Margaret Robertson

Пікірлер

@ibrahimabdulhaqq 8 күн бұрын

good

@mainrono 15 күн бұрын

Awesome, Thanks.

@margaretrobertson8848 15 күн бұрын

You are very welcome.

@sambamiam 18 күн бұрын

Hi Professor, I have a question about using AutoCAD for multi-view drawings. When I transcribe lines from the first view to use as reference lines for the new view, the Osnaps often select points like endpoints or midpoints along the reference line. However, I need to start my new line at a specific distance away from the original view that I have drawn. If I hold Shift, it turns off all Osnaps, causing the line to float left and right (of the reference line), and I have to zoom in a lot to Keep my tolerance. How can I snap to the vertical aspect of the reference line at a specific distance from another object without losing precision? Perhaps setting the first reference line based on the original vertical line and instead of running the first reference line long. I could simply type a distance approximately the same width of the drawn object and trim out the reference line is the answer. However, Is there a way to begin the drawing along the reference line without having to trim.

@margaretrobertson8848 17 күн бұрын

You could turn Ortho on (shortcut, F8), turn Dynamic Input on, and enter a distance. Or you could try the old-fashioned method of entering the first point, then typing @[x value],[y value]. To be honest, I often just use Offset and then Trim. Not the most efficient way, but it works.

@fixeratu 18 күн бұрын

Thanks you for sharing your knowledge, very well presented and extremely helpful. What is the guideline to define the minimum / maximum length of the keyway in the shaft. Does it depend of the diameter of the shaft? How does the length of the hub factors into it?

@margaretrobertson8848 18 күн бұрын

You are very welcome! Usually the keyway in the hub runs the whole length of the hub, because it's easier to cut, but I am not aware of any guidelines on length.

@SamuelMcCown-u9m 22 күн бұрын

very informative about this added benefit of being enrolled in the drafting program at Lane

@margaretrobertson8848 22 күн бұрын

I'm glad it was helpful!

@tangamtamil 26 күн бұрын

Give us ppt link

@margaretrobertson8848 26 күн бұрын

Sorry--it's part of a college class. There isn't a link. 🙁

@derickjuvenalis6464 29 күн бұрын

what is the name of the book?

@margaretrobertson8848 28 күн бұрын

The textbook is Madsen. Engineering Drawing and Design, 6th ed. The ASME standard is ASME Y14.3 - Multi and Sectional View Drawings .

@EE-pq8yn 2 ай бұрын

it's very important concept when you subtract two wall thicknesses from the outer diameter to get the inner diameter. Very tempting to subtract only one thickness 8-1 which is WRONG!!!!!! Thanks for making a video on that!!!

@margaretrobertson8848 2 ай бұрын

You are very welcome!

@charlesosare3667 2 ай бұрын

make another video like this or a playlist

@margaretrobertson8848 2 ай бұрын

Thanks, Charles. These were lectures for a class.

@charlesosare3667 2 ай бұрын

@@margaretrobertson8848 cool😎

@tonypriest1545 3 ай бұрын

Thank You Ma'am.

@margaretrobertson8848 3 ай бұрын

You are very welcome!

@MANJAMARA 3 ай бұрын

Mam, I am not a native American, but I have this stupid question: What is wrought iron, and what is cast iron? How do they differ? Thank you for the great and easy video on grades of material...

@margaretrobertson8848 3 ай бұрын

There is no such thing as a stupid question! Wrought iron and steel are both low carbon. Steel is iron + 0.5% to 1.5% carbon. Wrought iron has about 0.5% carbon and has a little bit of slag added, so that it is softer and can be "wrought" (i.e., hammered). It's not used so much anymore. (New products that are called "wrought iron" are often actually mild steel, just shaped to look like the old-time wrought iron pieces.) Cast iron has a higher carbon content: 3%-5%. It is brittle, not strong in tension but strong in compression. (It's similar to concrete, in that way.)

@PedroOjeda 3 ай бұрын

Do these evaporatize towers work in areas with high humidity in the air? A lot of these examples are deserts.

@margaretrobertson8848 3 ай бұрын

Good observation. Because warm air rises, this stack shape will still pull in cooler air and release warmer air out the top. (It's slow movement, however.) In dry climates, water can be inserted at the top of the tower, making a cooling tower, where it evaporates and then cooler air falls. So cool air is flowing down, rather than up.

@孙小圣-d8u 4 ай бұрын

你好

@shashikantkumar-wb7fy 5 ай бұрын

Please tell me the manual maths calculation also ❤oh dear❤

@margaretrobertson8848 5 ай бұрын

There's more detail about that in two videos, "ME02d keyways - help for assignment 2 - smaller shaft and hub" and "ME02e keyways - help for assignment 2 - larger shaft and hub."

