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I Forge Iron

Shop Class?


rockstar.esq

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8 hours ago, Frosty said:

Heck, try dividing a circumference in quarters or thirds without a string. 

 

That reminds me of something I was telling my kid last night.  I had a situation where we knew the length of several conduit runs but the supply house didn't label the cut wires with their length.  The guys wanted to make an apprentice roll them all out to figure out which was which.  This wasn't optimal because the conduit runs were very far apart and we'd waste a lot of time moving stuff around.

I measured the diameter of the coil to the nearest tenth of a foot, counted the coils, and multiplied everything by 3.1.  Most of the time, that math is simple enough to do in your head and it's sufficiently accurate to serve the purpose.

Somewhat related to this is an old trig trick.  Any triangle with equal length sides will have 60 degree angles.  Take a compass (makeshift if need be) and scribe a quarter circle arc.  Move the point to any spot on that arc and sweep the marker to where it intersects the first arc.  Connect those three points and you've got it.  If you need a 30 degree angle, divide the length of one side in half and connect that point with the opposing corner.  If you've got something that's square, you can simply set one length along the triangle's side, and slide it up or down until the other length corresponds to the opposing corner of the triangle.

 

 

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I wish I had access to shop classes, but at the same time I know I wouldn't have taken advantage of them. I was focused on programming and thankfully had access to classes on that later in my high school career.

I learned those skills from my dad while on the job. You would be amazed how many people I meet who can't even read a tape measure. When we hire a new person for flooring the first day is spent teaching them to read tapes and perform basic math. It's sad how far our school systems have fallen. When I was in high school trig and calculus we're the advanced math classes that only gifted students took.

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1 hour ago, genesaika said:

When I was in high school trig and calculus we're the advanced math classes that only gifted students took.

I had the same experience in high school. 

To add to it, I would say that when I finally did get to Trig and Calculus, the lessons weren't particularly aligned with practical application.  As I recall we were approximately 70% of the way through Calculus 1 when they finally got to "The fundamental theorem of calculus".  It's a lot like algebra where the very last thing you're taught is the quadratic formula which solves 90%+ of the quadratic equations you're likely to encounter.  

I had college instructors from the Math and Physics departments who hated the practical desire to "turn the crank" on a problem. 

I'm curious if the folks lucky enough to have had a metal-shop class in high school were taught to use more practical applications of mathematics?

 

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I didn't even get to take either. I moved each year of high school and practically had to start over from the beginning. My senior year I was taking physics, advanced software development and intro to algebra. Mind you I had taken algebra and algebra 2, but the school required that I have intro to algebra ( which wasn't a thing in my other schools) in order to take trig or calculus.

I should also note that I was teaching my class and the teacher in mathematics.

I feel that one of our main problems in education is perpetuation of the idea that test scores mean more than actual knowledge. The worst part is that those tests are standardized and we do not all learn in the same way. It's like judging a fish on how well it can climb, just because 90% of the class are animals that can climb.

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It is a shame that those malignant academic mathematics teachers insist on raw knowledge for its own purpose. They are loath to point out the practical uses for a concept. For example, trigonometry and calculus are extremely valuable and can be readily useful.

One of the primary uses that spurred the discovery of trig was in surveying. Also measuring the height of a (large) building or mountain without having to climb them trailing a measuring tape.

The two primary functions of calculus, namely the differential and integral were discovered in order to solve two very important practical problems

The differential function helped military artillery men to determine the angle of a cannon barrel in order to hit a target.

The integral was conceived to solve the actual amount a wine barrel, of a given height and girth, would hold. I.e. the gallons (liters), of wine  the barrel would contain.

Previously the ratios were compiled by trial and error. And those findings would be passed on to future users.

Why use an integral function to figure out the barrel volume? Because barrels are not straight sided they arcuate (bowed). The width changes as the height, of the barrel, changes.

Calculus is required in statistics among other areas.

For example, even psychology graduate students must learn rudimentary calculus in order to use statistics, in order know and use their practical uses.

SLAG.

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In high school I learned more about geometry in wood shop than in geometry class because I hated doing problems just to do problems. Applying the math to something I could see made it easier to understand.  Same with trig, I found it much easier to learn in the machine tool technology course at the community college, than in the math class.

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If one studies statistics thoroughly one can spot most frauds and data manipulations.

Any subject can be finagled.

Statistics is an acute example.

