Precision video

wfrancis · Nov 30, 2017

I started a video project to document my recreation of what is billed as the first micrometer as created by James Watt. The more I looked into how and where precision came from the more it facinated me so I elected to make my first video based just on the history of precision and measurement. This is obviously a huge subject so I had to focus on a subset and surely I could have gone a lot of other directions but I think what I chose is fair for an overview.

The more I dug into Watt's micrometer the more interesting the story became. The Science Museum London was kind enough to send me their notes on it but in email discussions with the Curator of Mechanical Engineering I was a bit shocked to hear it might not be what it appears to be. I'm temporarily living in Europe for a year and will be visiting London in the next couple of months to investigate the matter directly. This will be the subject of an upcoming video.

Here in Paris I am working to visit the Paris Observatory archives and review the expedition notes from Mechain and Delambre when they determined (slightly incorrectly but not their fault) the length of the meter. I'm hoping to see the original Provisional Meter and maybe even their repeating circles. Again, I'll make a video of whatever I come up with.

For now, I've pasted below the link to the first one and I have a couple more of the actual building process which I will finish editing and post (to youtube, I shan't bother you again here) in the coming weeks.

Origins of Precision and first project introduction - YouTube

enginebill · Nov 30, 2017

Please keep the updates coming here, your video looks great and am looking forward to your build.

c5h5nino · Nov 30, 2017

Excellent video! Keep up the great work!

Joe in NH · Nov 30, 2017

James Burke and "Connections" comes to mind.

Joe in NH

billzweig · Nov 30, 2017

It is nice to see the "Foundations of Mechanical Accuracy” by Wayne R. Moore.
One of my favourite books.

wfrancis · Jan 12, 2018

You guys are too kind. Probably not a surprise I'm a huge James Burke fan and I based a portion of this video on a clip he did in this same institution. I'll post that clip to my website. I have a long way to go to get to the quality work he did at the BBC but hey it's just me

This is a big step forward from me last one though.

This video is on some of the amazing objects in the Musée des arts et métiers. This covers mostly scientific instruments but the next part will heavily cover some of the really amazing early machine tools in the collections. I could make 100 videos on this place but I think I'll stick to 2 and then get back to posting the build videos from working on the Watt micrometer.

Edit: Hunter Davidson - the message you sent me on my website didn't have a return email address and I wasn't able to get in touch with you. Please contact me again with your correct email.

Chip Chester · Jan 12, 2018

Pop-up Guy! Burke used to 'pop-up' from below/out of frame and begin his presentation in an often-unexpected manner. Just keeping things lively, I imagine. Great shows.

I'll settle in on the OP's video later tonight...

Chip

wfrancis · Feb 7, 2018

Still working on my next video from Arts et Métiers with a lot of detailed info on some very early lathes but I keep finding deeper rabbit holes to follow.

Decided instead to publish now this video where I spent 8 months trying to figure out a good/fast way to make custom brass dials for the James Watt micrometer build (and other projects to come). I made a lot of mistakes along the way which I document at the end.

wfrancis · Mar 15, 2018

Since I'm still far away from my shop I've made another historical video. This time on Vaucanson's 1751 lathe. I'm curous if others agree on my choice?

PeteM · Mar 15, 2018

Seems like a great direction -- enjoyed your video and your style.

Don't have an answer, but you might think about how to make the material accessible to kids.

enginebill · Mar 15, 2018

Great video. I agree, without an industrial lathe there would no steam engines to power the industrial revolution.

Clownshoes · Mar 15, 2018

I understand it's not a video about Whitworth's three plate method but I see too many references describing it as simply rubbing the plates together or lapping them to one another. If you read Whitworth's paper on it the process involves planing, filing, then scraping (he doesn't even advocate grinding). Anyway, I hate to see the propagation of misinformation and there seems to be a lot of it out there on this topic so I would recommend reading Whitworth's paper. It is available for free through google books.

stephen thomas · Mar 16, 2018

Only watched part of the Vaucanson video above, something of an inspiration to me.
I like your style, clear development, and the materials you use must take a ton of work to find, edit and insert so seamlessly and well.

That said, I jumped every time you pronounced his name. Don't expect you to be a francophone but maybe practice the name of subject a little before doing the oral part? Everything else is so professional.

smt

wfrancis · Mar 16, 2018

Clownshoes said:
I understand it's not a video about Whitworth's three plate method but I see too many references describing it as simply rubbing the plates together or lapping them to one another.

