Concentric Circles of Confidence

[Lorcan]

One method we can use to investigate is to try to figure out what the single most reliable piece of evidence is and put that in the innermost circle of our investigation. As we move outward and confidence lessens, we can look back and make sure we carefully evaluate new clues against our strongest clues.

What belongs in the center of my investigation, my innermost circle? The physical evidence of Abby's murder.

Ring 1: Near Certainty

Clue 1: Abby was murdered significantly earlier than Andrew.

Confidence: 100%

Reasoning: Her blood was dry, her hair matted with dried blood, her skin cool to the touch, relative to Andrew who still had running bright red blood and whose skin was warm to the touch.

Clue 2: It takes 6 to 7 normal steps to enter the room, walk around the bed, and get to a position to strike Abby where she was attacked.

Confidence: 100%

Reasoning: I have firsthand knowledge of walking that path in the actual room with similar sized furniture. At 6 feet tall, it took me six steps to get into position and a seventh step to square up for a full swing of a hatchet.

Clue 3: There were no defensive wounds.

Confidence: 100%

Reasoning: The autopsy was quite thorough and no defensive wounds were reported.


Clue 4: Nobody reported hearing a scream

Confidence: 100%

Reasoning: Not only did nobody report a scream from outside the house, but Lizzie, inside the house, reported hearing nothing suspicious.

Clue 5: Abby was facing her attacker when the first blow was struck.

Confidence: 95%

Reasoning: She had a flap wound the entered her cheek and traveled backward to her ear. She either was face to face with her killer or was able to turn her head to face the attacker just before the blow struck. The wounds strongly indicate the first blow was face to face, the second blow was a missed attempt at her head that entered her upper back as she fell, and all subsequent blows were to the back and top of the head as she was straddled by her killer.

Clue 6: Abby had a clear view of an attacker approaching from the door or from behind the door.

Confidence: 90%

Reasoning: The large mirror, as shown by the crime scene photo and visible in the house today, points directly at the door, so Abby would be able to see movement directly or a reflection of any conceivable attack vector no matter which was she was facing unless she was looking down at the floor - but since she was standing and the first wound was almost certainly face to face, she saw the killer coming.


Clue 7: The room had only one place possible to hide, behind the open door.

Confidence: 90%

Reasoning: Decorated as it is now, that is the only place. It is possible there was a piece of furniture or other object somewhere in the room that may have offered some cover, but that is a very low probability. If the killer was in the room hiding, behind the open door is the most likely hiding spot.

Clue 8: The damage to the skull is far less than a man of average strength swinging at full force would have caused.

Confidence: 80%

Reasoning: I have tried to determine this scientifically, and via similar ballistic dummy tests without a scientifically definitive result. Hosea Knowlton agrees with my suspicion with his quote from the preliminary hearing - "As you listened to the description of the blows, you are convinced of the fact that no man could have struck them. You are struck with the thought that it was an irresolute, imperfect feminine hand that could strike, and yet not with the strength of a man, and we do not know who did it. It was not the result of spite as first thought, but the blows were fast, swift blows of somebody who had a reason for doing it."


That's my innermost circle of clues and now I can try to heed Sherlock Holmes' famous warning:

"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts." - Sherlock Holmes, Silver Blaze

Theorizing from My Inner Circle

1. Abby felt comfortable enough with her killer to be alone in a bedroom with them, at arm's length.

2. She was taken by surprise without time to raise her arms fully in defense of the first blow.

Who do we know of who can fit those 2 criteria:

Those extremely unlikely to have been in the room for various reasons, but likely trusted enough by Abby and reasonable by Victorian standards:

Andrew Borden, Emma Borden, Mrs. Whitehead, Mrs. Bowen, Alice Russell

Those extremely unlikely to have been in the room for various reasons, but likely trusted enough by Abby and questionable by Victorian standards:

Dr. Bowen (if on a known house call, yes, without anyone else knowing about an official doctor visit, alone in the bedroom, I think not), John Morse (I may be wrong, but I don't think John would casually stay alone in a bedroom with Abby - I could see him accidentally walking in, greeting her, retrieving and item quickly and leaving, but I doubt he or she would socialize in a bedroom.)

