Making Big Holes

 This was supposed to have been posted ages ago.  I thought I had posted it.  But I've searched the blog for various key phrases, and it seems I never posted it.  If I did, and you're reading it twice, my apologies.

 ~≈{👁}≈~ 

When one wishes to poke a hole in something, of arbitrary size, and especially when it's bigger than any drill bit you have... there are ~~several~~ well, two, machining options and one sloppy option.

Ze Boring Head
• Lousy ones are expensive.  Good ones are breathtakingly expensive.
• Large; the smallest I've seen (some rare beast Mr. Pete found), is about 1.5" in diameter (minimum hole size)
• Capable of very precise hole diameters
• Convenient to use- once the tool is set up, increasing the depth of cut is a matter of turning a screw
• Lots of off-center mass, tries to shake/sway/bend your machine, so best used in a full sized knee mill or a VERY stiff, square-column bench mill.
• Uses boring bars which usually have carbide inserts, so if you weren't into inserts before, you are now
• Best for deep holes like engine cylinders

Ze Fly Cutter
• So cheap they're nearly free.  Seriously, HF practically gives them away as door prizes (nearly - a set of five might be on sale for $10), and because it's basically a hunk of funny-shaped steel which has no built-in need of precision, there's no need to shop for anything better.  This is a tool fetishist saying this.  Cheap ones work fine, it's the cutter you'll want to spend your time and money on.  ( *cutters are almost never included)
• cutters can be made from inexpensive HSS square tool stock, which you grind to a cutting tip yourself - this is less convenient than carbide, but ever so much cheaper cost of ownership, and a very useful (some would say mandatory) metal shop skill to acquire. Use both ends of the tool stock.
• "tool setting" - that is, setting a fly cutter's cutter to a specific, precise diameter - is fiddly but you get used to it.
• readjusting depth of cut once you've set it is a simple matter of doing the tool-setting job all over again - wait, what?  Yeah, that's a fiddly disadvantage.  Did I mention they are cheap?

 AFAIK, that's it for precise and semi-precise holes.  The other large hole cutting options I can think of are not adjustable, and they make relatively imprecise holes.


 If your hole is a nice common dimension and not say, "pi inches", you might find a shell mill cutter that will do the trick, provided the material is less than an inch or so thick.  These are expensive.  The cost of re-sharpening shell mills is about 
the same as buying a new one.  Used ones on eBay tend to be dull.  These are non-trivial to sharpen, it requires a "universal tool grinder" and knowledge.


 A third option, for making approximate holes, and not cut to any tolerance, is ordinary hole saws. 
They are cheap.
  Good (AKA “bi-metal”) hole saws are quite capable of cutting steel, aluminum, brass, whatever, provided one:


• uses copious amounts of a good-quality cutting fluid*

• backs off the cutter frequently; lets fluid back into the hole, allowing teeth tips to cool a bit

• uses low cutting force - if you tend to burn up drill bits, this method is not for you


 
 I have a few garden-variety, hardware-store hole saws that have seen _extensive_ use, including cutting lots of circles out of .25 and .5in steel plate,
 and they are still sharp.  Done right, this method is _messy_.  It can be less messy if you’re willing to burn up your hole saw halfway through cutting a hole, but I recommend letting it be messy.

_____


* ie; preferably _not_ the stuff sold in the hardware dept for threading pipe - that’s the Lowest Common Denominator of cutting fluids; it works for carbon steel only, its high sulfur content stains copper and brass, it does you no good with copper, soft aluminum or stainless… 
personally I'm not a fan.


 I prefer Tap Magic™(standard grade).  It is expensive but I brush it on by hand so I only use a quart every year or two.  There are plenty of other good productss.
  Just use _something_.  The thing about the high performance fluids like Tap Magic is that they make difficult-to-machine materials like copper, 300 series stainless, and (gods-help-you) titanium, much easier to machine, with a cooler running
 tool, better chip breaking, and better surface finishes because little or no Built-Up Edge.  High-sulfur cutting oil from the
 plumbing department does nothing for these materials. And plumbers don’t much care about the surface finish of 
their pipe threads either - you might. ;)

 

 ~≈{👁}≈~ 

A New Angle On An Old Problem

    

When I grow up (hahahaha!)
I want to be just like Inheritance Machining. 
So if he chamfers all the things, then I must also.

 More honestly, I've always broken the corners of machined things to some degree - you can't hardly help it since even a clean 90º angle can cut flesh.  The amount of effort I've put into this depends a lot on the part or tool I am working on.  Sometimes a few strokes of a file suffices, sometimes just running some nasty burrs under the deburring wheel.

 When I make a thing, I like to break all the corners.  I've faked it with things like countersinks, which never have the right angle of 45º because they are countersinks.  But the results don't look as good or feel as good to the hand.

 Watching real craftsmen at work has has left me very dissatisfied with my deburring / chamfering game.  I began watching out for chamfering tools of various sorts, especially something with inserts, because although there are plenty of solid carbide cutters around, I can't sharpen one if it gets dull, and I do plan to use this hypothetical tool extensively.

