Reply To: High Tensile Steel Question

[SillyOldDufferModerator @sillyoldduffer]

Posted by Hopper on 27/12/2022 12:44:59:

Posted by SillyOldDuffer on 27/12/2022 12:29:25:

…

Not done the sums because the weight has to be CAD extracted…

 

CAD extracted? CAD extracted? Does nobody know how to do back-of-fag-packet geometry anymore?

We know from the drawing the main radius on the counterweight is 3 3/4" so we can calculate the area of a circle with that radius then halve it. Then deduct the square cutout in the middle that is 2 1/2 x 1 1/4". Then knock off maybe 10 per cent for those rounded corners with the smaller radius as a guesstimate. (or simply leave it on as a safety factor). Then multiply by the 1" thickness to give us the total volume in cubic inches. Then multiply by weight of material per cubic inch which is readily available. Simples. But it's 11pm here so I'm off to bed and leave you to it.

CAD extracted indeed.

I have no shame!

All in favour of 'weight of a round cow' estimates, but the counter-balance shape is more complicated than Hopper's simplification, and once the model is created the CAD package does all the necessary maths.

Assuming I drew it correctly the weight is:

Told the material is StCst10 GOST 1412-85 cast-iron, Solid Edge says the mass is 2.086kg and the volume 306741 cubic mm.

The centre of mass is shown by the purple dot. It's at coordinates X=0, Y=-17.04mm, Z=-12.70mm

Dave

PS.  Duncan got did first while I was typing.  Relieved to see our weights are within 200g.  The difference is because we've drawn the weight differently.  One or both of us has misinterpreted the 2D drawing – I expect it's me…

Edited By SillyOldDuffer on 27/12/2022 16:05:03

Edited By SillyOldDuffer on 27/12/2022 16:09:47