Re: Machine Shop

On 2/23/2025 9:22 AM, John B. wrote:

On Sun, 23 Feb 2025 09:05:50 -0600, AMuzi <am@yellowjersey.org> wrote:
 

On 2/22/2025 10:04 PM, Jeff Liebermann wrote:

On Sun, 23 Feb 2025 07:26:05 +0700, John B. <slocombjb@gmail.com>
wrote:
>

On Sat, 22 Feb 2025 13:06:13 -0800, Jeff Liebermann <jeffl@cruzio.com>
wrote:
>

On Sat, 22 Feb 2025 19:58:29 GMT, cyclintom <cyclintom@yahoo.com>
wrote:
>

On Fri Nov 8 14:03:46 2024 Frank Krygowski  wrote:

It doesn't exist, Tom. You can't pop a dent out a bicycle frame tube by
riding the bike. Thinking you can is a sign of insanity.

>
If you have a slight dent in high performance steel. the tubing can revert to its natural shape under stress.

>
Tom.  The only steel that might do that is spring steel (1095, 1060,
1075, 1080, etc).  Bicycle frames are not made from spring steel.  If
they were made from spring steel, they would ride like the proverbial
wet noodle.

>
Errr... 1095 is not "spring steel". At least not in the metal working
field. It is simply a high carbon steel and one common use is knife
blades and other cutting devices :-)

>
True, but I beg to differ slightly.  Wikipedia lists 1095 as "Blue, or
polished bright spring steel".  Same with McMaster-Carr catalog:
<https://en.wikipedia.org/wiki/Spring_steel>
<https://www.mcmaster.com/catalog/116/3630>
>
During the 1960's, I was working in my father's lingerie factory after
school.  We couldn't afford a resident toolmaker to build the sewing
machine attachments.  So, I was volunteered to do the work.  My father
took home a few tools and some stock including a box of assorted coils
of spring steel.  When he died in 1995(?), I inherited the tools and
metal stock which included some 1095 coils and scrap.
>
However, it seems that it's also suitable for knives.  I know a little
about knife making and sharpening.  I made one knife from a kit:
<https://www.knifekits.com>
I do fairly well (for a beginner) at sharpening.  1095 is considered a
good steel for knifemaking because of it's edge retention.  It's most
suitable for survival knives.  1095 has no corrosion resistance and
therefore poor edge retention in corrosive environments:
<https://www.bladehq.com/blog/knife-steel-guide#1095>
>
For bicycle frame use, it could probably survive a crash, but will
corrode away in the first rain.  If the tubing were thin enough, it
might be springy enough for self healing dents.  However, the same
springiness will also provide a springy ride.
>

>
If it doesn't dent or crease or crack, the forces were
within that steel piece's elastic limits.  Once that limit
is exceeded, to the point of a measurable dent, there has
been structural deformation (crystal slip).
>
Those limits may be of different values for different steels
of the same shape/dimensions but the principle is universal.
>
in short, 'spring steel' is a red herring here.

 You can  heat treat 1095 to a hardness that it won't bend at all :-)
(so  much for "spring steel")

OK, if it "won't bend at all" it will at some point (some higher value for force) fail by cracking.  Changing the objective value of force needed for permanent deformation doesn't change the principle.
Again, Mr Kunich described material deformation, that is, something beyond the elastic limit of whatever material it is. Permanent deformation is necessarily a change of the metal's structure; it did not, and cannot, 'pop back to shape'.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971