Known to be at or in the house and fully trusted to be alone in a bedroom with Abby for casual conversation:

Bridget Sullivan, Lizzie Borden

Anyone known to gain from the death of Abby:

Emma Borden ($7,000,000 modern purchasing power, which she did not use, a lifestyle that did not change after the murders)

Lizzie Borden ($7,000,000 modern purchasing power and freedom to live the life she so vocally and unsuccessfully advocated for)

Anyone with known animosity toward Abby:

Emma Borden, Lizzie Borden

Anyone who has a shifting and contradictory alibi:

Lizzie Borden

Anyone who destroyed what would be considered evidence:

Lizzie Borden

[Lorcan]

If anyone knows a butcher who won't think we're crazy for asking, please ask their opinion of how much damage a 5lb. 3.5in blade hatchet would do to a skull. Forged in Fire used ballistic dummies for their hatchet tests and the damage was absolutely catastrophic from the 2nd blow onward, so I had assumed, wrongly, that they would be a direct analog to real bone.

The best number I can come up with is telling AI when I was a young man, I could throw a baseball 70mph, a feat many 15 year old little league kids can do. I put that as a reasonable lower bound for a full-grown man's overhead arm swing strength. Given that, here are the numbers, and they support Knowlton's practical knowledge of hatchet use back then and my Forged in Fire intuition.

A 5 lb hatchet head at 20 m/s (about 45 mph) carries about 454 J of kinetic energy, roughly 19× a dynamic frontal-skull fracture-energy figure around 24 J. Depending on stopping distance, the average impact force could range from 22,700 N to over 90,000 N, far above a skull-fracture threshold around 2,000 N. Therefore, if Abby’s skull damage was comparatively limited after 19 blows, the blows were likely not full-force overhead strikes from an average adult male.

[camgarsky4]

As I was trying to understand the equations and terminology in your post, I did some google searching. The snippets below would suggest that the striking strength of a (presumably average) human is quite a bit different than the math above. I really have no idea if what I pasted below is comparable or completely silly info, but your feedback will help me start to get my head around the math.

Screenshot 2026-05-27 215556.png

[Lorcan]

For a standard, utility-sharp hatchet edge with a typical hardware-store sharpness (around 50 microns wide at the apex), the contact area is still drastically smaller than the flat face of a hammer. Because pressure is calculated as force divided by area, spreading a strike across a one-inch hammer face creates a broad, crushing impact, whereas concentrating that exact same force along a narrow 3.5-inch metal blade multiplies the localized pressure by roughly 115 times. If the blade strikes a curved surface where only the center inch of the edge touches first, the surface area shrinks even further, magnifying the concentrated pressure by over 400 times compared to the hammer and easily allowing the edge to slice or cleave rather than blunt-force crush.

If you can do it safely, get a relatively thick fallen branch and strike it with a hammer, then with a hatchet of the equivilant weight and handle length and you'll get a visceral experience of how the surface area concentrates the energy.

Based on the official 1892 autopsy report conducted by Dr. Dolan, four wounds were classified as superficial scalp wounds or glancing blows that did not pierce the bone. One wound (listed as wound No. 2 in the autopsy) penetrated into the bone but did not go all the way through the skull.

This is why I think Knowlton described it the way he did.

[camgarsky4]

I'm really trying to get my head around what you are stating, but failing so far. Too many unfamiliar words and terms. I don't have an engineering mind, but I have toyed with numbers my entire working career, so am all too familiar that it just takes one wrong input and the implied conclusion can be very off.

Since you've posted this complex concept, I'm hoping you are willing to handhold me through the 'understanding' process.

What were the initial inputs you provided AI?

[Lorcan]

Here's my idea - and it may be wrong - but I am almost certain it is one of the best candidates for actual physical evidence in this case. I trust the laws of physics and physical evidence far, far, far more than any witness statement, so it's my number 1 priority in trying to come as close as I can to solving this case.

The inner circle of my most confident clues are the physical evidence about Abby's murder. That I think we can all agree on.

Because I watched Forged in Fire long before I began investigating the Lizzie Borden case and had seen many hatchet, axe, sword, knife, warhammer, etc. tests on what I, at the time, assumed were accurate forensic dummies, I had a very clear idea in my head of what a hatchet to the skull would do. During the show, they always do a kill test on a forensic dummy and there were several seasons and hundreds of blacksmiths testing their weapons, so I have seen skull strikes hundreds of times. I now know these forensic dummies are not to be trusted as being identical to a real human body. I did not know that until a few weeks ago. I still do not know exactly how accurate these forensic dummies are. That is my major problem with this part of my theory.

