What Did You Buy Today?

[rwdenney]

That’s one of the reasons cars switched to alternators. If he had a generator system the voltage could have been fluctuating with engine speed. Don’t know for sure if this is the case with LED’s but certainly so with incandescent bulbs.

Either way it got your attention which is the point

John

LED's work the same way if they use the typical (and easy) approach of putting the LED in series with a resistor, whose job it is to pull the prescribed amount of current (usually 15 or 20 milliamps) through the LED.

Model A's originally used a cut-out relay to make sure that the battery didn't turn the generator into an energized motor when the engine was not running--it cuts out the battery when the generator output voltage is less than the battery voltage. The generator is current-limited using a third brush, and that is set based on the number of electrical devices in usual use (particularly the headlamps). LED's produce so little current drain that it wouldn't even be noticed by the original charging system. If the third brush is set for headlight use, the generator will often cook the battery at cruise RPM when the headlights are off. As I understand it, most Model A owners have replaced the cutout with a true voltage regulator packaged to look like the cutout, or they use an alternator with internal regulation that is packaged to look like the original generator.

Alternators in some applications will also let the voltage sag at idle, depending on the design of the voltage regulator. My old Toyota trucks don't kick the alternator in with battery-charging current until about 1500 RPM, for example. The traditional three-wire alternator in my 1973 GMC motorhome (which is closer in technology and chronology to a Model A than it is to any modern vehicle) uses a separate voltage-sensing circuit, downstream of a typical RV-style battery isolator, to adjust the regulator output. Doing so minimized sagging at idle, but could also allow alternator runaway if that battery isolator ever failed open. Many of us have replaced the isolator with a combiner that doesn't impose a diode voltage drop, and put the voltage sensing circuit closer to the alternator output. Most have also installed a diode right at the alternator output to bypass the battery isolator if it fails open. Runaway voltage causes fires.

Rick "fun with electrons" Denney

 

[rwdenney]

anyone remember vacuum operated windshield wipers? they would slow down and speed up with engine speed.

The original wipers on my GMC motorhome were operated by residual hydraulic pressure in the return line from the power-steering gearbox to the power-steering pump. One could also regulate the speed of the wiper using a valve operated by a slide control on the dash connected using a bowden cable. Many of us have replaced those with electric wipers using a kit made in our cottage industry. The kit borrows a wiper control system from a minivan. A true wiper delay is one of those modern conveniences we miss when we don't have it. The auto industry struggled with wipers that would work well on deeply curved windshields back in the day.

Rick "owns a 1973 GMC motorhome with wipers that work even if nothing else does" Denney

 

[projectnut]

I got sick and tired of not being able to get reliable results with my chepo telescoping gauge set. Then I noticed the plating was flaking off the gauging end! I decided it was time to get a good set. I went with the Mitutoyo 155-903, 5/16" to 6", 6 Piece Telescoping Gage Set. Just a joy to use, easily repeatable measurements. The set came with (as they all do) a rather flimsy plastic pouch, so I 3d printed a box.

I gave up on the snap gauges decades ago. I tried several sets and just couldn't get accurate repeatable measurements. Over the years I've gone with these. They span from .043" to over 6". The nice thing is that they can be used with either metric or imperial heads. It takes a couple minutes to set them up, but I can be sure the measurement is accurate when I'm done.

 

[ChazzC]

I vote that a special award for “Most Creative Taglines” be instituted and bestowed upon Rick “always makes me smile” Denney!

 

[rwdenney]

I have that same set. I really like them. They've been giving me consistent results. I did find a set if inside micrometers a while back, so these get used a little less now, but they're still handy. Sometimes I compare measurements between the ID micrometers and these, and get the same numbers down to 10ths. (More to see if I get consistent results. I'm usually the weak link!)

I bought one of those offshore bore gauges that use a dial indicator that has to be set using a known bore before use. I find it far more fiddly and troublesome than telescoping gauges, and rarely use it. The true bore micrometers are the ones with three inside points, but they are limited in bore range, so one needs a set and those puppies are expensive even one at a time. My telescoping gauges get used for sure. I have an old Lufkin set that does not include the largest sizes, plus a Japanese-made Lyndex set that may have come out the side door of Mitutoyo--both are better than the Fowler set I bought with my Fowler mics about 25 years ago (and which are probably also Japanese or Taiwanese).

