thanks so much Marc. this has been really helpful and although i suspected there was an easy way to do this acurately, i had no idea where to start. So glad youre getting mended, and we wont grudge you another month in the garden, promise!
Thanks for your explanation Marc. Got me to thining back to High School Trig......SCARY how long it's been, and how much I've forgotten. Be careful on the bike, don't need any road-rash...grin!
your a great shop teacher, but your health comes first. happy to see you doing so well. keep up the good work .when your healthy lifes problems seem easier to deal with .hope to see you back this winter thanks for every thing you do .
So glad to see you back and feeling healthy. Looking forward to your future videos in Sept. I hope you develop a view of cycling as not something you like to do but something you are required to do. That bike looks small and painful. Get a Trek 520. Take care.
I aced trig in high school, but that was a little more than 50 years ago. However, I really learned it then, not just passed the tests. So, today I am a lot slower to get the results, but am still able to get it done satisfactorily. Who would have thought that was useful knowledge long term back then. Somehow, intuitively, I did. The calculations were all done with tables, a slide rule, and longhand math in those days before computers and calculators, and I still have the slide rule and the tables as well if the computers all go dark. This is the kind of stuff that makes machining interesting... Thanks, Marc!
Hi Bob! I did my high school trig with a slide rule as well! I am not sure though that I would be able to use one today? Well at least not without a good magnifying glass!!!
Hello Marc I just found your channel and have been going over your videos. This question that I have will seem silly yo you but could you please go over in detail of how to read a micrometer? I have one that was givrn to me but I don't know how to read any of the markings at all. Thank you,
Hi Bob! We all have to learn things and most people don't know how to read micrometers so your question isn't silly. This video could help www.youtube.com/watch? You can link to all my videos easily through my free web site THATLAZYMACHINIST.COM Thanks for watching and be safe, Marc
devin wojtczak the two triangles can be proved to be similar. designate the point at the top of the part, at the edge of the angled section (where the left side of the '1"' measurement points), A; designate the intersection of the orange line coming vertically down from A & the green horizontal line B; designate the point to the left of B, where that green line intersects with the angled edge of the part, C. designate the point at the center of the circle (further left along the green line from C) D; designate the point where the angled edge of the part is tangent to the circle E. angle BAC is given as 20 degrees, which means that angle ACB is 70 degrees; angle DCE must be the same as ACB (because they're both formed from the same two intersecting lines, & neither is a complement to the other), which means that angle CDE has to be 20 degrees (because both triangles are right) an illustration: imgur.com/4NLwGdI
Hi Marc, Good to see you looking well. I've got to pull you up on a little units error though and an engineer should know better! The bicycle battery is rated in Ampere Hours, not Amperes.
Hi Paul! I did not know that, and I am not an engineer. I am a machinist and was never very good with electricity (I guess this proves it). Thanks for keeping me on my toes, and for watching, Marc.
marc, enjoy cycling, the benefits will come before you know it, but only if you're having fun. so if it takes an assist to keep you on the bike at first... why not? glad to see you back!
Hey Marc... you look great... keep it up and you will be 20 years younger in no time. ;) Hopefully you will start tinkering (more) again in the fall... if so, I'm looking forward to it... all the best and HAVE FUN... BE SAVE! ;)
I thought dude was trying to find how big of a piece you would need to make her part.What about the extra bit he marked as part of a half inch..?2.3233 isn’t the whole dimension of his piece.Im confused I guess.Ill watch a fourth time.Thanks
But you are still stuck with the unknown 1" measurement (theoretical - it should be...). A more accurate way is to first measure the "2.3233" measurement and then make another while putting a measuring block "horizontally" between the part and pin. Then using the difference between the both measurements and the thickness of the measuring block you have a right angle triangle that isn't depending on theoretical measurements. If a high level of accuracy is needed don't forget to check the squareness between the base and the surface the pin is resting against. Sorry for a bit of rusty english and lack of illustrations, if clarifications are needed please poke me and I'll see if I can give a better explanatiion. Glad to hear you're doing good and feeling better!
Dear Marc, this does not solve Emma's problem because what can she do to correct her part if she gets a different measurement result than expected by your calculation? She still will not know if the angle deviates or the 1" part at the back edge is not exactly 1"..She will only know that one or both of the two dimensions are wrong. But which one needs correction and by how much? Actually even if the measurment result equals the calculated result still both the angle and the 1" part can both deviate but compensate each other so that the measured result seems correct but your part still deviates from the required shape. You try to verify two dimensions with one measurement. That can not work. I am afraid you have to postpone your summer vacation a little and pick up a math book yourself... ;-) I help you a little so you can still catch your trip to your vacation. How about taking two measurements with two dowel pins of different diameter? You get two equations which you want to solve for the unknown angle I name "alpha" of which you are not sure if it is really 20deg and an unknown distance "x" of which you are not sure if it really is 1". A and B and C and D (the latter two for the different dowel pin diameter) can all be expressed as functions of the unknown alpha and other known dimensions. So you can solve your system of two equations for alpha and x. Then Emma finally knows the actual values of the twol unknowns and can correct them accordingly. Is it spare room workshop Emma or another one?
true but very expensive if you include a quality set of gage blocks. Also a vernier bevel protractor would work up to about a 10th of a degree unless the bevel is too small and the protractor too big. But scarcely equipped hobby workshops usually have neither of the two. So Marc's idea with the dowel pins and micrometer really suits home workshops very well if only that math were not so confusing....;-)
++Anonymic79: You are right of course when wanting to go by the book. Tolerances on dimensions and general tolerances you can see very often on decent drawings. And you should pull the tolerances also through the math operations where using toleranced dimensions. You are right. But to be honest I have not seen that done for many years in fields that are quite concerned about precision. Are you a physicist? They are the only ones I have ever seen doing that. The theory and the mathematical methods of error calculations is neat. But particularly in the mechanical field it is not very practical. In complex assemblies it would become complex already by carry through all error calcs. But it becomes even more complex because there are mechanical operations that interrupt the error calcs e.g. when several parts are clamped together and milled flat together. or when parts show unwanted gaps during assembly and you just pull them elastically together by their mounting bolts. And it has no adverse effect except on your error calculation. So even for precise assemblies the error calculation does not stand the test of practical application. For very special very critical applications usually with limited complexity error calculation can be very helpful. For high volume series production you could even include the probability of tolerances in form of Gauss curves and benefit from the fact that tolerances can cancel each other out. But that only makes sense with high volume production and certainly not home shop projects ;-)
rol eic, There is a much easier solution to the two pin method. An easier method to find the angle is to make one width measurement with the pin, followed by another width measurement with the pin sitting on an block of known height. then Tan(ø) = (∆Width)/(height of the block) Chris [NOTE i use ø as theta on my mac, because they dont give you a theta shortcut on a mac ]
There's your problem. Start peddling with your feet, instead of your hands. You can throw away the electric assist and you won't injure your wrist. Crazy Canadians...
Good to see you "online" again! You are looking fit for fight! Ty for the video
So happy to see you healthy and hear you're busy.
Good to see you back Marc !
Mark I am not a machinist but really enjoy your videos. You are a great teacher. Keep up the good work and enjoy your summer.
thanks so much Marc. this has been really helpful and although i suspected there was an easy way to do this acurately, i had no idea where to start. So glad youre getting mended, and we wont grudge you another month in the garden, promise!
I am glad things are okay and you are rocking and rolling... enjoy the remainder of the summer, teach...
Excellent presentation Marc!
Thanks also for sharing your gardening and bicycling activities.
Excellent video Marc , you look well and what ever you are doing keep it up as you look fitter than ever !
enjoyed.. the effort of the dry erase drawing deserves a moment of silence of
appreciation..
Glad to see you fighting fit and Enjoying life. Looking forward to some more videos. Best wishes, Brian.
Thanks for your explanation Marc. Got me to thining back to High School Trig......SCARY how long it's been, and how much I've forgotten. Be careful on the bike, don't need any road-rash...grin!
Excellent as always. Great to see you looking so well. Have a great holiday.
your a great shop teacher, but your health comes first. happy to see you doing so well. keep up the good work .when your healthy lifes problems seem easier to deal with .hope to see you back this winter thanks for every thing you do .
Good to see you well and on the improve. Looking forward to Sept.
Very clear and concise explanation. Kudos!