 Right then, I may have just made a tooling purchase error, but I will remain optimistic until I've actually played with the thing. (it should be here in a few days)

 Part of the issue with making my own is I still don't have a way to do decent heat treating. I can barely manage to heat things with a propane torch (oxyfuel tanks are nearly empy so they can't be used) and dunk them in water, observing the nitride color bands.  I've had mixed results.

 So I've kept my eyes open for a long time for a milling insert holder with a 45º cut.  Finally found one, cheap because it was missing the insert hold-down clamp.  One could make one if one had to (again with the heat treating problem) but fortunately, this one is still available - I haven't called for the price yet - from the maker. 

I was at first concerned that their catalog has this to say:

"This cutter was developed in 1982 for spot drilling and chamfer milling small slots
in non-ferrous part materials. If used prior to drilling in non-ferrous
materials it performs well. If used as a countersink after the hole is drilled it is
chatter prone."

(my note: AFAICT this is a consequence of their insert choice)

"It is not for use as a rotating cutter in ferrous materials since the (25 ) relief
angle is too weak."

Again, this refers to the inserts they provide.  Other inserts exist, as this size and shape is extremely commonplace, and many, many geometries and coatings are available, different relief angles, different chip breakers, flat with no chip breaker, etc.  Also, chattering is unlikely in my interrupted cut chamfering operations on the outsides of parts.  Even so, I bet with the right insert geometry I can do holes without chattering too.

"However, in the more rigid lathe environment
it can be used successfully to spot drill holes in ferrous materials.
We spot drill our Accu-Holds (4340) in CNC lathes at 900 RPM and
.0005 IPR, with tool life of 200 holes per insert corner.
It should never be used in a drill press."

 Well yes, and duh. :P  One does not use an indexible single-edged carbide cutter in a floppy drill press, ever.  I am imagining the stupid customer service calls which resulted in these warnings.  My mill is reasonably rigid as turret / knee mills go.

 Anyway, they are talking about drilled holes.  I can imagine the inserts they sell would chatter in drill holes, even tho that's what they sell their damned tool for.  But they are very focused on firearms, too, so they have weird viewpoints on tooling, they are not a generic tool supplier.  Anyway, my mill is more rigid (I think, can I prove that? hmm!) than my lathe and much more rigid than the drill press, so I might squeak by, heh.

 Hopefully the maker does not want too much for the insert clamp.  $10 seems reasonable to me.  $20 seems more likely.  It's a tiny piece of curved steel the size of your thumb nail.  OTOH, if they want $40 or more just because it's a $200 - $300 tool and they know it's useless without the clamp, then I'll tell them to fuck themselves and I will make my own clamp.  Business office opens tomorrow, we'll see.

 ~≈{👁}≈~

Relegated To The Safety Shelf

  A few weeks ago, I was watching a video of a steam calliope fire, and one of the things a friend of mine and I both observed was A) a lot of running around at first indicating a lack of any practiced plan, B) insufficient fire extinguisher size, type, and quantity, and also C) the fellow who eventually gets the gas turned off seems to have been unsure where his hot gloves were.

 It got me to thinking about the (rather nastier than propane) welding tanks I have in my shop, and the one inert gas bottle of shielding gas which is nevertheless pressurized to around 1,000 PSI until it is nearly empty...

 I have an A-B-C extinguisher in the shop now, and I really should also have a CO2 extinguisher.  But the latter are expensive!

 It occurred to me that I have a pair of too-heavy high heat gloves I never use.  I think I received them with my cutting rig, not sure.  All I needed was a shelf mounted above the fire extinguisher at the entrance of the shop...

I tinted the "airship" braces with a torch,
clearcoated with acrylic, then masked that
and painted the remainder gloss black.

The fancy finish isn't obvious on the
finished article, but I know it's there.

 I may have overdone the shelf a little too - a lot of filling and sanding before paint, so it wouldn't look like the scrap of plywood that it is.

 ~≈{👁}≈~

Stabistor And The Bipolar Power Supply

 "The stabistor was the crucial invention which first
made possible the stabbing of others over the internet..."

  This morning I was watching a fellow repair a vintage Hewlett-Packard instrument and the word "stabistor" came up.  Now, I got into electronics in the 1970s, I'm retired now, and I've never heard of a stabistor.

  A quick search turned up this Stack Exchange post from someone else who had never heard of one:

 https://electronics.stackexchange.com/questions/636786/what-is-exactly-a-stabistor-how-does-it-work-and-how-is-it-constructed

What is a stabistor?

 And that's pretty much it, in case you ever find yourself troubleshooting an HP 6826A, which by the way, is a fascinating instrument.  For more on that, here's the video I was watching:

This HP 6826A Can Output MUSIC?! Bipolar Power Supply Repair & Test

 ~≈{👁}≈~ 

 

"Do You Think The Software In My Welding Hat Needs Updating?"

  Yesterday, I put on my PPE for welding* and promptly flashed myself.  This isn't supposed to be possible, because it's an auto hat, and it has a low battery warning.  Well, I never saw the LED blink, but the battery did go dead, and thank Ghu I was tacking .124" strap together, so intensity & flux were low; it was very unlikely to have done any permanent damage.

The Culprit (cuz it's not MY fault I ran the battery down, er, wait-

  But I was annoyed.  I had just used the hat a few weeks ago, it functioned perfectly as always, and I did not see (notice?) the red 'Batt Lo' LED blink at the time. 

