roughness threads

[MBT]

Good evening to all
There was a confrontation in the office today...
the topic was "the roughness of threads"
In summary, speaking of standard metric series threads, on the construction design next to the mxx indication should a symbol of roughness be indicated?
and what value should be indicated, according to you?
a fixed value?
variable depending on the size of threads?
in relation to "prophetic" processing (torn or drilling) ?? ?

to you the word :tongue::finger:

 

[linch]

a normal thread that concerns a hole and a tree, is not subject to further refinement in addition to normal mechanical processing to obtain it, therefore it does not need to specify the degree of wrinkle to be obtained as standard.
the speech is different if referred to special threads (type screws recirculation, etc.), in that case it is indispensable to indicate the final roughness, treatments etc.

 

[gerod]

I know that many customers ask me (generally 6.3 or 12.5).
I found This is. according to tolerance there is a value.
Hi.

 

[Preparation-H]

Good evening to all
There was a confrontation in the office today...
the topic was "the roughness of threads"
In summary, speaking of standard metric series threads, on the construction design next to the mxx indication should a symbol of roughness be indicated?
and what value should be indicated, according to you?
a fixed value?
variable depending on the size of threads?
in relation to "prophetic" processing (torn or drilling) ?? ?

to you the word :tongue::finger:

consider that parts with a rectified thread with ra. 0.8 to threads with ra. 12.5
therefore as from table in the post of gerod depending on the degree of accuracy, the smaller will be the required roughness... :finger:

Bye!
p-h

 

[MBT]

thanks to all for the intervention
However, by reading well the table marked by gerod, it is clear that the degree of roughness is in function of the tolerance class of the size...
does not speak of class of thread tolerance
to understand, tells me that a hole ø100 h7 should have roughness ra 1,25
but does not refer to any threads.
I also see that the text says:
"for threads, thepossibly indication of the condition of the sides of the thread should be placed.... "
Does it mean that it is optional and should only be placed in particular cases?

 

[gerod]

However, I usually don't put them unless they are particular threads.
who threaded with male or chain definitely does not control the degree of roughness, we would miss.

 

[stefanobruno]

I know that many customers ask me (generally 6.3 or 12.5).

those few times I put them, my clients got them removed.
if they are indicated, even with coarse values, each thread immediately acquires an economic value greater than the standard.

Bye.

 

[linch]

Gentlemen, indicate a degree of wrinkle on a thread "standard"It's a boiata.
I work, and I have worked for companies that make quality of design their beliefs, and I have never indicated any wrinkles, if not in specific cases as indicated in post n°2.

 

[radio]

I press that I have never indicated values of roughness on threaded elements, also because I wonder how to measure e.g. a ra 3.2 value on a m12.
I did a small search on texts and manuals that I have at hand is I found nothing specific for threaded links.
among other things the old baldassini (10a ediz) shows a table that correlates the degree of accuracy with the max roughness (which for it6 values typical of the threads seems difficult to obtain, nourishment by turning), while in the new edition (19a) this table is gone; replaced by a more pragmatic text: "the indication of the surface state is not necessary when the processing is carried out in a usual manner, it ensures for itself a surface state adapted to the requirements. ".
Finally, it should be borne in mind that a coating (nickelling, galvanization of various types...) changes the roughness obtained by mechanical processing.
Bye.

 

[MBT]

Gentlemen, indicate a degree of wrinkle on a thread "standard"It's a boiata.
I work, and I have worked for companies that make quality of design their beliefs, and I have never indicated any wrinkles, if not in specific cases as indicated in post n°2.

in specific cases, of course, the rules fall
However, in fact, threading is a machining with particle removal
and as such, should be indicated.. .

I press that I have never indicated values of roughness on threaded elements, also because I wonder how to measure e.g. a ra 3.2 value on a m12.

Right.
but also you wonder how to measure roughness on a ø6 h7 where you indicate 1,6.. .

I did a small search on texts and manuals that I have at hand is I found nothing specific for threaded links.
among other things the old baldassini (10a ediz) shows a table that correlates the degree of accuracy with the max roughness (which for it6 values typical of the threads seems difficult to obtain, nourishment by turning), while in the new edition (19a) this table is gone; replaced by a more pragmatic text: "the indication of the surface state is not necessary when the processing is carried out in a usual manner, it ensures for itself a surface state adapted to the requirements. ".

Yeah, I noticed that.
but then I asked myself a question
the hole ø10 h7 above... should be clearly done with alestor
should I therefore omit indication of roughness???? ?
and what are the "executed" things?? ?

