stamped vs machined – any tells?

Come on in and introduce yourself!
General watch talk.
Post Reply
User avatar
dinexus
Posts: 1246
Joined: Sat Jun 06, 2015 11:22 pm
Name: Zach
Location: Marin

stamped vs machined – any tells?

Post by dinexus » Tue Jan 02, 2018 10:55 am

Apologies in advance for the wussy topic, but I figured I'd get better informed or more interesting responses here. Comment on the 'dink over the holiday had me wondering, as someone mentioned that "you can tell" that the watch in question had a stamped case, which explained why it was cheaper. Are there really visual tells that indicate a case has been stamped rather than machined? I'd always thought this was something you couldn't really see until it was in-hand, where you can get a better feel for the tolerances and weight.

Watch in question was the Captain Cook:

Image

PS: Happy New Year, BOD.

User avatar
JP Chestnut
Posts: 17820
Joined: Mon May 27, 2013 10:40 am
Name: Jacob
Location: Ithaca, NY USA

Re: stamped vs machined – any tells?

Post by JP Chestnut » Tue Jan 02, 2018 11:12 am

Hoedicky sucks, so I doubt they know what they're talking about. However, you can actually tell the difference between a forged metal part and one machined out of billet. Forged parts have metal grains which take on something of the direction of the part itself. Whereas billet parts have uniform grains. This occurs even when the forged part is machined to exact size post forging.

It's also why forged parts are often stronger in certain applications than ones that are made from a billet.

User avatar
ericf4
(TBD) Penis
Posts: 15614
Joined: Wed Dec 02, 2009 6:04 am
Contact:

Re: stamped vs machined – any tells?

Post by ericf4 » Tue Jan 02, 2018 11:22 am

one tell tale sign is if you see the Bagelsport logo on it, or if it ever appeared as a TWong post in the WRUW thread.
Visit my Music/Drumming Channel at:

https://youtube.com/ericfeuer

User avatar
Ryeguy
Posts: 5519
Joined: Fri Sep 09, 2011 1:03 pm
Name: Chris
Location: Rye

Re: stamped vs machined – any tells?

Post by Ryeguy » Tue Jan 02, 2018 11:43 am

My guess is most watch cases are actually both stamped and machined. This would be especially true for micros.

The reason I say this is stamping machines are expensive, as are the dies used by the presses. Dies are also specific to the design and are expensive to create. In contrast, multi-axis machine tools are relatively cheap.

My guess is most watch manufacturers start out with case "blanks", by which I mean roughly watch case shaped blocks of steel which can then be machined into the final case shape without too much waste steel.

This way you can create a single die and stamp out thousands of blanks as inventory items. You can later machine these blanks into a variety of case variants.

I'd bet in the Chinese / micro (I know - redundant) watch business, you'd find a multi-tiered supply system. One manufacturer might specialize in just the supply of stamped case blanks. They in turn sell these blanks to the case manufacturer the brand owner deals with. The blanks provide the limits of the case design parameters and the case manufacturer builds their catalogue of available case designs from the case blanks they have available to them.

User avatar
Ryeguy
Posts: 5519
Joined: Fri Sep 09, 2011 1:03 pm
Name: Chris
Location: Rye

Re: stamped vs machined – any tells?

Post by Ryeguy » Tue Jan 02, 2018 11:52 am

To add, here is how Breitling states they produce their cases, which is roughly what I state above: https://www.breitling.com/en/madeby/case-2637/

They begin with stamping and swaging, then move to machining. The higher the volume of the case design (Rolex Oyster, for example, with millions of units produced per year) the more cost effective stamping and swaging are.

The lower the volume of the case design (500 or less unit micro, for example) the less stamping is likely used and the more machining is leveraged.

For example, this is an image Eddie Platts posted years ago of the case blank used for one of his watches:
Image

User avatar
JP Chestnut
Posts: 17820
Joined: Mon May 27, 2013 10:40 am
Name: Jacob
Location: Ithaca, NY USA

Re: stamped vs machined – any tells?

Post by JP Chestnut » Tue Jan 02, 2018 12:33 pm

Ryeguy wrote:
Tue Jan 02, 2018 11:52 am
To add, here is how Breitling states they produce their cases, which is roughly what I state above: https://www.breitling.com/en/madeby/case-2637/

They begin with stamping and swaging, then move to machining. The higher the volume of the case design (Rolex Oyster, for example, with millions of units produced per year) the more cost effective stamping and swaging are.

