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Most use a follower rest but most only goes down to 3/16" [3.5mm] aBIX TOOL WILL GO DOWN TO Wtch A small box goes down to watch size here article on roller box and box tools works in tailstock too Small box tools Here’s a couple box tools I made to use with my little bed and tailstock lathe turrets for taking deeper and more accurate cuts off the diameter than with regular knee tools on relatively long and thin workpieces. They’re basically copie9d from pictures of existing designs, mostly Levin and Somma. Like on those the cutter is held more or less tangential to the work, opposite two adjustable supports set back a little to bear against newly cut surfaces. The larger of the two uses hardened rollers in screw adjustable blocks that are held in with dovetails, while the smaller one uses toolbits ground at opposing angles. Both have floating shanks, partly so I can replace them with others for different applications. They work okay - they’re kind of hard to adjust but that may be just me. The smaller tool is about 1-1/2” x 15/16” - it uses a 3/16” cutter and 1/8” back rests, and will pass up to about 1/4” work through the body. The bigger one is about 2” x 1-1/4”, uses a 1/4” cutter and passes 5/16”. Both have the tools tilted with 7° side cutting angle as well as front and side clearance, and use 40tpi adjusting screws

St. Elmo's fire (also called witchfire or witch's fire)[1] is a weather phenomenon in which luminous plasma is created by a corona discharge from a rod-like object such as a mast, spire, chimney, or animal horn[2] in an atmospheric electric field. It has also been observed on the leading edges of aircraft, as in the case of British Airways Flight 009, and by US Air Force pilots.[3] Illustration of St. Elmo's fire on a ship at sea Electrostatic discharge flashes across the windscreen of a KC-10 cockpit. The intensity of the effect, a blue or violet glow around the object, often accompanied by a hissing or buzzing sound, is proportional to the strength of the electric field and therefore noticeable primarily during thunderstorms or volcanic eruptions. St. Elmo's fire is named after St. Erasmus of Formia (also known as St. Elmo), the patron saint of sailors. The phenomenon, which can warn of an imminent lightning strike,[4] was regarded by sailors with awe and sometimes considered to be a good omen.[5] ?????? Cause St. Elmo's fire is a reproducible and demonstrable foZhengHeShips.gifrm of plasma. The electric field around the affected object causes ionization of the air molecules, producing a faint glow easily visible in low-light conditions. Conditions that can generate St. Elmo's fire are present during thunderstorms, when high-voltage differentials are present between clouds and the ground underneath. A local electric field of about 100 kV/m is required to begin a discharge in moist air. The magnitude of the electric field depends greatly on the geometry (shape and size) of the object. Sharp points lower the necessary voltage because electric fields are more concentrated in areas of high curvature, so discharges preferentially occur and are more intense at the ends of pointed objects. The nitrogen and oxygen in the Earth's atmosphere cause St. Elmo's fire to fluoresce with blue or violet light; this is similar to the mechanism that causes neon lights to glow, albeit at a different colour due to the different gas involved.[7] In 1751, Benjamin Franklin hypothesized that a pointed iron rod would light up at the tip during a lightning storm, similar in appearance to St. Elmo's fire.[8][9] In an August 2020 paper, researchers in MIT's Department of Aeronautics and Astronautics demonstrated that St. Elmo's fire behaves differently in airborne objects versus grounded structures. They show that electrically isolated structures accumulate charge more effectively in high wind, in contrast to the corona discharge observed in grounded structures.[10][11] ??????

Herd few photos of a Bubble Sextant sometimes know as Bubble Octant too. Used main in Aircraft some times on land Used atless into 1950’s. This style I do not know how long it was around . Note it is just a add mirror and tube level add Below in pdf is a manual too. Dave

Here pass from 1970’s patten too. A ball drop Today's hardness tester A ball drop notice the size [COLOR="#800000"][b] [CENTER]??? ??? [/CENTER]. [/B][/COLOR] This side I use on I purchased in the mid 1970’s I have posted this side only since 1999. one first got the Kro printer for drafting in 1979 I hardness for ?" plate since most die work using ?" stickand only side showed ============= other brand ============= This today's $279.00 you buy new 2025 =====The day I purchasedin mid 1970’s==== This is how came brand new in mid 1970’s. The above is side post since 1999 on groups. They used Millimeter in the mid 1970’s WHAT I SAY IS Hight lite to see answer COPY CAT WHAT DO YOU THINK?