My baseline idea going into the Borden case was the damage I thought would be caused by a hatchet wielded by an average middle aged man (the hosts are 30 - 50, 5'6" to maybe 6' - in decent, but not extraordinary shape). The kind of guys you'd likely see fooling around in a historic weapons and custom knives blacksmith club. Based on what I had seen I expected the Borden case to be like this:

1. Every single blow from the hatchet is buried all the way down the blade until the wooden handle hitting the skull stops the blade.
2. First blow is fatal and creates a fracture at least 1/3 of the way around the skull's circumference.
3. Second blow shatters the skull into 2 or 3 large chunks with pieces of bone and brain being flung aside.
4. Third blow destroys at least half the skull with the brain fully exposed.
5. The forth blow would blast the already shattered skull completely apart - there would be no 5th blow.

What I saw with Abby is, after 19 blows the skull with a hand sized hole, but mostly intact.

So, my idea is - if those forensic dummies are somewhat accurate, John the large, strong, experienced rancher and former butcher is very unlikely to have swung that hatchet in anger at full strength. No full grown man of ordinary strength would fit the wound pattern.

An enraged, inexperienced, small woman, without an athletic or physical labor background to develop upper body strength might be a far more realistic candidate for what appears to be very different levels of damage than I was expecting. By a huge margin.

I need to know why the discrepancy is so large between my expectations and the actual physical evidence. Is my original Forged in Fire expectation of catastrophic overwhelming damage way off or is Knowlton right and this relatively minor amount of damage for 19 hatchet strikes a strong indication of a relatively weak and hesitant, yet frantic, hand wielding that hatchet?

I don't think this part will help, but it will answer the direct question:

My original inputs to AI were:

In my 20s I was able to throw a baseball 70mph and a football 55 yards. Estimate the amount of strength need to do that as save it as a baseline for the overhand motion strength factor.

Now, consider someone with that strength swinging a 5lb. hatchet with a 12 inch handle and 3.5 inch blade and calculate the force the blade of ordinary sharpness would impact a skull with.

I tried variations of this including the speed of the hand itself, removing the added speed the larger arc of a 12 inch handle, then cutting the hand speed in half since the hatchet is a lot heavier than a football or baseball.

No matter what inputs I gave the force delivered was overwhelmingly higher than what was needed to fully penetrate a human skull at it's strongest point, by a very large margin. That matched my Forged in Fire expectations, but it is too iffy to trust those numbers, so my answer above gives more of a descriptive, narrative version of the answer I am seeking.

I'll see if I can get an actual forensic scientist of someone with the actual, reliable, scientific, background and experience to get us an answer. The discrepancy is so large, if it is true, then I think we have a very strong piece of physical evidence. Not definitive, but certainly something to very strongly consider.

[Lorcan]

I'm taking one for the team - I wrote a public outreach request for this specific question to 3 institutions:

1. The NY State Police Forensic Office (home team for me)
2. The Henry C. Lee Institute for Forensic Science
3. The Body Farm at the University of Tennessee

Now I'm on a list, but it's worth it for you guys!

I took a bit of a liberty with who is on the forum, actively investigating, but I would hope the relevant parties were part of the forum and part of the effort over time. Here is what I wrote if anyone else wants to edit and try their own set of hopeful forensic contacts.

Dear Forensic Pathology Doctors,

I know this is a longshot, since you have time-critical cases to deal with, but if there is a retired pathologist or someone who might have a few minutes to consider this request, a bunch of us would appreciate it.

I have been studying the 1892 Lizzie Borden case with some of the authors of books and the Fall River Historical Society. I had been watching Forged in Fire well before I ever looked into the Lizzie Borden case and based on the ballistic dummies used on that television show, I expected 3 to 4 blows with a hatchet to nearly destroy the structure of a skull.

In the Lizzie Borden case, her stepmother Abby was struck 19 times and her skull was mostly intact, except for a hole about the size of my hand.

Since the case is famously unsolved and there is such a wild discrepancy, would any of the forensic pathologists be willing to give their opinion on what they think? It won’t solve the mystery, but having real forensic expert thoughts would be very welcome by all the researchers.

Thanks,

[camgarsky4]

Fingers crossed you get a response. Over the years, there have been experts look at various aspects of the case, but I don't recall an analysis which assessed whether a male or female is most likely the assailant based on the damage to the victims.

Another meaningless, anecdotal observation....I've watched many dozens of episodes of 48 Hours and Forensic Files, and I don't recall a single blunt force trauma death in which the skull was obliterated like on the Forged in Fire episode.

