy stainless can be very tough.

 

[Mechanicboy]

Use the 303 stainless steel alloy is easier to machine than the others, but is not weldable. The 304 stainless steel alloy is the most commonly used. 304 stainless steel alloys is weldable and machinable. Thm:

The 316 stainless steel alloy is also known as marine grade stainless. It can be machined and welded like 304 but has much better corrosion resistance.

 

[Spell]

Problem I have had with the #3-48 dies is that they are poorly made with excessive burrs on the cutting teeth and incorrectly sized thread size.

I have no issues otherwise with cutting threads in stainless.

 

[bazmak]

There are cheap dies and good quality expensive ones.If you have limited use and are cutting say a 1/4" thread in brass or mild steel the the cheap ones will
suffice.However small threads are only doable with good quality expensive dies
And HSS is preferable over HCS for stainless

 

[R Degen]

Try Mcmaster carr they have good Dies

 

[Spell]

will keep McMaster in mind if I need some tools.

Thanks for all your advice, I now have the job done by cutting thread on lathe using a bush to support end while cutting the thread.

 

[Wizard69]

will keep McMaster in mind if I need some tools.

Thanks for all your advice, I now have the job done by cutting thread on lathe using a bush to support end while cutting the thread.

Nicely done!

Just a fair warning, good quality dies are expensive! As pointed out above most of the cheap tap and dies sets come with low quality dies, often they arent worth the money spent on the kit.

As for round split dies, those are for adjusting the class of fit! At best you get a couple of thou adjustment. That depends upon die size of course but in the end it is there for fit adjustment.