@raymondro5756 5 ай бұрын

That is so nice for you to share this amazing vedio. Is the PDF handout still available?

@margaretrobertson8848 5 ай бұрын

How kind. You are very welcome! I'm sorry--I looked but I cannot find it.

@adityabhargav1830 6 ай бұрын

Hello Margaret, thank you for lucid explanation. Really appreciate your work. I have a doubt. Flatness tolerance zone is two parallel planes seperated by flatness tolerance value and its location is not fixed. But where does the tol zone exactly lie? (since we dont have datum for it) In other words, in the table example, where does the top plane of tolerance zone lie? Lower plane will be at distance of tolerance value, but confused as where does the top plane lie. Hope you've understood what I am trying to ask.

@margaretrobertson8848 6 ай бұрын

Thank you, and you are welcome. Imagine the tolerance zone as a set of 2 sheets of clear glass, stuck together and floating in space. The set of 2 sheets of glass can be located anywhere and they can be tipped at any angle, as long as they are completely inside the size tolerance. In the table example, the top of the set of glass sheets could be located as high as 31". Or the bottom of the set of glass sheets could be located as low as 29". As long as they don't stick outside the size tolerance zone, they're correct. You're controlling only how flat is the surface, no matter how high or low it is and no matter at what angle it is oriented.

@adityabhargav1830 6 ай бұрын

@@margaretrobertson8848 Thank you for replaying. What I have understood is - Tol zone should not violate MMC /LMC boundary. But still my question is - where does top plane of tolerance lie in the available space? Is it like that top plane is tangential to topmost peaks of surface variations ( off course not violating MMC boundary) and lower plane is at distance of tol value from top plane. I have similar kind of query when we apply perpendicularity tolerance to surface. Here tol zone will be two parallel planes separated by tol value and perpendicular to given datum but again WHERE??

@margaretrobertson8848 6 ай бұрын

@@adityabhargav1830 Flatness controls form only; it doesn't have a datum. So the tol zone can lie ANYWHERE within the MMC/LMC boundary. And you are right, the plane would be found by being tangent to surface peaks. It is not easy to inspect. Perpendicularity does use a datum. It is easier to inspect.

@adityabhargav1830 6 ай бұрын

@@margaretrobertson8848 Thank you for clarifying my doubt. So is it okay to consider the same when we apply perpendicularly or angularity to surface? - tol zone within MMC LMC boundary and top tol plane tangential to highest peaks of surface variations

@margaretrobertson8848 6 ай бұрын

@@adityabhargav1830 Yes. And perpendicularity and angularity are inspected relative to a datum.

@冯孝伟 6 ай бұрын

Your video is so quality in every second, thanks. I have a question, Is there a situation that we can only use angle but not angularity.

@margaretrobertson8848 6 ай бұрын

Thank you. You can always use regular dimensioning without GDT, like dimensioning an angle, and you can put a tolerance on your dimension or let it use the tolerance in the title block. But that gives you a fan-shaped tolerance zone. If you want better control across the whole surface, and with a tolerance zone that stays the same thickness throughout, you can add an angularity control.

@Theodore_Evelyn_Mosby 7 ай бұрын

Thank you!

@Theodore_Evelyn_Mosby 7 ай бұрын

Thank you!

@margaretrobertson8848 7 ай бұрын

My pleasure. You are very welcome!

@roilap 8 ай бұрын

Great video Margaret! You explain this so well and so patiently. Thank you!

@margaretrobertson8848 8 ай бұрын

Thank you, Roi!

@harikumar4757 8 ай бұрын

Madam, it is very good teaching GD&T. 2:37 How to make gaga pin for whole pattern hole with pin gage dia .237, do have to still keep the centre main gage pin at (vc) .988.Because mentioned B at M in FCF of pattern hole. So at inspection can make both pin on single gage datum A ,at a time. Kindly reply.

@margaretrobertson8848 8 ай бұрын

Thank you. Yes--the six holes are specified at MMC and datum B for those holes is also specified at MMC, so you would make the center gage pin at VC of .988, and you would make six gage pins for the holes at their VC (MMC of .245 minus tolerance of .008 = .237).

@harikumar4757 8 ай бұрын

@@margaretrobertson8848 thank you for your kind reply

@Goofayball 8 ай бұрын

I loved 10:10 and 10:31 and got a little giggle! Trying to do wood working for this to make a giant pinion door with 9 teeth and a rack with 9 teeth. And this is helping a lot.

@margaretrobertson8848 8 ай бұрын

Cool. I'm glad this is helpful!

@Goofayball 8 ай бұрын

I loved 10:10 and 10:37 and got a little giggle! Trying to do wood working for this to make a giant pinion door with 9 teeth and a rack with 9 teeth. And this is helping a lot.