The lower the volume of the case design (500 or less unit micro, for example) the less stamping is likely used and the more machining is leveraged.

For example, this is an image Eddie Platts posted years ago of the case blank used for one of his watches:
Image
But is that forged (e.g., I guess what someone might call "stamped") or is it simply cast off a mold? I think it's cast with zero pressure applied anywhere.

User avatar
JP Chestnut
Posts: 17820
Joined: Mon May 27, 2013 10:40 am
Name: Jacob
Location: Ithaca, NY USA

Re: stamped vs machined – any tells?

Post by JP Chestnut » Tue Jan 02, 2018 1:11 pm

It's basically how the rougher thing is created that's the difference.

If you have a mold of that thing which you pour liquid metal into, that's cast. I don't think there's a single application where that's a desirable way to make something. Here's a broken cast crankshaft
Image
If you looked at the break point under a microscope it would look rough and shitty.

Alternately, you can poor liquid metal into a generic mold, like a cube. Once the cube cools you can apply pressure, which changes the molecular composition of the material.

Did you apply pressure and create a generic shape? Say another cube? If you machine that cube into a something, you (or at least I and the people I know) would call that machined part a "billet part".

Did you apply pressure to create a shape that mimics the shape that the part will eventually be? Then it's a rough forging. You then machine the part to size and it results in a forged part. Here's a rough forged crank and one after finished machining
Image

Here are some differences
Image

The billet part probably wouldn't look different than a forged one, unless you looked at the metal grains under magnification. Forged tends to be stronger since the grains align in a way that's consistent with the part's eventual shape, whereas billet is uniform throughout. Does it matter for watch cases? Functionally, probably not. However, when you pay $10,000 for a useless luxury trinket it should be made GD right.

User avatar
Ryeguy
Posts: 5519
Joined: Fri Sep 09, 2011 1:03 pm
Name: Chris
Location: Rye

Re: stamped vs machined – any tells?

Post by Ryeguy » Tue Jan 02, 2018 1:14 pm

JP Chestnut wrote:
Tue Jan 02, 2018 12:33 pm
Ryeguy wrote:
Tue Jan 02, 2018 11:52 am
To add, here is how Breitling states they produce their cases, which is roughly what I state above: https://www.breitling.com/en/madeby/case-2637/

They begin with stamping and swaging, then move to machining. The higher the volume of the case design (Rolex Oyster, for example, with millions of units produced per year) the more cost effective stamping and swaging are.

The lower the volume of the case design (500 or less unit micro, for example) the less stamping is likely used and the more machining is leveraged.

For example, this is an image Eddie Platts posted years ago of the case blank used for one of his watches:
Image
But is that forged (e.g., I guess what someone might call "stamped") or is it simply cast off a mold? I think it's cast with zero pressure applied anywhere.
You are correct - that blank could likely be a mold.

I would think molding the case would be even less expensive than stamping.

Just to add - a watch case is not a stressed part such as a crank shaft.

Is a forged part or machined from billet part "better" than an investment cast part? I don't know... I guess the answer is "maybe".

You can mold and machine a watch case that'll be shiny and pleasant to look at, plus be more water resistant than realistically necessary.

You can forge (swage) a watch case such as done by Breitling, and that case will be "better", but is the advantage going to be in any way recognized by a user in real life?

User avatar
dinexus
Posts: 1246
Joined: Sat Jun 06, 2015 11:22 pm
Name: Zach
Location: Marin

Re: stamped vs machined – any tells?

Post by dinexus » Tue Jan 02, 2018 1:38 pm

Damn fellas, this is super interesting. The punchline that I'm getting outta this though, is that visually speaking, there isn't really a way to tell just from looking at a case (unless you were maybe scrutinizing the grain of an unfinished one through a loupe), right? 'Dink gone misleading again.

Bremont's been pretty open about their case manufacture – steel rods from Norway that are cut, machined, and polished at Silverstone. I'm assuming the steel in rod-form didn't come out of a mold or a cast? That inherently means it yields a stronger finished product?

