I spent Sunday wiring up Scissorhands; the high current side is ready for testing. Its not so neat yet, however I ran out of heavy crimp trminals before everything was optimised (ie, the first try was a screw-up ). The terminals I like only seem to be available from RS Electronics (or possibly Farnell), even McMaster don't have them so its off to the RS trade counter later in the week. I also need more UMHW to make the roll-over hoops and Cut-To-Size plastics is in the same direction. After that, I hope to drop off the Ti sheet for waterjetting, making it a full-on build day.

I tried working out how much plastic the hoops might use mathematically; the rear hoop is roughly eliptical so I looked up a formula for the circumference of an elipsis. It turns out that this is totally impossible to calculate and mathematicains use integrals to apporximate the measurement. I gave up on that before my head exploded and will just have to make the hoop & weigh it.

I had just enough scrap to try out the smaller front hoop; it came in at only 120 grams, which is way less than expected.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Cant you just use a piece of string to tell you how long it is, then just use String length x material width x material thickness to calculate volume for your weight calcs
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https://www.halfdonethings.com/

use a piece of cardboard

make a hollow one and fill it with water, then measure the volume of that (temperature compensated of course), and convert using the appropriate mass : volume ratio. It's almost too easy!
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The Engine Whisperer - fixer of things

You are all sick & twisted individuals! It's easier to just make the part before knowing what it weighs - SC looks like being underweight so I'm not too worried.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

cad it in rhino or do the calculus.
it should be exact i would think, i mean its a simple shape
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Mechanical engineers build weapons, civil engineers build targets

That's a really clever idea - except I can't quite make Rhino do it. I started by importing an outline, which rhino said was a "closed curve with 17 sub-curves", which sounded promising. I extruded the curve 50mm and Rhino said it was and open polysurface and showed some weird artefacts when it rendered. Here is the part:

http://www.lovingangels.com/Nick/roll_bar.zip

Its like Rhino left a few gaps between the walls and the faces of the part
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Last edited by Nick on Wed Apr 18, 2007 9:52 pm; edited 1 time in total

quote:

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Originally posted by Nick:
http://www.lovingangels.com/Nick/roll_bar.3dm

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You have to right-click & "Save as.."
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Doesn't work for me either, I can download it, but it's a 1kb file... Reload it
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https://www.halfdonethings.com/

quote:

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Originally posted by TDT:
Doesn't work for me either, I can download it, but it's a 1kb file...

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Thanks everyone for looking

try saving this one; it worked for me and its 63% faster to download:

http://www.lovingangels.com/Nick/roll_bar.zip

The ISP must have a filter going, very annoying!
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

It has a volume of 201154.542mm^3

So if UHMW is 1200kg^3 that works out to be 241.385 grams...

I've uploaded the part so it's not buggerized as the one you had

http://www.crystalnode.net/files/roll_bar.zip - also making the render model correctly, it made the file size 1/4 the size

All i did to fix it was get your model, explode it, delete all the surfaces bar the bottom one, then selected the bottom surface and extruded it 50mm.
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https://www.halfdonethings.com/

Thanks for that, but why would your fix work any different to what I did - I started off with the same bottom surface I just selected the surface (Rhino actually said it was a curve) and used "extrude planar curve" - is that not the best way? It looks like I have much to learn about Rhino...
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Unbelievable! Your ISp doesn't allow Zip files to be downloaded Just the opposite of Brett's; perhaps renaming it as a JPG or GIF will work.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion