external and internal thread

[firedamage]

I try to model a shaft with external thread of m33x2,the
major diameter is 33 mm with 2 mm pitch.

But in the shaft drawing,there is no root diameter stated.
What root diameter should i use for m33x2 external thread?
Is there any table to refer?

Thank you

 

[ankarl]

For metric threads root diameter is major diameter - pitch

 

[firedamage]

So, the thread root diameter(external or internal) for this
case is

root diameter = 31 mm = 33- 2?

 

[sbiker]

for external thread (screw) M32x2 the root diameter (d3) is
29,546 mm

for internal thread (nut) the inner diamter (D1) is 29,835
mm

 

[firedamage]

Is there any chart to be refer to in the internet?

If yes may you provide me the address?

Thank you.

 

[sbiker]

Hi,
try for example
http://www.ring-plug-thread-gages.com/PDChart/Metric-
Fine-thread-data-30-64.html

Otherwise google is the best assistant

https://www.google.cz/search?
q=metric+thread+chart&hl=cs&prmd=imvns&source=lnms&sa=X&e
i=B6klULmuIa3Q4QSW7YDgAQ&ved=0CAgQ_AUoAA&biw=1920&bih=107
5

 

[firedamage]

Hi,

Thank you sbiker.

I am trying to model a hole on a shaft according to
picture 1.I wonder if the values entered into the pro E
correct or not in picture 2?


(PICTURE 1)
View attachment 5711


(PICTURE 2)
View attachment 5712

 

[sbiker]

Hi firedamage,
I'm afraid that's not correct. I thing it's necessary to
create a sketched hole at first and then create the
cosmetic thread M16.

In one feature it's possible to create a hole with
countersink and counterbore only in bad order (counter
bore and below it countersink).

Sketched hole:
View attachment 5713
View attachment 5714
Edited by: sbiker

 

[firedamage]

thank you for the reply sbiker,

What is the diameter for between the two lines? There is
not diameter stated in the drawing.Is it 16 mm or 14.917
mm?

I refer to this website,for m16x1,minor diameter female
thread = 14.917 mm.Is this correct?
Here is the address:

http://www.newmantools.com/tech/threadmf.htm

View attachment 5715
Edited by: firedamage

 

[sbiker]

Hi,
this diameter is 13.546 (see dimension in my picture in
previous post).

Here you have thread M16 which has standard pitch 2 mm
and d3=13.546. For this purpose it's necessary ty use
table for coarse threads:
http://www.ring-plug-thread-gages.com/PDChart/Metric-
Coarse-thread-data.html

The table in my first post was needed for fine thread
M33x2.

 

[firedamage]

Does it means that threads with no pitch value given in the drawing will have 2 mm pitch value?


How to determine wether the thread is fine or coarse?


Is it pitch=1 mm to 1.5 mm considered fine? >2mm considered coarse?


Thank you again sbiker.


You really helped me a lot.

 

[sbiker]

Hi,
no, this is part of engineering specifications.

There are many types of thread series standards. At this
time we are talking about metric threads.

This series has chart with basic (coarse) pitch:
http://www.ring-plug-thread-gages.com/PDChart/Metric-
Coarse-thread-data.html

where the pitch is given by the standard. This series can
be divided into 1st and 2nd choice:
http://en.wikipedia.org/wiki/ISO_metric_screw_thread

On the drawing if there is stated a thread without pitch
then there is clear that the pitch is given by this
"coarse" standard (for M5 it's clear the pitch is 0,8,
for M3 the pitch is 0,5 etc.).

If you need to use another pitch then it'c necessary to
specify it (e.g. M30x0,75, M28x0,5 etc.). There are other
standard series (fine threads, threads for fine mechanics
and optics - these series include threads with lower
pitches.)

According to engineering standards the thread description
should also include the thread tolerance:
http://www.boltscience.com/pages/screw8.htm

For example M16-6G (for internal thread) and M16-6g for
external thread (similar to tolerancing hole and shaft).

In case of another pitch e.g. M10x0,5-6g.

Is is more clear now?

Try to search the web for thread standards and you will
find plenty of websites dealing with this issue.

Pavel

 

[firedamage]

Thank you very much sbiker.

I am clear now.
However isn't root diamter of internal thread = minor
diamter female thread?
According to this chart,

http://www.ring-plug-thread-gages.com/PDChart/Metric-
Coarse-thread-data.html

at M16 root diameter for coarse thread = 13.835 mm?

Thank you

 

[sbiker]

Hi,
13.385 is female (internal) minor diameter (D1).

But for the male (external) thread the root diameter is
13.546 (d3) - see exact metric thread shape
http://cs.wikipedia.org/wiki/Soubor:Metricky_zavit.jpg

or

http://www.google.com/imgres?
hl=cs&sa=G&gbv=2&biw=1920&bih=1075&tbm=isch&tbnid=EaYiI13
LFl95EM:&imgrefurl=http://www.valvias.com/miscellanea-
metric-thread.php&docid=Ajpe-
za6jvLliM&imgurl=http://www.valvias.com/images/prontuario
/rosca/rosca-din-13.png&w=374&h=198&ei=4woqUK-
PKcfQ4QTX9oGwCw&zoom=1&iact=hc&vpx=469&vpy=554&dur=88&hov
h=158&hovw=299&tx=141&ty=74&sig=111524269104991666008&pag
e=1&tbnh=111&tbnw=209&start=0&ndsp=63&ved=1t:429,r:39,s:0
,i:192

Pavel

 

[firedamage]

Hi,

Thank you.Isn't this is female thread?
So minor diameter = 13.385?

View attachment 5719

btw,in pro/E, for external thread the purple line is
represented by root diameter while for internal diameter is
represented by major diameter?

 

[sbiker]

yes, you're right - mistake has arisen

the proper diameter in this case is 13.835

P.

 

[firedamage]

Thank you


in pro/E, for external thread the purple line is
represented by root diameter while for internal thread the purple lineis
represented by major diameter?

 

[sbiker]

Hi, yes

 

[firedamage]

Hi Sbiker,
Thank you.

One more thing, in the mod parameter, should i directly
enter pitch=2mm into 'thread per inch' section?(Shud I
change it to inch?)

Or need to convert the pitch to thread per inch and the
enter into 'thread per inch'?

View attachment 5720

Edited by: firedamage

 

[sbiker]

Hi,
these data are necessary to be specified only in case you
want to use the text note as annotation in the drawing or
if you need to work with these parameters later.
Otherwise you don't need to fill this table.

Into Thread_per_inch you write the pitch
M5x0,8
MAJOR_DIAMETER 5
THREADS_PER_INCH 0,8 (value doesn't correspond to
accurate name of parameter - a bit strange, but what can
we do )
View attachment 5721
Edited by: sbiker