3/8 shaft, is it strong enough.

[DonRotolo]

Originally Posted by lemiant

Solidworks thinks we can withstand 25lbs with a 2:1 safety margin, but that's hard to believe.

On one hand, don't rely on intuition to tell if something is good or not; engineers use math to prove it.

On the other hand, work hard to never lose that skepticism; always question the output of a software program, especially if you are not completely knowledgeable about how exactly it comes up with those numbers.
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OK, to help you get a better feel for this, try an experiment:
Take a 3/8" steel bolt, clamp it tightly (in a vise perhaps), and whack it with a 12 pound sledgehammer, dropped from about a foot (25 pounds of force, +/- 100%).
Did it bend?

[klunk]

Hi Guys,

Thanks for the additional support.

I've attached a very rough sketch up of the object to give you further clarity on the scale and materials I'm planning on using.

To paraphrase, the mallet should have some force but nothing too drastic. It's for a visual arts project. It is temporal construct and will most likely never be used again. It's sole purpose is to pound on the block of soil till the block breaks down. The block (made of topsoil) will be formed/petrified with just a mixture of pva and water, so it should be fragile enough to be destroyed by this mallet. What I would like to see and hear is the mallet making a reasonable pound upon contact with the block. That's it.

Thanks again. This place is great.

[klunk]

here's the attachment...

[klunk]

Hi again,

I found a Toshiba motor/gearhead the other day - http://www.youtube.com/watch?v=Txu9zKdbOmo and was wondering if anybody is familiar with them.

The details on the labels on both the gearhead and the induction motor are entirely erased...apart from the Toshiba logo and the names of the components. There is only some visible writing next to the gear ratio on the gearhead. It says 1:8 with the space immediately after the 8 scratched off.

Haven't the faintest on how to measure the speed/rpm/torque etc. Had a look at this http://www.electricneutron.com/elect...motor-capacity as an aid and realised it would take me two years to work it out.

Any body familiar with these motors that can tell me exactly what it's capable of just by looking at it? Hopefully I can use it on the above mentioned machine.

Thanks in advance,
K

[klunk]

its dimensions are almost exactly like this one.

[EricH]

Originally Posted by klunk

Haven't the faintest on how to measure the speed/rpm/torque etc. Had a look at this http://www.electricneutron.com/elect...motor-capacity as an aid and realised it would take me two years to work it out.

There are commercially available tachometers for the speed. Typically, you find those with your local R/C pilots or in a hobby store; in this case, you'd probably need to either simulate a second side of the prop or correct the reading for only reading one side.

[Ian Curtis]

Originally Posted by klunk

Hi again,

I found a Toshiba motor/gearhead the other day - http://www.youtube.com/watch?v=Txu9zKdbOmo and was wondering if anybody is familiar with them.

The details on the labels on both the gearhead and the induction motor are entirely erased...apart from the Toshiba logo and the names of the components. There is only some visible writing next to the gear ratio on the gearhead. It says 1:8 with the space immediately after the 8 scratched off.

Haven't the faintest on how to measure the speed/rpm/torque etc. Had a look at this http://www.electricneutron.com/elect...motor-capacity as an aid and realised it would take me two years to work it out.

Any body familiar with these motors that can tell me exactly what it's capable of just by looking at it? Hopefully I can use it on the above mentioned machine.

Thanks in advance,
K

The easiest way to measure RPM is to put the video in Windows Media player and go frame by frame. Check how many frames are in a second, then see how many revolutions it makes in a second. Multiply by 60 and you have RPM.

It's a pretty beefy looking motor. I'd say give it a shot.

[Brandon Holley]

The easiest way to make sure your design will work as intended, is to test it in the same conditions it will experience whenever possible. If I were you guys, I would overdesign this thing because you are really not heavily constrained (at least not in that aspect of the design).

A 5.5" cantilever is definitely not something to overlook, so I'm glad you are reaching out for assistance.

If you can take a screenshot of your Solidworks Simulation model, and list the relative information (material, load, etc.) I could get a pretty good idea of how much you can "trust" it.

-Brando