 But I haz a theory, to wit: I have the sensitivity turned up as high as is practical.  Any higher and just moving my head around can trigger the lens.  And I left it out of its black bag for weeks.  Between turning lights on and off and just moving around the dirty end of the shop, I probably triggered the lens (which draws current from the battery) many many times without realizing it.  Solution: put it back in the black bag when not in use, or put it in Grinding Mode so it won't trigger. 

(when it's in grinding mode, there's a blinking
LED to remind you not to weld-
wait, will that run the battery down too?
**sigh**)

 I'll bet it says something about storage in the manual, not that I ever read it, because I am a man's manly man, yes I am.  So I'll dig it out and read it after I post this.  Hey, at least I save manuals and I know right where it is.

(later: lies! I think I've lost it or accidentally thrown it out - it's probably downloadable)

 I do wonder why they don't have an on/off switch.  Oh wait, no I don't - because someone would forget to turn it on, and then expect the manufacturer to make them and their heirs and assigns wealthy for the next three generations because they got a few tiny pinholes drilled in their retina.  Silly me.  I sometimes forget I live in Litigatia.

 None of this idiocy on my part should be construed as a dig against that Viking lens.  In some ways (like color rendition, which doesn't matter much to me), it is better than looking through a 3M SpeedGlas™ lens.  It is just as fast.  The SpeedGlas™ lenses are also very nice tho.

 Both brands are crazy-fast, if adjusted well, you never see a hint of arc; the tiny park from a 9V battery is enough to darken the lens.  And you can adjust how long it stays dark when the arc extinguishes.

 Don't buy Chinese auto hats (hell, I wouldn't even trust the glass / shade in a passive hat from China) when it's your eyes on the line - ask me how I know this.  And the large lenses are oh so worth it.

 I am seeing batshit insane prices for these things right now.  The basic hat that came with the welder was really messing up my neck (IYKYK), so I picked up a Chinesium auto hat from HF for $40 and was worth less than that.  The next one was the Viking I have now.  I paid $240 but I'm not sure when.  I think I've  had it more than ten years not sure.  Anyway, the exact same model is $425 street price, or over $700 from The Welding Store (LOL).

 ~≈{👁}≈~

__________________
* In this respect at least, and since I started casually learning to weld around 1985 up to now, I have gone from casual (gloves and a mask) to ATGAT philosophy.  I've also gone from passive mask through Chinesium auto, to Viking/Lincoln auto.  I haven't had a welder's respirator but I think I'm going to get one soon. Manganese poisoning is no joke.

Value: A Viewpoint On Collecting by J. W. Courter

 Value: A Viewpoint On Collecting
©2025 J. W. "Bill" Courter

There are several theories why some goods and services are wanted or needed more than others and considered desirable enough for people to work or give up something else to get them. The most significant theories to explain market values have been:

1. Aristotle: Goods or services are valued the same as what is given in trade for them.
2. Karl Marx: Goods or services are valued at their cost of production.
3. Adam Smith: Goods or services are valued at what they will bring in trade or "exchange."
4. Austrian School: Goods and services are valued by individuals, as judged from their
personal (subjective) viewpoints.

 The Austrian School of Economics developed the modern subjective theory of value and applied it to the problems of economics. Its founders were Carl Menger (1840-1921), Friedrich von Wieser (1851-1926), Eugene von Bohm-Bawerk (1851-1914), Ludwig von Mises (1881-1973) and Friedrich A. Hayek (1899).  All were born in Austria. I have studied writings of Mises, Hayek and their students.

 The Austrian theory of value holds that the value of economic goods is in the minds of individuals and therefore is neither constant nor inherent in the goods themselves; that values of the same goods vary from person to person, and from time to time for the same person. Value is not intrinsic; it is not in things (although some things may have intrinsic value in our economy). Value is within the human mind. Value is reflected in human conduct. It is not what a man says about value that counts, but how he acts.

 A person makes a judgment of value based on his wants, tastes, desires, feelings, choices, or preferences which cause him to act in a certain manner at a given time, situation and environment in an attempt to substitute conditions he prefers for those he considers less satisfactory. This judgment of value is personal and subjective and is not open to proof or disproof. It can only be identified by an action from which it is influenced.  Value is always relative, subjective, and human. Value is never absolute, objective or divine.

 Individuals always believe what they have, and are not trying to dispose of, is more valuable in "use" to them personally, under the circumstances, than it would be in exchange." Thus when they do decide to make a trade, it is because they believe what they are offering to exchange is worth less to them personally than what they expect to receive in return. Barring force, fraud and mistakes in judgment then, both parties will consider themselves to have gained as the result of a voluntary trade.

 On a simpler note, my dictionary defines value as "the relative worth, merit, or importance...that quality of anything, which renders it desirable or useful."

Measures of Value. Historically measures of value have been a standard weight of a
commodity, such as gold or silver. Even so, no commodity is free from changes in value due to
the supply of it or demand for it. Establishing a reliable measure of value has been a major
problem of countries, politicians, and kings. The problem continues, as measures have not been
perfected. Today, we tend to think in terms of dollars but they are fiat and in reality, are paper
instruments of debt. The value of our dollar has depreciated for more than 60 years. Let's review
other day-to-day factors that affect "value."

