Jacobs' Physics of Tools Debate Corner

[American Locomotive]

Tagentially related anecdote: In the late 90s, all of the major dirtbike manufacturers (except for KTM) switched to aluminum frames. The new frames used these large aluminum box sections that were extremely rigid. Too rigid in fact. There were tons of complaints from riders that the new bikes were extremely harsh and uncomfortable to ride - the suspension just couldn't handle everything on its own and the bikes transmitted too much vibration and shaking into the rider. Over the next decade, the manufacturers released progressively "floppier" aluminum frames with thinner and smaller tube cross sections.

So if a titanium hammer is a bit "floppier" and offers some kind of innate damping, while still retaining adequate, strength, surface hardness and durability - I could see why carpenters might prefer them.

 

[HannibalLecter]

Tagentially related anecdote: In the late 90s, all of the major dirtbike manufacturers (except for KTM) switched to aluminum frames. The new frames used these large aluminum box sections that were extremely rigid. Too rigid in fact. There were tons of complaints from riders that the new bikes were extremely harsh and uncomfortable to ride - the suspension just couldn't handle everything on its own and the bikes transmitted too much vibration and shaking into the rider. Over the next decade, the manufacturers released progressively "floppier" aluminum frames with thinner and smaller tube cross sections.

So if a titanium hammer is a bit "floppier" and offers some kind of innate damping, while still retaining adequate, strength, surface hardness and durability - I could see why carpenters might prefer them.

Generally,there is no such thing as a "too stiff frame or chassis".BUT the problem specifically with motorbikes is that as a bike leans to a corner or exits leaning, the actual force that the suspension reacts, ISN'T fed through the suspension. So , the frame and rear swingarm must act like a spring, with some build in compliance. To understand it, try to push back inside a utility knife, first hold vertically the blade against something and then try at 20 degrees angle

As for the titanium hammer, I think the phenomenon has to do with viscoelastics and energy release rate, both in the hammer and the nail. Or like this; could you drive in a nail by hitting it with a bullet? Probably not, the head would shatter before any force would overcome the friction , despite the vast amount of energy. Or, the inelastic coefficient of impact between the nail and the titanium hammer is somehow more suitable

 

[Schurkey]

I’ve always hated air ratchets. Running a screw in, you pull the trigger and think ”this is great”, then the fastener goes home and the ratchet breaks your wrist. Are battery powered ratchets better? Are they like drill motors or are they like impacts?

You'd just love "reactionless" air ratchets. I thought they were a fabulous idea until I used one at work.

They've got an "impacting" mechanism that allows enough torque transmission to spin nuts/bolts, but when the joint tightens up, they just rattle like a stalled impact wrench.

Since the jobsite was using air ratchets to spin taps, at the point where they "impacted" the tap shattered. But that's not really the tool's fault, it was the fault of the workplace for misusing it.

Far as I remember, IR invented the thing, now there's multiple companies selling 'em.

https://www.amazon.com/dp/B0000224KE/?tag=atomicindus08-20

Follow on question: I think impacts impact radially. How do drill drivers work. Are they axial? Or are the screw guns like mini impact guns?

The screw guns I worked with had no "impacting" mechanism at all. They were essentially a 3/8 air-drill with lower-speed/higher torque gearing. The better ones had a "clutch" that would slip at a set torque, and the slipping kinda felt like "impacting"--and would break smaller screws only because the clutch was set at too-high a release force. The crappy ones had no clutch, and broke a lot of screws.

Gold is measured in Troy ounces/pounds. Iron is measured in Avoirdupois ounces/pounds. There are 12 Troy ounces in a Troy pound. A Troy ounce is 1.097 Avoirdupois ounces......................so, 12 x 1.097 = 13.164 Avoirdupois ounces. That is almost 3 ounces less than the common Avoirdupois pound.

Gold is also measured in pennyweights, and grams. Usually this is for small quantities like in jewelry, or gold mining as in pennyweight per yard. A pennyweight is 1/20 of a Troy ounce.

DING! DING! DING! We HAVE a winner! The individual Troy ounces weigh more than Avoirdupois ounces, but there's fewer of them in a Troy pound.

I think the "iron core" is a hypothesis that hasn't been proven.

I say the true, deepest, center-of-the-Earth core is uranium or other radioactive/heavy metal, and radioacive potassium.

Makes sense that the heaviest elements would sink to the lowest depths of the various planets.

The atomic reactions explain the magnetic field, and the heat generated.

This is a crappy link to a "headline" on www.nature.com, but I think I read a more-detailed article in "Discover" a decade ago.

Are there nuclear reactors at Earth's core? - Nature

Fission reactors may have been burning for billions of years.

www.nature.com

 

[Debcrow]

Maxwell's equations still fill me with fear and loathing 40+ years after what was the worst course, taught by a truly sadistic SOB, in my life.

Maxwell Smart ????

I also found that the courses taught had very little to do with preparing you the reality of the world. I was a gearhead and always taking things apart and putting them back together as a kid. When I finally got to go to a university, I already had 6 years in the Navy Submarine Nuclear power field as an electrician. I was not a great student, but I did get my engineering degree.
I also had many friends that were top 'book learning' students that could not figure out things as simple as what was wrong with their cars air conditioning after the belt broke.
I have always felt that there needs to be more Coop education involved at all levels of education to give people the feeling of what the real world is like and expects. The proof on paper and the actual results in the real world are not always consistent.

