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Alistair Hosie
04-18-2010, 03:11 PM
one of these before I haven't.?Alistair
http://cgi.ebay.de/Mitlaufende-Koernerspitze-MK4-Drehmaschine-Drehbank-Roehm_W0QQitemZ380225378099QQcmdZViewItemQQptZIndu striemaschinen?hash=item588732d733

NBbrad
04-18-2010, 03:28 PM
one of these before I haven't.?Alistair
http://cgi.ebay.de/Mitlaufende-Koernerspitze-MK4-Drehmaschine-Drehbank-Roehm_W0QQitemZ380225378099QQcmdZViewItemQQptZIndu striemaschinen?hash=item588732d733

Neither have I. I have spring loaded live centers, but no gage on them.

Looks like a pressure gage... neat.

Limy Sami
04-18-2010, 03:51 PM
Yes, it is a pressure guage, they're mainly used with face drivers, like these.

http://www.rohm-products.com/uploads/tx_userproducts/us_stirnseitenmitnehmer.pdf

MuellerNick
04-18-2010, 04:49 PM
Yes, they do have a pressure gauge. Mainly used if you do have long (slim) parts that expand with the work heat.

Nick

winchman
04-18-2010, 05:08 PM
Pressure?? Looks like RPMx100 to me.

DannyW
04-18-2010, 05:14 PM
.

... Or in situations when you can't "feel" the pressure that you're exerting with the tailstock (CNC).
Some CNC lathes don't have an oil pressure gage or pressure adjustment for the tailstock.
So you're totally in the dark, or always have full pressure on the revolving center. Especially on thin parts, high pressure is not a good thing.

Also, when a part wanders in the direction of the chuck, due to cutting forces, with this center you can spot this behavior and take appropriate action,
before the part comes loose from the center.

Regards,

Danny

JCHannum
04-18-2010, 05:16 PM
Pressure?? Looks like RPMx100 to me.

That is what I thought too, but if you enlarge the photo it is d(something)N X 100. Probably some silly metric pressure measurement, they keep changing them.

MuellerNick
04-18-2010, 05:20 PM
d(something)N X 100

Then it is not pressure, but force. It should read "daN".
Now it's your turn to convert that to weight! :D


Nick

DannyW
04-18-2010, 05:23 PM
Yes, the gage reads in daN.

Danny

John Stevenson
04-18-2010, 05:24 PM
A lot of the Italian copy wood lathes like the Locatelli have hydraulic tailstocks so they can automatically reduce the tailstock pressure on long parts as they are turned to thin sections other wise a constant pressure bows the work and you finish up wearing the part.

The tailstock pressure valve is part of the copy follower set up.

winchman
04-18-2010, 05:37 PM
Oops, too late.

John Stevenson
04-18-2010, 05:42 PM
No it's not.

Be damn well decisive.

.

Fasttrack
04-18-2010, 08:06 PM
daN? Decanewtons? That's 2.248 lbs per 1 decanewton.

Cool. I bet that thing costs a pretty penny...

clutch
04-18-2010, 08:20 PM
Thanks Nick for translating.

Clutch

juergenwt
04-19-2010, 02:03 PM
Puch. price 1994 = 960 DM. Reading to the red line = 900 deka newton.

MuellerNick
04-19-2010, 02:25 PM
It's listed in an catalog. Price is:
MT#3: 512.-
MT#4: 556.-
MT#5: 748.-
MT#6:1187.-

Plus taxes, minus discount
1 at about $1.30 I think.


Nick

Alistair Hosie
04-19-2010, 03:19 PM
Are you sure DM is not Deutsch Mark?

MuellerNick
04-19-2010, 03:23 PM
Are you sure DM is not Deutsch Mark?

No, I'm absolutely NOT sure. DM is Deutsche Mark. But that currency no longer exists. (Like Lira, Franc, Schilling, Peseta, ...)

2 DM were/are 1 € almost accurately. I think it was something like 1.97whatever


Nick

juergenwt
04-19-2010, 03:40 PM
Careful with those Newtons. Now, 2.248 lbs x 900 (red line) would be 2023lbs.

There are Newtons and there are Newtons.
Loads (force) are indicated in Newtons.
1N = 3.6oz
Strength (pressure) is indicated in Newtons per mm2.
1N/mm2 = 145 psi

Sealing torques are indicated in Newton meters.
1Nm = 9 in lb.
All has to do with space and gravity.
The old units did not work in space and on earth they were not exact enough.
Example: Difference of gravity between North Pole and Equator = 0.3%.
Between Seattle an Miami = 0.2%
One really longs for the good old days.

MuellerNick
04-19-2010, 04:14 PM
There are Newtons and there are Newtons.

No, there's only one Newton. It has only one single meaning. It is force, nothing else.
That was a joke when I wrote that you'd have to convert it to some weight.


The old units did not work in space and on earth they were not exact enough.

Nonono! You people of US of A will never learn that.
Before the Newton, there was the kp (kilo-Pond). That was exactly the force one kg (kilogram) made at exactly 9.81 m/s^2.
You call that "kgf". :mad: But that unit doesn't exist, it's an illegal construction. Twofold illegal. Because it is dependent of acceleration. "kg" exists, "f" exists and is a factor (femto). But factors do have to be leading the units. So this would be "fkg". Which also is nonsense, because it contains two factors. Femto and Kilo. And you can only have one factor in front of the units.


Nick

juergenwt
04-19-2010, 04:59 PM
Nick - we understand there is just one Newton and the use for force, pressure and torque is not hard to understand if you are working in the metric system like the rest of the world. Here it's a different story and I am hoping for a fast change to metric. You see, in most cases we have to convert to inch/pound or foot/pound or PSI etc. and that can be a real disaster if you don't know if you are working with Newton/mm2 or Newton meter. Large Industries have all changed to metric but the small local supplier is having a hard time as you can tell by reading this forum.
Here Newton/mm2 are referred to mostly as mega pascal. Most of us wish we would have changed over 20 years ago, but that was not to be.
Thanks for your answers.