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Liger Zero
07-07-2009, 05:52 PM
Neighbor is out mowing his lawn, once in awhile he runs his tractor through my yard and mows my lawn... in exchange I run my snowblower across his driveway to break up the plow-bank during the winter.

I'm listening to the mower run here this afternoon while playing with my mill-lathe-drill... Trying to figure out if I can face-mill stuff with it or if it's "beyond" the ability of the machine I think I got it figured out for the most part. More on that later.

Mower is making that laaaaaaaaaaaaaawn moooooooowweeeeerrr sound then all of a sudden BANG *HOAKR* BANG BANG *sputter* DIE *silence*

I run outside and see the neighbor waving huge clouds of smoke away, and I grab the CO2 thing assuming the worst. By the time I got over the smoke was clear and he's got the hood up.

Long story short, this model has a plastic fuel pump that consists of a couple of diaphragms, springs and a pressed in check valve thingy. Over time the plastic body cracked in such a way that the engine flooded though the "suction drive" port, resulting in a spectacular engine shutdown.

I help him get the thing into the garage, he starts draining the oil out and I'm looking at the pump... he's draining the oil out I'm looking at the pump. I put the pump down to help him with the heavy oil pan, then I pick up the pump again... and it happens: "Teh Machinist" kicks in. "I can make this."

Hour later I present him with an aluminum version of the faulty part, sans crack. Reassembled the pump with the original springs diaphragms and valve.

Engine is up and running again making that wonderful lawnmower sound. :) Just for giggles I looked up the cost of a replacement part at the local Engine Shop, $55 dollars plus labor... and that just gets you another plastic bauble.

I bet if I put my mind to it I could duplicate the rest of the pump out of aluminum (not just the damaged part) and it would outlast the rest of the tractor.

Quetico Bob
07-07-2009, 05:59 PM
Right On LZ, what having your shop is all about, besides all the fun stuff. Now if we could just get the other half to understand the principle and the benefits. We would be all set!

Cheers, Bob

Liger Zero
07-07-2009, 06:08 PM
My "other half" used to be a machinist before finishing her degree. Heck I wouldn't be able to manufacture those filters for my friend in quantity without her help, she's quite good with the lathe. :)

Quetico Bob
07-07-2009, 06:13 PM
Some people have all the luck. I'm sure you were not implying a gloat of any kind....:D

Cheers, Bob

Liger Zero
07-07-2009, 06:18 PM
Some people have all the luck. I'm sure you were not implying a gloat of any kind....:D

Cheers, Bob


Machining skills, quotes Star Trek and Star Wars without prompting, "forces" me to go see sci-fi movies with explosions and mile-wide plot-holes and fully understands why I need three lathes not just one or two. We're still working on the bench-grinder thing... as in "what, another one?!"

No sir not gloating at all. :D

Quetico Bob
07-07-2009, 06:29 PM
Some people have no scruples! And your one of them. :D

Cheers, Bob

rockrat
07-07-2009, 07:45 PM
Soon you'll get real crazy like me and start picking them up off the side of the road, fix them and put them on Craigslist.

rock~

tdkkart
07-07-2009, 07:56 PM
Hour later I present him with an aluminum version of the faulty part, sans crack. Reassembled the pump with the original springs diaphragms and valve.

Engine is up and running again making that wonderful lawnmower sound. :) Just for giggles I looked up the cost of a replacement part at the local Engine Shop, $55 dollars plus labor... and that just gets you another plastic bauble.


Before you get too excited, you're local engine shop is making a killing:
http://out2win.com/catalog/fuelpump.html
http://www.jackssmallengines.com/fuel_kpump.cfm

It is neat when you can pull this stuff off though. I can't count how many reduced shank drill bits and quickie welding jobs I did for one neighbor.

John Stevenson
07-07-2009, 08:09 PM
One trick when buying machine tools, either buy them or paint them the same colour.

You need greys or greens because women only see shades of different colours never the same colour.

"Is that new ?"

"No dear it was over in that corner and I have moved it"

"Why do you need three lathes "

"That ones does English threads, that one does metric and that one does American threads "

"So is that why you have three mills as well? "

"No dear that's because that one does rotary 4th axis work, that one does flat work and that one has a tilting head for angular work"

"So which one of the mills does metric ?"

"Now that's the problem I really need a metric mill but it means making more room, how would you organise the shop to make room for another mill ?

Once the organisation has been done how can she refuse a new mill, it was her idea after all ?

.

Evan
07-07-2009, 08:18 PM
So where is the picture of the thong?

Liger Zero
07-07-2009, 08:22 PM
Before you get too excited, you're local engine shop is making a killing:
http://out2win.com/catalog/fuelpump.html
http://www.jackssmallengines.com/fuel_kpump.cfm

It is neat when you can pull this stuff off though. I can't count how many reduced shank drill bits and quickie welding jobs I did for one neighbor.

Yeah that's quite a price diff even considering shipping.

Problem is though those are still the same sort of plastic-fantastic crap that I hate.