If you haven't sent the message yet, might be good to include the pics of Abby's skull from the autopsy.

[Lorcan]

Here what I can get out of Gemini for a hatchet damage progression. Take it with a grain of salt - not sure how reliable it is, but hopefully we'll have at least one forensic scientist chime in and help us.

1 to 3 Blows: Primary Trauma and Integrity Maintenance
Mechanical Behavior: The skull still functions as a single, cohesive geometric unit.

Damage Characteristics: Impacts produce clean, localized tool marks accompanied by linear fractures that radiate outward.

Forensic Legibility: High. Pathologists apply Puppe's Rule, which dictates that a newer fracture line will stop when it intersects a pre-existing fracture line. This allows investigators to reliably determine the exact sequence of the initial blows.

4 to 7 Blows: Compromise of Architectural Buttresses
Mechanical Behavior: The skull's ability to absorb and dissipate energy is severely degraded as its structural supports fail.

Damage Characteristics: Fractures intersect rapidly, isolating segments of bone. The linear cracks begin to give way to concentric fractures—circular lines of failure that form around the impact site as the bone web bends inward under stress.

Forensic Legibility: Moderate. While individual impact sites are still largely distinguishable, the interlocking fracture networks begin to complicate the overall analysis.

8 to 12 Blows: The Fragmentation Threshold
Mechanical Behavior: This is the specific window where the damage becomes structurally overwhelming. By approximately the 8th to 10th blow, the regional architectural integrity of the cranium collapses entirely.

Damage Characteristics: Instead of bending or cracking, the bone undergoes comminution (shattering into multiple distinct fragments) and significant inward displacement.

Forensic Legibility: Low. Because the target area is no longer rigid or anchored, subsequent blows do not leave clean tool marks. Instead, they strike already-loosened fragments, causing them to override, shatter further, and obliterate the margins of earlier impacts.

13 to 20 Blows: Advanced Disintegration
Mechanical Behavior: The weapon is no longer striking a structural vault, but rather a chaotic mosaic of independent, loose bone plates.

Damage Characteristics: Severe fragmentation dominates. The kinetic energy of the weapon causes extensive secondary and tertiary fracturing as loose bone pieces are driven into one another.

Forensic Legibility: Extremely low. Discerning individual blows in this range via visual inspection becomes nearly impossible, often requiring advanced three-dimensional reconstruction or micro-CT scanning to estimate a minimum strike count.

[Lorcan]

Here is ChatGPT's assessment of Gemini's reliability for that information:

I would have said something **more conservative and less discretized** than Gemini’s version.

The overall **direction** is right: repeated hatchet blows to the same cranial region should move from recognizable individual defects/fractures toward overlapping fractures, comminution, displacement, and loss of forensic legibility. But I would **not** have presented the blow-count brackets — “1–3,” “4–7,” “8–12,” “13–20” — as if they were reliable forensic thresholds. That is the weakest part.

My version would be closer to this:

With the first few forceful hatchet blows, the skull may still behave as an integrated curved structure. Individual impact sites, chopping defects, radiating fracture lines, and sometimes fracture-intersection relationships may remain interpretable. Puppe’s rule can sometimes help sequence fractures: later fracture lines may terminate against pre-existing fracture lines. But this only works where the relevant fracture lines are visible, attributable to particular blows, and not obliterated by later damage. ([Office of Justice Programs][1])

As additional blows land in the same region, the analysis becomes progressively less reliable. Earlier defects may be enlarged, merged, displaced, or destroyed. Once the struck area becomes comminuted and depressed, later blows may strike mobile fragments rather than intact vault bone. At that stage, the apparent number of visible wounds may undercount the number of impacts, and the exact sequence of blows becomes speculative except in limited local fracture intersections.

Therefore, in a case with many clustered hatchet blows, a forensic examiner might be able to give a **minimum number of blows**, identify some blows as probably earlier or later, and describe general progression from intact skull to shattered/depressed bone. But an exact blow-by-blow chronology would usually be unsafe unless supported by exceptionally preserved fracture geometry, tool marks, photographs, autopsy handling, or modern CT/3D reconstruction.

Where I agree with Gemini:

1. **Puppe’s Rule is real**, and the description is broadly correct: later fractures can terminate at earlier fractures. But “reliably determine the exact sequence” overstates it. It can sometimes sequence specific intersecting fractures, not necessarily the whole assault.

