7 ms·

I'd be interested to know how BMW manufactures those screws. The patterns in the metal in the image suggest the entire hole was drilled out? The deepest part ha

I'd be interested to know how BMW manufactures those screws. The patterns in the metal in the image suggest the entire hole was drilled out? The deepest part has circular marks inside that looks like the marks left by a facing tool on a lathe or similar. Then I guess the two wedges were inserted and the whole screw faced?

gloxkiqcza 8mo ago
The head was almost certainly milled out of a blank made on a lathe. Something like this: https://youtube.com/shorts/Yf-twqgWZQ8 https://youtube.com/shorts/Yf-twqgWZQ8
ROOFLES 8mo ago
CNC Milled and suface brushed. I Think these screws are going to be used in some decorative Panels etc. Would be cost prohibitive to use these all over the Car.
- cucumber3732842 8mo ago
  This. It's obviously an interior fastener. Maybe they'll have a cheaper one without the logo for the airbag module or whatever. OEMs have spent untold sums over the year hiding interior trim fasteners using all manner of push and snap fittings. A few low trim vehicles have bucked that trend recently, to much savings of labor and tool/die cost and no apparent ill effect in the mind of consumers. And now everybody is testing the waters.
jacquesm 8mo ago
Those are end mill marks.
- cucumber3732842 8mo ago
  Nearly zero chance of them doing that at production volumes though.
  - jacquesm 8mo ago
    Why not? A properly set up CNC machining center would turn those out by the bucketload. That's precisely the sort of thing that BMW does regularly with exterior details, no reason why they couldn't do it for a batch of bolts.
    - cucumber3732842 8mo ago
      You can make anything on anything. Doesn't make it smart tho. If this were a production run of a few dozen super high grade aerospace donkey dicks with five shoulders and four pockets, an oil channel, a precisely engineered break point and a 12-step heat treat process I'd say yeah, make it on your Swiss lathe with live tooling or bajillion axis VMC or whatever. But this looks to be a simple small, probably cosmetic or otherwise low-ish strength stainless or chromed fastener that BMW probably wants a few hundred thousand of. You'll be time, money, labor, frustration, managerial nitpicking, just about everything, ahead to just have the fastener industry and their existing expertise make it for you. The "bespoke" drive, the custom branding, those are all known-knowns to those guys. They'll whip up tooling for their screw machines and fill the same bucket in 1/20th of the time. https://www.youtube.com/watch?v=WJvQZko8uiU https://www.youtube.com/watch?v=WJvQZko8uiU Edit: replaced video link with better one. Obviously there's fiddle fucking around they're not showing and they're mix and matching footage of different products but the speed things move once you've got it all set up is broadly accurate. A whole bunch of these steps would be skipped or altered for a stainless fastener.
      - jacquesm 8mo ago
        I know how just about every fastener is made. I also know how to look for toolmarks on the work product and I guarantee you that the bolt in TFA was made by machining rather than by stamping. Because this is a marketing instrument, not just a fastener.
        cucumber3732842 8mo ago
        I'd be unsurprised if they photographed a the pre-production one that was milled. They will almost certainly not be making the bulk of them that way. It just doesn't make sense in any way. At minimum order qualities in the tens of thousands (which they will certainly exceed) it makes sense to sub out to specialists.
torginus 8mo ago
I don't see any geometry that would be hard for casting or milling, it's slightly more expensive because you can't do it in one go, but you have to lift the toolhead if you mill.
- shmeeed 8mo ago
  Screws aren't cast. And lifting the toolhead takes about .1 second. What's expensive here is milling this screw head at all, and in particular the surface finish. This is probably just a prototype for shows, though. At scale, screws heads are usually cold-formed, and this design would work for that, too. If you circular brush the head in the end, you'd get pretty close to this, even if you wouldn't get the finish in the pockets. But that doesn't make much sense there anyway, it'd get damaged by the fastening tool.
buildsjets 8mo ago
Unlike all the other guesses here, I actually do have experience with manufacturing specialty aerospace fasteners similar in size, shape, complexity, and precision as these. These are most assuredly being manufactured on a specialty tool called a “Swissing Lathe”, or Swiss CNC machine, because that is the machine you always use to make parts like this. It is a multi-headed turret mill combined with a lathe that can continuously feed a piece of long bar stock and continually spit out fasteners. They were invented many years ago to produce extremely high precision small screws for watches, and in fact Citizen is one of the main vendors of these tools to this day. Based on my experience I would expect the cycle time for making this part to be 30 seconds or so. Here’s a good video that eli5’s the difference between a Swiss screw machine and conventional CNC. https://youtu.be/y3y0tATB0lg?si=pkYDT3BV0-6C-aq5 https://youtu.be/y3y0tATB0lg?si=pkYDT3BV0-6C-aq5 And here’s a video with a high quality soundtrack that shows how the machine combines automatic lathe cuts, mill cuts, and thread rolling without changing machines, swapping cutters, or re-fixturing the work. https://youtu.be/MPAK5I1HJAw?si=fnMmjDp6ydYSDbfH https://youtu.be/MPAK5I1HJAw?si=fnMmjDp6ydYSDbfH And if you need some specialty fasteners made and have an unlimited budget I can reccomed these folks. https://centrix-us.com/ https://centrix-us.com/
utf_8x 8mo ago
For prototypes, almost certainly with a CNC lathe. For a large scale production, I would expect them to drop forge these...
MisterTea 8mo ago
The prototypes might be milled and/or produced via additive manufacturing (3D printing.) In production the heads are likely formed via stamping. Here's an old video I remember watching as a kid (Unfortunately quite pixelated) of the Robertson screw being manufactured which has a tapered square profile for the bit: https://www.youtube.com/watch?v=Td7GjAMAY7Y https://www.youtube.com/watch?v=Td7GjAMAY7Y (The Acme School of Stuff was awesome for its time and still is.)

