Die cast?

rockyhorror1297 · 05-29-2023, 12:14 PM

Hello! I recently made a post wondering why you don’t tend to see film cameras rust. I got a lot of great responses and learned a lot but there was still differing opinions on what metal was used for the actual body and chassis of the camera. Not talking about the top and bottom plates which tend to be brass but the actual main frame of the camera body. In this specific case I’m talking about the Pentax KM. I’ve heard from a repair person that die cast was used to make the body, and from what I’ve seen that seems to be the answer. I don’t know alot about die casting but I know steel isn’t commonly used so I’m guessing it’s aluminum. If anyone has anything to add or has a different answer, please let me know. Thanks everyone

Attached Images

**UncleVanya** · 05-29-2023, 12:54 PM - **1 Like**

It could be a lot of different formulations. Here’s a wiki article that talks about what might be likely:

Die casting - Wikipedia

rockyhorror1297 · 05-29-2023, 01:08 PM

Originally posted by UncleVanya

It could be a lot of different formulations. Here’s a wiki article that talks about what might be likely:

Die casting - Wikipedia

Would you say it is die cast though?

**UncleVanya** · 05-29-2023, 01:16 PM

Originally posted by rockyhorror1297

Would you say it is die cast though?

It does look like it. It doesn’t look machined. Also the article mentioned that the cost of startup is high but well suited to large volume production as the incremental costs are low.

**TwoUptons** · 05-29-2023, 03:35 PM

I've always assumed that many camera bodies were made by casting of what I always called "pot metal", which were relatively inexpensive metals to work with.

The origin of the term (according to Wikipedia) is the automotive industry, where it referred to whatever metals were "thrown into the pot" to be turned into castings.

I don't think the camera metals are nearly as haphazard, but I do think they are blends specifically chosen to make them amenable to casting, so not much iron... but probably more aluminum, zinc, etc. The K1 is magnesium, and I think also cast, so maybe some of that in the historical record as well...

But a lot of camera frames I've seen have something of a more coarse finish to the surfaces, so maybe not die cast, maybe something a little less precise, with flat spots and contact points machined later into the frame, though the guts of your KM sure look smooth...

-Eric

rockyhorror1297 · 05-29-2023, 03:37 PM

Originally posted by TwoUptons

I've always assumed that many camera bodies were made by casting of what I always called "pot metal", which were relatively inexpensive metals to work with.

The origin of the term (according to Wikipedia) is the automotive industry, where it referred to whatever metals were "thrown into the pot" to be turned into castings.

I don't think the camera metals are nearly as haphazard, but I do think they are blends specifically chosen to make them amenable to casting, so not much iron... but probably more aluminum, zinc, etc. The K1 is magnesium, and I think also cast, so maybe some of that in the historical record as well...

But a lot of camera frames I've seen have something of a more coarse finish to the surfaces, so maybe not die cast, maybe something a little less precise, with flat spots and contact points machined later into the frame, though the guts of your KM sure look smooth...

-Eric

Are you the same Eric that does repairs?

**TwoUptons** · 05-29-2023, 03:44 PM - **1 Like**

Originally posted by rockyhorror1297

Are you the same Eric that does repairs?

Ha. No. I am the Eric who breaks things

You're looking for Eric Hendrickson, I think, who used to post here occasionally, but his information is around somewhere...
https://pentaxs.com

-Eric

Last edited by TwoUptons; 05-29-2023 at 03:46 PM. Reason: Found the link...

rockyhorror1297 · 05-29-2023, 03:50 PM

Originally posted by TwoUptons

Ha. No. I am the Eric who breaks things

You're looking for Eric Hendrickson, I think, who used to post here occasionally, but his information is around somewhere...
Home-Pentaxs

-Eric

Ah okay! He repaired my KM last year. He does great work

hcarvalhoalves · 05-29-2023, 06:02 PM

Aluminum oxidation creates white streaks, do you see that? If not, I would guess it’s some zinc alloy, which is the second best option behind magnesium, since they didn’t advertise magnesium construction at the time.

**GUB** · 05-29-2023, 09:33 PM

I found a surprisingly relevant article while thinking about this thread.
https://www.sunrise-metal.com/aluminum-die-casting-vs-magnesium-die-casting/
It isn't all in favour of Magnesium.

titrisol · 05-30-2023, 05:35 AM

Spotmatics were made with an aluminum alloy as per Asahi literature of the time.
My guess is that it will have Al, Fe as main components, with some Mg and/or Mo for machinability.

