Brother CS-80 sewing machine bobbin winder not winding.

Brother CS-80

Yuck. What you have there is a bad case of decomposing rubber. That's when the vulcanization (sulfur cross links) fail and the rubber returns to a sticky, gooey, messy blob.

Ummm... it's totalled and is not going to work. Replace the bobbin winder assembly.

The black slime is what's left of the rubber bobbin drive. I can't tell from here what caused the disintegration, but the most likely cause are aeromatic hydrocarbon solvents found in cleaning solutions. Furniture stripper, carbeurator cleaner, and such might cause it. However, if the rubber was properly make, it should be impervious to solvent attack. However, if the rubber was badly made, it might happen.

If the other belts were properly cured, they would be impervious to solvent attack. Looks like the bobbin winder drive wheel wasn't made so well.

Wrap the mess in cellophane plastic wrap to keep the sticky mess from migrating. The stuff is very messy and difficult to clean.

This looks like the correct assembly. Please verify before ordering:

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Hi Jeff,

This machine was never opened before so I'm going to say that the wheel was made as cheaply as possible. It was stored for a while and maybe sitting around in the garage may have exposed it to temperature extremes. In any case, thanks for the great links. That allowed me to search for the rubber ring

($4 + $3.25 shipping) instead of the whole assembly (~$19 + $11 shipping).

Thanks for your reply.

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David Farber
Los Osos, CA

I don't think that will work. That's for a babylock series machine. The CS-80 is not listed on the list of compatible sewing machines for the rubber tire. There was also a note on one of the pages I listed indicating that the rubber tire was NOT available seperately. Unless you want to experiment, methinks you will need to purchase the entire assembly.

Nothing useful in the manual:

If you want to go cheap, measure the size of the rubber tire and visit your local plumbing or hardware supply store. Dig through the pile of rubber faucet gaskets for something similar. The exact shape and size is not very critical, as long as it makes contact and doesn't slip. If you're really cheap, get a slightly larger o-ring, cut it to size, and glue the ends with cyanoacrylate adhesive. There might be a slight bump as it turns, but it won't affect anything.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

winder.jpg

winder-2.jpg

winder-3.jpg

top

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way,

I've never sen te like of that, gooey rubber plenty of times. So all that model will go the same way. Presumably the result of over-plasticised plastic rather than a rubber formulation as you say it is non tacky. Whenever that happens with rubber then there seems to be a contagion that affects all the rubber bands in a piece of kit, perhaps not the case with what you have there I would get some small neoprene O rings and stretch 2 or 3 over the pulley to take up the width , if not enough diameter then 1 or 2 more stretched over that underlying layer. Then perhaps look out for a proper replacement

Hi Jeff,

I actually did a bit more research after my last post to make sure I was getting the correct part. This place lists the tire as compatible with the CS80 model so I purchased it there.

I really don't expect Brother, like many other companies, to make it easier for you to buy one small part off of an entire assembly when it can make more money selling the whole thing. This has been going on in the service industry since the beginning of time. I don't consider myself being really cheap. I consider it being smart. Speaking of cheap, how cheap was it of Brother to use a tire like that in the first place?

Thanks for your reply.

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David Farber
Los Osos, CA

I may have to resort to a home made repair as you suggested if the $4 tire I bought isn't a good fit.

Thanks for your reply.

--

David Farber
Los Osos, CA

I

And is the "proper" replacement going to be plastic also? If you burn a bit of the gooed original is it a rubber or plastic smell?

I assume before the tire morphed into the tacky mess, it was made of rubber. The replacement I ordered will also be made of rubber. After a bit more research, this is the website where I placed my order.

I already cleaned off the mess so I don't have any sample left to burn. The plastic pulley that supports the tire looks good and does not appear be deformed in any way.

Thanks for your reply.

--

David Farber
Los Osos, CA

Ok. That should work.

The fun part will be getting the sticky rubber goo off the plastic spindle. Have your latex gloves and noxious solvents handy.

Actually, they don't want to sell any parts. Most of the parts available come from 3rd part aftermarket vendors, that either reverse engineer the parts, or have some manner of arrangement with the factory. Some countries require manufacturers to provide parts for anywhere between 5-10 years (such as 10 years for autos in the USA), which is what inspired this practice.

Incidentally, I managed to find the one Brother sewing machine that lacked a downloadable manual from their web pile (XL2030). So, I sent them an email asking for a copy and was rewarded with a free printed original in the mail. I have access to a very fast Canon document scanner and plan to scan the manual eventually. (4.1MB) Notice that it's scanning both sides of each page.

Yep. However, I've also seen it from the manufacturers point of view. It's much easier and more profitable to setup a board exchange program, than to sell individual parts. Brother is not going to get rich selling $3 rubber tires.

Incidentally, I once calculated what it cost my employer to ship an empty box. That's a product that costs zero to make, but which still has to carry the overhead such as purchasing, inventory control, documentation, billing, shipping, etc. That was $75 in about 1980. Probably much more today.

I consider myself very cheap. If a used rubber tire were available, I would buy it.

I haven't bought O-rings and similar parts for many years, but I do recall paying about 2 cents each for something similar in quantities of 1,000.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

rubber.

