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 Post subject: Amperite - Before I reinvent the wheel....
PostPosted: Mar Mon 12, 2018 11:07 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1762
Location: Monroe, NC 28112 USA
I have several sets that use the Amperite 1A iron wire ballast. Most are not even in as good a condition as this one.

Reproducing the graphic is no problem. There is gold paper on which you can laser print opaque black.

My question is: Has anyone figured out a source for deep drawn end caps like this? Or does anyone know how to reproduce them in a home shop? I think they are too deep and small for brass spinning which I've done a little. Not worried about the actual iron wire element. Most folks are going to operate using a regulated 5 Volts... At least I do...

Comments welcome.

Robert


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Mon 12, 2018 11:36 pm 
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Location: Tucson, Arizona U.S.A.
Quote:
My question is: Has anyone figured out a source for deep drawn end caps like this?

Are you sure they are drawn? I don't have any resistors like yours but newer resistors and RF chokes with ends like these are just molded solder. If so, that would be a lot easier to reproduce although some experimenting with molds would still be required.

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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Mon 12, 2018 11:42 pm 
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Joined: Nov Fri 30, 2012 3:35 am
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Location: Phoenix, AZ
I know what you mean about the Amperite iron wire filament regulators ... I have an Ultradyne L2 battery-powered superhet with them, and they are corroding to look like the one in your image. Thankfully all of them still work in my set, but it probably is only a matter of time. I wonder if a person could dissect one of the older style electrical cartridge fuses (the type that clips into spring contacts, bigger than a 3AG) to salvage the metal ends. I've seen 20 amp and 30 amp cartridge fuses (I don't know the formal type number, but undoubtedly someone else on this forum can quote it) with ends having a diameter that appears similar to the Amperite. After dissection, it might be possible to support the metal end over a hole drilled in a wood block and go in from the back side with a tapered center-punch to stamp the conical shape. Just a thought.
R/ John


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Tue 13, 2018 12:17 am 
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Jim Mueller wrote:
Quote:
My question is: Has anyone figured out a source for deep drawn end caps like this?

Are you sure they are drawn? I don't have any resistors like yours but newer resistors and RF chokes with ends like these are just molded solder. If so, that would be a lot easier to reproduce although some experimenting with molds would still be required.
Egads, a modified bullet mold :shock:

There was or still is folks who make custom bullet molds, the hollow back is a retractable pin. The body can be glass or phenolic tubing hiding a dropping resistor...

I've cast thousands of rounds for blackpowder. Goes real fast, less than12 seconds. Mold is smoked with a candle. Kept at just below melt point on a nearby hot plate. A hard alloy like 95/5 or mix your own alloy.

Chas

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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Tue 13, 2018 1:23 am 
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Location: Seattle WA US
Those ends, slightly pointy, look like the ends on "festoon lamps". Such lamps are still used for interior lighting in imported cars.
-Chuck


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Tue 13, 2018 2:24 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1762
Location: Monroe, NC 28112 USA
Chuck... You are right about the similarity to festoon lamps. But ARRGH! I can't find that factory in China that must be knocking the end caps out by the millions per week. :x

I hate to buy LED festoon lamps and take them apart.. Will have to take some measurements tomorrow in the shop and see if any on eBay are the right OD. Looks like some are as cheap as 25 cents...

Robert


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Tue 13, 2018 2:45 am 
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Joined: Oct Thu 02, 2014 5:57 am
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Location: Memphis, TN
You'll have to do a little light metalwork and some cosmetic tweaking, but what about a copper pipe reducer? Looks like it would serve as a decent base to start from:

https://www.supplyhouse.com/Elkhart-321 ... gLpzvD_BwE

You could cut down the reduced flange, fold it in, and with some careful soldering you could rework that part to have a similar look to what you have. Then you either have a plug for a mold without having to risk an original, or just paint the repro part and use it as is.

I used to know a guy who built incredibly detailed plastic models of classic cars. The interiors in them looked like something out of 'Honey I Shrunk the Kids.' He told me once what fabric he used: He had a stash of quilted/textured toilet paper. Stop and think about that. These award winning plastic models used butt wipes for upholstery.

Never underestimate the value of 'repurposing.' :lol:


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Tue 13, 2018 5:21 am 
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Location: Austin, Texas
You can still get the non LED bulbs but they are probably more expensive than the LEDs.
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The caps may be more what you need than the LED parts.
I still have some of the bulbs from my Volvo driving days. The caps are about 9mm diameter by 9mm high.
Another choice would be to turn some brass rod on a lathe. There would be a smaller diameter area to insert into the tube rather than overlap it.

Actually, I think I could turn some good end caps out of brass rod. Just bore the hole for the tube and then turn down to a thin wall.
The pointed part would be solid brass but no one would know that.

If you don't care about the resistance or lack of resistance, just make the whole thing like a brass dumbbell, solder dip the ends, and put the new label around the center.


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Wed 14, 2018 3:30 pm 
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Location: Dayton Ohio
Might be able to find those bulbs at an auto salvage yard (junk yard) pretty cheap.
Maybe ask if they can save the duds for you?

-Steve

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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Wed 14, 2018 3:50 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1762
Location: Monroe, NC 28112 USA
I can do all those things, I have a lathe... What I hoped to find is something I'm sure is being made that would take the grunt work out of it for people without shop tools. I guess I need to try Google searches in Mandarin?

The end caps on the Amperite pictured is 7/16" (0.435 - 11mm) diameter. The cylindrical length is 0.375 and the pitch cone angle is about 60 degrees with a 1/8" dia. tit about 1/16" high....

I can see form factors close to that but cannot find any drawings that show the actual dimensions of the stampings.

Phooey!

Robert


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 Post subject: Re: Amperite - Before I reinvent the wheel....
PostPosted: Mar Wed 14, 2018 4:10 pm 
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Location: S. Dartmouth MA 02748-1225 USA
Robert Lozier painfully wrote:
I guess I need to try Google searches in Mandarin?

The end caps on the Amperite pictured is 7/16" (0.435 - 11mm) diameter. The cylindrical length is 0.375 and the pitch cone angle is about 60 degrees with a 1/8" dia. tit about 1/16" high..

https://www.alibaba.com/

I found a few U.S. manufacturers of metal findings that could make them. Without inquiring, I speculate there will be a minimum tool and die cost. Far, far, exceeding any recovery...

https://en.wikipedia.org/wiki/Jack_Ma

GL

Chas

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