Certina Diamaster

In 1975, Certina presented the Diamaster. The special feature was the scratchproof sapphire glass and the tungsten carbide case, which came from Rado. Rado itself used this case for the Diastar models. To produce the case, tungsten and titanium carbide with cobalt or nickel powder were first pulverized, the mixture pressed and pre-sintered at a temperature of 1000°C. Then the blanks were moulded into the final shape and finally sintered at 1400°C. The case volume shrank by 30%, which gave the alloy its high hardness of 8.5 on the Mohs scale. Finally, the cases were ground and polished with diamond.
The Diamaster models were available with three different types of movement. As an automatic, first apparently with the 25-651, then with the self-winding 919-1, next with the tuning fork 29-152 movement, and as a quartz version. Furthermore, you could choose from among three different case colours (white, yellow or aubergine). So there were a total of 26 different models from which to choose. In addition to the men’s versions, smaller women’s models were also available.

One of the most beautiful models would certainly be the Diamaster with the tiger’s eye stone dial, which you can see in the overview below.
In May 1976, during his visit to Munich, the then-reigning World Heavyweight Champion Muhammad Ali was chosen to be a Certina product ambassador. He was presented with a Diamaster, as you can see in the article appearing in Certina’s company magazine, “Echo” (Oct. 76 issue).

In 1977, a new version of the Diamaster, with a redesigned case, came onto the market. This model was available in automatic and quartz versions.

Model	Reference no.	Calibre	Dimensions mm	Comments
Diamaster Automatic	913 1230 31	Certina 25-651 Certina 919-1	D: 40 H: 14	Various dial versions, partially without Rado logo. Scratchproof tungsten carbide case from Rado Water resistant to 220 metres From 1975
Diamaster C-Tronic (Tuning Fork)	742 1240 31	Certina 29-152 ESA 9164	D: 40 H: 14	Various dial versions, partially without Rado logo. Scratchproof tungsten carbide case from Rado Water resistant to 220 metres From 1975
Diamaster Quartz	913 1230 31	Certina 29-252 ESA 9181	D: 40 H: 14	Various dial versions, partially without Rado logo. Scratchproof tungsten carbide case from Rado Water resistant to 220 metres From 1975

	Model	Reference no.	Calibre	Dimensions mm	Comments
	Diamaster Automatic	n.b.	Certina 25-032 ETA 2789	35 x 42 x 13	Quickset day and date Various dial versions Scratchproof tungsten carbide case from Rado From 1977?
	Diamaster Quartz	n.b.	n.b.	35 x 42 x 13	Various dial versions Scratchproof tungsten carbide case from Rado From 1977?

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