Utility. Originally utility was the sole reason for buying most items. The importance was given
to its capacity to produce a desired effect such as light (lamp), heat (stove or fuel), or a station
wagon (you have lots of kids to carry). Many antiques have lost their utility value as our
technology and world changed. I think of whale oil lamps, fleams, glass insulators, and carriage
clocks for example. Aladdin kerosene mantle lamps possess considerable utility value today and
I suppose that is one of the principal reasons why they are still manufactured.

Intrinsic Value. Things like gold, silver, copper, diamonds, and precious stones have historical
value, as they have often been measures of value. Gold jewelry always has a value based on gold
content regardless of the workmanship or artistic value of the piece. Things that possess
"intrinsic" value often are a "store of value" and are used as a medium of exchange for other
goods (i.e. they became money).

Workmanship. Skills that turn raw materials into things people need add value to those
materials. I think of cabinetmakers, glassblowers, silversmiths, and craftsmen who created our
furniture, glassware, tea service, and cathedrals, for example. The numbers of our expert artisans
have diminished to the point where workmanship may not be effectively reproduced. Things like
veneer and parquetry work, glass cutting, goldsmith, and carved furniture have become "lost
arts" and consequently are especially valuable.

Provenance and Pedigree. Historical attribution often adds a premium to the object. The label
of a maker, the bill of sale, an autograph, quality known to be associated with the maker, or even
previous ownership are examples that document the importance of provenance.

Rarity. There is no question that rarity plays an important role for collectors in determining
value. This is especially true in coins and stamps. Consider, however, that there must be enough
items for collectors to collect; otherwise can one of something be so rare as to be extremely
valuable?
Often it is the least costly or least valuable item, commonly made, that ends up being the rarest.
These items may not have been popular when they were made, few may have survived, they
were breakable or not saved, or they tended to be used frequently and consumed. Consider things
like chalkware items, fragile Christmas ornaments, glass oil lamps, tin toys, and paper ephemera.

Condition. The only acceptable condition is perfection when we purchase something new. The
item must be and function as intended. We generally do not buy things that are repaired,
restored, or do not function as "guaranteed." Think about that crescent wrench, your television,
VCR, electric blanket, etc. In contrast, we will buy antiques or collectibles that show signs of
wear, chips, missing parts, and a certain amount of damage. The rarity, workmanship, or
provenance of the item may well over come these defects.

Market Awareness. Most collectors study and read to improve their knowledge. They may start
out with a nostalgic reason, "I remember that as a kid," but study and appreciation take over and
you accumulate more than one as the [text missing in source document]

Inflation. I must add inflation to the equation of factors that challenge our concept of value.
Inflation is a large increase in the quantity of money, which results in a drop in purchasing power
of each unit. Simply put, more dollars are needed to buy the same object today compared with
ten years ago. This is why antiques and yes, even Aladdin lamps, have been "stores of value" and
inflation hedges during the last forty years. Inflation tends to drive investors to tangible assets,
such as fine art and antiques (or other commodities). We can often buy an older lamp or piece of
furniture with fewer dollars than a newer one. And the workmanship of the older one may be
better!

Age. Generally older objects have greater value to collectors than those recently made. Rarity,
provenance, and other factors (above), including nostalgia, all greatly complicate the desirability,
familiarity, and perhaps affordability.

30-Year Rule. This leads me to comment on the 30-year rule. Harry Rinker, editor of Warman's
Americana and Collectibles and popular author and lecturer on antiques, says, "For the first
thirty years of anything's life, all its value is speculative." This rule applies directly to collectibles
and things manufactured (i.e. limited editions), especially to be collected.

 Thirty years allows time for the vast majority of objects to be used, discarded or deteriorate.
Also, there has been sufficient amount of buying and selling to establish a steady market by
collectors who have become rich enough to buy back their childhood.

Appraisal. The principles of valuation in professional appraisal practices are discussed and
defined in a useful manual by the American Society of Appraisers. In addition to most points
discussed above, this book defines important concepts such as fair market value, replacement
value, liquidation value, cash value, estate value, and donation value.

 I conclude by saying yes, we can and sometimes do pay too much by placing a personal value on an object or house that is out of proportion with the values set by others. That is why we study auction results, evaluate quality, and attend conventions, read, and compare opinions with others who are knowledgeable in the field. We buy and enjoy our purchase because we have valued it higher than owning the money that we exchanged (paid) for it.

 In the final analysis, the value of any object or good is worth exactly what a willing seller and a willing buyer agree to exchange it for at any given moment in time.


References:
Albertson, Karla Klein. 1989. Real vs. Artificial Value: What is an antique actually worth?
Antique Review 15 (10):26-27.
Anon. 1989. A Handbook on the Appraisal of Personal Property. Am. Soc. Appraisers, P. O. Box
17265, Wash. DC 20041. 192 pp.
Greaves, Bettina B. 1975. Free Market Economics, A Syllabus. The Foundation for Economic
Education Inc. Irvington-on-Hudson, NY 10533. 242 pp.
Greaves, Percy L. Jr. 1974. Mises Made Easier. Free Market Books, Dobbs Ferry, N.Y. 157 pp.
Mises, Ludwig von. 1963. Human Action, Third Revised Edition. Henry Regnery Co., Chicago.
907 pp.
Rinker, Harry. (Editor) Warman's Antiques and Warman's Americana and Collectibles. Warman
Publishing Co., Willow Grove, PA 19090.