Without statistics most of us would be 'lost in the wilderness". And most of us are.

I eagerly await the expected screaming dissents with anticipated glee. Bring it on Pilgrims!. 

SLAG.

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1 hour ago, SLAG said:

Any subject can be finagled.

 

That is very true.  Just yesterday I was looking at the photos that accompanied a press release about a "3D Printed house" that was on display in Austin Texas for SXSW.  They claimed it was 800 square feet and built in 24 hours for 3rd world housing needs.  There wasn't much clarification.  Eyeballing the photo, it's more than a little probable that the square footage included a wrap-around "porch" that constituted over half the total area quoted.  

OK, so maybe I'm being picky about that measurement.  Well, the 24 hours probably isn't really true either.  That's how long "printed" part of the house takes.  It doesn't include stuff like windows, doors, roof, paint, insulation, or the perfectly flat concrete slab they need to start with.  

Again, maybe I'm quibbling.  What about it's claim to be a solution for 3rd world housing needs?  Perfectly flat concrete slabs, literal tons of water, temporary tents large enough to fully protect the entire site while the machine is running, electricity, windows, doors, wood, steel, insulation, paint.  Sure seems like a long list of requirements for a 3rd world situation.  

I don't mean to denigrate the machine or the knowledge and skill of the people who developed it to this point.  I think it's entirely possible that they will find ways to overcome it's current deficiencies.  The thing that galls me is the marketing that makes the brazen assumption that we won't notice that all this technology is capable of building, is a crude mud hut.  What, pray tell, do these people think they're replacing?

To tie this all back into the topic of the thread, I can't help thinking that if the parties involved had shop classes when they were in high school, they might have made different decisions.

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I never got past algebra, couldn't think of a reason to take more. The only goal in my algebra class was that we follow the steps and our answers match the one in the book. Pretty darned useless when that's all it's good for is following steps you don't need. Virtually all the answers were obvious so following the steps was make work. What's geometry, something to eat?

No trig or calc, those were for the gifted students in my high school, there was one class a day after regular school hours for the brilliant few. My graduating class June 1970 was 1,013 students and the smallest since. Total school enrollment was around 9,500 and growing, construction was constant and the temporary classrooms were still on the grounds when I moved to Alaska in '96, there were more of them though.

I love my compass! Well, make that plural I have the things all over the place, especially in the shop. Dividers too, straights, inside, outside, from itty bitty to large enough to spit roast a turkey. 

I learned more math, geometry especially, in shop. You just can't do anything practical in anything like a sensible way without a little geometry. I wonder how many math teachers get cheated buying flooring? More than I'd like to think I bet. I don't think I could count how many times I could've used trig or calc. To calculate how tall a tree is without climbing or cutting it down I have to wait for a sunny day measure it's shadow, measure the shadow of a yardstick and reduce the fraction. And heck that only tells you how HIGH it is, not tall. Gotta fall it to measure that one. 

A friend of mine used to be a substitute teacher but couldn't stand to teach the subjects as required. One of his angriest examples was a high school geometry class that drew pictures and didn't so much as do addition. 

I wish I had an answer for any of this, I don't. 

Frosty The Lucky.

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i never had use for calculus in everyday life, but I used to love trigonometry and it has always been very useful particularly for fabrication.

18 hours ago, Frosty said:

Reminds me of stick quiz. Answer a question wrong and get hit with a stick. Twine makes a good measuring device too. Heck, try dividing a circumference in quarters or thirds without a string. 

Frosty The Lucky.

Life without string is chaos ... Rudolf Smuntz

In case you run out of string, try multiplying the diameter by 3.14 and then divide by 4 or 3 or whatever you need :)

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25 years ago in a school district that was mostly rural with the exception of a few towns that were trending towards sub-urban we had a great shop, welders, sheet metal set-ups, Johnson forge and 2 very nice Peddinghaus anvils, jewelry making tools, etc.  As well as a wood shop, and a drafting lab (mostly paper back then but they did have 2 CAD systems).  Despite some funding fluctuations the school has managed to retain most of it and apparently the jewlery classes are the most popular electives offered, waiting list every year!  They also have an agreement (and daily bussing) to a near by vo-tech highschool for access to machine shop, auto tech, and trade classes.  

Everyone got Geometry and Algebra I/Trig, and if you were headded for college Algebra II and Calc.   I have yet to find much use for the calculus but I use geometry and trig every day, the trig really clicked when I built my first complicated roof!

