Zarwerks shop spy cam ....

[johnshenry]

I am as much a die hard strictly stock enthusiast as anyone else, so usually when anyone comes to me asking to support a "mod", I am inclined to shy away. But in this case, someone restoring a split wanted a wiring harness kit and wanted help running a 12 volt system, with 6 volt semaphores. So knowing what I know about semaphores, current draws (I am a retired electrical engineer) I quickly searched for a 1 ohm "power" resistor, and Amazon had them on my porch in a shade less than 24 hours. My customer had already paid for the harness, and the 12 volt mod resistors and I figured I would just test them, take some measurements before tossing them in the box with his shipment.

But then I realized that this might be a "Zarwerks Spy Cam" moment.

Originally I had thought about putting a dropping resistor on each sem circuit, maybe stuffing them in the sem pockets, but upon getting these resistors and realizing that they were pretty big, I came up with a better solution.

A stock semaphore, in good or better condition, draws right at about 6 amps of current at 6 volts. Math dictates that this a 36 watt power draw. It also dictates that the sem is a 1 ohm resistive load on the circuit. So the simple math is, if you want to add something to the circuit to "Drop" the voltage to the sem to 6 volts from 12 volts, you simply need another one ohm load in series to drop 6 of the 12 volts. A one ohm resistor does the trick, but before sending this solution on its way to my customer, I wanted to verify, and photograph it.

In this first couple pics, I have a restored SHO grooved semaphore connected to one of my reproduction semaphore harnesses, and an original semaphore switch. Activated with the switch, my voltage locked power supply ("CV" means constant voltage)shows it supplying 6 volts to the circuit, and it drawing 5.5+ amps from the supply. The display also shows it pulling about 33 watts of power.

In the modified circuit pics, I have added a second semaphore for no other reason than to replicate a real world circuit, and I have added the (gold colored) 1 ohm, 100 watt resistor to the input power lead on the sempaphore harness. This wire normally pics up 6 volts, switched, right off the ignition switch. The idea here was that only one resistor is needed since it can be introduced into the circuit before the semaphore Right/Left switch, and thus be able to drop the voltage into the switch. Of course only one semaphore can be activated at a time, but for what it is worth, this is a 100 watt capacity resistor and it *could* easily support two 36 watt loads.

The voltmeter in this pic is reading the voltage across the resistor and you can see that it is 5.9 volts, or very nearly half the 12 volts from the supply. But the power supply shows what is important here. I had dialed the (fixed) voltage up to 12 volts. As you can see from the readout, the current through the circuit (sem and resisitor) is still only 5.5 amps. Total power is 66 watts, 33 watts are being dissapated by the sem and 33 watts by the resistor. As far as the semphore is concerned, nothing has changed from the 6 volt system. It is not being over driven, it is not overheating.

These resistors are dirt cheap and available from Amazon for under $4. Here is the link:

https://www.amazon.com/dp/B077ZMFZM6?psc=1&ref=ppx_yo2ov_dt_b_product_details

(I bought a bunch).

While I am not really interested in selling sub $10 parts, I did solder some correctly color coded wires to them and will offer a "Convert Semaphore harness to 12 volt" option to my harness kits in the future. I have soldered some of the color correct PVC wire to the ones I bought, if you want one, PM me.
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John Henry

'57 Deluxe
'56 Single Cab

[VW_Jimbo]

My first Oval was a 55, back in 1988. I used a similar resistor but it was a ceramic resistor, 3 of them in parallel, reducing the 12V upgrade to operate the 6V solenoid. Worked great! At the time, I was dating my wife and her father was an Electrical Engineer. He designed the circuit for the semaphores. I went to Radio Shack and picked the resisters up. The next day I had working semaphores! It was so cool!
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[scarabee]

Three resistors in parallel looks to be a good idea for heat dissipation, instead of just having one.

[finster]

like he says - 'it was so cool!'
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"we're here on Earth to fart around" kurt vonnegut

nothing lasts, nothing is finished, and nothing is perfect...

[splitjunkie]

[scarabee]

Yes, electronics 101...

[johnshenry]

A favorite MIG Rescue technique that I like. Here, a snapped off flush clutch pressure plate M8 bolt in the flywheel. This one was just over torqued, and there is no real thread corrosion/resistance. But it had to come out and there was no way to grab it. Yes, I have EZ Outs, and have used them successfully one time out of 722 tries. This MIG technique is undefeated.

In this case, I tape a rusty M8 nut over the snapped off bolt shank, then poke a hole in the tape over the nut. The idea is to get the MIG wire arc to grab the shiny bolt shank first, so a rusty nut helps out. I just shoot the MIG wire into the nut bore, and fill the void with molten metal. Let it cool just a bit, then turn the shank out with a wrench.

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John Henry

'57 Deluxe
'56 Single Cab

[VWLady]

You can also use a washer, weld a blob and then add a nut and weld that to the nut inside.

Agree this is the best solution to snapped off fasteners

[Ted2]

Great idea. Thanks for sharing.

[splitjunkie]

This is a very good method.

In the case of a snapped off fastener with no rust locking it in place, an easyout probably would work fine. If it won't turn easily, I quit immediately. I never use them if the fastener is stuck by rust or tight interference fit though. That just doesn't work and makes things worse with the super hardened piece left in the bolt.

I have even used a worn down dremel cuttoff wheel to cut a slot for a screwdriver, but then again, only for a fastener that is not locked in place by rust.

I once broke off a 8/32 tap in a piece of cast iron I was cutting some threads into and thought I was screwed but I tapped on the end of it with a punch a few times and used some needle nose pliers to grab the flutes and it backed right out.
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Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[johnshenry]

[VWNate]

Great thread ! .
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-Nate

One last Beetle : 1959 #113 DeLuxe survivor ~ 36HP & full synchro tranny, 6 volts etc.

[VW_Jimbo]

[Martin Southwell]

What's wrong with drilling and tapping?

[johnshenry]

[Martin Southwell]

Fine, but not everybody has welding equipment or experience.

[wagen19]

[cory464]

[finster]

[Jacks]