Copyright (c) J. W. Courter 2003 (adapted from publication in The Mystic Light newsletter,
17(5):1990, which covers antique and Aladdin brand lamps).

 ~≈{👁}≈~ 

"The value of a thing is what that thing will bring on eBay." - me

Aladdin Mantle Lamps (reprise?)

 I may have posted about this before, but if I did, it was a long time ago, and I got a couple questions about it from net-acquaintance, so here we go again, maybe. :)

 BTW, if anyone needs info on Aladdin mantle lamps, I've been studyin' on 'em for a while now.
I know have one, because DEAR GOD THEY ARE EXPENSIVE, ahem.

 Their value is that they are vastly brighter than regular wick lamps; on the order of a 60w incandescent
bulb, similar to a gas pressure (AKA Coleman, etc) lamp.  Because combustion is nearly 100%, they also emit much les odor vs. wick type lamps.

 In addition to being four or five times brighter than a regular wick lamp, they have four or five times lower fuel consumption, and four or five times great burn time, for a given amount of fuel, vs. regular wick lamps.

Let's be honest, you can't read by a wick lamp, they're just dismal.

The two, er three, er four most useful bits of arcane Aladdin knowledge which I have distilled from the mantle lamp boffins are this:

• For Denver and higher elevations, you must swap the standard chimney for a "MaxBright High
Altitude/High Output chimney". And that is simply a matter of there being less oxygen in a square
foot of air up here, than there is at sea level.  To get the mantle properly hot, a stronger draft of air
is required, and that's what that chimney does.  It makes a world of difference.  Not for use on
shelves, lol; the standard chimney is already tall - these things want a 4% fuel, 96% air mixture for
best operation.  The high output chimney is even taller.  The total height of my lamp is 26.5in.

• Antique Aladdin brand mantles, if you can find any, are better than any others. Ideally, the ones
from Brazil, because they had the most Thorium, IIRC.  Anyhoo, the balance of light-emitting salts
used in the mantle is different today vs. old mantles, because people were worried about manufacturing
workers being exposed to the Thorium dioxide ingredient, which is slightly radioactive.  The mantles
were never any danger to users.  They are brighter than newer mantles, and the quality of light (color
balance) is superior in the old mantles.  I have found old ones on etsy and ebay, but they are getting
harder to find.  Once burned, the mantles are just as fragile - or more so - than the mantles used in
pressure lanterns, so handle gently.

• fuel: K-1 kerosene (clear only). Do not use "odorless lamp oil" (paraffin oil) sold for wick lamps. It will soot up your mantle and destroy it in short order.  To make matters more confusing, Aladdin sells a
purified kerosene product they call "Aladdin Lamp Oil" which is NOT paraffin oil, and which some
people claim tends to smoke less.  I have not tried it because it costs more.  And um, well, if your lamp is smoking it is badly out of adjustment! (see document linked below)

• Aladdin Lamps carry a price for their bright light; they are the Italian sports car of the emergency
lighting world.  The lamp is slightly fiddly to light compared to a wick lamp, and then it takes ten or
fifteen minutes to warm up, during which time you have to keep an eye on the mantle, starting with
the vaporizing wick low, at first.  This is not terribly different from starting up a pressure lamp, it
just takes more time.

 A great treatise from Aladdin's service department, found in a letter to a customer in 1933, can be
found here:

https://aladdincollectors.org/wp-content/uploads/2025/02/Aladdin-Kerosene-Mantle-Lamps.pdf

I recommend downloading and printing out a copy.

I also recommend printing out every other emergency how-to resource you own, and binding them
if possible (staples and cheap plastic binders from office store seem fine) so you can access them
when the power has been out for say, a week, and your UPS is dead, and the nearest city is a smoking
crater, things like that.

PDF files are useless in a real emergency, and I just realized I have a ton of them.  Oops.  Sigh.

 ~≈{👁}≈~

It's What I Do: I Toke And I Know Things*

  I always find myself working along edges and in corners, where the Gotchas hide.

 I am a generalist and a synthesist, always have been, in large part due to profound and mostly untreated ADHD.† I am the opposite of a Subject Matter Expert.  I have a tendency to start projects larger than my attention span, and subsequently lose interest in them.

 So the knowledge I have collected throughout my life tends to be all over the place.  I have always had a thirst for knowledge, and have been an autodidact my entire life.  If something piques my interest, I dive in headfirst and I don't come up for air until I feel I've at least got a firm grasp on the subject.  I never acquire the deep understanding that an actual expert (ie; 10,000 hours working in the subject, minimum)
has.

 Long experience (I think it took me longer than most to figure this out) eventually taught me that having a decent grasp of a subject does not keep the Gotchas aways if you insist on working near edges and in corners.

 So now, I am actually more proud of knowing where the limits of my knowledge are, in most any subject I know anything about, than I am of what I know with certainty.  Because it is just as useful and important, but few people manage it.  Most people think they know more than they do.  I spent most of my life using that vewpoint.  But that viewpoint isn't baked into your brain.  You can change it. ;)

 ~≈{👁}≈~ 

__
* No, the famous line is not in the books, if you were wondering. Check out this resource.
† Ritalin stopped working in my 60s.  I didn't know that was even possible.

