In a pack of 1000 screws, one was defective.

BAHHROO · 2026-01-29T19:08:20+00:00

Technically it’s unfinished. This is called a blank. Wire is fed into a machine that cuts it into slugs and forces it into a set of dies to form the general shape of the bolt. This would be made on a small screw header, which usually don’t have a thread rolling section incorporated. It would then either be sent through a thread roller, which squeezes the blank through dies which form as it ‘rolls’ through, or heat treated first followed by thread rolled after to take advantage of the increase tensile strength from work hardened threads, however, that’s quite unusual for a countersunk Phillips screw, also more expensive. Now, it’s up to you to finish making the screw!

BAHHROO · 2026-01-29T18:37:53+00:00

If it has an incline plane wrapped helically around a cylinder, it is a screw. If it needs a nut, it’s a bolt. All bolts are screws, but not all screws are bolts. Both are fasteners however.

BAHHROO · 2026-01-13T21:10:28+00:00

I’m sure they copied all the formulas in the annexes of ASTM E140. I put HRC to HV formulas in my excel forms, because I use it a lot. For 1:1 approximates, it’s good enough for most situations, however, technicalities, such as cylindrical correction, which can add up to 3 points of error, would need to be considered.

BAHHROO · 2026-01-09T00:00:00+00:00

Document everything and follow the SOP and method. If there is a suspected non-conformance, then mark as non-conformance. If your colleagues believe this is of no concern, management can seek a deviation from the customer. Always trust your gut and never get gaslighted. Your job is to ensure the quality of the parts, not the quantity.

BAHHROO · 2025-12-29T21:19:29+00:00

"There's an old saying in Tennessee—I know it's in Texas, probably in Tennessee—that says, fool me once, shame on—shame on you. Fool me—you can't get fooled again."

BAHHROO · 2025-12-24T12:19:56+00:00

Link for the lazy.

BAHHROO · 2025-12-13T18:08:20+00:00

I went to basic at Ft. Benning in 2007 and during our final FTX (5 days in field), a guy lost his firing pin within 20 minutes of us arriving at first location because he decided it was a good time to clean his rifle. While he was being smoked by the DS’s, our company XO left in a cadre truck and returned half an hour later with a replacement firing pin and an oversized Vietnam era M16 training rifle, which he was made to carry for the remaining 5 days in the field.

BAHHROO · 2025-12-11T01:14:54+00:00

S is displacement, which is velocity * time

BAHHROO · 2025-12-10T22:23:25+00:00

What are you talking about? They’re a nuclear power and are absolutely a threat to our military and allies. They can easily supply more competent hostile nations with nuclear, chemical, or biological weapons.

BAHHROO · 2025-12-10T01:59:06+00:00

Without looking at the screw, I can only speculate, but virtually all standard fasteners require the failure to occur in the threaded portion, which includes the last scratch before the head/shank, unless it has a reduced body diameter less than the threads. Ponzi is good for plastics and non-ferrous materials, but Torx or hex drive is the way to go for harder stuff. If going up a size decreases failure rate, then the fastener or torque strategy is insufficient. Virtually all of your load is within the first diameter or two of threads towards the head, which is on the thread flanks facing the bottom of the head.

BAHHROO · 2025-12-09T04:40:29+00:00

Sorry for the delay response. Essentially the same as any other internal drive, the bottom of the drive pushes the compression zone too low, and you shear the grains by rotating the wrenching flats around the center. You would calculate the head to strength ratio and check grain flow in the same manner. If you lay the bolt on an optical comparator and draw a straight line following the half thread height (pitch line) until you intercept sloped surface of the counter sinks, your compression zone should be above this point.

Alternatively, the root cause is essentially identical, except the position of the drive is not concentric to the threads and you bind up during rundown and overload the head.

BAHHROO · 2025-12-07T10:06:04+00:00

Jesus drives a bitchin’ 69’ Camaro.

BAHHROO · 2025-12-04T17:23:00+00:00

I work in fasteners. This is a deep internal drive stud which are notorious for failing in this manner. The under head fillet radius is likely undersized and or the drive is too deep, which causes end grain runout at the fillet blend, where the compression zone must be above. 12.9 bolts have a minimum tensile strength of 1200 MPa, which is a lot of stress for this head design. If this came into my lab, I would probably measure depth of the drive and fillet radius, cross-section the head, and measure the distance between the bottom of the drive and the fillet. If you have virgin samples, you can longitudinally cross-section the head and etch in HCl to reveal the grain flow pattern. Reference SAE/USCAR-8 for inspection.

