Building a DIY HCCT

[Matt in California]

Three and half years ago was looking into coil testers and came up with the tuna can coil tester : viewtopic.php?f=2&t=3153&p=33039&hilit=tuna#p33039

Three years ago I started working with the Ford Arduino Coil Tester (FACT) and for the last few years developed code and a PCB: viewtopic.php?f=2&t=9072&hilit=FACT+diy&start=200

Now I am working on making a HCCT. I started by reviewing Gary Tillstrom

Tillstrom_Coil_Tester-Instructions.pdf

(166.12 KiB) Downloaded 94 times

My plan is to use a tube design. I cut down a 8x8 inch to a 2x8 .25 thick tube.

I cut the tube with a hacksaw and welded it back together:

The plan is to use two flangers bearings:

Matt

[BE_ZERO_BE]

Matt,

Please post as you go.

[Matt in California]

Thanks Bob!

Just wanna explain a bit of my logic here. I was looking at the design in the plans listed above. I thought two parallel flanges might be a little bit more straightforward and I wanted to think of a design that didn’t require welding. I have access to a welder but I know that not everyone does. So then I bought the two flanges figured out the dimensions of the tubing and went to the local metal supplier. My hope was to find a 2 x 10 cut off in their scrap bin. They virtually had no tubing. They did have about a 12 foot section that they would sell for about $20 a foot. When I asked them about smaller pieces they said they sell that or scrap. I didn’t really wanna spend over $200 so I went to the local scrapyard and was disappointed to hear they no longer sell to the public. This got me to thinking how does anyone build anything.

Anyway that is the backstory that led me to get a 8 x 8 that I cut down from a friend. Because it was not wide enough I needed to attach a plate here you can see it spot welded with holes to hold the magneto coil.

I try to follow the given measurements, but after drilling one hole I decided to just hold the coil in place and drill the remaining holes using the magneto bracket as a guide. I was very glad that I did this because the holes have a very tight tolerance. In the end I tap the holes and everything looks OK.

[Rich Eagle]

Very nice. Kalamity Dick would have been so envious.
Keep up the good work.
Rich

[Duey_C]

Nice old hack saw! My arms hurt for you if yours didn't. 1/4 wall, uff da.
Neat project!

[Matt in California]

Nice old hack saw! My arms hurt for you if yours didn't. 1/4 wall, uff da.
Neat project!

Duey,
Yeah cutting four feet of quarter inch steel was a fun task. I should do advertisements hacksaw blades This hacksaw is really the best one I have ever used. I have a angle grinder, but wanted to work inside and only had half a cutting disk left. Sometimes in patients gets in the way of laziness! Those bent strips on top are what I cut out. I plan to use those for the base.

I started drilling holes for the flange bearing and ran into trouble.

Things were not lining up. I’m not sure if I didn’t follow the measurements or does bearing was just different. I decided I needed to use the main shaft for as a reference. Does seem to be close enough for the magneto holes, Even though the lines don’t look perfect:

I decided to drill the center hole where the shaft would go and use a socket to center the flange bearing for drilling.

You can see how far off the first hole is:

[browning]

Here is the worlds heaviest and least practical HCCT (not really hand cranked). All I need is the spark ring.

[Matt in California]

Here is the worlds heaviest and least practical HCCT (not really hand cranked). All I need is the spark ring.

David,
Now that you got our attention! That truly would be the heaviest Model T coil tester especially if you never used it as a lathe

What is the battery for?

Matt

[BE_ZERO_BE]

David,

Nice variation on a motorized HCCT.

[Ed Fuller]

Matt,

When I first started following the forum around 15 years ago, it seemed as though building your own HCCT was all the rage. I remember seeing several posts of different builds going on.

I got bit by the bug and started following the same plans as you that were written by Gary. I got about this far, and like most of us, other projects took over. This is about as far as I got. Maybe it’s time to dust it off and finish it?

[browning]

That is the setup I made to test the rare earth magnet flywheel vs. the stock setup. The benefits are that I can test at various fixed rpm and easily change air gap as well as switch back and forth with different flywheel/magnet configurations. The battery is there because we have been fooling with solid state voltage regulators to see if we can create a charging system. The jury is still out on that one. If the magnets on the flywheel look like medium density fiberboard it is because they are. Its easy to machine on the CNC router and inexpensive enough to throw away when they don't work. The "real" ones will be 6061 aluminum if it goes that far.

[Matt in California]

Ed,
Yes you need to finish that! Looking at your example it looks like you are most of the way done. Except for the part that’s not mentioned of exactly how you cut the wood out. Of course I am assuming that your magnets are charged

David,
Sounds like you’re doing a pretty interesting experiment. I hadn’t analyzed it enough to see what you were using for magnets!

The next step was the fun part! Not everyone has capacity to drill a hole over 1 inch. But not too long ago I was at estate sale and purchased some large Morris taper drill-bits.

Look how small those other holes look!

