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I can't read the text above the thread but it looks like it may be a feature on the part. Can you speak to the person who made the print?
 
I can't read the text above the thread but it looks like it may be a feature on the part. Can you speak to the person who made the print?

It is a customer of mine that's asking for my help and I've told him to contact his customer as NC50 isn't enough for me to do anything.

So far what his customer has sent him is useless. One of the "things" sent by his customer was an 84 page standard. Looks as if there is more than one type NC50.

This information is what I'm lookin for.

NC50.info.jpg

Where is the pitch diameter to be measured?

Taper in degrees?

Pitch diameter tolerance?

Would seem simple but apparently not.

If I get an answer to those 3 questions I'll post how I'd measure it.
 

That seems to be on gauges. If my customer wanted to buy a gauge he wouldn't have contacted me. What he's bought from me previously several times measures thread pitch diameter. Usually ACME and Tr but also metric.

I started on Buttress a few years ago. That proved interesting.

http://f-m-s.dk/Buttress Thread Measurement.pdf

I'd be more than happy just to know the answer to the 3 questions in post#5.

Don't get me wrong. Thanks for posting but I can't use it to make anything.
 
I wish some of you would read the OP before giving advice. Is a NC50 thread a standard thread and only one single type? It doesn't seem to be.

It is my customer that is making the part that requires an NC50 thread. I have suggested that he contact his customer for information re the thread. What he got from his customer was an 84 page standard that didn't help him or me. It makes me think his customer, or whoever they are in contact with, doesn't know anything about the thread specs in question.

If I can get the information that's shown in the sketch on post #5 I can make a measuring gauge for him and almost certainly much cheaper than anything else he´d have to buy.

Previously I've made measuring equipment for the API threads below, both external and internal) for a few customers and they were satisfied.

API.example.jpg

The problem is that my customer doesn't know what his customer wants and, unless I get the information I ask for in post #5, I can't help or make anything for him.

In brief, the information I'm asking for is in fact more for my customer than me as he can't even start to machine anything until he knows what he's to make. So far I'm getting the impression his customer, or at least the person they are in touch with, doesn't know either.
 
(PDF) Specification for Threading and Gauging of Rotary Shouldered Thread Connections | Raphael Ferreira - Academia.edu

You cut to fit Gages.
If you are cutting a Pin the Box Gage has a .625 stand off. If cutting a Box the Pin Gauge is Flush with Face.
What does the part look like? Can your customer supply Gages?

Folk from Texas seem to know most about API threads.

I looked at your link and came up with this as being, what I regard, as most relevant to what I'm looking for.

APIa.jpg APIb.jpg APIc.jpg

If there is only one NC50 then this might just be what I need.
 
Somebody on PM not so long back invited members to ask him if they had any thread data problems,ask him.

You just can't help being an idiot can you? You even keep claiming you don't follow me around or reading my posts :)

The guy you're referring to never posted that he knew everything on threads, just that he knew more than most. If I recall correctly that was yet another thread you trolled.
 
Looking through some old papers/drawings (wasn't looking as much as just tidying up) found I had a drawing with the information I needed. The name of a company is on it so I can't (won't) make it public.

My thanks to those that did try and help.
 
Gordon,

I didn't see this thread soon enough. NC-50 is the same as 4-1/2 IF. IF I recall, I may have sent you the drawing of the details for this thread. API Spec 7-1 does not give all of the information needed to cut the thread if that's what you needed. Anyways, glad you found your answer.

KenS.
 
Gordon,

I didn't see this thread soon enough. NC-50 is the same as 4-1/2 IF. IF I recall, I may have sent you the drawing of the details for this thread. API Spec 7-1 does not give all of the information needed to cut the thread if that's what you needed. Anyways, glad you found your answer.

KenS.

Ken,

As mentioned there's no need to go further than Texas for info on API threads. Yes you are the guy that got me started down the API thread path and it's a helluva windy road.

How my customer cuts the thread is his problem. I can "only" come up with a way to measure it.

