Nathan 4000C's in 1.5" Scale

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AnthonyDuarte
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Re: Nathan 4000C's in 1.5" Scale

Post by AnthonyDuarte » Wed Jan 06, 2021 12:19 pm

The molds for the lifting mechanism are now finished. They proved to be much more challenging than I thought! As is typical with this kind of work...

The fulcrum bracket has two round features that are offset from each other by about .056", which requires 2 parting lines on the mold. It took a little while to figure out a way to part it up that wouldn't be too obnoxious to machine.

4000C Bracket Mold.jpg
Fulcrum Bracket Mold Closeup

4000C Bracket Closeup.jpg
Lever & Link Closeup

4000C Knuckle closeup.jpg
Knuckle & Fulcrum Bracket Closeup

Nathan 4000C 1.5'' Assembly 2.JPG
CAD model of lifting mechanism

datman
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Re: Nathan 4000C's in 1.5" Scale

Post by datman » Wed Jan 06, 2021 4:15 pm

I love this quality of modeling and processes :) :) :)

datman
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Re: Nathan 4000C's in 1.5" Scale

Post by datman » Wed Jan 06, 2021 4:16 pm

Wish they suited what I would like to build (BR55)

AnthonyDuarte
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Re: Nathan 4000C's in 1.5" Scale

Post by AnthonyDuarte » Fri Jan 08, 2021 2:36 pm

Thanks datman!

Was able to test the main body mold today. I purposely didn’t put any vents in so I could see where potential problem areas were. Now I know where vents are required. Usually takes a few tries to figure out how hot the mold needs to be and what pressure the wax needs to be for everything to come out right. How the mold is oriented often makes a big difference too. So this attempt isn’t too pretty, but here it is anyway.

The gray wax is water soluble and will dissolve out leaving behind the desired cavity.

This is hands down the largest mold I’ve made for a hobby related part. 18 hours to machine and 6 million lines of G-code. And that doesn’t include the core mold.

Onto the overflow and bottom cap!

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Berkman
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Re: Nathan 4000C's in 1.5" Scale

Post by Berkman » Fri Jan 08, 2021 2:55 pm

Pardon my ignorance, but if I understand the process right you had to make a seperate mold for the gray core as well?

I guess something like 3d printing the mold simply won't cut it for a production run ?

AnthonyDuarte
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Re: Nathan 4000C's in 1.5" Scale

Post by AnthonyDuarte » Fri Jan 08, 2021 3:18 pm

Berkman,

The core does require its own mold. 3D printing molds for me is not even remotely economical. The cost and turnaround time is not comparable to just milling a mold, especially since the surface finish of printing can't touch what I can get off the mill. And the longevity of a 3D printed plastic mold VS aluminum... well there's no comparison.

If I ever implore 3D printing it would be to have wax patterns printed directly in a high resolution castable resin. That would be practical for low quantity runs of extremely complicated parts. I'm considering doing this for the top mounted check valves.

Anthony

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Chris Hollands
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Re: Nathan 4000C's in 1.5" Scale

Post by Chris Hollands » Fri Jan 08, 2021 5:46 pm

Anthony you don't have a twin brother or maybe we can clone you to produce even more great items - LOL
Amazing work .

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NP317
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Re: Nathan 4000C's in 1.5" Scale

Post by NP317 » Sat Jan 09, 2021 1:22 am

Our Live Steam "hobby" is incredibly fortunate to have you and your remarkable expertise making scale products for us.
Thank you!
RussN

AnthonyDuarte
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Re: Nathan 4000C's in 1.5" Scale

Post by AnthonyDuarte » Sun Jan 10, 2021 1:59 pm

Thank you Chris and Russ! You’re too kind.

All the molds are now complete. The first major hurdle of the project has been successfully cleared.


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datman
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Re: Nathan 4000C's in 1.5" Scale

Post by datman » Sun Jan 10, 2021 3:20 pm

:) :) 8)

kcameron
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Re: Nathan 4000C's in 1.5" Scale

Post by kcameron » Sun Jan 10, 2021 9:25 pm

Looking at the core vs finished part, just what thickness is the wall for a lot of that thing? Part of my brain wonders how much alignment wiggle you've got yet keep enough wall thickness in the part. Doesn't look like much.
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AnthonyDuarte
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Re: Nathan 4000C's in 1.5" Scale

Post by AnthonyDuarte » Mon Jan 11, 2021 12:14 pm

Ken,

The wall thickness along the center cylinder is .05". The core is held very securely in the mold and can't shift. The only variation in wall thickness would be from differences in shrinkage due to the temperature of the aluminum when shooting, but that won't amount to more than one or two thousandths.

Anthony

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