NEMP, HEMP, SREMP Oh My! (money-saving education for preppers)

v1.1 includes minor typos and corrections - 4/7//26
v1.2 includes additional text in HEMP section - 4/8/26
v1.3 edited text in several areas for clarity - 4/10/26

 "First you need to hit the barn,
next you wait fifty to a hundred shakes.
And then the bomb blows up."

You can all stop worrying about nuclear (or simulated) EMP.  This article will explain why.

1. Understanding NEMP (Nuclear ElectroMagnetic Pulse)

 First of all, everybody gets EMP wrong.  Movies get EMP wrong.  Writers get EMP wrong.  Preppers get it wrong, but it's hardly their fault, they're constantly being lied to.  "NASA Engineers" (who just happen to sell EMP protection snake oil) get EMP wrong.  Your mother's hairdresser's uncle, who saw an EMP once, gets EMP wrong.  Unless your name (was) Dr. Carl E. Baum, you've probably been getting NEMP wrong.  I got it wrong for decades, and I have been a nuclear weapons (outsider) wonk since I left the USAF in 1985.

 After this, you will not get EMP wrong and you may go about educating others or just feeling smug about it, whichever suits you.  ;)

 'EMP' is an acronym for ElectroMagnetic Pulse, which is an intense burst of radio waves created by nuclear explosions.

 The high altitude version has enough range to be a problem; it can easily reach the ground two hundred miles below.  The strength of the signal is so great, it can damage electronics and induce damaging currents - much like the solar wind - into power or telephone lines.  EMP is not harmful to life... unless you wear an external electronic medical device.  One (complicated) EMP pulse occurs per nuclear detonation.

 There are two flavors of 'real'* (as in, generated by a nuclear detonation) - EMP:

  HEMP (High altitude Electromagnetic Pulse)

 This is the big powerful EMP effect everyone thinks of when they think of EMP, for example when a ground burst happens and everyone's car stops working in The Day After (ludicrous scene - does not happen in real life; read on for why). 

 HEMP occurs when a very high-yield missile warhead - roughly a megaton or higher - is detonated above two hundred miles altitude.  The effect is maximized at this altitude because the expanding shell, or wavefront, of radiation has room in the low-pressure region to expand before striking the atoms of the atmosphere.  Involving a greater volume of air increases the number of electrons involved.

 The enormous burst of gamma radiation, and to a lesser (and later) extent neutrons, from the nuclear detonation, violently changes the direction of travel of electrons. This motion, combined with the Earth's magnetic field also interacting with them as they move, causes the electrons to dump energy as radio waves across a big chunk of the electromagnetic (radio) spectrum.

 The rise time of the signal is extremely fast; around 100nS, or 100 billionths of a second.
The duration of the main body of the pulse is a few tens of microseconds, or millionths of a second.
All of an EMP signal's energy is delivered within that time period.

For more on this, please see Section 2 of this DTRA-sponsored report.

This diagram is for a 10MT burst. 
There are no 10MT weapons in anyone's inventory.
Important: the effects on the ground are negligible if yield is much below 1MT

 That's the majority of the HEMP signal.  Long after the main pulse, two smaller pulses occur, with completely different mechanisms of creation: first, the heat and energy from the bomb physically striking the ionosphere, causes a small pulse, and after that, the swelling of the ionosphere from being heated rapidly, causes another little bump.  These are called the MHD signal because 'magnetohydrodynamic signal' is too much of a mouthful to say at cocktail parties.

"types" is the wrong word - "parts" would have been better... but it's a nice chart

  But those two signals weren't the part everyone was worried about, as they did not contain enough energy to affect electronics.  They were only of interest to researchers with sensitive equipment.

 Note that all of these multiple source effects cause the pulse to be stretched out in time, with a long tapering tail after the very fast-rising front edge of the pulse.  The chart above is idealized.

 Note that all HEMP measurement and characterizing ceased when atmospheric testing ended in the 1960s.  The phenomenon requires a lot of space to occur, it cannot be recreated in a lab or an "EMP bomb" (those have been studied, but physics got in the way and they were abandoned as ineffectual)

 The pulse has a funny shaped outline, due to the complex phenomena which create its various parts, but its bandwidth is known; HEMP has significant energy from DC to 4 GHz.


 SREMP (Source Region Electromagnetic Pulse)

 This effect is not known to most people, most preppers, most writers.  And that's fine, because you don't need to know about it.  Why don't you need to know about it?  Okay, so SREMP is a weaker EMP effect created by atmospheric detonations, be they airbursts as is most common, or ground bursts.  And, like HEMP, the effect is negligible with sub-megaton warheads.

 SREMP is lower intensity than HEMP, and it has a much shorter range: a maximum of about two miles.  Your average modern boosted fission weapon (with a fusion stage or not!) has a radius of total destruction at least five miles.  If you aren't destroyed by the blast or heat, the SREMP won't reach you, and you can start worrying about fallout.  If you're close enough for SREMP to zorch your electronics, you and your electronics will be almost painlessly destroyed by the fireball and mach stem.  Forget about SREMP.