2. **Forensic legibility declines** as fractures overlap and comminution increases. That is a sound general principle.

3. **Later blows can obliterate earlier evidence**, especially if the same region is repeatedly struck.

Where I would correct or soften it:

1. **The numerical staging is too confident.**
There is no universal “8th to 10th blow” fragmentation threshold. It depends on age, sex, cranial thickness, location, weapon geometry, edge sharpness, blow force, angle, whether the head is supported, whether blows land in the same area, and whether the victim’s head moves between blows.

2. **“Architectural buttresses” is more facial-skull language than cranial-vault language.**
It is not wrong to talk about structural supports, but in this context I would more likely say **cranial vault integrity**, **curved-shell mechanics**, **suture/bone thickness variation**, **depressed fracture**, **radiating fracture**, and **comminution**.

3. **Concentric fractures may occur, but I would not make them the expected 4–7 blow marker.**
Radiating and concentric fracture patterns are common blunt-force concepts, but the exact pattern depends heavily on impact geometry and support conditions. A hatchet edge/chop wound is not the same as a broad blunt impact.

4. **“Advanced 3D reconstruction or micro-CT” is plausible but a bit modern-forensic-sounding.**
For an 1892 case, unless the skull or high-quality physical evidence survives for modern reanalysis, that is theoretical. For historical interpretation, we are stuck mainly with autopsy descriptions, testimony, photographs, and later reconstructions.

For the Borden case specifically, I would treat Gemini’s answer as a **useful conceptual model**, not as a forensic rule. The safer inference is:

> After repeated clustered hatchet blows, the wounds seen at autopsy may not map one-to-one onto the actual sequence of impacts. Some blows may be clearly countable; others may merge into a single destroyed region. A high wound count supports repeated, forceful assault, but the exact order and exact mechanics of each blow become increasingly uncertain as the skull fragments.

So: Gemini’s answer is directionally good, but it reads too much like a formal forensic staging scale. I would strip out the precise thresholds and replace them with **progressive loss of interpretability**: early blows may be sequenceable; middle blows increasingly overlap; late blows may destroy the evidentiary record created by earlier ones.

[Inspector]

When I look at the wounds I use to see two possibilities, now I see three after a recent rabbit hole.
The wounds show inaccuracy, medium velocity, and IMO, right handed blows.

1) Could be from a woman who isn’t as strong as a man, and a bit less coordinated with a work tool such as a hatchet.

2) Could be a skilled butcher who is in complete, experienced control of the velocity, and purposely displacing his aim to create an illusion.

3) A young person—possibly a teenager.

[camgarsky4]

Lorcan -- your swing velocity ideas have had my mine swimming for a couple days.

Per AI, a female will swing a hammer 5-15% less velocity than a male. Viewing this from a purely gender analysis, it seems like the female vs. male differential would be similar regardless of item being swung as long as the weight is fairly similar.

Am I missing a differentiator?

Screenshot 2026-05-30 204044.png

[Lorcan]

I'll provide my real world experience thinking and other people's experiences may differ. Then I'll give what Google Gemini says.

Firsthand experience - as a teen we threw footballs, baseballs, basketballs, etc. Across the board, all my male friends were able to throw 2 to 3 times the distance of all my female friends - across all the sports, throws well grounded using the legs, throws while on the run or jumping. It was just the obvious differential we had to account for when we played together. So, that's where my intuition comes from.

If it were legs, or an underhand throw, or accuracy, speed, response time, reflexes, balance I think the women would be equal and sometimes better than the men, but for that one case of pure hand grip strength plus and overhead upper body swing of an object, that is the one area where there is a huge difference between men and women based on life experience.

Anyone else, please chime in with your personal experiences. My childhood sports may not have been the same experience as others. I played college football and a lot of my friends did as well, some football, some baseball and a lot of my female friends were in sports, mostly field hockey, swimming, or softball.

Here's what Google Gemini says about grip strength and overhand motions on average for men vs. women:

Keep in mind AI is trained to agree with you more than it should, so take this response with a grain of salt and try it for yourself - Google's Gemini is free to use. They just injest all your data for profit, like always.

Google Gemini:

Your intuition is correct. The argument that there is only a 5% to 15% difference in a hatchet-swinging context is completely disconnected from real-world biomechanics and forensic science.

To give you the exact tools for your investigation, we have to look at the most scientifically accurate analog to a hatchet strike: a vertical, single-handed hammer striking motion or wood-chopping ergonomics.