The

About 2 weeks ago an audio cassette recorder returned for repair. It was made in 1986 and I repaired it about 15 years ago using a 2 cents O ring, stretched onto the take-up spool pulley. Not bad for about 3 hours use a day, someone who never moved away from cassettes . That O ring had eventually split but no gooey mess, replacement one a bit thicker and a bit larger diameter

(...)

I repaired 16 mm motion picture projectors in my yout. A *very common* problem was transmogrification of the neoprene drive wheels and belts into a gooey mess.

A quick replacement, but a slow cleanup first. :)

--Winston

When I first started out in the business (mid 1970's), I had an Ampex reel to reel machine come in for repair. Probably this exact model:

I opened it up and I had to ask my boss what the gooey black stuff was inside the machine. To me, it looked like somebody had spilled sludgy motor oil into it. None of the belts were recognizable. I soon learned to stay away from those Ampex machines as every one of them had the same problem.

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David Farber
Los Osos, CA

did you work for NASA or some other goverment organization?

I usually ignore one line cute remarks, but since this is a topic that interests me, I'll make an exception here.

No. I have never worked for the govermint. I did that calculation working for Intech Inc, in Santa Clara CA, for the marine radio division.

If you have a problem with my numbers, try doing the calculation backwards. Take a publicly traded company (so that the numbers are available), and obtain a number for how much they spend each year on everything. Then, multiply their approximate parts and labor costs times the number of units shipped in the same time period. The difference is the selling price plus overhead, which must be paid by the customer. Assume break even and zero taxes to keep things simple. Divide by the number of units shipped and you have the cost of shipping an empty box with zero value contents.

Yet another way is to use a rule of thumb. Conventional wisdom has it that in order for a company to grow, it has to sell its products at about 5 times the cost of parts and labor. That makes the parts and labor only 20% of the selling price, with the rest going to overhead, taxes, growth, dividends, and the executive retirement plan. Therefore, the cost of shipping an empty box would be the 80% of the average product selling price.

Incidentally, iSuppli has done the difficult part for many products. For example, the cost of manufacture for the Amazon Kindle Fire is about $202.

Amazon sells it at roughly cost. No clue what they're thinking.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

This math is as nonsense as those "calculators" from places that do backups and datarecovery where you type in numbers and they claim you lose

10% of your annual revenue per minute your computers are down or whatever.

The only way it costs $75 to ship a box is if you factor in your 100 million dollar failed SAP installation as part of your "billing costS" or whatever, and then blame the box for the expense.

That might be a stretch, but the real numbers are fairly close. If the sales organization can't take orders for a day, that business will probably go to their competition. Assuming 7x24 or about 350 working days per year, the loss of one day sales is 1/350 the of the gross, or about 0.3% The actual losses will be higher due to repair/recovery costs, overtime to recover, and loss of reputation. The last is fairly significant. I know of one shopping web site that went dark for only about 3 hours. However, there was a dramatic drop in subsequent sales for about a month due to rumors that the company had gone out of business because their web site was down. My guess is about 1% overall loss for a days downtime.

I don't think anyone would be interested in my 30 year old calculations. Also, I can't disclose number for current customers because of confidentiality requirements. Sorry(tm).

Perhaps the 16GB iPhone 4S would be a suitable example. It costs about $200 to manufacture, but sells retail for $500 from various vendors, or $650 from Verizon. Using the $500 sales price, the cost of shipping an empty iphone box is: $500 - $200 = $300 The $300 pays for everything EXCEPT the product. For Verizon, 3.25 times cost is rather low for electronics. 4.0 to 4.5 times cost is more typical.

The $75 per empty box is problematic, but the reason is not obvious. If a company shipped just one product, the $75 would be valid and useful. However, if the company shipped a wide variety of products, some expensive, and others low cost, the overhead costs would be distributed unevenly among the various products and quantities. It would not be possible to assign a single "empty box" price tag to a single product. It could be expressed as a percentage of selling price (markup), but is usually more complexicated, having a fixed cost for fixed overhead, and a variable cost that depends on the product cost to manufacture. My $75 figure was mostly the fixed overhead, that was not attached to any particular product.

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

this would sound more reasonable, but it all depends on what the business does. Airlines barely function when their computers are running, shut them all off and they they just don't work at all.

If your business is a tuckpointing company, it's doubyful you'd even know if your own website was down.

this has to be a joke. If you're not from NASA, it's got to be lehman brothers, enron or arthur anderson to say with a straight face that it costs $300 to ship an iphone because the retail price is $500 and the phone costs $200 to make.

The new tire arrived and it fit perfectly. The dimensions of the unmounted tire are:

16.5mm o.d. 9.8mm i.d. 3.7mm tire thickness

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David Farber
Los Osos, CA

Quite real. The $300 difference between the retail price and the cost from Apple is a conglomeration of profit and expenses. The profits to Verizon and its stockholders. The expenses are a mixed bag of executive compensation, sales incentives, advertising, taxes, packaging, shipping, distribution, documentation, support, shrinkage, returns, repairs, political contributions, debt retirement, assorted bribes, charitable contributions, publicity, lavish product announcement parties, slush funds, ad absurdium. If you think you can sell a smartphone with less overhead, you're welcome to try. If you need reassurance, just take any company and estimate the number of employees that do NOT directly contribute to the production of the product. People that do design, engineering, bookkeeping, support, shipping, warehousing, etc. Now, try to run a company without them. (yes, I know you can outsource or virtualize an entire company).

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS