Metal Lathe Tutorial 20 : Snap Gauges & Depth Gauges

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[stu]

One caution on snap gauges: If you want them to last, don't let them snap open without being inside a bore. The little slot and pin that holds the anvils in place inside will eventually break, and the pieces will go flying across the room. When I'm done using mine, I always hold the anvils together with my fingers before I release the lock and let them expand slowly. I can't tell you how many broken snap gauges I've thrown away because of this.

[clydedecker]

Quinn, I'm not a machinist and never will be but I'd send anyone to be your student/apprentice. Your explanations and treatment of difficult situations is superb. Thank you for sharing.

[prodoverjeff]

I bought a set of telescoping gauges at a used tool store years ago. No idea what they were, but they were cheap and I liked them. A few years later while reboring a screw machine turret, I needed a way to measure "how big?" Remembered those things, and figured using them and a mic would give me the info I needed. I thought I was a genius, then an old timer asked me what I thought those were built to do.

[iantheorem]

I enjoy hearing your little puns and silly banter. In the past 2 hours I have learnt so much from you.

[machobunny]

This is an old video. Don't know if you'll ever see the comment, but THANK YOU. I am pretty smart, maybe, but I couldn't have ever just figured that out. Life Changing. Well...that part that's spent screwing up measurements.

[griplove]

Nicely done! I’ve never used a depth mic and the way everyone explains them has made me delay getting one. This made perfect sense. Thank you, I learn so much from you.
Also, let’s talk about you making me laugh. 5:48. 😂

[jeffanderson]

I’ve be darned, that’s how to use a snap gauge.
Thank you.
For hobby machinists like myself, we never had any formal training. I remember learning how to read a micrometer in metal shop but that’s the extent of it.

[jorgeconcheyro]

Now I know why you have to go so light with the micrometer when measuring the snap gauge. Great video Quinn, cheers from Buenos Aires.

[britishreaction]

Very interesting, thank you. An extremely lucid explanation of how to use a snap gauge.

[ninthmn]

Excellent video Quinn. Best explanation of the how and why of snap gauges I have seen. Love the depth Remix

[michaeljohnson-linn]

Quinn, during my apprenticeship the lecturer who was explaining how to use the snap/bore gauges always referred to a technique called feathering. As you advised in your video it is best practice to ignore the ratchet mechanism and feel (feather) the micrometer anvils onto the snap gauge. One interesting technique that we apply at Rolls-Royce is Gauge R & R methodology. The R’s stand for Repeatability and Reproducability, this is where the technician who is measuring a feature repeats the same measurement a number of time to ensure accuracy of the reading. You can take this further and ask another technician to measure the same feature using exactly the same measuring equipment. In the ideal world all the measurements will be very closely grouped together. This can be used as part of the six sigma reporting technique to assess accuracy of your measurement process. Informative video as always.

[Stellar]

Please do not stop making videos your amazing! Cheers

[danedewaard]

Those "Thumbs Downs" mean their "Thumbs Up" is somewhere else!!! Shame on Thanks for all your good work!

[DEtchells]

Hah, another super-useful video! It’s funny, when I saw you starting to use the snap gauge, I thought “hey, wait a minute, she has that misaligned!” I figured you were going to just point out to us that you needed to hold it straight, but of course, we’d have no idea whether we had it exactly on-center or not. Duh! - just start high and move it *through* center and you’ll get the accurate measurement! Also an important tip about not counting on the stem-clamp to hold the pistons against arbitrary force from the mic. I’m gonna get out my snap gauge set and mic and so some practicing :-)

(I’m also finally a Patreon supporter now; I’m a lottle ashamed by how long I’ve been freeloading 😔)

[marcmckenzie]

Quinn, I wish I'd had these two segments on metrology in the shop when I very started. Lots of mistakes in junky measurement tools at the beginning. To the newbies out there, she's right - buy quality especially on your measurement tools. (I too skipped all the fancy dancy bore gages and other delights). And by the way, thanks for the awesome stickers!

[larryshaw]

While I don't vise a depth that's that often I appreciate your refresher course on them.

[pilgrimm]

Thank you Quinn Great tip on using a snap gage.

[johnapel]

Very good descriptions as usual. I have heard some bizzarre descriptions of snap gage use.
I also now have an earworm. That's ok, it's a good song.
Thanks and Meow.

[kevinmartin]

Another thing to ensure is that the snap gauge is straight when you measure it with the micrometer. The tip radii of the anvils will generally be smaller than the radius of the bore being measured so if the snap gauge anvils are not lined up with the micrometer anvils you will get a low reading.

[markengineeringSA]

Another great video, Quinn, making workshop measuring a snap ☺️