@markheatherington8367 8 ай бұрын

Thanks for the video! As a fellow Oregonian who lives in the Cascade foothills I use this method as well. Every evening cool air comes down to the valley from 6000' and flows through my N/S orientated house. Only had to use the heat pump last summer during the weeks where the wildfire smoke was in the hazardous category.

@amanpreetsingh5370 9 ай бұрын

I tried this formula but correct for only 90degree angle not for other angles to find exact bend line

@amanpreetsingh5370 9 ай бұрын

I want quick calculation because in interviews they usually ask to calculate bend line

@amanpreetsingh5370 9 ай бұрын

What would be the Circumference formula for different angle other than 90 degree?like 45degree,122.5degree etc

@margaretrobertson8848 9 ай бұрын

Good question. Circumference / (360/angle). For example, 360/45 = 8. That is, 45 degrees is 1/8 of a circle. So for a 45 degree angle, it's circumference/8.

@peterpiper5300 9 ай бұрын

Im curious about closing the windows during daytime. If we close the windows, wouldnt there would be no air circulation?

@peterpiper5300 9 ай бұрын

Can you show real world application of this to multistorey compact houses in hot cities. Thanks.

@margaretrobertson8848 9 ай бұрын

You need to be in the kind of hot climate where it is markedly colder at night. So, a desert climate is perfect, and a tropical climate is not. It will work in a temperate climate, too, if the urban heat island effect isn't too great. Then you want thermal mass to absorb heat: concrete, stone, etc. Try doing an internet search under "night ventilation" or "night flushing." See if you can get "Heating, Cooling, Lighting: Sustainable Design Strategies, 5th ed." by Lechner from your library. It's super helpful.

@peterpiper5300 9 ай бұрын

I wonder if this can be applied to multi story smaller, compact houses in the city. Wish you can show samples. Thanks.

@margaretrobertson8848 9 ай бұрын

It probably could. Try doing a google image search, and you will probably find a bunch of examples.

@HashlandXXX 9 ай бұрын

"Hall of Shame" award. I'm glad that exists, and I remember certain parts of San Francisco that were similar. Too hot in the summer, too cold in the winter, and people barely used those areas.

@冯孝伟 10 ай бұрын

Hi Margaret, if a feature was respected with a compound datum A-B, does that mean the feature needs to be within the tolerance zone from datum A and datum B at the same time ? The purpose of using datum A-B instead of using datum A and datum B separately is making sure neither of them has precedence over the other?

@margaretrobertson8848 10 ай бұрын

Yes. The two datums are used together is if they are all one datum. You can imagine a line that connects the centers of A and B, and that is in effect the datum. You use compound datums with parts that rotate. The inspector puts the part into an adjustable gage.

@manhphucnguyen4123 10 ай бұрын

thanks

@margaretrobertson8848 10 ай бұрын

You are welcome!

@user-smshonudj1jb35vd 11 ай бұрын

I just found your channel today and I'm in love. You cover so many subjects that are of interest to me. It's a real treasure trove!

@margaretrobertson8848 11 ай бұрын

How wonderful of you to say so! Thank you!

@QwertyCanada 11 ай бұрын

Thank you

@janmuyllaert8565 11 ай бұрын

can I suggest the break lines at 11.57 don't truly represent the distance between the previous and next tooth down the line , they show the distance as at the end of your rack.we always used this " cutting " technique when drawing long axles and shafts on an A4 format .sometimes several break lines at different diameters were needed for the lathe operator to turn the piece .I like the explanations all the same.

@margaretrobertson8848 11 ай бұрын

Good catch. Yes, I agree with you.

@LouisG-gw4no Жыл бұрын

Hoping for your contact info because I need someone to help me design a rack and pinion gear system...

@margaretrobertson8848 Жыл бұрын

Hi Louis - I am afraid that is beyond something I can do. Have you looked at the video "ME05 rack & pinion gears?" It's rather general, but could get you started.

@eliesebanta8145 Жыл бұрын

I'm sorry, this video was years ago, but I need to clarify. I am very confused as to why the unit for deadload of joist is in psf. Thank you!

@margaretrobertson8848 Жыл бұрын

The problem (from a textbook, by Onouye) gives the dead loads of each kind of element in pounds per square foot. He is saying that if you look at a section of joists in this building, every square foot of that will weigh 3 pounds. You could think of the "joists" section as being a solid slab of joist material. The joists are 2 feet apart, so each lineal foot of joist carries TWO square feet of weight. You might want to have a look at the video "Struc24d load tracing - tributary area quiz;" at the beginning it might give a little more detailed explanation--for the rafters instead of the joists, but it is the same approach.