I was happy to see the shavings were not getting too hot. I did drill a half inch hole as a starter.

Things are looking pretty good with the bearing and shaft in place.

[Matt in California]

I will do the two pieces I cook out of the original 8x8 inch tube for the base.

Drilled some holes and checked fit:

Welded it on:

I consider myself more of a grinder than a welder… In this case I just left my welds.

[Matt in California]

Here is the start of the collar for the handle. Keeping things within budget I started out with a large nut.

It just had to be barely reamed out with the 15/16 drill. (Actually most of the threads were left when I was done.

Then I tapped a couple holes in the side for the set screws:

Well a small start for the crank...

[Matt in California]

I don’t know about you but when I see a old chair leg like this I see a bunch of handles

I used the drill about halfway from both directions method. First I started with a smaller drill...

The bolt I had is actually a timber bolt, but a carriage bolt would have worked, by just filing the square from under the head. I liked that this one was not treaded up the shank.

[Matt in California]

I got the handle installed:

I added graphite inside the handle. It turns very smoothly.

[Matt in California]

Happy New Year!

Here is what I did for a hole in the coil box and spark ring. I don’t get any extra points for ease of manufacturing/assembly.

[BE_ZERO_BE]

Matt,
I see you are using a brake drum for a spark ring.
Allen used a modified brake drum on some of their HCCT's.
They increased the diameter of the inner diameter to avoid the spark
from jumping to the shaft.
Here is the Allen drum.
 

IMG_2933.JPG (32.61 KiB) Viewed 6353 times

[Matt in California]

Bob,
Thanks for the tip and photo! I was under the understanding that the gap should be a quarter inch. With that I tried to make everything else greater than a half inch. Let me know if you see any problems with that logic.

Thanks!

Matthew

[Ron Patterson]

A properly working Model T ignition coil should produce enough energy to jump a spark gap of 1/4 inch.
If you make the gap greater you take the chance of the coil shorting to ground inside the coil and damaging it.
With the spark ring and pointer your using you will need to keep the inner perimeter of the ring and tip of the gap clean.
These parts have a tendency to get a small amount of corrosion and needs to be kept clean. I suggest you keep a small wire brush and clean these parts the first time, every time you periodically use it. The Allen design HCCT with the brake drum/very pointed gap tip is very susceptible to this problem.
Lastly the tip of the spark gap pointer should have a rounded tip with a radius of about 1/8 inch otherwise the tip will quickly corrode and the gap will cease to be jumped.
Ron Patterson

[Matt in California]

Ron,
I appreciate your insight and tips. Thanks for underscoring that a larger spark gap may destroy the secondary of the coil.

I was not aware of the needed maintenance for the HCCT pointer. It is helpful to know that the pointer should be rounded off to reduce corrosion. Is it better to use something like steel or stainless steel?

Matt

[Ron Patterson]

I have found Brass works best.
RP

[Matt in California]

I have found Brass works best.
RP

Thanks Ron!

This is how I figured out how much I needed to shim the magneto coil ring:

For the next stage I worked on recharging the magnets. I removed all the magnets cleaned everything up and attempted to charge them on a friends old magnet recharger system. I had a couple of magnets with Ford script on them and they seem to charge a lot better than these ones off of the non-starter flywheel.

This impact screwdriver came in very handy for tightening the magnets down:

I used a Harbor Freight 170 amp welder (please excuse the mess):

[Duey_C]

That's not a mess. It's a busy work shop.

[Ron Patterson]

Matt
Perhaps you were not warned about cracked magnets?
I suspect ho had some cracked magnets? That would account for your magnets that did not recharge well.
Search this Forum for "cracked magneto magnets" and you fill find the easy procedure to check them for cracked magnets. These will need to be identified, replaced and recharged for the magneto to produce adequate output.
Ron Patterson

[Ron Patterson]

Cracked magnets

[Adam]

Matt
Perhaps you were not warned about cracked magnets?
I suspect ho had some cracked magnets? That would account for your magnets that did not recharge well.

AND/OR…. He has some magnets that he re-charged against their original polarity.

[Matt in California]

Matt
Perhaps you were not warned about cracked magnets?
I suspect ho had some cracked magnets? That would account for your magnets that did not recharge well.
Search this Forum for "cracked magneto magnets" and you fill find the easy procedure to check them for cracked magnets. These will need to be identified, replaced and recharged for the magneto to produce adequate output.
Ron Patterson

Ron,
I did wire brush the magnets and didn't see any issues.

Thanks for the advice to search the forum. I found this:
viewtopic.php?t=1747
The advice I see here is:

• Ring Test

• Magniflux

• Zyglo (fluorescent dye)

I can see how magnifluxing would be highly desirable for safety reasons. I am not sure that cracked magnets is the issue that I am having unless all the magnets on this flywheel are cracked. The test that I used was pulling the magnet against a scale with a metal strap. The Ford script magnets came off around 9 lbs and the magnets on the flywheel were about 4 lbs. Are there different magnetic capacities depending what era the magnets come from? Or is the test of just putting a magnet against a piece of metal and reading the pull on a scale inaccurate?

