broken Pneumatic ratchet

[LCHIEN]

I went to use my pneumatic 3/8" drive ratchet today. Hadn't used it in quite a while.

It ran but wouldn't stop. It has a lever which actuates a plunger and the plunger is sunk all the way down and so it acts like its pressed and the plunger won't return to the up position.
There's a screw cap opposite the plunger on the body of the ratchet.

Its a Craftsman I got some time back from eBay but there's no part or model number visible anywhere.

Any suggestions on what to do, what to look for?

[Stytooner]

Sounds like it may just need some TLC. Take it apart being careful not to loose anything (spring) and just clean and lubricate it. Inspect the O-rings if present. Petroleum jelly works great when putting it back together. Careful again not to plug any tiny holes with it.

[LCHIEN]

Upon inspection and reading another thread on another on-line forum I took the cap off and it revealed a spring, a gooey mess of plastic, and the other end of the plunger button.

I guess there is a plastic ball spring loaded against a seat and the plunger pushes it against the spring to let air by.
The plastic ball valve disintegrated over time.

I read that a ball of 11/32 or 3/8" steel (think ball bearing) was used to replace the plastic ball and it works fine? The plastic ball is $4 and another $8 shipping.
Why Sears used a plastic ball is beyond me.

So I'm thinking a steel ball from the hardware store is the way to go.

Any comments?

[dbhost]

It all depends on the design. My old Blue Point did the same thing last year. There is a screw on cap that looks kind of like a brush cap just opposite of the plunger part of the trigger that comes off, there should be a seal on a spring, in mine that dried out and broke off. I just ordered a replacement. HOWEVER you need to know the model number of the air ratchet to get the right parts...

For what it's worth, I got the cheapie Central Pnuematic air ratchet while I was waiting for Snap On to send me the parts I needed. It works almost as well as the Blue Point, and if it breaks, I just send it to the recycler without worrying...

[LCHIEN]

yeah I see HF has several models all alike for about $20 which means $16 with a coupon...
So if it takes too much effort to fix...

[LCHIEN]

THis is a picture of a Sears air ratchet ball valve from

http://www.searspartsdirect.com/part-number/81015215/0009/875.html?utm_source=google&utm_medium=cse&utm_term=81015215&sid=SPDxGPROD&gclid=CMSgwbGngMkCFVFafgodG9gIGA#

but I don't know for sure that its from my air ratchet, having no visible model number.
Its a semi-ball and has a recess for the spring on the opposite side.
But the guys at the other forum said that a steel ball worked fine.
Guess its worth a try for less than a buck the ball would cost.

[LCHIEN]

Cleaned out all the crap from the old plastic valve best I could. Jewelers screwdriver, WD-40 and a Q-tip.
dropped a 3/8" chromed ball bearing in the spot.
Cap has a small recess to hold one end of the spring, the other end would rest in a recess in the plastic valve but in this case will just push against one side of the metal ball.
works great, leaks no air.
43 cents at Ace Hardware.

All fixed.
Probably last a lot longer, too.

[Stytooner]

Excellent repair job. That is probably one part that you will never need to replace again. Can't say the same for the seat though.

[LCHIEN]

i thought of that. Looks like it seats to an o-ring.
Even if it doesn't, It doesn't get that much use. If the seat wears out, look out HF!

[dbhost]

That semi ball seat pic you show looks exactly like the one from my Blue Point air ratchet. And I can almost bet the HF air ratchet is the same part... It is probably pretty standard...

I am liking the metal ball idea though. Pretty cool and I bet it will radically outlast the original! And the seat, and the impeller, and... you get the idea.

[LCHIEN]

The thing that bothers me is...

I'm an engineer with lots of experience, But I've never made consumer goods. Always high dollar, tough service oil-field industrial equipment whose annual quantities could be measured in most often 5-10 pieces per year to maybe as many as 1,000's per year. Compared to consumer equip which is 100,000 per run.
The development expense was always a huge part of the cost.

IF we were designing such a valve it would be machined steel - partly for longevity and partly because designing a molded plastic part would be prohibitively costly for up front mold costs.

The fact that Sear's contractors could design a air ratchet with sales point of $40 to 60 dollars and causing this thing to have a life span of say 15 years before a major failure. whereas putting in a metal valve instead of a plastic one could make it last 30 years and cost maybe a dollar more???

We see this all over - my garage door openeer has plastic gears that wore out after 15 years... a new set of gears will make it run another 15 years, but why put me thru the headache, and expense of fixing it (or as many people will do, simply replace it). A set of metal gears would have lasted 30 years or more and be only a few percent more expensive.