 As for where SREMP come from...

Q: "If EMP requires low gas pressures or vacuum, how can it occur in atmosphere?"
A1:  Smart-assed answer (and wrong): There is a vacuum inside the physics package. :)
        It's not so much that any vacuum is required, it's that a larger signal occurs when
        the gammas strike a larger area/volume of air at once. Only way for that to occur
        is if the expanding shell of radiation gets to expand for a while before it hits air.

A2: The real reason is that jamming those gammas into air does create the same
       Compton shower effect, but the gammas can't penetrate the air very far, and the
       size of the "irradiated sphere of air" is much much smaller, so the generated signal
       is quite small.


 2. Why HEMP Is Not A Danger Either

 Reason #1: HEMP requires two things to happen: altitude of a minimum of two hundred miles, and a very large yield warhead, of at least 1 MT or higher.  The intensity of the effect tapers off quickly with warheads below 750kT yield.

 Since both Russia and the USA dismantled their megaton-class missile warheads in the early 2000s, using the fissionables to make smaller, lighter, more efficient physics packages, the conditions for creating HEMP can no longer be met.  MT-class gravity bombs are obviously of no use here, but those are slowly leaving our arsenal too.  They are simply inefficient; generals would rather have more warheads.

 Reason #2: HEMP was never thought of by anyone as a valid form of attack, because the effects on the ground turned out to be too unpredictable.  The areas of high intensity are crescent shaped, nested with areas of low-to-no intensity, and the direction this occurs from the burst is unpredictable - the effects are impossible to aim, and the effects do not blanket large areas.  To effectively blanket either the USA (don't forget Alaska) or Russia (don't forget northern Siberia) you'd need to throw away a dozen or more MT-class warheads (!!) ...on a long shot.  No general was ever going to waste a single MT class weapon on a lousy bet like that.

3. Conclusion

 It appears extremely unlikely, absent the failure of multiple baroswitches and inertial sensors all at once doing it by sheer accident, that we will ever see another ground-affecting EMP event, even in the event of a nuclear war.  Other nuclear weapon wonks agree with me.

 Every single person, self-proclaimed "NASA engineer", and company who sell EMP protection products are charlatans pushing snake oil.  Most of their filters etc wouldn't work, also.

___
* an example of simulated EMP are pulsed magnetic fields created by "EMP Simulators", such as the famous Trestle at Kirtland AFB. These do not reproduce the nuclear EMP waveform.  Instead, they typically create an approximate square wave pulse with risetimes and pulse widths corresponding to the NEMP bandwidth of 4 GHz.  This is typically accomplished by firing a Marx generator (a device which makes very short, very high voltage pulses) into an antenna structure made of wires, typically something called a TEM cell, which just refers to its shape and how the EM wavefront travels through it.

 Note that the military largely stopped performing EMP susceptibility testing in the 1990s.  If the military stopped worrying about EMP, shouldn't you?

 ~≈{👁}≈~

___
 I want y'all to know just how difficult this article was to write. Not because of any PTSD thing from the USAF, but because most of it was written with a kitten on my lap. 😍💖

How To Use A Scriber - When The Map IS The Territory

Part 0. Move along, owners of CNC machine tools; you'll never use this stuff.  ;)

Part 1. The Whys And Wherefores

 The general idea of scribing lines directly on work to assist in fabrication, is to coat the surface to receive the marks with a thin layer of dark, non-flaking dye, and then using a sharp scribe to cut through the dye, making a physical groove mark in the material.

"Why scribe lines at all?  I own Sharpies™ er, Marker™, er, flow pens!"

 Because the width of the mark from an Ultra-Fine-Point Sharpie™ super fine pointed flow pen (cough) is .015 - .020, while the width of a scribe mark averages .004 (the size of some human hairs), that's why.

 "Who actually needs instruction on how to use a scriber?  How hard can it be?"

  Potentially everyone because the methods used will determine how close your layout comes to the print.  Furthermore, we have a couple generations behind us (so far!) who aren't acquiring good hand-eye coordination in school, so a few tips ought to save some frustration, and perhaps help those disadvantaged folks - who probably never skinned their knees on a jungle-gym either - get started faster.

If accuracy doesn't matter, why are you using a scriber-and-fluid*?
Don't make unnecessary work for yourself.  I only rarely do
manual layout, but it sure is handy once in a while!

If accuracy matters a lot, you don't do layout at all.
  Choose a 0,0 on your part, put it in the mill, and
use the DRO to locate all features after that.
I jest; I get that this is not always possible.

 Hand layout methods are only useful within a single order of magnitude of accuracy, to wit:

.1 in. can be done with a paint marker.  Think structural steel and mag drills.

.01 in. is achievable with manual layout if you're consistent and careful. That's where this post lives.

.001 in. ain't happening with manual layout methods; choose another fabrication path.

 Why NOT to use scribed layout:

• It makes a physical groove into the material which may need subsequent removal if that
  surface will show.

• It typically raises the surface of the material surrounding the scratch mark, so cannot be used
  on dimensioned surfaces.

• If you screw up a marking, do your part dimensions allow you to grind or mill them off to start over?

Part 2. Getting Started / The Tools

 To do traditional manual layout, you need...