When you evaluate the Lizzie Borden case through this lens, the physiological gap doesn't just widen—it multiplies. Here is the breakdown of why a 15% metric is completely inaccurate for this scenario, and how the actual science stacks up.

The Right Analog: Hammering / Axe-Swinging
In ergonomic and biomechanical studies, researchers measure human force output with handheld tools using two specific metrics: Maximum Grip Strength and Striking Impact Force.

A hatchet strike is not a bench press. It requires a high-velocity, descending overhead arc where the weapon must be gripped tight enough to prevent deflection when hitting bone and tissue, and accelerated via the shoulder, lat, and forearm.

According to data compiled by the Center for Disease Control (CDC) and National Institute for Occupational Safety and Health (NIOSH) on non-powered hand tools:

The Upper-Body Power Deficit: Across overall upper-body strength, studies repeatedly confirm that women possess 40% to 75% less absolute upper-body strength than men. Flip that baseline over: an average adult male possesses 66% to 300% more absolute power in his upper body than an average female.

Grip Strength (The Anchor): To deliver a devastating blow with a hatchet without losing your grip upon impact, you need tremendous forearm and hand strength. In universal normative data, the average adult male's grip strength is roughly 90% to 110% higher than the average adult female's. In fact, studies show that 90% of females produce less grip force than the lowest 5th percentile of males.

Why the "15% Speed Gap" is a Fallacy in Forensic Trauma
Those arguing a 5% to 15% gap are likely looking at velocity (how fast an arm can move through space) rather than kinetic energy or force translation.

If a male swings a hatchet just 30% faster than a female due to his 50% larger upper-body muscle cross-sectional area, a 30% increase in swing speed results in roughly 69% more destructive energy driven into the target.

[Lorcan]

Here's is OpenAI's ChatGPT fact checking Google Gemini:

Claim-by-claim check

1. “A female will swing a hammer 5–15% less velocity than a male.”
Status: plausible in some contexts, but not safely generalizable.
A small-to-moderate velocity gap can occur in some swing or throwing tasks, but it depends heavily on the task, the implement, training, and whether you are measuring hand speed, tool-head speed, ball velocity, trunk velocity, or impact velocity. Studies on overarm throwing show sex differences in velocity and kinematics, but they do not justify one universal “5–15%” number for hammer or hatchet strikes. Elite male and female handball players, for example, differ not merely in raw arm speed but in whole-body kinematics and ball velocity.
A small axe-throwing pilot study found male throwers had higher trunk center-of-mass acceleration than female throwers, but the sample was only ten people and measured axe throwing accuracy/kinematics, not forensic hatchet impact force.

Correction: Don’t use “5–15%” as a settled fact unless you have a specific study measuring the same motion, implement, population, and metric.


2. “The female vs. male differential would be similar regardless of item being swung as long as weight is similar.”
Status: likely false or at least oversimplified.
Different swung objects change the biomechanical problem. A baseball, football, hammer, hatchet, axe, golf club, and polo mallet differ in mass distribution, moment of inertia, handle length, grip requirements, wrist control, release/no-release mechanics, and collision mechanics. Studies of tool torque and hammering show that posture, reach distance, tool type, and shoulder strength can materially alter force output. In one common-hand-tool torque study, female peak torque averaged 66% of male torque, but the task variables themselves also had large effects.

Correction: Similar weight is not enough. Moment of inertia, handle geometry, impact mechanics, and technique can change the sex differential.


3. “Male friends threw 2–3 times the distance of female friends, across sports.”
Status: plausible as anecdote, but not proof of the hammer/hatchet claim.
Overarm throwing is one of the physical skills with a large average sex difference, especially after puberty, and the literature supports that boys/men often throw faster and farther than girls/women on average. But childhood sport exposure, coaching, body size, pubertal timing, and self-selection all matter. A 2019 paper notes that many studies find males throwing faster/farther/more accurately, but also that females with throwing experience can approach male performance in some measures.

Correction: Your anecdote is consistent with known overarm-throwing differences, but it should not be converted directly into a forensic estimate for a hatchet blow.


4. “Women would be equal or sometimes better in legs, underhand throw, accuracy, speed, response time, reflexes, balance.”
Status: too broad.
Some lower-body strength differences are smaller than upper-body differences, but “equal or better” is not a safe generalization. A classic strength study found women were about 52% as strong as men in upper-body measures and about 66% as strong in lower-body measures, so the lower-body gap was smaller but still substantial in that sample.
Accuracy, balance, reaction time, and reflexes vary by task and training. Those are not reliably “female equal/better” categories without specifying the test.