 

[merkyworks]

I also had many friends that were top 'book learning' students that could not figure out things as simple as what was wrong with their cars air conditioning after the belt broke.

I refer to your friends as “calculators”. They can do the math you give them but they are only as good as the data you gave, bad data = bad results, cause they don‘t understand what is really happening.
A good engineering team will have a person like this to tackle all the "hard math", you just dont want to let them design things lol.

 

[1cargarage]

Question about carbon content:

Is a steel's carbon content (percentage) measured/expressed in
% by mass?
% by volume?
% empirically?

or some other percentage?

It's a detail that I think is overlooked...
Thanks

 

[Jacobs976]

Question about carbon content:

Is a steel's carbon content (percentage) measured/expressed in
% by mass?
% by volume?
% empirically?

or some other percentage?

It's a detail that I think is overlooked...
Thanks

That's actually a pretty good question. Also a fairly common issue, figuring out % by X without X being defined.

I don't have the answer unfortunately but the guys I know making engine blocks with a carbon tolerance of .0001% don't either. They add carbon by weight to increase content and test a sacrificial casting to check content with a computer till it's within .0001% of target. I think it's basically an xrf machine so it might be the same measurement system as a standard unit but they just see the percentage through the interface.

They, along with me, would assume it's based on weight(mass) looking at it logically though. That said, logic isn't always reality.

 

[F-22]

I think the standard practice is to specify the percentage in relation to mass. By volume would give you less practical usage in metallurgy (would need to do conversions...). Typically much easier to measure the weight than the volume.

I think that for steel with 0.2% carbon content by mass, you can calculate around 0.69% of carbon content by volume. Hope I didn't shoot too far off

 

[Private Lugnutz]

Maxwell's equations still fill me with fear and loathing...

Maxwell Smart ????

C'mon. On this thread and on this topic?! Has to be Maxwell Edison from the Beatles' song!

"Bang, bang, Maxwell's silver hammer
Came down upon her head
Bang, bang, Maxwell's silver hammer
Made sure that she was dead"

Is a steel's carbon content (percentage) measured/expressed in
% by mass?
% by volume?
% empirically?

By weight. The last two digits of any 4-digit AISI/SAE steel grade is the mean carbon content of that grade’s permissible carbon range by weight % when melting the steel. For AISI/SAE grade 1045, for example, "45" is the center point of a permissible range of 0.43 to 0.50%, with a nominal average carbon content of 0.45 wt.%. It varies in different places in an ingot, billet or bar, so a mean is necessary.

 

[AreBeeBee]

C'mon. On this thread and on this topic?! Has to be Maxwell Edison from the Beatles' song!

"Bang, bang, Maxwell's silver hammer
Came down upon her head
Bang, bang, Maxwell's silver hammer
Made sure that she was dead"

By weight. The last two digits of any 4-digit AISI/SAE steel grade is the mean carbon content of that grade’s permissible carbon range by weight % when melting the steel. For AISI/SAE grade 1045, for example, "45" is the center point of a permissible range of 0.43 to 0.50%, with a nominal average carbon content of 0.45 wt.%. It varies in different places in an ingot, billet or bar, so a mean is necessary.

Well, Lugz, arriving here from the Stiletto thread, I'd say I made my point over there: higher speed of swing, thanks to a lighter hammer head, yields more sluggo on the nail head and probably less wear and tear on the arm joints.

This is interesting, but I'm no metallurgist nor physicist and so I get lost easily in the weeds.

 

[Private Lugnutz]

I'd say I made my point over there:

Making it over here carries more weight. Nyuk nyuk, nyuk.

...higher speed of swing, thanks to a lighter hammer head, yields more sluggo on the nail head...

Not to reduce anyone else's contributions, rife with figures and rhetoric, to clubishness, but you're in pretty good company with that take. It's not unanimous, though.

This is interesting, but I'm no metallurgist nor physicist...

Aha. The formula had me fooled.

...I get lost easily in the weeds.

That's what Newton said after he got beaned by an apple.

 

[Jacobs976]

higher speed of swing, thanks to a lighter hammer head, yields more sluggo on the nail head and probably less wear and tear on the arm joints.

Only thing I can add really, more weight or more speed can increase applied force.

Finding the right balance is the key. Too light and you might take more swings but too heavy and you're looking at potential strain injuries.

Short of it, Ti might not be best for everyone because there's a personal preference involved beyond the metallurgy.

 

[AreBeeBee]

Only thing I can add really, more weight or more speed can increase applied force.

Finding the right balance is the key. Too light and you might take more swings but too heavy and you're looking at potential strain injuries.

Short of it, Ti might not be best for everyone because there's a personal preference involved beyond the metallurgy.

Agree. I'd be curious to know whether Stiletto made tests regarding titanium head weight and handle length before settling on the current designs for production.

 

[Jacobs976]

Agree. I'd be curious to know whether Stiletto made tests regarding titanium head weight and handle length before settling on the current designs for production.

They probably had some in house studies that touched on those aspects but they probably maintain somewhat close to the standard design to make it easier to transition to Ti and notice the difference.

All I really know is they've focused on limiting recoil as much as possible with Ti and the geometry but that's all I've heard talked about.