class 2a vs class 3a thread pricing

[qrovin]

noobie owner with a noobie question

is there a difference as far as how much to charge for a 2a class fit and 3a class thread fit

if so how much difference ?

 

[Matt@RFR]

$10,000.00.

 

[ManualEd]

One piece, or a million pieces?

Tapped, milled, turned?

Size, shape, and most importantly, colour?

 

[Gordon B. Clarke]

noobie owner with a noobie question

is there a difference as far as how much to charge for a 2a class fit and 3a class thread fit

if so how much difference ?

As pointed out it very much depends on what size etc. you're making. Tap and die or ....?

One cost that should be added is the price of whatever you use to make sure the thread is within tolerance.

To "answer" your question - I doubt if there is any percentage that can be used.

Tolerance class 2A is the foundation
1A = 1,500 x 2A
2A = 1,000
3A = 0,750 x 2A
1B = 1,950 x 2A
2B = 1,300 x 2A
3B = 0,975 x 2A

As you can see the tolerance on a 3A is 3/4 that of a 2A.

 

[sagespecialized]

So you want to charge more to add or subtract cutter comp....interesting...

 

[MK Proto]

So you want to charge more to add or subtract cutter comp....interesting...

Depends cant cutter comp a tap (If he is using a tap).

Maybe a more difficult material where a 2a would make a 100 good parts and a 3a will make 10 good parts.
To many variables from what he posted.
He also said he was a noob, so if he gets us the right information we would be in a better place to help him.

 

[sagespecialized]

I still don't see it...

A 2A thread is external, threading insert (turning) adjusted with comp. Thread mill (milling) adjusted with comp...

If it was 2B or 3B, internal, that is driven by tap size (GH number) chosen for the appropriate tolerance and material. Or if the thread is big enough to be thread milled, again cutter comped to meet the gage size.

Regardless I just don't see how it would affect pricing...

The only variable I see would be if the thread was going to be thread rolled and you have to hold to the tenths on your size, but that is a hole different process animal with it's own costs etc. and 2A, 2B, 3A or 3B should have no bearing on cost I wouldn't think. Let's see what he comes back with...

 

[Gordon B. Clarke]

I still don't see it...

A 2A thread is external, threading insert (turning) adjusted with comp. Thread mill (milling) adjusted with comp...

If it was 2B or 3B, internal, that is driven by tap size (GH number) chosen for the appropriate tolerance and material. Or if the thread is big enough to be thread milled, again cutter comped to meet the gage size.

Regardless I just don't see how it would affect pricing...

The only variable I see would be if the thread was going to be thread rolled and you have to hold to the tenths on your size, but that is a hole different process animal with it's own costs etc. and 2A, 2B, 3A or 3B should have no bearing on cost I wouldn't think. Let's see what he comes back with...

Yes and No. A supplier seeing a thread specified as 3A instead of 2A can be just about certain that the customer will give this thread extra inspection and attention. This means that the supplier will have to be damn sure that what he delivers is to spec. That extra attention from the supplier will probably cost a little more but as to quantifying how much more is down to how meticulous the supplier normally is.

A 3A tolerance isn't (or at least shouldn't be) given on a "not so important" thread. If I ordered a thread with a 3A tolerance you can be sure I'd have a reason and I wouldn't accept "almost" correct. Would I expect to pay a little more? Probably.

Bottom line? If a thread tolerance is specified as 3A assume it will be inspected with diligence.

Any supplier telling me that it didn't matter whether I ordered 2A or 3A and that the price would be the same would be put in the WTF category.

 

[hanermo]

The price for the whole (nice pun. Grin.) will go up 500$ / job plus 3x for the cost of a normal hole.

You need 3A/3B no-no go gages to make sure its in spec.
These are very expensive.

You likely then need special inserts, attention, and techniques, to make sure that you can actually make the thread to specs.

And yes, anyone who specs a 3A thread, will then test it with gages, most likely.

A small 0.25 mm thread, threadmill for same, costs 500€.
(0.25 mm trapezoidal thread, for oprtronics, microscopes, etc. From vargus, worlds biggest threading insert maker).
The customer will pay for it, as you wont have one in use, and wont be using it regularly to amortise it.

E.g.
If its 1 lot of 500 pieces, with one hole with a 3A thread, I would charge the 500+300+3€/hole for it.
As its likely to be an aerospace part, or similar, the customer will pay it.
I would also make very sure the threads are clean, good and in spec, and the part is in spec, before delivery.

 

[Bobw]

Any supplier telling me that it didn't matter whether I ordered 2A or 3A and that the price would be the same would be put in the WTF category.

I'm the supplier that would tell you that it didn't matter....

Then I read your reasoning... Since you are "the thread guy", you see it from the thread side, I'm a "parts" guy, and
I see the whole part...

You are correct in a way... The stuff I deal with that has a class 3 thread on it.. The threads are usually the
easiest thing to deal with, and those parts are going to be inspected with a fine tooth comb.. I'm going to pay just
as much attention to the threads on "those" types of parts weather class 2 or 3... So it really doesn't matter 90% of
the time.

