Lift Peg (Spring) Source?

[dkavanagh]

When I checked on Saturday, it was a 1 week wait and we placed an order. I'll let you know if that happens. We'll use a dowel till then.

[dtengineering]

Century Spring product number C-333 is very similar in diameter (O.D. And wire) and just happens to be 9" long. You'd still have to cut the ends off, but there should be a tonne of these around.

https://www.amazon.ca/Century-Spring.../dp/B000BD6BUE

And I warned the woman I spoke to at Essentra Components to expect a surge of orders. FIRST can have that effect...

Jason

[RoboTigers1796]

Originally Posted by dtengineering

Century Spring product number C-333 is very similar in diameter (O.D. And wire) and just happens to be 9" long. You'd still have to cut the ends off, but there should be a tonne of these around.

https://www.amazon.ca/Century-Spring.../dp/B000BD6BUE

And I warned the woman I spoke to at Essentra Components to expect a surge of orders. FIRST can have that effect...

Jason

Thanks! I just grabbed one until the mcmaster one shows up. (american link for the lazy -https://www.amazon.com/CENTURY-SPRING-C-333-Extension-Spring/dp/B000BD6BUE)

[sanddrag]

Century Spring 5518 looks like it may be usable. Anyone agree or disagree?

[Tottanka]

Originally Posted by Ari423

The five regional distribution centers are in Atlanta, Chicago, Cleveland, Los Angeles, and Princeton (NJ).


Also have any Israeli teams found an Israeli distributor with an equivalent spring?

Nope, and mcmaster doesnt ship to Israel even if it was in stock.

[JamesBrown]

Originally Posted by sanddrag

Century Spring 5518 looks like it may be usable. Anyone agree or disagree?

Century Spring E-41


I think you want Century Spring E-41, the rate constant matches on that one.

Disclaimer, I am an EE, and I know nothing about springs.

Originally Posted by dtengineering

And I warned the woman I spoke to at Essentra Components to expect a surge of orders. FIRST can have that effect...

Jason

Current lead time from Essentra is 8 Days

[RyanCahoon]

Originally Posted by JamesBrown

Century Spring E-41

There's a couple left here https://www.amazon.com/875-135-158-7.../dp/B002P4VHD8

[RichardChycoski]

Already gone. :-)

For now, I've ordered the McMaster-Carr 9664k66, which is smaller in diameter (.750) but has somewhat similar spring characteristics.

It was in stock, to be shipped today.

Of course, now that I've said this in a public forum...

[Drivencrazy]

For what it's worth, I was able to find a similar spring at our local ACE Hardware, it was shorter than the regulation spring which is of course not ideal, but it should suffice for a few rounds of prototyping.

[JoeRames]

Ordered ours from here. Few days. http://www.midlandhardware.com/639807.html

[sanddrag]

Originally Posted by JamesBrown

Century Spring E-41


I think you want Century Spring E-41, the rate constant matches on that one.

Disclaimer, I am an EE, and I know nothing about springs.

I'm not sure you're correct. McMaster defines the "rate constant" whereas century spring defines the "spring rate." Two different things. Is my understanding of this incorrect?

[dtengineering]

Teams in larger cities, or more industrial areas, should also be able to find a local spring manufacturer that may be able to help you out by building a custom spring.

It might cost a bit more, but you never know... when a couple enthusiastic young people ask for help, sometimes they get more than just a spring.

Jason

[JamesBrown]

Originally Posted by sanddrag

I'm not sure you're correct. McMaster defines the "rate constant" whereas century spring defines the "spring rate." Two different things. Is my understanding of this incorrect?

First, refer back to my disclaimer, I don't know much about springs, but here is what I can gather.

First, you are right, spring rate and rate constant are different. However I suspect that what is shown on the E-41 Spring is in fact the rate constant. After comparing quite a few manufacturers, all of them list a value of ~159 for rate, rate constant, or spring rate for these 36inch pieces of what seems to be spring stock. However at shorter lengths they list a Spring rate instead. I believe the E-41 is the equivalent of the McMaster Part, and the 5518 is a 12 inch spring made out of similar stock.

If the term Rate on the E-41 page is not an error then I am not sure I can explain the physics of that spring as all of the physical characteristic match other parts, but the Rate Constant would be off by a factor of 36.

Long story short, you are definitely right, but I think both parts actually work. But someone may want to confirm with Century Spring if they are going to order from there.

[RoboChair]

https://www.mcmaster.com/#9664K66 is reasonably close to the same spring force and only 1/8" smaller diameter.

[Moonsault]

Does anyone know if we can use a magnet to help put the gear on the peg?