Designed To Fail: How Cheap Manufacturing Turns a New Saw Into Trash

csusbgeochem1 (57)in #life • 6 years ago (edited)

How a $7 USD Part Fixed The Profit Margin

One persons trash is another persons treasure! Welcome everyone! One day while out in the garage going about working on what I was, @beckymeep was out walking the dogs. Next thing I know I look up and see her with a used table saw slung over her shoulder. I thought "what the?". Turns out she found it on a curb, obviously left out by someone who didn't want it, so she picked it up and brought it home. We don't own a table saw, and Becca figured it would be a nice addition to my tools. I considered, if the motor was still good then it was worth the fix. Honestly I had a friend with me hanging out, who gave me the idea to do a steemit post on this as well as help me get the pictures.

Tools Required For The Job

Vice Grips
22mm Deep Socket
Socket Wrench
#2 Philips head screw driver
Digital Multimeter
Spare piece of 12 gauge wire at least 6 inches in length.
NEW 125 v 20 amp Single Pole Single Throw (2 spade connector) Rocker Switch

So Whats The Deal With This Curbside Pickup Anyway?

The first thing that came to mind when we set this thing down was "whats wrong with it?". After plugging it in and no response from the switch nor thermal reset button; I pulled out the digital Multi-meter, Philips screwdriver and was set to figure things out.

I flipped it upside down to reveal the internal components. I was interested in checking out the electrical connections located inside a plastic box.

First, for safety reasons, the saw blade needed to be removed. The center nut was a 22mm and to keep the blade from rotating, vice grips were clamped to it. I was VERY CAREFUL as the saw blade was sharp.

Once the blade was removed, the center nut was replaced so I did not loose it.

The Philips screws on the front were then removed to free the plastic box to reveal the electrical components.

I made sure to store all hardware in a safe location.

After unscrewing the box I noticed it wouldn't budge and needed to remove a bracket retaining the power cord to the frame of the saw.

Once removed, I slid back the plastic box from the rear of the power switch and circuit breaker to reveal the terminal connections.

To be safe I marked both top wires with permanent marker so I would not mix up the wiring.

I Decided to first test the circuit breaker for continuity.

I first set my Multi-meter to the lowest Ohms setting available.

I then prodded both the rear spade connectors with the Multi-meter probes.

Continuity exists with a complete circuit. The small amount of electricity sent out by the Multi-meter is detected by the probes to prove continuity. This is evident by the small detection of resistance in the circuit. If no detection of resistance, the circuit is broken and the part is bad. The circuit breaker reported a small amount of resistance and therefore showed continuity and was good.

Next up was the switch before moving on to testing the motor.

I conducted the same test as with the circuit breaker. The rear of the switch was noticeably more dustier

And BINGO! No continuity was detected at the switch meaning it was potentialy dead.

The connections to the switch were removed and a jumper wire was used to jump the connections, essentially bypassing the switch. If the motor ran when plugged in, the switch was bad.

The motor was then plugged in and tested for viability.

As shown in the video above the motor started up with the jumper wire installed. The switch was the culprit so I removed it from the saw to check out what type I would be needing. This is where I discovered a SERIOUS manufacturing flaw.

The switch, that was rated at 12 amps max at 125 volts, was used to turn on a motor that had a PEAK draw of 15 AMPS at 120 volts!! My first thought was this was a mistake so I checked the circuit breaker rating to make sure it was the same as the switch.

NOPE! It was rated properly to run the motor, with a peak of 15 amps. This would throw the breaker if the 15 amp motor overloaded. BUT WHY put a 12 amp switch in line with a 15 amp motor? It did not make sense and the nearest I could figure is they cut cost on manufacturing by adding in a lower rated switch. This means that if the motor was put to its max for a long enough period of time, the switch would fail long before the circuit breaker tripped to protect the motor. This was a serious manufacturing flaw, basically guaranteeing anyone really using this saw would melt the switch and break the saw. Unless someone was smart enough to check, it would just be another trash item.

I sourced a new switch with a peak amperage of 20 amps, so that the switch was rated well above both the motor and circuit breaker. The switch was $7 USD total not counting the 30 miles worth of gas used to pick it up. The manufacturing part number is listed below in the picture.

Now although the new switch did not have the lock out pull tab, the dimensions were exactly the same fitment.

I installed the new switch and plugged in the rear wires.

I screwed back on the protective box and the bracket that held down the power cord.

Once everything was back together I made sure to confirm the switch was functional and that the saw was now in fully working order.

So for a total of a half hour of time and $7 USD @beckymeep and I came up on a working table saw.

Thanks for taking the time to read this post and I hope that all of you out there find a curbside pickup to build upon.

All photos, unless stated or sourced, belong to @csusbgeochem1 and require permission for reuse. Animations and cover photo created by @csusbgeochem1 using GIMP.

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#engineering #woodworking #steemstem #socalsteemit

6 years ago in #life by csusbgeochem1 (57)

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steemseph (65) 6 years ago

I'm really happy when I see someone reusing and repairing. Wanna know what sucks? Some people just don't think they have time for anything else than to throw it away and be done. Sometimes, when I'm working with a "facilitator" or "logistics" type person that's serving a another group (the bread winners), we are unable to save things or even spend time considering the reusability of some items that are "in our way."
Pfff... especial if I am "on the clock." I try to convince my boss to let me get it repaired and I use local repair shops. Shops with nice real people in them. Not "burger flippers."

Also twisted is... some consider their trash a potential liability thereby restricting reusability.

We are conditioned to think more is better too. Oh and then there's planned obsolescence... i'm sure you've discussed it all before.

Awesome DIY post!!!

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effofex (62) 6 years ago

Totally adding this to my little file of examples of 'why design for maintenance and disassembly matters'.

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mattlovell (49) 6 years ago (edited)

The original switch was rated at 19A@125V and 12A@250V. (using the UL standard)

You will see your new switch is rated similarly (20A@125V and 15V@277V, and a weird 16A@150V below the line), Its just notated differently.

Awesome find though! its amazing what people throw out...

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csusbgeochem1 (57) 6 years ago

OH so thats what the 19 and 20 mean. I guess those are two different standards, I was confused by the difference in one amp. Figured those might be model numbers, but was also wondering why both voltages were rated at the same amperage.... Still makes you wonder why the switch went before the breaker lol.

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mattlovell (49) 6 years ago

well, I think you where right in your assumption that it was to save a few cents on the manufacturing... things are not built like they used to be. that table saw wasn't meant to be put to continuous use, or passed on to your kids... it was a 'disposable' tool... you just gave it a second life :)

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Designed To Fail: How Cheap Manufacturing Turns a New Saw Into Trash

How a $7 USD Part Fixed The Profit Margin

Tools Required For The Job

So Whats The Deal With This Curbside Pickup Anyway?

Awesome DIY post!!!

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