Thank you Don for taking the time to pass on your knowledge.

I could watch this sort of stuff for hours! toolmaking is one of the most interesting trades one could do!!! It's - can't wait to get up & go to work in the morning type of interesting.

Great to have you back. I'd like to add one small point: in geometry, only straight lines and planes can be considered parallel. Lines and planes which are a constant distant distance apart, but which are not themselves straight, are equidistant but not parallel. Not to be too pedantic, but in order to think clearly, it helps to have your head on straight.

This is a great learning experience for "Flatness & Parallelism" with GD&T Surface-plate Inspection. Thank You! T T (Tom) Vanderloop, Author, Mechanical Designer & Consultant: ATEA, AWS & SME-Life Membership/Leader

This guy is amazing. He knows so much and even better, he can explain things clearly.

I have recently purchased an inexpensive (new) granite plate, calibrated AA. Its opened up a whole new world for me.Now, as Don has pointed out, I can test objects to see if they are flat. However, the nightmare is making a cube!A cube that is 90 degrees on ALL corners. Perfectly square at all points.I can grind a cube. test the cubes opposite face on the table to a 10th'. BUT, have I made a parallelogram type shape? Are the upright faces, perfectly square to the surface plate?You can take an engineers square to the side face and physically see a problem. (Gap at the top, no gap at bottom).If your dealing with THOU's, no problem. Use a feeler gauge.If you need to check the problem to 2 tenths or less and actually measure the piece, from bottom to top (up and down), so you can adjust the block for re grinding. That I have NOT found a solution to.Winding a height gauge up and down is no good unless you know the height gauge is 100% up right to a factor of nothing. Otherwise you could be measuring the deflection of the height gauge.I seriously would love to know how to measure bottom to top, with precision.TIP for curved pieces on a known flat surface table.Clean everything to the last.Place piece on table and gently twist it on the surface. Just touch the corner and rotate the piece.Turn it over and twist it again.If its bent you can feel the piece SPIN on the high spot in the middle, even if the piece is a thou off.You can tell your piece is curved in a instant and grinding can often cause curvature.My Thanks once again to Don, who has made me THINK about problems and to stride to achieve perfection.

I LOVE IT! I am from Poland so we actually use metric system here, and it gets confusing very quickly when you have to switch from the world of milimeters/microns to 0.0001 of an inch... But anyways, I would really love to watch an in-depth explanation of how to measure perpendicular surfaces and potential factors that distort measurement. Thank you for your work!

So glad to see you're making more videos! Watching you, OxTools, and Abom79 has inspired me to apply for a toolmaker's apprenticeship. Your videos have been very informative and I've watched nearly every one of them! Thanks again!

you made my day ;> i build limit plug gauges by hand-lapping. sometimes i have to make an absolutly parallelism. that is realy a good show to understand what i have to do.

Hi Glen and Don. Great to have you back. Thanks, John

Nice to see you and Glen again. There are a lot of different factors to look at when measuring. Good demo on why the surface plate has to be flat to start with.

As always very well explained Don. And really happy your back.It took me a long time to learn, but blindly trusting anything new in the shop as being correct without a check to be sure will sooner or later ruin your day. Inaccuracy's can't be compensated for unless you know what and where they are.

happy to see that you are back making videos.

Great to see you again! Awesome Video!

Welcome back BOYS!!!, Great quick thought provoker. Thanks for the videos as always. Take Care.

Good to see you back ....

Glen is like a mad scientist!! Cool dude

Glad to see you back making videos! I was wondering what if any advantages would a large cast iron surface plate have vs a granite surface plate?

thanks don, really appreciate you sharing your knowledge and expertise. I bought a abrasive machine company # 1 1/2 I think it's 1946 ish. I trying to make my world a little flatter.

Thanks Don. Enjoyed your very informative video and for passing on your experience and knowledge.

Good to see you back again

feliz año nuevo , un saludo desde Argentina.

Thanks a bunch, Don, for sharing with us! :)

As always, tons of useful information.

I had to grind these 16 tool steel cutting rings that were 8mm thick and the tolerance was 4 microns (0.004mm) and when these rings (10 inch in diameter) can back from hardening they worped and bent. The magnetic chuck would pull them flat but after I ground them they would ping back to the bent shape. I had to play around with the chuck to get them flat. So much work involved

That is a great video for Students, well done.

Great to see you boys back!!!! Have you ever found a parallel to have an S bend in it Don?

Very interesting. Thank you!

Nice to see you back again. We all know why you have a white smock... But what about Glen ????

Great discussion!

Please provide elaborate information regarding how to measure size of NPT TAP. PLEASE

can you make a video on lapping Gage surfaces for wringing

whats the name of that tool you used to measure flatness

Don, I enjoy the Metrology portion of machine shop work and wold be interested in seeing how to check for the parallel being perpendicular.thanks

Does anyone know of any video's that demonstrate rounding mandrels with the "3 rounds method"?

Thanku so much

the tolerances you are talking about surely would require,what we called a "standards room" with a standard temperature.

Hi, it's good to see you. M.K.S.

So how to check the squareness? How people made the world-first perfect 90 degrees angle?

Wow, wondering wich applications require such precision, not automotive I guess

Great lesson Don! I like your height gage what kind is it? I'm a tool junky haha!

Don thanks for a great video. I have a question. When a print calls out for flat but does not give a tolerance, what would be except-able on crs that will not be machined to make it more flat?

Nice video. But I like when you show some interesting work on the mashine.:))) Thank colleague for you chanel.

When will you do a video about keeping things perpendicular particularly on the grinder

I don’t understand how tenths change to millionths?

Tq.

dad taught me these things as a child

what is a perfect surface?

"Lambs to the cosmic slaughter!!"

Are the tools you are making available in Europe, guys ? Great videos!

Patience and skill, I'm going to the moon

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