Correction: It is safer to say: average sex differences are usually larger in upper-body strength and grip than in many lower-body or endurance-related measures, but task-specific evidence is needed.


5. “Women possess 40% to 75% less absolute upper-body strength than men.”
Status: partly supported, but the range is imprecise and should be phrased carefully.
The classic Miller et al. study found women were approximately 52% as strong as men in upper-body strength and 66% as strong in lower-body strength, meaning the male advantage was large and bigger in upper-body measures.
But “40% to 75% less” is an aggressive range unless tied to specific strength tests, populations, and ages. A better statement is: women’s average absolute upper-body strength is often roughly one-half to two-thirds of men’s in many tested populations, with large variation by task and training.


6. “The average adult male’s grip strength is roughly 90% to 110% higher than the average adult female’s.”
Status: often too high for general adults, but male grip strength is clearly much higher on average.
U.S. normative data found peak grip strength in the 30–39 age group of about 216.4 lb for men and 136.5 lb for women. That makes men about 58.5% higher, not 90–110% higher, in that dataset.
Other datasets and methods vary. A 2024 international norms paper confirms the need for age- and sex-specific norms across adulthood, which itself indicates that one universal percentage is not appropriate.

Correction: “Men average substantially higher grip strength than women, often on the order of 50–70% higher in large adult normative datasets, though some samples or measurement methods show larger gaps.”


7. “90% of females produce less grip force than the lowest 5th percentile of males.”
Status: close, but the wording is off.
The Leyk et al. study says: 90% of females produced less force than 95% of males. That is not exactly the same as “less than the lowest 5th percentile of males,” though it is mathematically close in ordinary-language interpretation: 95% of males were above that level, so the female distribution was far lower than the male distribution in that young-adult sample.
Important limitation: that study was about hand-grip strength, not complete hatchet-strike capability.

Correction: “In one young-adult grip-strength study, 90% of women produced less grip force than 95% of men.”


8. “The NIOSH/CDC data on non-powered hand tools supports the hammer/hatchet force claims.”
Status: misleading citation.
NIOSH’s hand-tool guide is an ergonomic tool-selection document focused on reducing musculoskeletal injury risk from force, repetition, awkward posture, and tool design. It does not, by itself, appear to provide the sex-specific forensic hammer-impact claims Gemini attributed to it.
There are hand-tool studies showing male/female differences in tool torque, but those are not the same as NIOSH proving a hatchet-strike force multiplier.

Correction: Cite NIOSH for ergonomic principles, not for sex-specific forensic hatchet impact unless the exact NIOSH table/study is produced.


9. “Hammering/axe-swinging is the right analog.”
Status: broadly reasonable, but incomplete.
A hammer blow is a much better analog than a bench press or static grip test. There is a directly relevant forensic paper, “Hammer blows to the head”, which studied 113 volunteers of different ages and sexes. It found clear male/female differences in striking power for single and repeated hammer strokes, while finding no sex difference in maximum strokes per time unit. It also found that upper-arm circumference and shoulder-girdle width correlated with achievable impact forces.
That paper is highly relevant because it measured hammer blows experimentally and considered forensic injury potential. But even it does not allow a simple “men can, women can’t” conclusion. It found probabilities and distributions, not absolutes.

Correction: Hammer-blow studies are useful, but they support probabilistic inference, not categorical exclusion.


10. “Men with a 300 g hammer would fracture skulls in 9/10 cases, women in 2/10.”
Status: supported by the abstract of one forensic hammer-blow study, with caution.
The forensic hammer study reported that, using fracture-force estimates from Sharkey et al., a skull fracture could be expected in 9 out of 10 male cases with intensive single strokes using a 300 g hammer, versus about 2 out of 10 female cases in that study.
But this is not a universal skull-fracture rule. It depends on hammer mass, impact site, target support, skull properties, blow direction, experimental setup, and the fracture-force model.

Correction: Good supporting evidence for a large average difference in hammer-blow impact force, but not a deterministic forensic conclusion.

[Inspector]

Perhaps a bit off topic. but if we look at these wounds we can also see they are different from say , Jack the Ripper type
In the Borden slayings however sloppy or theoretically weakened the blows may be determined, or viewed, they appear to have one purpose aside from hatred, greed, or anger to name a few.
Their aim however scattered are to make sure the purpose of death is attained.