Matt

[Matt in California]

AND/OR…. He has some magnets that he re-charged against their original polarity.

Adam,
I used a compass and magnetized accordingly. But when I saw the issue I reversed the polarization with the Ford Script magnets and found they still had twice the holding power (i.e. 9 lbs vs 4 lbs) of the other magnets.

Matt

[Ron Patterson]

It is uncommon to find a newly disassembled Model T flywheel that does not have at least one or more cracked magnets.
You cannot visually check for cracked magneto magnets.
Magnaflux and Zyglo is not necessary. Do the ring test and don't be bashful when banging one end of the magnets on the anvil of your vice. If the magnet rings like a tuning fork and doesn't break in two pieces they are fine.
It is not good practice to reverse the original magnetic orientation of Model T magneto magnets, but if your magnet re-charger can produce a full saturation recharge (at least = or > than 5000 Ampere Turns for Model T magnets) you should be OK.
Ron Patterson

[Matt in California]

It is uncommon to find a newly disassembled Model T flywheel that does not have at least one or more cracked magnets.
... Do the ring test and don't be bashful when banging one end of the magnets on the anvil of your vice. If the magnet rings like a tuning fork and doesn't break in two pieces they are fine.
It is not good practice to reverse the original magnetic orientation of Model T magneto magnets, but if your magnet re-charger can produce a full saturation recharge (at least = or > than 5000 Ampere Turns for Model T magnets) you should be OK.
Ron Patterson

Ron,
Thanks for taking the time to explain! I still need to paint the unit. My thought was after I get everything working I could take it apart. At that point I could do some testing on the magnets. I need to address the fact that magnets are not consistent offset from the flywheel...

I did do a search into Ampere-Turns and now understand that is the number of amps times number of turns. It seems that Tom Carnegie came up with the 5000 Ampere turns using a 200 amp welder and 25 turn coil ring. In the thread where he posted about that (http://www.mtfca.com/discus/messages/506218/528397.html), he also conceded that it was very likely the welder was producing far less amperage in this scenario.

My welder is classified as 170 amp. I would need an meter and see how much it’s pulling, but I think I will move on at this point.

Matt

[Matt in California]

I needed to do was get the gauges. I connected with Bob Cascisa. As many of you know he restores these early gauges. He even offered me a set of panel gauges that would work at a reasonable cost. I ended up getting the following NOS gauges off of eBay:

One gauge I needed to remove the basil:

Hi temporary mounted them on cardboard for prototyping testing:

I mounted the unit on a pedestal I got at a local estate sale:

(I wish I could get this photo upright.)

Here is the breakdown of my expenses:
$5 Pedestal (Great find from an estate sale.)
$17.95 two flange bearings
$24.99 amp meter
$32.80 volt meter
$12.00 hardware (nuts & bolts)
$0 steel (got this from a friends scrap pile)
$0 Miscellaneous electrical parts came out of my stash
$$$ Elbow grease
$92.74 TOTAL

That’s far I have come in under $100, but in hindsight I now understand why something that is over $1000 can still be worth it! This took a lot of time.

[Matt in California]

A quick update:
My first test of the HCCT. I was using a rebuilt coil that I had on the shelf. The gauges were jumping a bit and the current was over 2.0 amps. I was’t sure what was wrong so I put the coil in the FACT unit that I built, saw the cushion spring needed adjustment. Placed it back in the HCCT and the gauge movement smoothed out and it read a little over 1.3 amps at 6 volts.

Initial observations:
1. The HCCT is up and running.
2. I really had to crank the HCCT to get it up to 6 VAC. Maybe the issue is weak magnets.
3. The FACT unit is a great alternative to the HCCT. The live o-scope feature maybe even a lot easier to tuning a coil. It also is about 1% the weight.

Matt

[Scott_Conger]

Congratulations on the successful maiden run of your HCCT

FWIW, a voltmeter on a HCCT is a "fun" thing but not a "necessary" thing. Coils are current operated across a range of voltages, so while you may in fact have weak magnets, there is no certain reason why you must attain 6V with your device.

Since you DO have a HCCT with a voltmeter, your coil(s) should throw sparks anywhere between 2VAC and 4.5VAC, and depending on magnet strength, HCCT RPM might need to be in the 120+ RPM range.

For reference:

Ford Hand Cranked Coil Tester Booklet (2).pdf

(2.91 MiB) Downloaded 76 times

[J1MGOLDEN]

A very knowledgeable individual that no longer associates with Model T things told me the reason for the 1/4th inch gap is because a spark that jumps 1/4th inch in free air needs 2,500 volts to make the jump and in a good compression the spark needs that 2,500 volts to jump .025 of an inch.

That is why the spark plug gap is set to the .025.

I have never found that statistic verified anyplace.