@margaretrobertson8848 Жыл бұрын

Actually, what would be of more help is the video "Struc24b tributary area." It is rather short, and it shows you how the tributary width, or load strip, is always halfway between supports.

@eliesebanta8145 Жыл бұрын

Thank you for your big help, ma'am Margaret! I didn't thought I would get a response right away! I'll get to the video that you said. Thank you very much!

@margaretrobertson8848 Жыл бұрын

@@eliesebanta8145 You are very welcome! I hope that it helps!

@Mytraism Жыл бұрын

Landing is requires at every 30’ according to addag

@margaretrobertson8848 Жыл бұрын

(Or every 40' for slopes 1:16 to 1:20) Thank you very much for taking the time to comment. I will correct this.

@Mytraism Жыл бұрын

@@margaretrobertson8848 thank you. I was unaware of that. Would you please let me know where I can find that information in ADA. Thanks again.

@margaretrobertson8848 Жыл бұрын

@@Mytraism It is a little indirect. ADAAG 2010, section 4.8.2 says "The maximum rise for any run shall be 30 in (see Fig. 16)." Then FIg. 16, "Components of a Single Ramp Run and Sample Ramp Dimensions" shows a table. For a slope of 1:12 to < 1:16 with a max rise of 30 in, it notes max horizontal projection of 30 ft. For a slope of 1:16 to < 1:20, it notes max horizontal project of 40 ft. If you calculate how long is the base of a triangle with a height of 30 in. and a slope of 1:16, you get a length of 480 in. or 40 ft.

@Mytraism Жыл бұрын

@@margaretrobertson8848 thanks so much. I was totally unaware of that!

@margaretrobertson8848 Жыл бұрын

@@Mytraism They don't make it obvious. And thank you again for your help, too.

@Mytraism Жыл бұрын

Max allowable riser is 7”, thread is Min 11 in interior applications according to Ibc

@margaretrobertson8848 Жыл бұрын

Thank you. I had some old data in there that I should have changed by now.

@Mytraism Жыл бұрын

@@margaretrobertson8848 I like your lectures a lot. I have looked at half of them today and will look at the other parts soon. 7 3/4” risers are used in residential single family and are allowed by IRC.

@margaretrobertson8848 Жыл бұрын

@@Mytraism Yes. Thank you for your very kind words!

@Mytraism Жыл бұрын

@@margaretrobertson8848 I also wanted to mention that I find your selection of contemporary building examples to explain ADA ramps really helpful. I learnt a lot from it. I also didn’t know how much of ADA is geared towards wheelchair users and not enough towards others with other types of physical challenges. The definition of disability you presented was the first time I had ever seen. I am looking for more lectures on sustainability design. If you know of any resources that I could use please let me know.

@冯孝伟 Жыл бұрын

5:03, based on the rule 1#, the form must perfect at MMC, why we still can make the tolerance of the pin's OD(±.002) tighter than the perpendicularity which is called out by .006. Hoping for your answer,thanks in advance.

@margaretrobertson8848 Жыл бұрын

Perfect form at MMC is the size of the envelope, the hole within which the pin must fit. The pin can be smaller, and it can tip. As long as it fits within the hole, that is all that matters.

@冯孝伟 Жыл бұрын

Hello, MMC has a benefit to get an extra tolerance, at which situation we must use w/o MMC?

@margaretrobertson8848 Жыл бұрын

Bonus tolerance only happens when a geometric tolerance is applied at MMC, that is, when there is an M in the feature control frame. When an actual part is any size other than MMC, you get a bonus tolerance. The amount which the actual size departs from MMC is the amount of bonus tolerance you get.

@冯孝伟 Жыл бұрын

@@margaretrobertson8848 thanks for the feedback

@omkarbamane1894 Жыл бұрын

how to specify the tolerances on tooth thickness in spur gear case ?

@margaretrobertson8848 Жыл бұрын

Give tooth thickness in a gear cutting data table. (Machinist will use that to set up the gear-cutting machine.) You can give tolerance in drawing title block, in a separate note, or directly on the tooth thickness in the data table. Standards for selecting tolerance classes are in American Gear Manufacturers Association (AGMA) handbooks.

@冯孝伟 Жыл бұрын

Your GD&T videos are really great, if you had separated the viedos form other courses, you would have got more viewers.

@margaretrobertson8848 Жыл бұрын

Thank you!

@冯孝伟 Жыл бұрын

Hi, why circularity cannot be applied with a MMC modifier ?

@margaretrobertson8848 Жыл бұрын

Good question. Because circularity is a surface control, which means it is applied regardless of feature size. It is measured by contacting the surface, which requires specialized equipment. That is why it is not used often.