So glad to see you back and feeling healthy. Looking forward to your future videos in Sept. I hope you develop a view of cycling as not something you like to do but something you are required to do. That bike looks small and painful. Get a Trek 520. Take care.
Thx for the quickie. Glad you are doing well.
Marty
Marc, you’re looking good my friend! Keep up the cycling it is a great way to stay in shape! Love your videos! Greetings from Oklahoma!
Good content as usual. Glad you are getting healthy and enjoy the summer :-)
Thanks. Hope the bicycling proved enjoyable.
I aced trig in high school, but that was a little more than 50 years ago. However, I really learned it then, not just passed the tests. So, today I am a lot slower to get the results, but am still able to get it done satisfactorily. Who would have thought that was useful knowledge long term back then. Somehow, intuitively, I did. The calculations were all done with tables, a slide rule, and longhand math in those days before computers and calculators, and I still have the slide rule and the tables as well if the computers all go dark. This is the kind of stuff that makes machining interesting... Thanks, Marc!
Hi Bob! I did my high school trig with a slide rule as well! I am not sure though that I would be able to use one today? Well at least not without a good magnifying glass!!!
Most wonderful, GREAT WORK !!! , thanks
Great little quickie as always. Can't wait until next one. Have a great holiday " have fun but be safe" 🚴 btw what have you done to your right wrist?
As an engineer I always enjoy a math puzzle! Have a great "rest of the summer" Marc!
Hope your August isA gooder looking forward to September.
Thanks , l have been watching yours Videos you are great machinist
Very interesting and informative. It is amazing how much we forget when we don't use something like trig
Super bien expliqué!
Very nice math lesson...
Enjoy your summer!
Dear Marc, thank you very much
Lesson: 15
good to see you
Hello Marc I just found your channel and have been going over your videos.
This question that I have will seem silly yo you but could you please go over in detail of how to read a micrometer? I have one that was givrn to me but I don't know how to read any of the markings at all.
Thank you,
Hi Bob! We all have to learn things and most people don't know how to read micrometers so your question isn't silly. This video could help www.youtube.com/watch? You can link to all my videos easily through my free web site THATLAZYMACHINIST.COM Thanks for watching and be safe, Marc
Maybe a dumb question but.... how would I know the 20deg angle of the triangle comming from the center of the circle?
devin wojtczak the two triangles can be proved to be similar.
designate the point at the top of the part, at the edge of the angled section (where the left side of the '1"' measurement points), A; designate the intersection of the orange line coming vertically down from A & the green horizontal line B; designate the point to the left of B, where that green line intersects with the angled edge of the part, C. designate the point at the center of the circle (further left along the green line from C) D; designate the point where the angled edge of the part is tangent to the circle E.
angle BAC is given as 20 degrees, which means that angle ACB is 70 degrees; angle DCE must be the same as ACB (because they're both formed from the same two intersecting lines, & neither is a complement to the other), which means that angle CDE has to be 20 degrees (because both triangles are right)
an illustration: imgur.com/4NLwGdI
You explained that better than I could! Thanks! Marc
please take your own advise. Have fun! thanks for sharing.
Would love to retrofit an old bike with a hub motor. Any recommendations on brand and source possibly in Canada? love your videos
Random thoughts: Love your videos. Thanks for your time and effort. Enjoy the summer. Will await your return.
Hi Marc,
Good to see you looking well.
I've got to pull you up on a little units error though and an engineer should know better! The bicycle battery is rated in Ampere Hours, not Amperes.
Hi Paul! I did not know that, and I am not an engineer. I am a machinist and was never very good with electricity (I guess this proves it). Thanks for keeping me on my toes, and for watching, Marc.
marc, enjoy cycling, the benefits will come before you know it, but only if you're having fun. so if it takes an assist to keep you on the bike at first... why not? glad to see you back!
Hey Marc... you look great... keep it up and you will be 20 years younger in no time. ;)
Hopefully you will start tinkering (more) again in the fall... if so, I'm looking forward to it... all the best and HAVE FUN... BE SAVE! ;)
I thought dude was trying to find how big of a piece you would need to make her part.What about the extra bit he marked as part of a half inch..?2.3233 isn’t the whole dimension of his piece.Im confused I guess.Ill watch a fourth time.Thanks
Enjoy your month of August. You weight looks very good, Marc.