The K series are probably made of the same or a more advanced alloy, as the Japanese industry advanced tremendously in those years, and they shared information between industries

If anybody knows it would be Gerjan Van Oosten (Argos in forums)

05-29-2023, 12:14 PM	#1
rockyhorror1297 New Member Join Date: Mar 2022 Posts: 21	Die cast? Hello! I recently made a post wondering why you don’t tend to see film cameras rust. I got a lot of great responses and learned a lot but there was still differing opinions on what metal was used for the actual body and chassis of the camera. Not talking about the top and bottom plates which tend to be brass but the actual main frame of the camera body. In this specific case I’m talking about the Pentax KM. I’ve heard from a repair person that die cast was used to make the body, and from what I’ve seen that seems to be the answer. I don’t know alot about die casting but I know steel isn’t commonly used so I’m guessing it’s aluminum. If anyone has anything to add or has a different answer, please let me know. Thanks everyone Attached Images

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05-29-2023, 12:54 PM - 1 Like	#2
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,401	It could be a lot of different formulations. Here’s a wiki article that talks about what might be likely: Die casting - Wikipedia

05-29-2023, 01:08 PM	#3
rockyhorror1297 New Member Join Date: Mar 2022 Posts: 21 Original Poster	Originally posted by UncleVanya It could be a lot of different formulations. Here’s a wiki article that talks about what might be likely: Die casting - Wikipedia Would you say it is die cast though?

05-29-2023, 01:16 PM	#4
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,401	Originally posted by rockyhorror1297 Would you say it is die cast though? It does look like it. It doesn’t look machined. Also the article mentioned that the cost of startup is high but well suited to large volume production as the incremental costs are low.

05-29-2023, 03:35 PM	#5
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,213	I've always assumed that many camera bodies were made by casting of what I always called "pot metal", which were relatively inexpensive metals to work with. The origin of the term (according to Wikipedia) is the automotive industry, where it referred to whatever metals were "thrown into the pot" to be turned into castings. I don't think the camera metals are nearly as haphazard, but I do think they are blends specifically chosen to make them amenable to casting, so not much iron... but probably more aluminum, zinc, etc. The K1 is magnesium, and I think also cast, so maybe some of that in the historical record as well... But a lot of camera frames I've seen have something of a more coarse finish to the surfaces, so maybe not die cast, maybe something a little less precise, with flat spots and contact points machined later into the frame, though the guts of your KM sure look smooth... -Eric

05-29-2023, 03:37 PM	#6
rockyhorror1297 New Member Join Date: Mar 2022 Posts: 21 Original Poster	Originally posted by TwoUptons I've always assumed that many camera bodies were made by casting of what I always called "pot metal", which were relatively inexpensive metals to work with. The origin of the term (according to Wikipedia) is the automotive industry, where it referred to whatever metals were "thrown into the pot" to be turned into castings. I don't think the camera metals are nearly as haphazard, but I do think they are blends specifically chosen to make them amenable to casting, so not much iron... but probably more aluminum, zinc, etc. The K1 is magnesium, and I think also cast, so maybe some of that in the historical record as well... But a lot of camera frames I've seen have something of a more coarse finish to the surfaces, so maybe not die cast, maybe something a little less precise, with flat spots and contact points machined later into the frame, though the guts of your KM sure look smooth... -Eric Are you the same Eric that does repairs?

05-29-2023, 03:44 PM - 1 Like	#7
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,213	Originally posted by rockyhorror1297 Are you the same Eric that does repairs? Ha. No. I am the Eric who breaks things You're looking for Eric Hendrickson, I think, who used to post here occasionally, but his information is around somewhere... https://pentaxs.com -Eric Last edited by TwoUptons; 05-29-2023 at 03:46 PM. Reason: Found the link...

05-29-2023, 03:50 PM	#8
rockyhorror1297 New Member Join Date: Mar 2022 Posts: 21 Original Poster	Originally posted by TwoUptons Ha. No. I am the Eric who breaks things You're looking for Eric Hendrickson, I think, who used to post here occasionally, but his information is around somewhere... Home-Pentaxs -Eric Ah okay! He repaired my KM last year. He does great work

05-29-2023, 06:02 PM	#9
hcarvalhoalves Pentaxian Join Date: Aug 2010 Location: São Paulo, Brazil Photos: Gallery Posts: 1,019	Aluminum oxidation creates white streaks, do you see that? If not, I would guess it’s some zinc alloy, which is the second best option behind magnesium, since they didn’t advertise magnesium construction at the time.

05-29-2023, 09:33 PM	#10
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	I found a surprisingly relevant article while thinking about this thread. https://www.sunrise-metal.com/aluminum-die-casting-vs-magnesium-die-casting/ It isn't all in favour of Magnesium.

05-30-2023, 05:35 AM	#11
titrisol Pentaxian Join Date: Dec 2007 Location: In the most populated state... state of denial Photos: Gallery \| Albums Posts: 1,852	Spotmatics were made with an aluminum alloy as per Asahi literature of the time. My guess is that it will have Al, Fe as main components, with some Mg and/or Mo for machinability. The K series are probably made of the same or a more advanced alloy, as the Japanese industry advanced tremendously in those years, and they shared information between industries If anybody knows it would be Gerjan Van Oosten (Argos in forums)