Image

User avatar
BacoNoir
Posts: 6396
Joined: Tue May 10, 2016 6:33 pm
Name: Roger
Location: Colorado

Re: stamped vs machined – any tells?

Post by BacoNoir » Tue Jan 02, 2018 1:45 pm

You won’t even be able to tell with a loupe unless you are looking at a broken piece. We are talking about microscopic level inspection and even then you’re going to have to prepare the material (grind, polish, acid etch) to remove the texture (brushing, bead blasting, high polish) to reveal the grain structure.
www.simplynoble.net
Time Magazine Person of the Year - 2006

Image

User avatar
BacoNoir
Posts: 6396
Joined: Tue May 10, 2016 6:33 pm
Name: Roger
Location: Colorado

Re: stamped vs machined – any tells?

Post by BacoNoir » Tue Jan 02, 2018 1:47 pm

dinexus wrote:Damn fellas, this is super interesting. The punchline that I'm getting outta this though, is that visually speaking, there isn't really a way to tell just from looking at a case (unless you were maybe scrutinizing the grain of an unfinished one through a loupe), right? 'Dink gone misleading again.

Bremont's been pretty open about their case manufacture – steel rods from Norway that are cut, machined, and polished at Silverstone. I'm assuming the steel in rod-form didn't come out of a mold or a cast? That inherently means it yields a stronger finished product?

Image
Round bar stock is likely extruded and heat treated to the client specifications before it gets delivered.
www.simplynoble.net
Time Magazine Person of the Year - 2006

Image

User avatar
Ryeguy
Posts: 5519
Joined: Fri Sep 09, 2011 1:03 pm
Name: Chris
Location: Rye

Re: stamped vs machined – any tells?

Post by Ryeguy » Tue Jan 02, 2018 1:53 pm

Rod is typically drawn / swaged. Imagine a big block of steel being pulled by big motors through gradually reduced sized dies.

Rod mills are pretty impressive (and dangerous) places to see. The rod increases velocity as it passes through the dies. At the end of the mill there is typically a reel to coil up the rod. If that reel ever fails, imagine jumping on an uncapped tube of toothpaste, except instead of toothpaste, you have red hot steel rod.

Morgan Construction, in Worcester, MA, was a major manufacturer of steel rod mills.

Ruger Firearms was a leader in investment casting of firearms components.

User avatar
Ryeguy
Posts: 5519
Joined: Fri Sep 09, 2011 1:03 pm
Name: Chris
Location: Rye

Re: stamped vs machined – any tells?

Post by Ryeguy » Tue Jan 02, 2018 4:43 pm

Actually, the forged / stamped / milled case discussion is leaving out an important development - additive manufacturing. You can use metal additive manufacturing to create Ti or Stainless watch cases with no machining required.

Here are some case studies from an AM machine manufacturer, one of which is a custom watch maker: http://www.renishaw.com/en/additive-man ... ies--31460

Really cool stuff in my opinion, and potentially the next Renaissance of domestic watch making.

User avatar
toxicavenger
President Tranny
Posts: 48085
Joined: Fri Mar 12, 2010 8:25 am
Name: HeadDIK
Location: Colorado Springs

Re: stamped vs machined – any tells?

Post by toxicavenger » Tue Jan 02, 2018 7:24 pm

Ryeguy wrote:
Tue Jan 02, 2018 1:53 pm
Rod mills are pretty impressive (and dangerous) places to see. The rod increases velocity as it passes through the dies. At the end of the mill there is typically a reel to coil up the rod. If that reel ever fails, imagine jumping on an uncapped tube of toothpaste, except instead of toothpaste, you have red hot steel rod.

User avatar
dinexus
Posts: 1246
Joined: Sat Jun 06, 2015 11:22 pm
Name: Zach
Location: Marin

Re: stamped vs machined – any tells?

Post by dinexus » Tue Jan 02, 2018 8:21 pm

BacoNoir wrote:You won’t even be able to tell with a loupe unless you are looking at a broken piece. We are talking about microscopic level inspection and even then you’re going to have to prepare the material (grind, polish, acid etch) to remove the texture (brushing, bead blasting, high polish) to reveal the grain structure.
Guess I have my answer. Pretty awesome info in here though. Thanks!


