Lammas hardness tester

[Piet VermaatParticipant @pietvermaat68506]

Rod Jenkins wrote about the construction of the Lammas hardness tester in MEW no 245. He mentions a double lever multiplying the force 24 x.

Could someone please explain how that works?

Thanks.

PV

[Piet VermaatParticipant @pietvermaat68506]

double lever system

[Brian WoodParticipant @brianwood45127]

Hello Piet,

​I don't know the specifics with this design, but it is very probably the same as the method used on hardness testers generally.

In those, it is quite simply the effects of leverage of a weight, in this case of 5 kg, acting on a pivoted bar with a ratio of 24:1 from the fulcrum point. The known weight (5kg) is at the long end of the bar and the ratio multiplies its effect at the shorter end by 24 times

Regards Brian

[Roderick JenkinsParticipant @roderickjenkins93242]

Piet,

Here is a diagram of the mechanism

The first lever gives a 3x multiplication of the force to 15kg. The second lever has a 8:1 ratio so multiplies the 15kg x 8 to give a force at the indentor of 120kg.

Hope this helps,

Rod

[Piet VermaatParticipant @pietvermaat68506]

Thank you Brian and Roderick for the explanation.

PV

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