• a flat, clean, and brightly lit workspace
• layout fluid or flow pen in a dark color
• a scriber
• a steel scale or ruler
• a compass, probably
• vision magnification
• a prick punch
• a center punch
• a square

- When I say 'brightly lit', I mean as bright as you can stand it without getting a headache.  The brighter the workspace, the smaller your pupils, and the smaller your pupils, the greater your eyeball's visual acuity.  Your eyes perform at their best, and typically develop less eye fatigue, in brightly lit spaces.  My workspace is insanely bright.

- Layout fluid, sometimes called 'layout dye' is compounded such that a thin layer is very dark, allowing scribed lines on shiny metal to contrast brightly, and such that the dried fluid does not flake when scribing.  It is not terribly expensive, and a little goes a long way unless you work in production.  As a hobbyist, I've been working on the same little bottle for over ten years.

You can use "flow pen" aka Sharpie™ for small areas.

 I'm sorry, I do not have any tips for getting the commercial products to brush on evenly, I've been making a mess of it since 1976.  >_>   Part of my problem is that it dries faster here in Denver than it did where I learned to use it - in Illinois.  You can also get it in a spray can for big layouts; I've never tried that.

- Scribers come in several flavors, but for layout purposes, you'll probably want the pen type.  HSS points are less likely to break if you drop it or absent-mindedly tap the tip on something.  Carbide tips will mark hardened material and last a very long time between sharpening or replacement.  Don't spend more than $10, all you'll get is a fancier handle.

- A scale's markings are dimensioned from the physical end of the scale. Zero is the physical end of the metal.  This is handy for butting the end of the scale against things to take a measurement referenced off that feature.

- A ruler's markings are dimensionsed from a zero marking on the ruler.  This is handy for referencing another line, etc.  Most fabricators/machinists/bodgers have a preference for one or the other.  I find I do not need rulers, I can just use the "1" on the scale and subtract 1 from the measurement.

- Curved features are a given in metal working.  You'll need a compass AKA 'dividers', preferably one intended for a machinist and not a draftsman, so it will have hardened or carbide points in the kit.  I use a drafting compass and I have to sharpen one of the (plain steel) points too often.

- When you are trying to determine whether two lines are actually aligned, it sure is handy to have some kind of magnification.  If you already wear glasses, there are magnifying lenses which attach to the frames and flip into or out of your line of vision.  Many folks including a close friend swear by the Optivisor™ or MagniVisor™ headbands, but for some reason, the visor magnifiers give me a headache. YMMV.

top: Starrett No 816a prick punch -- bottom: shop-made center punch

Part 3. Methodology

 When reading drawings, never use the drawing to directly compare to your part - ie, don't use it as a ruler or gauge; use the dimensions printed on it of course, but place your layout marks on the part manually.  This is because printers will often happily print your drawing a few percent larger or smaller than exactly 100% even while telling you it's exactly 100%.

 Making straight lines on dimension
  Lines have non-zero thickness.  Declaring one side or the other of a line to be the reference edge rapidly leads to stacked dimensions and confusion during layout.  So we always deal with the center of a line.  This is part of the allure of scribed layouts; scribe lines have less thickness than Shar- I mean, "flow pen" lines, and because the line is a groove, it self-centers the scriber for subsequent marks.  It's easier to stay closer to the desired dimension if a line is narrow, and scribed lines can be arbitrarily narrow.

 When making a line from a point to a point, be sure to hold the scribe square to your ruler or scale at first, to ensure the point is exactly on dimension before you put it at an angle for making the line.  When you start scribing, support the point well so it doesn't chatter.

  Making center punch marks on dimension
 Ideally, you would only ever make a center punch mark at the intersection of two lines you have high confidence in.  The lines let you know how close your punch point is to where it ought to be before you whack it.  Post-whack, the lines let you see how well you did and whether you ought to move the mark.

 Using a "prick punch" (Starrett makes beautiful ones, and it's a small item with no moving parts, so fairly affordable even new - you can also make your own if you have a heat-treat oven), make your first punch very, very light, holding the punch vertical to the surface.  Even a small angle on the punch can move the mark off of dimension. Using a loupe, examine the mark.  It should be circular - not oval - and centered on the lines.

 If it isn't centered, a light mark which is only slightly off can be moved by holding the punch at an angle (pointy bit toward direction mark needs to go, hammery bit away from desired direction), and hitting it just a little bit harder with the prick punch.  This makes the mark deeper and wider, with the new mark's crater bottom now in a different place.  Note this makes the top of the hole slightly oval.

 A light mark is all you need if that location will only be used with a compass to make curved features.

 If the part will be drilled in that location, then enlarge and circularize the mark by placing your regular center punch (which has a much wider angle on the point) in the mark and giving it a good smack.  

I suggest you practice this on scrap before you need to use it on a real part.  ;)

BTW, I don't recommend automatic center punches for layout work, but they're great for casual cut-drill-and-weld sortsa work.

 ~≈{👁}≈~

 My next post will be off-topic from shops and tools, and will discuss Nuclear EMP and why you can stop worrying about it.

________________________________
*ain't got layout fluid? Shar- (er I mean, Magi-, dammit, I mean flow pen) -- also works.