Sent from my iPhone using Tapatalk

User avatar
Grahamcombat
Posts: 4314
Joined: Sun Aug 21, 2011 5:24 pm
Name: Graham

Re: stamped vs machined – any tells?

Post by Grahamcombat » Tue Jan 02, 2018 9:13 pm

toxicavenger wrote:
Ryeguy wrote:
Tue Jan 02, 2018 1:53 pm
Rod mills are pretty impressive (and dangerous) places to see. The rod increases velocity as it passes through the dies. At the end of the mill there is typically a reel to coil up the rod. If that reel ever fails, imagine jumping on an uncapped tube of toothpaste, except instead of toothpaste, you have red hot steel rod.
And THAT is why we can’t have any MKII’s.


Sent from my iPad using Tapatalk Pro

User avatar
dnslater
Posts: 6804
Joined: Mon Apr 25, 2011 6:52 pm
Name: Nick
Location: Indiana, USA

Re: stamped vs machined – any tells?

Post by dnslater » Wed Jan 03, 2018 3:31 am

Great info here Jacob! I do believe that the method of fabrication of the watch case is of little importance (forge vs cast vs machined) given that a wrist watch has no real major structural requirements (tensile, compressive, shear) other than resisting a little pressure and ensuring that the material is solid and free of voids. Finishing is really the key with luxury wrist watches. I can't recall of any instances where a steel wrist watch case actually broke under normal conditions that didn't involve Terry's Rolex.

User avatar
streetracer101
Posts: 8787
Joined: Tue Nov 15, 2011 6:41 pm
Name: Mr Shackleford

Re: stamped vs machined – any tells?

Post by streetracer101 » Wed Jan 03, 2018 4:43 am

dnslater wrote:Great info here Jacob! I do believe that the method of fabrication of the watch case is of little importance (forge vs cast vs machined) given that a wrist watch has no real major structural requirements (tensile, compressive, shear) other than resisting a little pressure and ensuring that the material is solid and free of voids. Finishing is really the key with luxury wrist watches. I can't recall of any instances where a steel wrist watch case actually broke under normal conditions that didn't involve Terry's Rolex.
Of more importance are the seals to ensure that they can withstand the pressure and fluids found in certain cavities.

Sent from my XT1585 using Tapatalk


User avatar
jeckyll
Honorary Assistant Jr. Hall Monitor in Training
Posts: 11910
Joined: Thu Feb 25, 2010 10:11 pm
Name: Björn

Re: stamped vs machined – any tells?

Post by jeckyll » Wed Jan 03, 2018 7:01 am

streetracer101 wrote:
Wed Jan 03, 2018 4:43 am
dnslater wrote:Great info here Jacob! I do believe that the method of fabrication of the watch case is of little importance (forge vs cast vs machined) given that a wrist watch has no real major structural requirements (tensile, compressive, shear) other than resisting a little pressure and ensuring that the material is solid and free of voids. Finishing is really the key with luxury wrist watches. I can't recall of any instances where a steel wrist watch case actually broke under normal conditions that didn't involve Terry's Rolex.
Of more importance are the seals to ensure that they can withstand the pressure and fluids found in certain cavities.

Sent from my XT1585 using Tapatalk
More the corrosiveness of the fluids I fear :gayumbrella:
We all have the same enemy. The enemy is the tyranny of the dull mind. - - Tom Robbins

User avatar
JP Chestnut
Posts: 17820
Joined: Mon May 27, 2013 10:40 am
Name: Jacob
Location: Ithaca, NY USA

Re: stamped vs machined – any tells?

Post by JP Chestnut » Wed Jan 03, 2018 9:32 am

dnslater wrote:
Wed Jan 03, 2018 3:31 am
Great info here Jacob! I do believe that the method of fabrication of the watch case is of little importance (forge vs cast vs machined) given that a wrist watch has no real major structural requirements (tensile, compressive, shear) other than resisting a little pressure and ensuring that the material is solid and free of voids. Finishing is really the key with luxury wrist watches. I can't recall of any instances where a steel wrist watch case actually broke under normal conditions that didn't involve Terry's Rolex.
I agree with you as far as metal cases go. However, all bets are off when it comes to composites. :thumbsup:

Post Reply

Who is online

Users browsing this forum: derekwilliams, Emeister, Google [Bot], mattcantwin, mellonb1, Panerai7 and 310 guests