It's important, I think, for we hobbyists to own several calibrating bores in various sizes so that we can practice our technique against a known bore. I have four of them ranging from 7/8 to 3". Pros get more practice than we do, and are also more likely to have access to high-end bore mics.

Rick "learned proper technique--at last--watching Abom videos" Denney

 

[projectnut]

I had a 1948 Chevrolet 3/4 ton (1600) pickup truck for over 20 years. It was the Deluxe model with the 5-window cab. The windshield wiper motor was a hybrid vacuum/electric unit. It normally ran on engine vacuum, but had a sensor diaphragm that would activate an electric motor driven vacuum pump on hard acceleration or when climbing hills. It had to be an expensive unit to build. I never quite understood why they didn't eliminate the vacuum portion and just go with an electric motor if they already knew the vacuum unit would need assistance.

 

[rwdenney]

I had a 1948 Chevrolet 3/4 ton (1600) pickup truck for over 20 years. It was the Deluxe model with the 5-window cab. The windshield wiper motor was a hybrid vacuum/electric unit. It normally ran on engine vacuum, but had a sensor diaphragm that would activate an electric motor driven vacuum pump on hard acceleration or when climbing hills. It had to be an expensive unit to build. I never quite understood why they didn't eliminate the vacuum portion and just go with an electric motor if they already knew the vacuum unit would need assistance.

The hot-rod outfits sell backup electric vacuum pumps to those with overcammed engines that don't pull much vacuum at idle, for the purpose of ensuring that vacuum-assist power brakes will be available even if the engine isn't supplying it. I use one of those in the motorhome, too--losing power brakes in a 10,000-pound vehicle can be a problem.

Rick "used to be able to leg-press 750 pounds but it may not be enough" Denney

 

[matthewsx]

I bought one of those offshore bore gauges that use a dial indicator that has to be set using a known bore before use. I find it far more fiddly and troublesome than telescoping gauges, and rarely use it. The true bore micrometers are the ones with three inside points, but they are limited in bore range, so one needs a set and those puppies are expensive even one at a time. My telescoping gauges get used for sure. I have an old Lufkin set that does not include the largest sizes, plus a Japanese-made Lyndex set that may have come out the side door of Mitutoyo--both are better than the Fowler set I bought with my Fowler mics about 25 years ago (and which are probably also Japanese or Taiwanese).

It's important, I think, for we hobbyists to own several calibrating bores in various sizes so that we can practice our technique against a known bore. I have four of them ranging from 7/8 to 3". Pros get more practice than we do, and are also more likely to have access to high-end bore mics.

Rick "learned proper technique--at last--watching Abom videos" Denney

I have an engine project that I’m doing and am thinking about ordering a digital bore gauge. Anyone have economical recommendations?

John

 

[projectnut]

Standard bore gauges are easy to setup if you use a ring gauge to calibrate them. Ring gauges can be expensive depending on how many you need. I use a tool makers vise and gauge blocks to set the known distance. I originally tried using a micrometer in a stand, but it was far too finicky.

As for brakes on a motorhome our 2013 Winnebago Adventurer built on the F53 Ford chassis uses the Hydro-Max system. If a sensor detects low vacuum an electric pump supplies pressure from the power steering circuit to brake calipers. It has full braking power with or without the engine running.

Ours is built on the 22,000 lb. chassis and has an additional towing capacity of 4,000 lbs. We have towed our 2004 Jeep Wrangler over 175,000 miles behind either our 2001 Adventurer (110,000 miles) and our 2013 Adventurer (65,000 miles).

 

[projectnut]

I have an engine project that I’m doing and am thinking about ordering a digital bore gauge. Anyone have economical recommendations?

They usually go cheap at used equipment dealers. Over the years I've purchased 6 different sizes. Most were in the $50.00 to $75.00 range. Dealers like to move them on quickly because the whole unit or parts tend to disappear off the shelves. One of the dealers I frequent kept the last 4 off to the side because he knew I was interested in them