Toss a J in there with the class 3 (and I know all J threads are class 3) and the price goes up a bit,
need to buy the right inserts and keep real close attention to the tip of the insert, one tiny chip, or some build
up, and that stupid tight tolerance root radius is shot.

The types of parts where they hand you a nut or bolt and say "this has to go on/in there". Much lower price.

 

[Gordon B. Clarke]

I'm the supplier that would tell you that it didn't matter....

Then I read your reasoning... Since you are "the thread guy", you see it from the thread side, I'm a "parts" guy, and
I see the whole part...

You are correct in a way... The stuff I deal with that has a class 3 thread on it.. The threads are usually the
easiest thing to deal with, and those parts are going to be inspected with a fine tooth comb.. I'm going to pay just
as much attention to the threads on "those" types of parts weather class 2 or 3... So it really doesn't matter 90% of
the time.

Toss a J in there with the class 3 (and I know all J threads are class 3) and the price goes up a bit,
need to buy the right inserts and keep real close attention to the tip of the insert, one tiny chip, or some build
up, and that stupid tight tolerance root radius is shot.

The types of parts where they hand you a nut or bolt and say "this has to go on/in there". Much lower price.

I didn't quite "get" your post. If you didn't need a 3A tolerance would you really make that your call out?

Yes a thread with a 3A tolerance would get more attention than none, which would mean 2A. Any customer specifying a 3A tolerance on a thread would probably only have it on a special "part" so I'd take it for granted (better safe than sorry) all dimensions would be checked. I didn't mention that as the OP only asked about 2A and 3A.

 

[Bobw]

I didn't quite "get" your post. If you didn't need a 3A tolerance would you really make that your call out?

Any supplier telling me that it didn't matter whether I ordered 2A or 3A and that the price would be the same would be put in the WTF category.

I'm just saying that I understand what you are saying, and your reasoning... But from my point of view as the
guy making the parts, it doesn't really matter to me, class 2 or class 3... Possibly because 90% of what I see
is class 3 or J threads. That should put me in your WTF?? category, but if its what you(I) do day in and day out,
its not a big deal.

Its kind of like ±.001 or ±.030 on a simple short pin... Cost won't change, I'm going to hit it within a half anyways.

 

[sagespecialized]

I'm with you on this one BobW. Quality is Quality and you use the appropriate tools to get the job done right.

Why would one treat a 2A thread quality any different then a 3A thread quality. Parts still need to meet the gaging requirements regardless, and it surely doesn't take any longer to spin the go and nogo gages to verify either thread type.

 

[Gordon B. Clarke]

I'm with you on this one BobW. Quality is Quality and you use the appropriate tools to get the job done right.

Why would one treat a 2A thread quality any different then a 3A thread quality. Parts still need to meet the gaging requirements regardless, and it surely doesn't take any longer to spin the go and nogo gages to verify either thread type.

I would hope the NoGo doesn't spin

 

[Gordon B. Clarke]

Its kind of like ±.001 or ±.030 on a simple short pin... Cost won't change, I'm going to hit it within a half anyways.

Sigh. If only more suppliers were like you

I am guessing though that you aren't always the one giving the lowest offer.

 

[Bobw]

I am guessing though that you aren't always the one giving the lowest offer.

I try not to be.

 

[Matt@RFR]

I try not to be.

If I could "like" this 1,000 times, I would.

 

[Gordon B. Clarke]

Then I read your reasoning... Since you are "the thread guy", you see it from the thread side,

I've nothing against being regarded as "the thread guy" but it'd be more correct to refer to me as "one of the thread guys"

An example. If mrainey and I posted conflicting information re for example thread tolerances I'd probably go with what mrainey wrote over my own as the immediate answer LOL

I have his ThreadPal program and it saves me time from having to go through my thread library. OTOH if I want more info than "just" tolerances then I have to read.

You can be sure though I'd do some searching to find out which version was correct.

No names mentioned none forgotten but there are a few that help me with thread issues. Nobody knows everything

 

[Bobw]

I have his ThreadPal program and it saves me time from having to go through my thread library. OTOH if I want more info than "just" tolerances then I have to read.

I put off buying Threadpal for quite a few years... Its just info I can look up elsewhere..

I finally did buy it a while back.. It paid for itself in less than 2 weeks... I didn't have
to go find the stupid Machinery's Handbook (where did I leave that thing now?). Didn't have
to look up the formula for calculating thread wires. Didn't have to go figure out where I left the
J thread spec. Didn't have to google all over the place trying to figure out drill sizes for
metric form taps... Didn't have to sit around and crunch #'s to figure out pitch diameters on
some specials...

Should have bought it years ago. It really is a time saver.

 

[Gordon B. Clarke]

Should have bought it years ago. It really is a time saver.

I think many don't think about how much time they use searching and calculating. Time is after all money and a person or company can get quite a bit of work done for the cost of PayPal.

No I don't have any shares LOL