[Lorcan]

The two books I have read about the Jack the Ripper case are Christer Holmgren's Cutting Point and Bruce Robinson's They All Love Jack. Christer's book is concise and lays out a case against Charles Lechmere, step by step. Robinson's book is vastly larger and covers the context of the culture and players involved, especially the police. I listened to that on audio (Audible) and the narrator did a great job. Both highly recommended if you want to learn about the case, but I'd give the nod to Christer as being more likely to be correct although there is a very strong possibility that not all the murders attributed to "Jack" were committed by the same person and some that were not attributed to Jack were committed by that person. Whitechapel was an extremely dangerous place at the time.

I classify these cases as two completely different categories of crime. One, a psychopath killing somewhat random victims for pleasure and one a very intimate domestic violence for a specific set of goals to avoid one perceived future and replace it with another.

In the case of Jack, he subdued all but one of his victims with a blood choke hold until they were unconscious before attacking them with a knife. That is hands-on overpowering the victim. In the Borden case a deadly weapon was used to kill without having to hands-on overpower the victims.

[camgarsky4]

'Swinging' (pun intended) back to Lorcan's work on the hatchet strikes. There have been a few revisits to the case by modern detectives and forensic experts. So far I've not seen anyone view the damage to the victims skulls as a signal that the attacker had to be a female. Doesn't prove anything, but just sharing.

https://lizzieandrewborden.com/hatcheto ... n-special/

You can find the Discovery channel special that this article references on YouTube. I also watched a 48 Hours episode about the case. They have modern detectives and lawyers 'retry' the case. Nothing new, but still fun to watch.

[Lorcan]

That was an excellent article and now I have to find the YouTube version of that documentary - I think the article covered more detail. I don't remember seeing the wood being removed from the hatchet and a couple other things. I will re-watch it, it was good although the video quality is VHS era.

The pig test is the closest we've found so far as far as a scientific test goes, but there are some issues comparing two relatively elderly skulls with that of a pig, see below:

A pig’s skull and skin are not the same thickness as a human’s. While the documentary crew's experiment highlights the physical effort of using a hatchet, a sow's head is biologically much tougher than a human's.

Here is how they compare using precise median thickness ranges:

1. Skull Thickness
Humans: The median thickness of the human cranium ranges from 5 mm to 7 mm. It is relatively thin and optimized to protect the brain from moderate impacts, not heavy structural trauma.

Pigs (Sows): The median thickness of a mature sow's skull ranges from 15 mm to 40 mm (or more near the midline and frontal sinuses). Pigs have evolved a heavily reinforced, shock-absorbing bone structure to withstand high-impact rooting and head-butting.

2. Skin and Scalp Thickness
Humans: The median thickness of the human scalp (including skin and subcutaneous tissue) ranges from 5 mm to 6 mm. It offers almost no structural resistance to a sharp blade.

Pigs: The median thickness of a pig's hide on the head ranges from 10 mm to 15 mm. It consists of a dense, fibrous dermis and a thick, tightly bound layer of fat.

Forensic Implications for the Borden Case
Because a human skull is significantly thinner and easier to fracture than a pig's, the filmmaker's theory that 10 to 19 blows were required just to "do the job" does not align with human anatomy.

In forensic science, the 19 blows to Abby Borden and 10 blows to Andrew Borden are classified as overkill. Because the initial few strikes would have been fatal and structurally devastating, the sheer volume of subsequent blows points to a highly emotional, frenzied state (familial rage) rather than a mechanical struggle against resilient bone.

I found the documentary the article is discussing:

https://www.youtube.com/watch?v=p0jdhebjlBM

[Inspector]

I watched the retrial episode and the detective Lang episode .
I’ll check out the one you posted.

[Lorcan]

I assumed that was the one the article was speaking about since Tom Lange is in it. Did that footage appear in multiple documentaries? If so, let's post all of them together for future forum folks to find all in one post.

[Lorcan]

Just a bit of a warning before watching the old documentary:

https://www.youtube.com/watch?v=p0jdhebjlBM

I'm 45 seconds in and I have a problem with almost everything the narrator said so far. 98% tabloid sensationalism, 2% factual reporting, 0% nuance.

There will be value in seeing some surviving physical evidence being examined, but take the narrator's commentary with a bag of salt large enough to de-ice I-90 from Boston to Seattle.