What you sent me years ago was very much appreciated as well as invaluable. The "problem" I've had this time is my customer's customer reluctance (my diplomatic way of saying their lack of knowledge) to give the necessary information. What they did send my customer was an 84 page API standard and in that there seemed to be more than one NC50 plus a heck of a lot of addendums.

Unless you object you'll be my "go to guy" for API threads next time I run into a problem. If I can ever do something for you don't hesitate.

A hearty "Thanks" isn't enough but a hearty thanks nevertheless :cheers:
 
Gordon, I always try to help when I can on this stuff. I've learned a lot over the years about these threads and in fact, one old timer, back in 1980 explained to me a lot about API thread design that most today have no knowledge of how these threads work. This old timer was a tool engineer for a large oil tool company back then. His lessons were priceless to me back then, and still are today. :)
 
This will not help any, just an odd story. I worked in a shop that threaded drill stem joints for a couple of years. Every now and then then the shop would have to make a new thread size. The drill was the foreman would come out with a hardened and ground go gauge and make a pair of gauges from whatever material was on hand usually 4140. I never saw the original gauge again, whether it was rented and sent back or just stored in the locked room with the shop made gauges I do not know. The time I was there I do not remember ever being allowed in that room. Can't say that I ever saw into the room from the doorway. These shop made gauges were cut with hand ground braised carbide tools. The grinder had a silicon carbide wheel with just a plain tool rest. All the tool joints we made would be gauged with these shop made gauges. Never saw one replaced at the time I assumed the originals were still in that room but thinking about it they were probably so expensive they were just rented.
 
This will not help any, just an odd story. I worked in a shop that threaded drill stem joints for a couple of years. Every now and then then the shop would have to make a new thread size. The drill was the foreman would come out with a hardened and ground go gauge and make a pair of gauges from whatever material was on hand usually 4140. I never saw the original gauge again, whether it was rented and sent back or just stored in the locked room with the shop made gauges I do not know. The time I was there I do not remember ever being allowed in that room. Can't say that I ever saw into the room from the doorway. These shop made gauges were cut with hand ground braised carbide tools. The grinder had a silicon carbide wheel with just a plain tool rest. All the tool joints we made would be gauged with these shop made gauges. Never saw one replaced at the time I assumed the originals were still in that room but thinking about it they were probably so expensive they were just rented.

Damn LOL you've got me thinking.

API gauges are very expensive so I'm wondering if it's possible to buy one in the USA, not use it, and return it (after copying it as good as possible) saying the purchase was a mistake? The flaw in that thought is I doubt if it's possible to cheat the same gauge supplier more than once.

Moving on. Is it possible to rent gauges in the USA? That's something I've never heard of anyone doing. If a car can be rented then why not a gauge?
 
I am guessing the gauges would be close to $10,000 USD each, not sure what they were 40 years ago. That shop is closed and the machines and inventory are scattered now so there is no one I can ask. Ken may know since he is still in the industry. Google might be able to help. Kind of specialized industry, rentals could be available word of mouth without a Google presence.
Inserts and tool holders are readily available here so a better quality gauge could be constructed than what we used. Look at toolflo.com I think they have API inserts.

I thought I was just telling a funny story, hope it helps after all.

Added thought back then there were companies that rented "subs" and tool extractors. Things would break off in a well and specialized tools were made to try to retrieve them to salvage the well. Subs were adapters from one thread size to another, that company I worked for did build subs. Maybe the same companies rented gauges? If not they might know who does.
 
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FredC, I know API gauges are very expensive but don't know just how expensive. Your "guess" is probably close to being right. Got a feeling Ken would know.

My customer, and who got me started with this thread, was only making a 1 off, so paying that kind of money for a gauge would have been mad. Suffice to say the person that sold that 1 off didn't know what he was selling. To him it was just a threaded item.

API threads have, in comparison to all other threads I know, have a very small pitch diameter tolerance. I believe around 0.002".

Anyway, thanks for your "history" :cheers:

Ken, if or when you read this, are there any other thread types I can ask you about if need be?
 








 
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