Why Build Excellent CAD Into Your Awesome CAM Product?

My Crom, am I that far removed from automotive work that I've forgotten what a serpentine belt looks like? My last two vehicles have been new, and I've had very little to do under the hood since then except a few belts per decade since 1991. Astounding. Har!

Make a sawtooth cutter for less resistance? (Juuuust kidding.)

(Hadda look DP up: Diametral Pitch, right? "The Diametral Pitch of a spur gear is equal to the Pitch Diameter divided by the number of teeth on the gear. The Diametral Pitch of a spur gear may also be calculated by adding 2 to the number of teeth on the gear, and dividing that total by the Outside Diameter of the gear.")

That's the great part about knowing how to build your own stuff, isn't it? My life wouldn't be -nearly- as interesting if I wasn't a full-blown tool user. How do the tool-fearing folks manage? Wow!

They probably wonder why we'd want anything we can't just buy.

Browning had relatively reasonable replacements for the munged gears on my ex-trade school South Bend.

-jsw

With good reason.

This set of values and attitudes about making and fixing things, which we mostly share here, is fine as long as you don't do a complete accounting -- including what else we might do to make money. It's best not to dig too deep, because it could make one cry.

I think about it every time I'm fixing my 60-year-old furnace or replacing 90-year-old cast iron plumbing, while my son (who barely knows which end of a screwdriver to hold on to) is frolicking on a warm beach somewhere, chasing girls. d8-)

That's great! Now you have an ex-trade-school South Bend with nifty gears!

I wonder about my choices until someone mentions their $200-a-month cable bill or an auto body shop tells me the quarter-sized rust repair I made would have cost $800.

The bank sent a credit card ad offering purchase points for typical bills, which it listed as $99 for cell phone, $134 for cable, $129 for electric, $225 for gas and $450 for groceries. I pay less than a quarter of that.

Think I'll go down and pump some more transmission oil into the 1968 Maytag.

-jsw

So you save about $9,300, not counting your time. Now try figuring your time.

That's a little less than I got for my last raise. You're a Mensa member, right? Think about what you could be making.

Or don't. It can make you cry.

Seriously, we do these things because we want to, not because it makes a lot of financial sense.

And besides, when I cut out the old 2-in. cast iron drain pipes that run down my wet wall, I had a great excuse to buy a new Milwaukee Sawzall. What could be more fun than a new demolition toy?

Two thousandths over 250 feet, in crossed axes and parallel for height? The best part of a job like that is that the customer couldn't measure it, anyway.

It's like the job we had making electrical connectors for Princeton's Tokamak fusion reactor, in 1973. There were tapered holes bored through the center of the cylindrical connectors that met at the middle, specified to +/- 0.0002" at specific distances from the ends, with an additional spec for straightness of the tapered sides. We called every metrology equipment manufacturer in the country and no one could tell us a practical way to do it. We could have used metering balls except that we'd get incorrect readings if the roundness wasn't there, and this was electrolytic copper. Roundness wouldn't be there.

So we told the purchasing agent we'd have to turn down the job. "Don't worry about it," said the P.A. "Our engineers couldn't measure it, anyway." So we made 2,000 of them and they were happy.

Gunner , that was a sometime-in-the-future-maybe-probably attachment for the Gingery shaper I'll be building . I have neither the money nor the need for a gear shaper .

The R&D business rises and falls with the economy. When I worked I put in lots of overtime and let everything else go, in between I tried to catch up. I've been retired for a few years and am still trying to catch up.

My machining and computer "hobbies" were efforts to learn job-related skills such as Windows administration. I post here to practice technical writing. A lack of communication skills hindered my advancement into engineering.

-jsw

I want to build a shaper for the same reason a dog licks his balls . Because I can . I have the materials . I have the equipment . I have the time . I wiill be paying for the propane I use to melt my aluminum , but that'll be the only out of pocket cost - and I'd be very surprised if I use over 20 bucks worth .

I found that home-machined demo parts to pass around at meetings convinced the Ph.Ds to tell me the final result they needed and let me figure out how to accomplish it, especially when it was outside their discipline. Electrical engineers are easily impressed by mechanical tricks, and vice versa. Chemists had to be fairly familiar with everything since they could be working alone.in any industry.

-jsw

I pay $120 for two landlines + DSL + Trac phone, $47 for electricity, $51 for gas, zero for cable ($12,000 savings in a decade), and a couple hundred in groceries. We're atypical, I believe.

I just put ~$18 into my 2002 MagicChef (by Maytag) washer this morning. It was leaking at the pump, so I traced it to a leaky drain hose. The replacement was $16.95. It was slow to fill on hot so I replaced the totally crusted-up sieve washer on the hose so it let water through again. The rust on the screen was solid.

A job I worked on specified a 63 finish on a tiny inaccessible taper, about like a countersink with a .100" diameter around a .050" hole. No way to get any kind of gauge to check it.

We finally asked the customer's engineers how they checked it.

"We just look to see if its shiny!"

David

One of the reasons I don't reload ammo is that the alleged cost savings don't factor in the value of my time. That's OK for those who find reloading recreational in itself. I don't, I'd rather spend more time shooting.

And I haven't done an oil change in years, I can't do it as cheaply as I can have it done, especially since they put oil filters where you have to lift the car to get at them.

Not interested in paying someone to shoot for me, though.

:^)

David

David

On the other hand, if you relax the tolerance on inch parts to two decimal places the odd-numbered eighths are always wrong.

-jsw

My overly ambitious beginner project was a milling vise for a small lathe. I learned many valuable lessons about cutting and measuring accurate dovetail slides, such as not to try it again without better milling and measurement equipment.

-jsw

Notice I wrote for a LATHE. The vise part of it came out well enough. The problem was smoothing the milled vertical slide dovetails without degrading their accuracy.

-jsw

I think you've overcome that lack, Jim. You're posts are always clear, which is most of the job of technical writing -- besides having a pretty good idea of what you're talking about.

That's become my approach, too. I build flyrods because I love building fishing rods, but I only do it when it's too cold to fish. I wouldn't spend a minute building one when the trout are rising.

I admit, though, that I still change my own oil and filters. It probably doesn't make any sense but I know just what oil is going in there, and I don't use cheap filters.

I don't trust those oil-change mechanics. I use a new copper washer; clean the seats really well; and I use fresh oil on the filter gasket. I've seen them applying used oil, and I've had to poke a hole in filters they've seated to get enough purchase to remove them.

I do have good ramps.

Dovetails don't scare me . I've built a Holes Creek ball turner for the lathe and a boring head for the mill with brass gib locking dovetails . Both have micrometer adjust . I had this book several years ago and actually started making the patterns then just lost interest . I have a lot more time now and my skill set has grown considerably . The time has come .