Author Topic: SC 500D Dial (9C) Structural Repair/Restoration  (Read 493 times)

Offline TelePlay

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SC 500D Dial (9C) Structural Repair/Restoration
« on: May 05, 2017, 04:10:58 AM »
Working on a plain 1975 SC 500. All was well and it the dial tested in at 9.45 PPS. But, when turning the dial, it felt like a coffee grinder about half way through the full dial cycle.

Removed the dial from the bezel and tried to see what what dirt or bearing damage was causing the grinding. Turn out it was the three aluminum rectangular posts that hold the two flats together. It's the same construction as a WE 9C. The posts are anchored to the flats by spreading the posts protruding through the flats. The post are quite large providing plenty of surface area to stabilize the flats but the small rivet type posts, if made of aluminum, can loosen over time, as was the case with this dial.

First picture shows the back of the dial.

Second photo Shows the three posts as they appear on each side.

Third photo shows the large rectangular metal supports/spacers holding the flats together.

Fourth photo shows the set up I devised to re-secure the posts. That's a 30 pound chunk of steel with a cut in it which allowed me to drive a round ended stainless steel pin so the head would fit nicely in the to bottom flat acting as a rivet backing bar. The round head fit into the existing round depression created when the metal bars were first riveted in place. I used a large, flat punch on the top post and with one strike, flattened the top post and expanded the bottom post.

Fifth photo shows the posts after re-setting them.

The dial now runs smooth and only lost 0.4 PPS, down to 9.05 PPS, which I suspect will increase once the dial is ultrasonically cleaned and oiled.

I'm sure this has been done by many others in the past and there may even be a topic on it somewhere on them forum. I couldn't find it. Anyway, it's a way to tighten up 9C dials for a few more years use. I can see how dialing over the years would loosen the small posts. The real fix would be to replace the aluminum spacers with, say, solid brass rods of the same length with holes drilled and threaded into each end so the flats could be bolted together with a bit of Loctite on the threads, a real fix but not worth the cost or the time. Would be easy to replace the aluminum spacers with threaded brass if done one at a time.

Once the set up is ready, only take a minute to re-set the three spacers.

Offline TelePlay

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #1 on: May 05, 2017, 05:11:27 PM »
To finish this up, after repair the dial measured 8.48 PPS so ultrasonically cleaned it. I really like the new solution I came up with, and posted somewhere else on the forum a few months ago, that is 2 teaspoons of Simple Green and 1/2 teaspoon of ammonia in 40 ounces of water. After cleaning for 25 minutes, rinsing and drying it, the dial measured 8.80 PPS so oiled it with Moebius. After operating it through a couple dozen cycles, it measure 8.85. Let it sit for 10 minute periods and the PPS kept climbing up (9.09, 9.13, 9.06, 9.05, 9.16, 9.25, 9.29).

So, it stopped increasing at 9.25-9.29, so tried something different. Rather than let the dial return normally, I forced it to get the governor to spin faster than normal, and got this:

9.54, 9.30, 9.73, 9.75, 9.74, (9.75, 9.75, 9.78)

The last 3 in parenthesis were 3 full rotations in a row (like dialing 0 3 times) without forcing a return after the first  9.75 measurement. At least it is now better than the original 9.45 PPS speed.

It seems spinning it fast either spread the oil and/or caused the governor to break up whatever was limiting its movement (spun out some water?) to over do its job.

Learned a lot on this cheap dial. And they can be "saved" when starting to grind (was interesting watching the gears move up and down as the mounting flat walked around with the loose spacers and how that felt when dialing a number).

These are the images after cleaning to show how nice the parts come out of that cleaning solution.

Offline TelePlay

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #2 on: May 05, 2017, 07:09:11 PM »
John, just a quick question. Do you put the entire dial(as seen in the photos) inside the solution when you are cleaning it?

