CORRECTION>HOW TO MAKE A MODELT COIL TESTER

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Model T Ford Forum: Forum 2013: CORRECTION>HOW TO MAKE A MODELT COIL TESTER
Top of pagePrevious messageNext messageBottom of page Link to this message  By Eugene Adams on Tuesday, November 05, 2013 - 04:11 pm:

I owe a great big apology… especially to anyone who might have already gone out and bought the brass fittings.

It has been 5 to 6 years since I made a coil tester and I was working from memory when I made up my original post.
I said the brass thread size was 8/32…. /b{I should have said 10/32.}

Here is my original (corrected) write-up,
Let me pass the benefit of my experiences to others on this subject.
Model Trs, (being the unique people they are), most should understand this. I love you guys and gals and wouldn’t go to the extensive efforts to prepare all of this for anyone else.

If electrical systems are ‘Greek’ to you and you would like to build your own tester, maybe my instructions will help you. I have made and sold many coil testers at Hershey and on eBay.

How is a tester wired? Pictures are better than words. (the 1000 words thing, don’t ya know). Schematics can be confusing. By looking at my pictures you should be able to know what to buy and what you will need to do to put one together. Some woodworking expertise and imagination and with experimentation will certainly help.

Understanding the route of the current as it goes through the wires.
Follow the wiring. (The color of the wires is not important.)

Let’s start with the Positive (+) current starting at the wire nut marked X. picture1. It goes through the on/off switch to the + post of the ammeter… through the ammeter and through the hole marked C. The wires at C go to a contact that touches the button on the bottom of a coil. The other wire coming from the contact goes to post X which is one of the points on the top of the tester. When the points are close enough, the spark jumps to the other point and comes down post Y. From Y it goes to the contact that touches the bottom (side) button on a coil. The current goes through the coil and out the top button on the coil and through the wire at hole B and to the negative (-) wire of the battery cord.

As you position the wires make sure that none of them come close to each other. Sparks could cross over where they shouldn’t.

The brass points and other contact pieces can be fashioned with tin snips. The brass from which I fashioned the various contacts and points is available at Taylors, True Value, Ace or similar hardware stores. Our store displays them in a little ‘stand-up” box and is located near the selection of aluminum panels for storm doors and other selections of metal strips and tubing.
The points and contacts that touch the coil buttons are of different thicknesses than the points. The button contact pieces have to be thin enough to have some flexibility. See what they look like in picture #9.

The brass screws, washers, nuts and knurled nuts are available in little drawers at the True Value/Ace types of hardware stores. You just have to hunt through a lot of drawers. MAKE SURE THAT ALL THREAD SIZES MATCH. 10/32 THREAD. See the last picture for a list of parts needed.

My 3rd picture should give you some idea of where the ammeter sets in the line of events. (consider the whole tester as being my unit and picture (in your mind) the ammeter as being installed in it.)

The Model T purist will tell you that the huge heavy coil tester is necessary to set your coils correctly. So what about the hundreds of thousands of guys who got by and only used a Buzz Box?

SO WHERE DO I GET A SUITABLE AMMETER? Look on eBay. Look for: ammeter dc 0-3 or ammeter dc 0-5 (always specify dc). 0-5 is OK… 0-3 would be better. So what if it doesn’t look antiquish… who cares as long as you can adjust a coil to 1.3 amps?


There is an ongoing question, which way does direct current flow? If you Google the question… it seems that no one is really sure.

I will be glad to answer any questions and help you in any way that I can. Contact me by clicking on my name. I am nearing 89 and I still love helping people. If you successfully make a tester, I hope you will send me a picture of it.
Add this Forum post to your favorites for quick recall.
See the website at the very bottom.
Have some serious fun.

**********************************************

If you would like to go back to the original post to view other pictures Clickhttp://www.mtfca.com/discus/messages/331880/398352.html?1383499840
Below are corrected picture showing correcting thread sizes.
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Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, November 05, 2013 - 07:20 pm:

Here's my tester. It shows up multiple sparking, and allows me to set the coils to take the same time to fire as each other.
http://members.iinet.net.au/~cool386/tester/tester.html
tester


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Tuesday, November 05, 2013 - 11:30 pm:

Gosh, if you are going to that much trouble why not attach the alligator clips to the meter and connect it between the timer wire and the coil terminal on the box?


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