Finally, it should be borne in mind that a coating (nickelling, galvanization of various types...) changes the roughness obtained by mechanical processing.
Bye.

Yes, it is.
I in the specific case referred to a threaded hole, with the classic hand or machine male.. .
without additional treatments

 

[linch]

in specific cases, of course, the rules fall
However, in fact, threading is a machining with particle removal
and as such, should be indicated.. .

Right.
but also you wonder how to measure roughness on a ø6 h7 where you indicate 1,6.. .


Yeah, I noticed that.
but then I asked myself a question
the hole ø10 h7 above... should be clearly done with alestor
should I therefore omit indication of roughness???? ?
and what are the "executed" things?? ?

h7 is a dimensional tolerance, the degree of wrinkle refers instead to the degree of surface finish of that tolerance.
are two things not always connected to each other.
For example, a h7 can be obtained from a fine turning, but the degree of wrinkle obtained will not be that of a harassment, even having the same tolerance.
wrinkle is a design choice, which also determines the processing system.

 

[MBT]

h7 is a dimensional tolerance, the degree of wrinkle refers instead to the degree of surface finish of that tolerance.
are two things not always connected to each other.
For example, a h7 can be obtained from a fine turning, but the degree of wrinkle obtained will not be that of a harassment, even having the same tolerance.
wrinkle is a design choice, which also determines the processing system.

partially true
the two things must necessarily be consistent
exasperating the reasoning, I cannot ask for a tolerance it 6 with roughness 12.5 ...
I will have to ask with roughness 0.8, for example
in fact there are tables that determine the degree of maximum roughness according to the tolerance class
that then the processing is done with alestore, with lathe, with rectification or with divine interposition, little changes.... the important thing is that tolerance and roughness are respected.

I think that the most appropriate solution is that of put on the working symbol with removal of truciole but omettere the value of roughness
What do you think?

 

[radio]

....
I think that the most appropriate solution is that of put on the working symbol with removal of truciole but omettere the value of roughness
What do you think?

In this case, however, (think about the case of a threaded tie for example) excludes the possibility of making the thread by rolling.
different is the case of a threaded hole, unless you want to get it for lost wax casting... :tongue:
I don't know, if I don't strictly need the surface finish, I wouldn't throw it at the ball.

 

[MBT]

In this case, however, (think about the case of a threaded tie for example) excludes the possibility of making the thread by rolling.
different is the case of a threaded hole, unless you want to get it for lost wax casting... :tongue:
I don't know, if I don't strictly need the surface finish, I wouldn't throw it at the ball.

That's true. I would rule out the roller... :finger:
It is also true that for small batches of pieces, and on "human" dimensions, you do not consider the rolling.
I mean... If I have to make 10 pieces m20, I will thread them with the chain, not with the roller.
if I have to make 1000.... another speech:

 

[linch]

I think that the most appropriate solution is that of put on the working symbol with removal of truciole but omettere the value of roughness
What do you think?

The removal of trucile is so obvious that I would omit it.
I think it's complicated to file something without removal of truciole.
thread value and any stop form tolerances.

 

[cacciatorino]

I know that many customers ask me (generally 6.3 or 12.5).
I found This is. according to tolerance there is a value.
Hi.

also the baldassini (19 edition) reports the same identical images, who copied?? ? ?


However never put any such indication on the drawings. I think they could be useful in two cases: screws of maneuver (tp or spheres) that are usually already ready, or threads subject to stresses of fatigue or transmission of heat, so maybe it could have a minimum of utilities, indicate a value of wrinkles to be respected.

 

[cacciatorino]

The removal of trucile is so obvious that I would omit it.
I think it's complicated to file something without removal of truciole.
thread value and any stop form tolerances.

Well the pieces in large series are made by rolling, a workmanship in cold heat.

 

[radio]

also the baldassini (19 edition) reports the same identical images, who copied?? ? ?
....

do you refer to the table that correlates precision degrees and roughness max?
If you could tell me what page?
I also have the 19th and 19th balds, and I can't find it, while I find it on the old 10th and.
Bye.

 

[linch]

Well the pieces in large series are made by rolling, a workmanship in cold heat.


Yes, it is.
I in the specific case referred to a threaded hole, with the classic hand or machine male.. .
without additional treatments

How do you roll a threaded hole?
Was the discussion about this or was it wrong?

 

[sampom]

How do you roll a threaded hole?

..exist the males "to roar", and are very (mostly) used.

greetings
Marco:smile: