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Re: Hardness tesrters

 

Sounds great too?
It will work too.?
?
It bouns that makes work to a senceres like you said a mini metal detector and time.?
?
When purchased the first I play around with aluminum
Found about 18"? drop I could read reading of hardness of different aluminum. I had no real use as work in steel and iron. I also did have a way market the tester.?
?
Like your ? idea
Dave?
?
?
On Thu, Mar 6, 2025 at 07:34 AM, Bill in OKC too wrote:

Should figure out how to measure the induced voltage. Would be a cool addition to the demonstration.?
?
Bill in OKC?
?
William R. Meyers, MSgt, USAF(Ret.)
?
Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.?
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better.
Expect in one hand, expectorate in the other. See which one gets full first.
?
?
On Wednesday, March 5, 2025 at 02:11:43 AM CST, Jerry Durand via groups.io <jdurand@...> wrote:
?
?
Any charts for ceramic bearings so you don't need to worry about magnetism??

BTW, I did a demo of magnetism with non-magnetic materials.? Dropped a strong magnet through 200cm of 10mm copper tube.? Took a while to fall out the other end, something nobody in the room had seen or expected.

I did include a wave of a Harry Potter magic wand, just for extra effect.

On 05-Mar-25 11:07, davesmith1800 wrote:
Remember the surface being bounced test needs to clean of oil , any coating and Degaussing.
This note is not on drawings
?
Re: Hardness tesrters

 

¿ªÔÆÌåÓý

Voltage would be pretty low, but I'll bet the current is pretty good.

200mm long pipe, not cm.

On 06-Mar-25 18:34, Bill in OKC too via groups.io wrote:

Should figure out how to measure the induced voltage. Would be a cool addition to the demonstration.?

Bill in OKC?
Re: Hardness tesrters

 

Should figure out how to measure the induced voltage. Would be a cool addition to the demonstration.?

Bill in OKC?

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
Good judgement comes from experience. Experience comes from bad judgement.?
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better.
Expect in one hand, expectorate in the other. See which one gets full first.



On Wednesday, March 5, 2025 at 02:11:43 AM CST, Jerry Durand via groups.io <jdurand@...> wrote:


Any charts for ceramic bearings so you don't need to worry about magnetism??

BTW, I did a demo of magnetism with non-magnetic materials.? Dropped a strong magnet through 200cm of 10mm copper tube.? Took a while to fall out the other end, something nobody in the room had seen or expected.

I did include a wave of a Harry Potter magic wand, just for extra effect.

On 05-Mar-25 11:07, davesmith1800 wrote:
Remember the surface being bounced test needs to clean of oil , any coating and Degaussing.
This note is not on drawings
Re: Hardness tesrters

 

I know feeling of Harry Potter magic wand and dropping ball.
Back in 1970¡¯s when first purchased it I would be ok for cast iron wheels and if work i would be happy.
I was very surprised how well it worked on everything
?
Dave
?
On Wed, Mar 5, 2025 at 12:11 AM, Jerry Durand wrote:

Any charts for ceramic bearings so you don't need to worry about magnetism??

BTW, I did a demo of magnetism with non-magnetic materials.? Dropped a strong magnet through 200cm of 10mm copper tube.? Took a while to fall out the other end, something nobody in the room had seen or expected.

I did include a wave of a Harry Potter magic wand, just for extra effect.

On 05-Mar-25 11:07, davesmith1800 wrote:
Remember the surface being bounced test needs to clean of oil , any coating and Degaussing.
This note is not on drawings
Re: Hardness tesrters

 

You need to make a chart for ceramic bearing balls.
?
Blacksmith use for long time.
The machinist hammer ball is used for hardness too.?
?
The one purchase in 1970¡¯s the patten was in not losing the ball.?
Check against a Rockwell test it was mark every time .?
?
Dave?
Re: Hardness tesrters

 

¿ªÔÆÌåÓý

Any charts for ceramic bearings so you don't need to worry about magnetism??

BTW, I did a demo of magnetism with non-magnetic materials.? Dropped a strong magnet through 200cm of 10mm copper tube.? Took a while to fall out the other end, something nobody in the room had seen or expected.

