Where can I find this?

I need a 4 pound cylindrical weight with a 1" diameter hemispherical striking surface. I have no idea where to even begin looking for this....

Uh, can you tell us what it's for? That might help me picture what you want/need. 4 pounds huh? How much to the weights that are used in older double-hung windows to balance the lower sash?

I think they are around 4 pounds.

It is for impact testing. I am just using a description from MSHA.

Sex shop?

Hit up a machine shop. They can turn the end of a 1" steel bar to form the hemisphere you need. Just make it the right length to hit 4 lbs.

Pi x .5 squared x Length (x.283) = 4lbs

.283 is the weight multiplier for mild steel

You need 17.997 inches of 1 inch round mild steel.

If my math is correct

This forum rocks!!

mthomson22 wrote: Pi x .5 squared x Length (x.283) = 4lbs .283 is the weight multiplier for mild steel You need 17.997 inches of 1 inch round mild steel. If my math is correct

There are many childish things I could say about this post. But for once, I'll be grown up.

In reply to DrBoost:

I've hit one of those window counterweights with a mower before......steel beat cast iron.

mthomson22 wrote: Pi x .5 squared x Length (x.283) = 4lbs .283 is the weight multiplier for mild steel You need 17.997 inches of 1 inch round mild steel. If my math is correct

I am thinking that is what I am going to end up doing.

DrBoost wrote: Uh, can you tell us what it's for? That might help me picture what you want/need. 4 pounds huh? How much to the weights that are used in older double-hung windows to balance the lower sash? I think they are around 4 pounds.

Off topic, those are some of the finest anchors for small boats in rocky streams.

pilotbraden wrote:

DrBoost wrote: Uh, can you tell us what it's for? That might help me picture what you want/need. 4 pounds huh? How much to the weights that are used in older double-hung windows to balance the lower sash? I think they are around 4 pounds.

Off topic, those are some of the finest anchors for small boats in rocky streams.

Or nunchucks for Chuck Norris.

93EXCivic wrote:

mthomson22 wrote: Pi x .5 squared x Length (x.283) = 4lbs .283 is the weight multiplier for mild steel You need 17.997 inches of 1 inch round mild steel. If my math is correct

I am thinking that is what I am going to end up doing.

Keep in mind that if you go with a hemispherical end, the length for 4 pounds will be slightly longer.

Weight = [(2/3)Pi x r^3+Pi x r^2 x L] x rho

where r = .5", rho = .283 lb/in^3, Weight = 4lb.

Comes out to 17.663" cylinder length, plus half an inch for the radius of the hemispherical end, or 18.163" overall length.

I suppose you want some kind of attachment point at the opposite end though, right? That'll jack up the calculation again.

if you drill a simple through-hole neat the top for attachment, you should be able to calculate the weight loss of the cylindrical void, then add that back to the total target weight to get your new target length.

Just curious, but most dictated methods have suppliers for the recommended equipment. Did this one not? Or was the price a lubeless shag?

In reply to ultraclyde:

To be honest, it is only a semi-scientific test to shut some salesmen up.

I would consider making it slightly underweight, then filling it with some lead from melted tire weights, then drilling that lead to get it dead nuts on to 4 lbs, depending on how scienteriffic you want to be.

Would suck to have the exact part you want in steel and it weighs 3.98 lbs instead of 4.00 lbs. If its overweight you can always file a little bit off.

Wouldn't it be easier to make it slightly oversize and file down the mild steel itself?

93EXCivic wrote: In reply to ultraclyde: To be honest, it is only a semi-scientific test to shut some salesmen up.

In that case, just find something that's close to four pounds and smack him in the head with it.

Woody wrote:

93EXCivic wrote: In reply to ultraclyde: To be honest, it is only a semi-scientific test to shut some salesmen up.

In that case, just find something that's close to four pounds and smack him in the head with it.

That sounds like an excellent plan to me.