gloxkiqcza 8mo ago

The head was almost certainly milled out of a blank made on a lathe. Something like this: https://youtube.com/shorts/Yf-twqgWZQ8 https://youtube.com/shorts/Yf-twqgWZQ8

ROOFLES 8mo ago

CNC Milled and suface brushed. I Think these screws are going to be used in some decorative Panels etc. Would be cost prohibitive to use these all over the Car.

cucumber3732842 8mo ago
This. It's obviously an interior fastener. Maybe they'll have a cheaper one without the logo for the airbag module or whatever. OEMs have spent untold sums over the year hiding interior trim fasteners using all manner of push and snap fittings. A few low trim vehicles have bucked that trend recently, to much savings of labor and tool/die cost and no apparent ill effect in the mind of consumers. And now everybody is testing the waters.

jacquesm 8mo ago

Those are end mill marks.

cucumber3732842 8mo ago
Nearly zero chance of them doing that at production volumes though.
- jacquesm 8mo ago
  Why not? A properly set up CNC machining center would turn those out by the bucketload. That's precisely the sort of thing that BMW does regularly with exterior details, no reason why they couldn't do it for a batch of bolts.
  - cucumber3732842 8mo ago
    You can make anything on anything. Doesn't make it smart tho. If this were a production run of a few dozen super high grade aerospace donkey dicks with five shoulders and four pockets, an oil channel, a precisely engineered break point and a 12-step heat treat process I'd say yeah, make it on your Swiss lathe with live tooling or bajillion axis VMC or whatever. But this looks to be a simple small, probably cosmetic or otherwise low-ish strength stainless or chromed fastener that BMW probably wants a few hundred thousand of. You'll be time, money, labor, frustration, managerial nitpicking, just about everything, ahead to just have the fastener industry and their existing expertise make it for you. The "bespoke" drive, the custom branding, those are all known-knowns to those guys. They'll whip up tooling for their screw machines and fill the same bucket in 1/20th of the time. https://www.youtube.com/watch?v=WJvQZko8uiU https://www.youtube.com/watch?v=WJvQZko8uiU Edit: replaced video link with better one. Obviously there's fiddle fucking around they're not showing and they're mix and matching footage of different products but the speed things move once you've got it all set up is broadly accurate. A whole bunch of these steps would be skipped or altered for a stainless fastener.
    - jacquesm 8mo ago
      I know how just about every fastener is made. I also know how to look for toolmarks on the work product and I guarantee you that the bolt in TFA was made by machining rather than by stamping. Because this is a marketing instrument, not just a fastener.
      - cucumber3732842 8mo ago
        I'd be unsurprised if they photographed a the pre-production one that was milled. They will almost certainly not be making the bulk of them that way. It just doesn't make sense in any way. At minimum order qualities in the tens of thousands (which they will certainly exceed) it makes sense to sub out to specialists.

torginus 8mo ago

I don't see any geometry that would be hard for casting or milling, it's slightly more expensive because you can't do it in one go, but you have to lift the toolhead if you mill.

shmeeed 8mo ago
Screws aren't cast. And lifting the toolhead takes about .1 second. What's expensive here is milling this screw head at all, and in particular the surface finish. This is probably just a prototype for shows, though. At scale, screws heads are usually cold-formed, and this design would work for that, too. If you circular brush the head in the end, you'd get pretty close to this, even if you wouldn't get the finish in the pockets. But that doesn't make much sense there anyway, it'd get damaged by the fastening tool.

buildsjets 8mo ago

Unlike all the other guesses here, I actually do have experience with manufacturing specialty aerospace fasteners similar in size, shape, complexity, and precision as these. These are most assuredly being manufactured on a specialty tool called a “Swissing Lathe”, or Swiss CNC machine, because that is the machine you always use to make parts like this. It is a multi-headed turret mill combined with a lathe that can continuously feed a piece of long bar stock and continually spit out fasteners. They were invented many years ago to produce extremely high precision small screws for watches, and in fact Citizen is one of the main vendors of these tools to this day. Based on my experience I would expect the cycle time for making this part to be 30 seconds or so. Here’s a good video that eli5’s the difference between a Swiss screw machine and conventional CNC. https://youtu.be/y3y0tATB0lg?si=pkYDT3BV0-6C-aq5 https://youtu.be/y3y0tATB0lg?si=pkYDT3BV0-6C-aq5 And here’s a video with a high quality soundtrack that shows how the machine combines automatic lathe cuts, mill cuts, and thread rolling without changing machines, swapping cutters, or re-fixturing the work. https://youtu.be/MPAK5I1HJAw?si=fnMmjDp6ydYSDbfH https://youtu.be/MPAK5I1HJAw?si=fnMmjDp6ydYSDbfH And if you need some specialty fasteners made and have an unlimited budget I can reccomed these folks. https://centrix-us.com/ https://centrix-us.com/

utf_8x 8mo ago

For prototypes, almost certainly with a CNC lathe. For a large scale production, I would expect them to drop forge these...

MisterTea 8mo ago

The prototypes might be milled and/or produced via additive manufacturing (3D printing.) In production the heads are likely formed via stamping. Here's an old video I remember watching as a kid (Unfortunately quite pixelated) of the Robertson screw being manufactured which has a tapered square profile for the bit: https://www.youtube.com/watch?v=Td7GjAMAY7Y https://www.youtube.com/watch?v=Td7GjAMAY7Y (The Acme School of Stuff was awesome for its time and still is.)