And the in this case, its not obvious to me, why do they use a custom molded part which cost them a molding expense and then parts which they pop out for a penny apiece, vs. a ball bearing which thy can buy in 10,000's without NRE costs, for a few cents?

Do we live in a throw away world? Is there some secret profit motive in spare parts and replacing tools with deliberately limited lifespans (e.g.a weak part that has to be replaced)

I can tell you this, if I saw a tool or door opener that cost 50 or 100 dollars and it said plastic gears, will last 15 years under normal use
and next to it was another that cost 52 or 102 dollars and said it it had metal parts and would last 30 years, which would you buy?

Too bad the gears and valves are inside where you can't see them!

[LinuxRandal]

As an engineer, you are given a set of parameters to design to.
As someone who has turned wrenches, we HATE you engineers, sometimes, for how tight of quarters you leave us to fix things. In that case, HOWEVER, the engineers design for the assembly line, and NOT for the mechanic (speed of assembly). They then employ ones to take the vehicles apart to figure out book time and if any special tools need to be made.
This isn't any different.

Sears contractor, is probably not exclusively contracted to Sears, so there may be design goals from multiple companies. Also, in the air ratchet case, not everyones air is clean (moisture/dirt issues), so that may be a design choice.
Then you have economies of scale and new tech like 3d printing. (cheaper molding, quicker patterns, and parts cost drop, per quantity, verses parts that drop to a fixed point, due to obtaining quantity. aka plastic molded parts, verses metal purchased parts)
That doesn't count the business man perspective:
1. I need to make three times what the cost of any part is (and fit in a price point that I know will sell x)
2. I am NOT providing anymore then legally required repair information, because I don't want to be responsible for fixing someone else's screwup/attempt to fix. I also want this to be at a point that they buy another one, rather then fix it. I don't want to have to carry parts, longer then I am required, unless I can use the same design, over and over and over and over.....
3. Short term, my stockholders want to see a profit this quarter, they don't care about their retirement funds being up in 25 years.

We do live in a throw away society. They call it a CONSUMER society, NOT a CUSTOMER society.
I would be surprised if your ratchet didn't match Chicago Pneumatics air ratchet. They used to rebrand them for a lot of people including Sears. (some of the higher end ones were IR). I don't remember the prefix number for them though. (off the top of my head, something like 928),

How would the plastic gears, affect the motor if they were some other metal? (as the company) Would we be replacing more motors, which are more expensive, under warranty, then the x number of gears we either fix, or send out replacement parts for the customer to fix?

[capncarl]

I completely agree with your statements about tool mfg's cheapening a product by using sub standard parts. That's what I've been ranting about with my Ridgid battery tools. I've thrown away a box load of pneumatic tools for exactly the reason cited here, and most of them were pre harbor freight when their replacement was costly!
I've researched online battery problems for our handheld tools quite extensively and found that nearly every mfg has problems with their batteries. The ones that didn't seem to have problems, I suspect that they have wiped the negative reports off the internet. One of the main problem that is obvious with lithium batteries is the way the battery likes to be charged, each cell likes its own charge. Radio control plane builders figured this out years ago. The tool mfg's keep building batteries with the cheap chargers that overcharges all cells or half charges some and the batteries die. Some mfg's even go as far to keep from fixing the problem as put in circuitry that switches the battery off when it has a problem, like that was going to solve anything, and the consumer has to buy a new battery. Properly charged a lithium battery would last a very long time, longer than the plastic tool it dangles from.

What LinuxRandal said about engineers is true as well, they should have to work on their own products before the first one sold. That would show them. If you think the automotive engineering is bad about building something hard to work on just look at the recreational boat engineering, or lack of it. They build a hull, throw in the wiring harness, plumbing and gas tank then lay the liner which is the floor, sides and top cap then they inject expanding foam in that void. As well as being floatations, which they proudly boast safety, this foam stiffens up the pitifully thin fiberglass hull and supports the floor. Some of the better builders use plastic pipe for wiring conduit to essential electrical devices so the cheap wires they use can be replaced the day the warranty runs out, but most builders skip this part. These way overpriced water toys are virtually impossible to work on without sawing them to pieces.
Enough of my rant.
capncarl

[dbhost]

I am not going to fault the engineers for designing products that aren't serviceable. That is not what they were tasked with doing. If you want to fault anyone for maintenance / serviceability being an after thought at best, blame the executives and bean counters that figured out long ago that they can sell us more crap if they build crap that breaks and can't be easily repaired.