Wouldn't a shadowgraph solve that easier?
But you are still stuck with the unknown 1" measurement (theoretical - it should be...).
A more accurate way is to first measure the "2.3233" measurement and then make another while putting a measuring block "horizontally" between the part and pin.
Then using the difference between the both measurements and the thickness of the measuring block you have a right angle triangle that isn't depending on theoretical measurements. If a high level of accuracy is needed don't forget to check the squareness between the base and the surface the pin is resting against.
Sorry for a bit of rusty english and lack of illustrations, if clarifications are needed please poke me and I'll see if I can give a better explanatiion.
Glad to hear you're doing good and feeling better!
Oups. Now I saw that Shadowdog500 had posted the same solution already :-)
Lesson learned, read first then post.
Marc, all i can say young man is 'CARPE DIEM"，Sincere regards. Joe.
Marc.
Enjoy the break
Dear Marc, this does not solve Emma's problem because what can she do to correct her part if she gets a different measurement result than expected by your calculation? She still will not know if the angle deviates or the 1" part at the back edge is not exactly 1"..She will only know that one or both of the two dimensions are wrong. But which one needs correction and by how much? Actually even if the measurment result equals the calculated result still both the angle and the 1" part can both deviate but compensate each other so that the measured result seems correct but your part still deviates from the required shape. You try to verify two dimensions with one measurement. That can not work. I am afraid you have to postpone your summer vacation a little and pick up a math book yourself... ;-) I help you a little so you can still catch your trip to your vacation. How about taking two measurements with two dowel pins of different diameter? You get two equations which you want to solve for the unknown angle I name "alpha" of which you are not sure if it is really 20deg and an unknown distance "x" of which you are not sure if it really is 1". A and B and C and D (the latter two for the different dowel pin diameter) can all be expressed as functions of the unknown alpha and other known dimensions. So you can solve your system of two equations for alpha and x. Then Emma finally knows the actual values of the twol unknowns and can correct them accordingly. Is it spare room workshop Emma or another one?
one could confirm the angles with a sine bar.
true but very expensive if you include a quality set of gage blocks. Also a vernier bevel protractor would work up to about a 10th of a degree unless the bevel is too small and the protractor too big.
But scarcely equipped hobby workshops usually have neither of the two. So Marc's idea with the dowel pins and micrometer really suits home workshops very well if only that math were not so confusing....;-)
A $35 set of angle blocks would also work. my $35 set will work to 1/4º Chris
++Anonymic79: You are right of course when wanting to go by the book. Tolerances on dimensions and general tolerances you can see very often on decent drawings. And you should pull the tolerances also through the math operations where using toleranced dimensions. You are right. But to be honest I have not seen that done for many years in fields that are quite concerned about precision. Are you a physicist? They are the only ones I have ever seen doing that. The theory and the mathematical methods of error calculations is neat. But particularly in the mechanical field it is not very practical. In complex assemblies it would become complex already by carry through all error calcs. But it becomes even more complex because there are mechanical operations that interrupt the error calcs e.g. when several parts are clamped together and milled flat together. or when parts show unwanted gaps during assembly and you just pull them elastically together by their mounting bolts. And it has no adverse effect except on your error calculation. So even for precise assemblies the error calculation does not stand the test of practical application. For very special very critical applications usually with limited complexity error calculation can be very helpful. For high volume series production you could even include the probability of tolerances in form of Gauss curves and benefit from the fact that tolerances can cancel each other out. But that only makes sense with high volume production and certainly not home shop projects ;-)
rol eic, There is a much easier solution to the two pin method. An easier method to find the angle is to make one width measurement with the pin, followed by another width measurement with the pin sitting on an block of known height. then Tan(ø) = (∆Width)/(height of the block) Chris [NOTE i use ø as theta on my mac, because they dont give you a theta shortcut on a mac ]
There's your problem. Start peddling with your feet, instead of your hands. You can throw away the electric assist and you won't injure your wrist. Crazy Canadians...
Even simpler would be to turn around and back peddle out of it! If going forward takes energy, going backwards must produce some?
There you go, teaching me even more. Enjoy your summer sir!