Yes, almost. The shunting and pulse wires are soldered to the black connector block so I bundle those, wrap them around a wood dowel, tape them to the dowel and lower the dial into the solution until the solution just reaches the black connector block. That's deep enough to clean all of the moving parts. When cleaning, I do stop the cleaner each 5 minutes over 25 minutes to rotate the mechanism a few times and use a spring clamp to stop the return in different places so that there are not gear or other contact type parts of the dial that do not get exposed to the cleaning process. Rotating it breaks up loosened crud and gives a cleaner dial mechanism.

When doing a #2, 4H or 5H (with the number plate removed), I just drop the whole mechanism into the solution turning it over each time I rotate the mechanism.

After cleaning (I use distilled water I catch out of my basement dehumidifier to make the cleaning solution), I spray the dial with tap water, shake the water off and then use a wash bottle with distilled water to rinse all of the tap water out (to make sure there are no tap water minerals left when drying the dial). After the distilled water, I use dry compressed air to blow out all water, let it sit in a warm place for a hour or two and then oil the bearing points and gear contact areas.

That seems like a lot of work but it isn't. After the cleaning, it only takes 5 minutes total to get it to the oiling stage, and that take another 5 minutes at the most.

The one liter ultrasonic cleaner I bought a few years ago is one of the best things I've done in collecting restoration equipment. Currently, they sell for $50 to $70 usually with free shipping from a US based supplier.

In case anyone is interested, this one is identical to the one I use and the cheapest on eBay right now.

     http://www.ebay.com/itm/Ultrasonic-Cleaner-1-3-L-Liter-Industry-Heated-Heater-W-Timer-Jewelry-Cleaning-/142338697323

There are others and while listings end, new listings for the same cleaner always show up.

Pvt-telco

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #3 on: May 05, 2017, 08:32:36 PM »
Thank you for all of that info, and I had also wondered if it would do damage to the governor but I guess in this case it does not. And this is a great process when you can't dissassemble a dial like I do due to the fact that most of it is rivotted together, and great job with it.

Offline TelePlay

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #4 on: May 05, 2017, 10:50:08 PM »
I've submerged WE, AE and now a SC governors without problem. The cleaning also cleans the crud pour of the governor. That's why my final rinse is distilled water, to make sure no dissolved solids are left in the governor to harden when it dries out. Also use distilled water for the cleaning solution to keep the ultrasonic waves from driving anything, dissolved solids in tap water, into areas that are impossible to rinse out.

Offline TelePlay

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #5 on: May 06, 2017, 04:12:25 PM »
I forgot to mention that after I blow the dial free of water, I hold the dial in my hand and heat it with a hair dryer on low until the dials warms up to hopefully evaporate any trapped water, such as in and behind springs. I also lubricate the springs since I have seen too many that were rusted when first take out for cleaning.

Offline TelePlay

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Re: SC 500D Dial (9C) Structural Repair/Restoration
« Reply #6 on: May 10, 2017, 06:16:55 PM »
A bit off this topic but related.

Thanks to someone's demand that I have to put 10% ethanol gas in my two cycle engines, I had the honor and privileged today of tearing down my leaf blower carburetor. It just didn't want to run at full speed last fall. Yes, the diaphragm was all ballooned out in all the wrong places. No varnish but the diaphragm was toast, both of them, actually.

The place I bought it said they ultrasonically clean carbs so I thought I'd give it a try. I was really happy with my new cleaning solution (40 ounces of distilled water, 2 teaspoons of Simple Green and 1/2 teaspoon of Ammonia). With 25  minutes at about 110 degrees F, the carb body came out looking brand new. The brass throttle plate looked as good as Jeff's nicely restored AE dial.

The solution also did a excellent job on the plastics. The air cleaner cover stuck to my hand as I threw it in the bath but after 10 minutes, looked like NOS. That mixture is cheap and really works on dirt and grease, even 3 year old sticky grease. Just saying in case anyone want to try it.

And, I get to rebuild my weed eater next week and both of them again in about 3 years. And 3 years after that . . .
« Last Edit: May 11, 2017, 01:33:58 PM by TelePlay »