I did include a wave of a Harry Potter magic wand, just for extra effect.

On 05-Mar-25 11:07, davesmith1800 wrote:

Remember the surface being bounced test needs to clean of oil , any coating and Degaussing.
This note is not on drawings
Re: Hardness tesrters

 

Remember the surface being bounced test needs to clean of oil , any coating and Degaussing.
This note is not on drawings
Re: How sextant works gif

 

Update include at bottom knots and km.

1A_ Sextant build MAR 5 2025.PDF
1A_ Sextant build MAR 5 2025.PDF

Re: How sextant works gif

 

Chart on degree vs miles and time vs miles?
?

1A_ Sextant build Feb 5 2025_1_.PDF
1A_ Sextant build Feb 5 2025_1_.PDF

Re: Broken Tap remover

 

Broken Tap remover

 

If ever break a tap here a low cost machine.?
?
https://www.aliexpress.us/item/3256807236835449.html?ug_edm_item_id=3256807236835449&pdp_npi=4%40dis%21USD%21%24668.44%21%24244.66%21%21%21%21%21%4021410e8e17409930996665071d56b8%21%21edm%21%21%21&edm_click_module=alg_product_3_5731715720&creative_img_ind=4&edm_log_data=gmod-edm-item-list-three-columns.track-edm-item-list-three-columns-log-link&tracelog=rowan&rowan_id1=aeug_edm_92102_1_en_US_2025-03-03&rowan_msg_id=gunsCOWS_92102_%2443728ba50a6446c5920855ae62c76158&ck=in_edm_other&gatewayAdapt=glo2usa
Re: On the Funny Side

 

Re: On the Funny Side

 

Re: GPS VS SEXTANT / ASTROLABE

 
Edited

I agree ??
Thank you for bringing the time up.?
?
It surprising what how far lust one minute off is at the equator.?
?
?Calculation 1??
Diameter at equator
(1/1) 24,500. ¡Â? ? ? ??
(1/2) 24. =? ? ? ??
One hour at equator is?
(1/3) 1,020.833 ¡Â?
(1/4) 60. =
One minute At the equator =
(1/5) 17.014. Miles,
?
One second at the equator = 1,497 feet. ?and 10 seconds is 1.7 miles
That is a long distance?
?
Dave?
?
Re: GPS VS SEXTANT / ASTROLABE

 

?*?How Accurate does a?*?
?*?Celestial Fix need to be?*?
This also includes GPS ?
Part 2 of 2 ?
Celestial navigation is used when you are far out at sea, when no other methods of position fixing are available.
?
If you are hundreds of miles from the nearest land, 10 miles of error in your position is not too significant.
?
Remember, in the middle of an ocean, you will be using a small scale chart. The chart probably covers most of the ocean.
?
Your position only needs to be accurate enough for you to make landfall in roughly the right place. After that, visual navigational techniques can take over.
Aka {LINE OF SIGHT} easly 10 miles or more.
Re: GPS VS SEXTANT / ASTROLABE

 

¿ªÔÆÌåÓý

Need a good watch if you want latitude and longitude.?

On 02-Mar-25 20:25, davesmith1800 wrote:

