Hi there Don
Yes - terminology through communication is what I need far away. So I
should use cutter not the 'knife' for turning tools right? I'm
studying Materials Engineering and turning is my temporary hobby that
allow me to realize some projects. For example integral spheres for
photometrical measurements.
2H13 is an old Polish label. Now we use European but they are not
intuitive for me so far. Do you know any site that deals with US.
Alloys nomenclature?
The carbide inserts are the only usable. Maybe ceramics can be right
too. There's something weird with turning speed for threads. Let
consider pafana.pl carbide inserts. Average turning speed for
stainless steel is 100 m/min. Now having 42 diameter I should set my
machine to:
n = 1000*Vc/pi*D = (1000*100)/(3.14*42) = 758 [turn/min]
This is some speed! Stopping the machine will cost some time
Oh BTW
how you name this small distance (synonym is paddock) where you must
set your cutter and turn on machine. This distance has smaller
diameter than thread.
Note that the size of the lathe, and the rigidity and power will
determine whether you can use carbide tooling to get a better
finish. Your "2H13" appears to be one of the European steel
designations, and I am not familiar with it. But 13% Cr would
probably make that a rather tough steel. Perhaps Ed Huntress could
pop up with a close equivalent in US steel grades?
My lathe is rather powerful enough (1800 turns/min) and my spindle
handle 100 mm rollers. Take a look:
http://tme.szczecin.pl/~jacek/Myslov...alworking.html
2H13 can be toughened so that 60-70 HRC is possible but I don't think
it was toughened. I can check with Vickers hardness test after cutting
my work. The surface is struggled because of hard shavings fall (I
don't know if 'fall' is good here, maybe flow down or something).
It may even be that it would be better to grind the threads instead
of to try to cut them -- but this will require a rather expensive
setup.
Yes however in my city, a common pitch is 1.2 and I need 1.0 with 42
diameter (mm). Also the length of thread is small - max. 5 mm.
Are you doing this as a hobby, or are you in a commercial machine
shop? The tools which would be standard in such a commercial shop
are less likely to be found in a home shop for hobby use.
As I wrote this is a hobby for University purpose. Imagine that we
have Technology Hall. They have digital lathes from Sandvik but they
don't know how to cut thread with good surface for right price. It is
also some relation problem. I did ask first can the chief do it for
me. He told me he doesn't have a time and went away to a tools room. I
did ask another guy. He shook his head. Now all the peoples (it was
vacation time) staying and looking at my work. It looks like (I can't
put drawings on my server for a while):
------------------
| |
| 70mm dia ---- |
|---------- | | |
| | /xxxx | | A |
---------------- |--------------------- ---- |
| ^ | |-
| | -----------------------|-|
- lathe mount | |42mm dia B | |
(spindle) | | ---------------------- |-|
| | | |-
---------------- |--------------------- -----|
| | \xxxx | | A |
|---------- | | |
^ | -----|
| | |
cut it here ------------------
xxxx - is an area of thread (42mm dia and 1 mm pitch). As you see the
diameters is 70 vs. 42 so the side (flange) is a problem for them
The want the thread to be reversed. That is technologically logical. I
told them I didn't have right cutter to perform A notch and what is
important to have absolute match (on axis) of thread with B opening.
The chief who is really nervous threw some insults at me that if I am
wise then I can do it myself and polishing will be to expensive for me
and went away again. As you see I'm trying did as he said
As an indication of the sizes of lathes, Mine is an old Clausing
which will swing 12" (300 mm) diameter over the bed, and somewhat
smaller (at least 6" (150 mm) over the carriage. I consider this on
the large end of hobby lathes, though there are others here with
larger machines. Mine is sufficiently rigid to be happy with carbide
tooling and reasonably tough jobs.
I would say the same instead of threads
Carbide tools can give a smoother surface to the cut, but they often
require higher speeds and more rigidity from the lathe than
equivalent HSS tooling can. Carbon steel requires *much* slower
speeds or the tool overheats and looses its temper.
That is so. I will try to use ready thread cutter (carbide soldered to
the grip) and grind it so that it can be used with that flange.
With Kind Regards,
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