Having a background with the stuff I know for a fact the chosen material and the application do not match. This sort of service calls for a metal piece.

Liger Zero
07-07-2009, 08:23 PM
So where is the picture of the thong?
Let me check with the wife before I post it.

wierdscience
07-07-2009, 08:42 PM
Good on ya,it feels good to win one every once in awhile.

Circlip
07-08-2009, 05:29 AM
Whilst your observations on the right material for the job are admirable LZ, compare casting and machining with a one shot plastic molding. Not advocating the latter, but down to eekingnomics.

Regards Ian.

Liger Zero
07-08-2009, 12:35 PM
It's not a one-shot plastic piece, three separate pieces for the housing and at least two for the valve.

I know for a fact that molding these in bulk would cost far less than casting or machining. *shrug* No intention of going into mass production.

Errol Groff
07-08-2009, 12:42 PM
So apparently your neighbors mower did not look like mine did last spring after it suddently stopped..

http://neme-s.org/Fire/a_hot_time_in_the_old_town_tonig.htm

Now using a new to me, pre-owned, MTD rider that works great so far. $250 vs. the $1000 to $2000 for a new one.

Liger Zero
07-08-2009, 12:48 PM
So apparently your neighbors mower did not look like mine did last spring after it suddently stopped..

http://neme-s.org/Fire/a_hot_time_in_the_old_town_tonig.htm

Now using a new to me, pre-owned, MTD rider that works great so far. $250 vs. the $1000 to $2000 for a new one.

Yeah. I saw all the smoke and assumed that's what I was going to encounter in the back yards. :eek:

You'd think they'd design these pumps so they don't suck an entire tank of gas into the crankcase upon failure... or is that intentional?
...Slow leak slowly poisons the oil and causes the bearings to seize suddenly.

Wouldn't put it past them.

oldtiffie
07-08-2009, 01:13 PM
John,

you live dangerously but can still charm the birds both out of the trees - and their knickers - but the boom will be lowered sooner or later!!!

Live a short life but a merry one - while the good times last!!

I must say that post as a good example an alternative colourful language. I am tempted to give it a go but being of Irish (Mick and Prod) extraction, I may only see things in shades of green and orange as opposed to some who only see in black and white with no recourse to shades of grey - at all.

I wonder how LZ would go with that stunt of yours with his wife being a machinist??

If he did, I'd guess we'd be passing the hat around for two widows instead of one.

digger_doug
07-08-2009, 01:30 PM
Neighbor is out mowing his lawn, once in awhile he runs his tractor through my yard and mows my lawn... in exchange I run my snowblower across his driveway to break up the plow-bank during the winter.


Last time the neighbor did that to me, I borowed my friends backhoe,
promptly dropped (2) 4,000 "mafia blocks" on the property line
to keep him out. Had a delivery of fire wood, used my driveway,
and drove over my field (to get to his place) he told the driver
it was o.k. to do (85,000 lb oshkosh) never did fill the ruts.

Has a tractor mounted snowblower, and never once offered anything,
even after doing a portable weld job, and other work for him for
gratis.

There are friends, and there are neighbors.....

Your set-up sounds like a better situation.

Liger Zero
07-08-2009, 02:39 PM
The arrangement came from me having a "just" a snow-blower and him having "just" a lawn-mower for awhile.

Works out quite well, I love blasting those huge plow-drifts apart with the 'blower. My kind of winter-sport. :D

The Fixer
07-08-2009, 02:59 PM
So many of these small engine units sit idle for long periods and condensation forms in the fuel tanks causing most of the carb problems. While that aluminum piece you made may look nice and even work well there is a strong possibility that down the road it may well be the cause a of poor running condition due to corrosion. Some manufacturers have even gone to plastic carb bodies!

jmho
al

Liger Zero
07-08-2009, 05:13 PM
Interesting.

It's a tradeoff situation and here is how:

Plastic materials fail when exposed to petrol, sunlight, temp changes and vibration. Even a petrol "resistant" polymer will degrade over time, especially when the other factors are present.


Aluminum does not degrade in sunlight, will not fail from this range of temp changes and the vibration is a non issue.

Long term the corrosion could be an issue but my thinking is given the amount of "plastic-fantastic" in the rest of the engine something else will cause a permanent failure long before this block of aluminum does.

Falcon67
07-08-2009, 05:25 PM
From my manufacturing days - I remember engineers telling me that all plastics shrink. Depending on construction, they will eventually fail in some capacity, crack, split, embrittle, etc. Fuel or no fuel, in the sun or in the dark.

Liger Zero
07-08-2009, 05:36 PM
From my manufacturing days - I remember engineers telling me that all plastics shrink. Depending on construction, they will eventually fail in some capacity, crack, split, embrittle, etc. Fuel or no fuel, in the sun or in the dark.

The amazing thing is I sat in class after class at Umass to learn this. :D

One of the reasons you can't just up and change a material on the fly, each mold has to be built for the material. Nylon is going to behave differently than Krayton.