My son is just entering highschool one district over from where I lived as a kid, and his school has a similar academic regimin.  The shop classes are slightly different from what I had, they have a minimal wood shop and no fabrication shop to speak of, but they have a pretty good machine shop and an absolutely incredabel 3d printing/CADD lab, and a good robotics lab.  The kids also have the bussing to a tech school option as well.  They also have a jewlery making studio with popular classes.  We are not a wealthy district, the school admin has just prioritized educational activities over other stuff.  The athletic fields and gym are pretty shabby and the less I say about the cafeteria the better, but despite years of level funding or cuts they have managed to keep the shops and labs open.  

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Our high school  had a very good girls basketball program that went to state championships almost every year for like 2 decades.  So the school did put alot of resources towards athletics.  We have 2 gyms, pool, large weight room, a couple baseball fields, football field.  Although football enrollment has been down to like 4-5 students per year, so they have been playing for a larger school a few miles away.

Cafeteria?  We have one in the elementary school.  They make the food, pack in hot cabinets, bus it to the high school, and serve in the gym.

They also bus students to BOCES  a vo-tech school for things like cosmetology, heavy equipment operating, forestry, mechanics, diesel mechanics, etc.

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19 hours ago, Marc1 said:

i never had use for calculus in everyday life, but I used to love trigonometry and it has always been very useful particularly for fabrication.

Life without string is chaos ... Rudolf Smuntz

In case you run out of string, try multiplying the diameter by 3.14 and then divide by 4 or 3 or whatever you need :)

That only works if you can access the diameter. Picture drilling 3 evenly spaced holes in a section of pipe that comes out of a wall and goes into the deck or whatever.

Also works a treat for odd shapes. That may be how Vlad positioned the nails in the Ottoman's hats. Neat counted to Vlad you  know. :rolleyes:

Frosty The Lucky.

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  • 3 weeks later...

My school has a shop class... mostly a wood shop because my teacher dosent like metals very much but he still teaches us how to use the machines properly and safely. We had to start doing the great spring cleaning early because we are building s brand new shop and gym. Pretty excited to use all the new equipment.

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  • 1 month later...

Have to agree with Biggun,

Never seen a set of plans calling for 10-24 that wasn't improved by changing it to 10-32. 

When I was in Highschool we had two Delta Unisaws, one with a dado blade.

Fellow cut the tip of his thumb off his junior year on the table saw.

No lawsuit, he knew HE screwed up.

Next year same fellow cut the tip of his other thumb off in the dado saw. 

Same ambulance ride, same self responsibly, no law suit.

Shame on this litigious society.

A final thought on tapping;

Most of the called out tap drill sizes are TOO SMALL.

They would work well in free maching brass or dead soft steel and are calculated to provide about 70% thread. 

A quick google search will bring up a " theoretical percentage of thread" chart. 

Using such, one can figure the best tapdrill to use by considering the following variables; hardness of material being tapped.

Aluminum can be tapped safely at 75% thread, stainless steel should  be around 40%

Thickness of material especially compared with tap diameter.

A 1/4 nut is a 1/4 inch thick.

A half inch nut is a half inch thick.

Material thicker that the diameter of the tap can be threaded with a lower % of thread, thinner should have a higher percent.

In general 50% thread is the most that is required so most specs are wrong and have you drilling too small a hole and breaking taps. 

Again this is especially important with stainless steel and other hard to tap metals.

 

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I'm 24, grew up and live in north east Scotland, I got a basic "Shop" class in high school when I was 15/16 but it was very basic, no taps, or taught about steel types, hardening processes etc. I taught myself that and then proceeded to teach the teacher. (I have an amazing father who has taught me endless amounts luckily)

I was never any use at maths, I can do it but it takes a very long time. T can get there if I have a practical explanation, eg. gear ratios, building houses, technical drawing etc. I know my times table up to 5x and don't know trig or much else to be honest. but I do have an apprenticeship (time served) in Mechanical Engineering that I worked extremely hard for, and I also think that's one major problem with my generation is they lack the will to try hard for something (Exceptions obviously).

I always carry a Zeus book with me for hard equations, tapping sizes etc. which helps tremendously.

 

On that note, i work with an "Engineer" (HVAC) who claims to be one of the best in the industry yet I had to teach him how to drill holes properly with a battery drill because he kept snapping my drill bits which were 10mm (0.39" ?)

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