Here how sextant works

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

?? Sextant vs GPS ?? Part 1 of 2 GPS is the most accurate around 40 inch or 1 meter. The drawback list. Satellite ? and other countries take out Satellite and space debre Sun spots Thunder ? Power aka battery dead 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: . Errors reading the measurement from the sextant Errors identifying a celestial body Potential inaccuracies in your chronometer Errors in identifying prevailing atmospheric conditions Errors in your calculations Rounding errors Errors plotting the final fix operator holding the sextant On plus side is no power need No satellites Works with Sun spots Works when electronics does not 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]

Most production machine Shop will have this for both quoting and doing. This also used in design and engineering so can receive the finished whan on part. This finished can change the cost of making the parts. This where I used is beside the drafting board. First start with black plastic and later purchase the chrome one for better view. So if see this on drawing you know more about why. Dave

Here little data on magnetic north vs true north.

Designing a small BUBBLE SEXTANT & build . Here my first drawing of a Pocket Bubble Sextant. Please comment Dave Note PDF file is a clearer drawing

Photos of machine shop in 24" kitchen cabinet plan to be in a Armoire as remember Dave

The following items have been added to the Files area of the [email protected] group. /5)Charts_&_Tables/HARDNESSTESTER Hardness (3) (1).pdf By: davesmith1800 <davesmith1@...> Description: A simple hardness test using a paint stick and 3/8" hardened ball from a ball bearing

Here photos of my cross feed exstension. I polished by using the threading die chuck die in the lathe chuck. Then screw thread in the tailstock. Put the on slow and ran the die over the thread over the threads about 5 or 6 times. The last photos of the nut on cross slide is from the internet I did not to disable my lathe. Dave

Sextant tap and see how works . Note hos mirror moves then plumb to the horizon

Building ideas & History The history of navigation dates back to ancient times, with significant developments in various civilizations. The first part Celestial navigation, use of landmarks, and early navigational instruments Celestial Navigation: Ancient navigators used the positions of celestial bodies, such as stars, the sun, and the moon, to determine their position and direction during travel. The North Star (Polaris) was particularly significant in the Northern Hemisphere Use of Landmarks: Sailors relied on visible landmarks such as mountains, cliffs, and coastlines to orient themselves. When landmarks were absent, they used dead reckoning, calculating their position based on speed, direction, and elapsed time Early Navigational Instruments: Tools like the astrolabe, a device for measuring the altitude of celestial bodies, and the compass, which provided a way to determine the direction of travel, were crucial for ancient navigation These techniques and tools enabled ancient sailors to navigate vast oceans and uncharted territories, expanding trade and communication across vast distances Indo-Pacific Navigation: Began with the Austronesians from Taiwan, who spread southwards into Island Southeast Asia and Island Melanesia around 3000-1000 BC. They used tools like star navigation and wave detection to navigate the Pacific Greek Navigation: By the third century BC, the Greeks began using the Little Bear (Ursa Minor) to navigate. They also used circumpolar stars to determine latitude Chinese Compass: In China between 1040 and 1117, the magnetic compass was developed and applied to navigation, allowing sailors to continue their course even when visibility was limited Portuguese Exploration: In the 16th century, Portuguese explorers took the lead in long-distance oceanic navigation, opening a network of ocean routes covering the Atlantic, Indian, and western Pacific oceans. Modern Navigation: The invention of the sextant in 1757 and the chronometer in the late 18th century revolutionized navigation, allowing for accurate determination of longitude and latitude. Open to public after 1983. The Global Positioning System (GPS) was developed in the 20th century, transforming navigation into a modern technological marvel . Flight 007 from Alaska to Japan open up GPS. THE EVENT (Korean Air Lines Flight 007 (KE007/KAL007)was a scheduled Korean Air Lines flight from New York City to Seoul via Anchorage, Alaska. On September 1, 1983, the flight was shot down by a Soviet Sukhoi Su-15 interceptor aircraft. The Boeing 747 airliner was en route from Anchorage to Seoui.) This even that open up GPS TO World