?? Sextant vs GPS ???
?
Part 1 of 2
?
GPS is the most accurate around 40 inch or 1 meter.
?
The drawback list.? ?
?
  1. Satellite ? and other countries take out
  2. Satellite and space debre
  3. Sun spots?
  4. Thunder ?
  5. Power aka battery dead?
  6. About anything effecting electronics.? ? ? ?
??????
?
The Sextant?
?
While the theoretical maximum accuracy of a celestial fix is 0.1 miles, in reality you will probably never achieve closer than 1 mile.
?
?
?
How Accurate is a Celestial Position Fix?
The theoretical accuracy of a celestial position fix is based on the accuracy of a sextant. Most sextants let you measure angles to within 0.1 minutes of a degree. 0.1 minutes {6 seconds 0.12 miles 600 feet at equator } on the altitude of a celestial body translates to 0.1 nautical miles on the surface of the earth.
?
In reality, however, it is almost impossible to actually achieve an accuracy of 0.1 minutes with a sextant.
?
You are taking your measurements from a moving boat, which is floating on a moving ocean. The horizon needs to be clear, and the celestial body needs to be a perfect, bright speck.
?
It is far more realistic to get an accuracy of 1 minute with a sextant in day-to-day conditions.
?
An accuracy of 1 minute with the sextant implies a final position fix accuracy of 1 mile.?
?
With some reading in WW2 the Navey found it 1? with a good operator most was under 5 miles .
?
Of course, getting that sort of accuracy relies on minimising every other source of error. Unfortunately, in celestial navigation, there are plenty of potential sources of error: .
?
  1. Errors reading the measurement from the sextant
  2. Errors identifying a celestial body
  3. Potential inaccuracies in your chronometer
  4. Errors in identifying prevailing atmospheric conditions
  5. Errors in your calculations
  6. Rounding errors
  7. Errors plotting the final fix
  8. operator holding the sextant
?
On plus side is?
  1. no power need?
  2. No satellites?
  3. Works with Sun spots
  4. Works when electronics does not?
  5. No power need or batteries?
?
Fortunately though, practise and precision can be used to reduce or eliminate most of these errors.
?
?
?
We can therefore say that an experienced navigator can realistically expect an accuracy of around 1 mile when completing a celestial position fix.?
?
?
?
Beginners, on the other hand, will be lucky to achieve an accuracy of 10 miles the majority of the time.
?
?
?
Dave?
GPS VS SEXTANT / ASTROLABE

 
Edited

?? Sextant vs GPS ???
?
Part 1 of 2
GPS is the most accurate around 40 inch or 1 meter.
?
The drawback list.? ?
?
  1. Satellite ? and other countries take out
  2. Satellite and space debre
  3. Sun spots?
  4. Thunder ?
  5. Power aka battery dead?
  6. About anything effecting electronics.? ? ? ?
??????
?
The Sextant?
?
While the theoretical maximum accuracy of a celestial fix is 0.1 miles, in reality you will probably never achieve closer than 1 mile.
?
?
?
How Accurate is a Celestial Position Fix?
The theoretical accuracy of a celestial position fix is based on the accuracy of a sextant. Most sextants let you measure angles to within 0.1 minutes of a degree. 0.1 minutes {6 seconds 0.12 miles 600 feet at equator } on the altitude of a celestial body translates to 0.1 nautical miles on the surface of the earth.
?
In reality, however, it is almost impossible to actually achieve an accuracy of 0.1 minutes with a sextant.
?
You are taking your measurements from a moving boat, which is floating on a moving ocean. The horizon needs to be clear, and the celestial body needs to be a perfect, bright speck.
?
It is far more realistic to get an accuracy of 1 minute with a sextant in day-to-day conditions.
?
An accuracy of 1 minute with the sextant implies a final position fix accuracy of 1 mile.?
?
With some reading in WW2 the Navey found it 1? with a good operator most was under 5 miles .
?
Of course, getting that sort of accuracy relies on minimising every other source of error. Unfortunately, in celestial navigation, there are plenty of potential sources of error: .
?
  1. Errors reading the measurement from the sextant
  2. Errors identifying a celestial body
  3. Potential inaccuracies in your chronometer
  4. Errors in identifying prevailing atmospheric conditions
  5. Errors in your calculations
  6. Rounding errors
  7. Errors plotting the final fix
  8. operator holding the sextant
?
On plus side is?
  1. no power need?
  2. No satellites?
  3. Works with Sun spots
  4. Works when electronics does not?
  5. No power need or batteries?
?
Fortunately though, practise and precision can be used to reduce or eliminate most of these errors.
?
We can therefore say that an experienced navigator can realistically expect an accuracy of around 1 mile when completing a celestial position fix.?
?
Beginners, on the other hand, will be lucky to achieve an accuracy of 10 miles the majority of the time.
?
Dave?
?
[img]https://th.bing.com/th/id/OIP._r0SgDl4wmCPBVt4pQVWSAHaFj?w=166&h=124&c=7&r=0&o=5&dpr=2&pid=1.7&PC=EMMX01[/img]?
Re: On the Funny Side

 

Re: On the Funny Side

 

Thus what need next Halloween?
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Re: On the Funny Side

 

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