PSN-L Email List Message

Subject: Re: Glass?
From: tchannel1@............
Date: Mon, 12 Nov 2007 11:35:41 -0700

```Chris,   You have enlighten me.   "Not to put too fine a point on it"  =
(the subject that is) but  would then, diamond on diamond be the best of =
all?

Not knowing how I might do this, but I have many carbide tipped saw =
blades.  I have never looked too closely at one tooth, but they have a =
point and some flat surfaces.  If I could get some of these teeth off, =
or get replacement teeth from the people who resharpen my blades, would =
these be good pivots surfaces?  Say one tooth point resting on one tooth =
flat side.  (arranged in a set of two) pivots for a vertical pendulum?   =
Thanks, Ted
----- Original Message -----=20
From: ChrisAtUpw@..........
To: psn-l@.................
Sent: Monday, November 12, 2007 10:07 AM
Subject: Re: Glass?

In a message dated 12/11/2007, tchannel1@............ writes:
Hi Folks,   Just wondering about materials for roller on roller or =
balls on plates.   I know the limitations of glass, but a question about =
its smoothness, is the surface of glass as smooth or smoother than these =
hardened and polished steels?
Hi Ted,

Probably about the same. You get an optical finish with fine =
polish on metal. However glass is a rapidly solidified liquid.
My second question is one of friction: If you have one ball on one =
plate you would have one point of friction.  If you have one ball =
resting between two rollers, (in the V) you would have two points of =
friction, but the load would be divided, because its resting on two =
points, so is the end result of friction loss the same?
It is the surface to surface properties which are important. The =
actual static friction is proportional to the load, so halving it and =
using two points will likely give a very similar result. However, if you =
put a fixed vertical load on a ball resting on two rods, the loads at =
the two points are increased to give the same resolved vertical force. =20

When we talk about friction in pendulum suspensions, it is not =
this static friction to which we are referring. It is the tiny rolling =
contact loss as the materials are compressed and relaxed. No materials =
are perfectly elastic. Glass is poor in this respect and tends to chip =
easily.

Regards,

Chris,   You have enlighten me.   "Not to =
put too=20
fine a point on it"  (the subject that is) but  would =
then,=20
diamond on diamond be the best of all?

Not knowing how I might do this, but I have many carbide tipped saw =

blades.  I have never looked too closely at one tooth, but they =
have a=20
point and some flat surfaces.  If I could get some of these teeth =
off, or=20
get replacement teeth from the people who resharpen my blades, would =
these be=20
good pivots surfaces?  Say one tooth point resting on one tooth =
flat=20
side.  (arranged in a set of two) pivots for a vertical=20
pendulum?   Thanks, Ted

----- Original Message -----
From:=20
ChrisAtUpw@.......
To: psn-l@..............
Sent: Monday, November 12, 2007 =
10:07=20
AM
Subject: Re: Glass?

In a message dated 12/11/2007, tchannel1@............ =
writes:

Hi Folks,   Just =
materials for roller on roller or balls on plates.   I =
know the=20
limitations of glass, but a question about its smoothness, is the =
surface of=20
glass as smooth or smoother than these hardened and polished=20
steels?
Hi Ted,

Probably about the same. You get an =
optical=20
finish with fine polish on metal. However glass is a rapidly =
solidified=20
liquid.

My second question is one of =
friction: If you=20
have one ball on one plate you would have one point of =
friction.  If=20
you have one ball resting between two rollers, (in the V) =
you=20
would have two points of friction, but the load would be divided, =
because=20
its resting on two points, so is the end result of friction =
loss the=20
same?

It is the surface to surface properties =
which are=20
important. The actual static friction is proportional to the =
halving it and using two points will likely give a very similar =
result.=20
However, if you put a fixed vertical load on a ball resting on two =
rods,=20
the loads at the two points are increased to give the same =
resolved=20
vertical force.

When we talk about friction in pendulum=20
suspensions, it is not this static friction to which we are referring. =
It is=20
the tiny rolling contact loss as the materials are compressed and =
relaxed. No=20
materials are perfectly elastic. Glass is poor in this respect and =
tends to=20
chip easily.

Regards,

=
Chris
```