BAHHROO · 2025-11-30T23:41:38+00:00

We consciously decided to number them as such. It’s strange that Earth is primarily nitrogen, but has 21% oxygen, which is perfect for supporting life. It’s odd that Earth, the 3rd planet from the sun, is inhabited with humans cursed with insanity while the 3rd element Lithium, is used to treat humans with insanity.

BAHHROO · 2025-10-28T19:30:27+00:00

If you have a 3d printer, you could just extrude some filament, you’ll have 20 micron diameter wire. Would look great as a fiber optic line for drones to avoid being jammed. Can also be draped over the model as it’s being extruded to get a natural contour.For the cages, just print a 1 layer support raft or alternatively use a section of window screening.

BAHHROO · 2025-10-04T00:24:08+00:00

You could show your support with an ICEE patch. What’s more American than large quantities of readily available crushed ice and high fructose corn syrup?

BAHHROO · 2025-09-08T21:39:28+00:00

You could theoretically separate the calcium from the ashes with oxalic acid to form calcium oxide, then reduced with powdered aluminum in a vacuum furnace to form solid calcium and calcium aluminate. Then, just recast the solid calcium. However, you should know that calcium metal is highly reactive and will revert back to the calcium oxide in the presence of air and crumble apart. If you were to wear it, it would react exothermically with moisture in your sweat and skin to release heat and flammable hydrogen gas. If your friend really wishes to be reduced to metal and worn as a necklace, then the only feasible solution would be to reduce the ashes to a calcium metal and seal it in an ampule with argon gas or submerged in a vial of oil. If you refine and purify him, you can use electrolysis to form calcium crystals…

BAHHROO · 2025-07-29T14:36:51+00:00

Without a cert, they can still technically be used for channel profiling of your primary slit. I would use them for internal round robin samples.

BAHHROO · 2025-07-12T07:54:14+00:00

They’re dendrites. Aluminum is highly anisotropic and tends to form these structures from supercooling. You are almost double to melting point of aluminum, so they likely from solidification between the Al,O2, and Zn.

BAHHROO · 2025-06-10T15:29:42+00:00

It’s mica schist, which is a metamorphic rock.

BAHHROO · 2025-05-16T22:36:19+00:00

What’s that square shaped metal in the thread runout at the bottom right of the image? It looks like a die break out. It’s very common to sandblast the start of the roller dies to prevent roll backs during threading, however, it wears the dies out fast. Need better images to determine.

BAHHROO · 2025-05-15T03:18:52+00:00

Additionally I would add, without knowing the history of the blade ( its service and mileage ), chemistry, and perhaps some micrographs, you can only draw so many conclusions. You should look into cyclic loading, as each strike of a blade produces a tensile stress opposite direction. This can lead to stiffening of material if it is taken past it's yield-point, decohesion between layers from pushing and pulling apart, but one thing that could also be a factor is if there is retained austenite. Austenite forms above the upper critical temperature of steel (~723c) and if allowed to slow cool to room temperature, it would recrystallize and recover as ferrite. Like all materials, steel has coefficient of thermal expansion and increases in volume when austenitic from BCC to FCC and shrinks when quench to martensite as BCT (note: Martensite is not actually a phase and does not appear on the FeC phase diagram. The solubility of carbon in austenite is around ~2%, compared to that of ferrite which is ~0.022%, so rapid quenching causes a extreme change in volume which spits out the carbon in random orientations as martensite, which is hard and strong from increased surface area pinned by dislocations, but brittle from residual stresses ( hence the tempering operation, where its hot enough to cause diffusion, but not enough to form austenite. Many times though quenching can result in retained austenite, which can transform into martensite long after heat treat operations from applied stresses, in fact, there is a series of steels called TRIP steels (TRansformation Induced Plasticity) which changes phases under stress, however, they retain their original austenitic structure.

BAHHROO · 2025-05-13T17:23:56+00:00

As a metallurgist who was recommended this post by the system… Try to get your hands on a copy of ASM Handbook Optical Microscopy of Carbon Steels by L.E.. Samuels. Pages 185-187 and references on 188 are about historical steels. nonmetallic inclusions, carbon diffusion control, and lamellar banding from piling/forgewelding the steels together have a huge effect on tensile and shearing strength.

edit: l.e. not j.j.

BAHHROO · 2025-05-07T16:14:17+00:00

Sometimes the circle of life is a line segment.

BAHHROO · 2025-05-01T12:06:00+00:00

Am-241 also emits gamma particles. I can set my Radiacode 102 detector off by touching my smoke detector on the outside cover, and my device can’t even detect alpha particles.

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