My source for that video is The Foundations of Mechanical Accuracy by Wayne Moore which mentions lapping three plates together as a way to achieve a reasonably flat plane (p 21).

Popular YouTuber Tom Lipton (oxtoolco) recently made a series of videos where he lapped three cast iron rounds together to good effect. Here's the first video in that very interesting series:

Making flat lapping plates 1 - YouTube

I haven't read Whitworth's paper recently but I have no doubt what you say is correct for the scope of his paper. My thought is lapping compounds and methods have moved on since then.

wfrancis · Mar 16, 2018

stephen thomas said:
Only watched part of the Vaucanson video above, something of an inspiration to me.
I like your style, clear development, and the materials you use must take a ton of work to find, edit and insert so seamlessly and well.

That said, I jumped every time you pronounced his name. Don't expect you to be a francophone but maybe practice the name of subject a little before doing the oral part? Everything else is so professional.

Thank you, I appreciate the kind words. It is a lot of work and research. I'd say probably 100 hours to do all the research and find all the materials for this. I have to do the writing and narration over and over again to get a version which I think is acceptable (not that I think it's great) and I'm pretty slow at all the video editing. Also, this video started out as something very different and went through 4 major revisions and in all the rewriting I burned a lot of time. On the upside I have a lot of material for another day ...

As for my pronouncation, I know it could be better. In my previous video I talked about Vaucanson as well and a French friend here told me it's not perfect, but it would be hard for a non-native (or very well practiced) speaker to get it right. I don't think mine is too far off from James Burke's version, though. But, point taken.

Loom History Moving to Computer - YouTube

Clownshoes · Mar 16, 2018

wfrancis said:
My source for that video is The Foundations of Mechanical Accuracy by Wayne Moore which mentions lapping three plates together as a way to achieve a reasonably flat plane (p 21).

Popular YouTuber Tom Lipton (oxtoolco) recently made a series of videos where he lapped three cast iron rounds together to good effect. Here's the first video in that very interesting series:

Making flat lapping plates 1 - YouTube

I haven't read Whitworth's paper recently but I have no doubt what you say is correct for the scope of his paper. My thought is lapping compounds and methods have moved on since then.

I don't see where Moore says anything about lapping the plates together, p.21 and the several pages after explain the scraping process in even more detail than Whitworth does, only later does he mention the word lap and it is in reference to addressing the burrs caused from scraping and the marking compound can potentially have a lap effect which leads to the inspection phase of the procedure to further refine the accuracy. I don't know if people are confusing the marking task with lapping but the three plate method is done with scraping.

With regards to the video you mention, I've seen a youtube video where a man eats 100 carolina reapers but I'm pretty sure that's not the proper way to enjoy chili peppers but who knows, I think he was pretty popular too.

enginebill · Mar 16, 2018

I believe lapping was common to make surface plates before Whitworth advocated scraping three plates together. I read that he mentioned that the smooth grey surface of a lapped surface plate did not mean that it was flat when only two plates were used.

Clownshoes · Mar 16, 2018

enginebill said:
I believe lapping was common to make surface plates before Whitworth advocated scraping three plates together. I read that he mentioned that the smooth grey surface of a lapped surface plate did not mean that it was flat when only two plated were used.

Don't confuse lapping the high spots down instead of scraping them with "lapping the plates together", very different things. The plates are brought into contact to mark the high spots so they can be subsequently removed or as Whitworth calls it bringing one surface UP to the other via some means (scraping or otherwise). No where in the literature do I see mention of grinding the surfaces into one another and conceptually I don't see how that would produce a true surface, you'd just be transferring error back and forth, maybe that error gets smaller over time but it's completely uncontrolled and subject to a host of problems. It would also be completely unmanageable with larger plates and you will see reference in both documents (Moore in particular) to the problem of elastic deformation of the plate and the great care that must be taken when handling and supporting them during the marking process, obviously if one were to grind them together back and forth with the intent of removing material it would create all kinds of unwanted stresses.

enginebill · Mar 16, 2018

Clownshoes said:
Don't confuse lapping the high spots down instead of scraping them with "lapping the plates together", very different things. The plates are brought into contact to mark the high spots so they can be subsequently removed or as Whitworth calls it bringing one surface UP to the other via some means (scraping or otherwise). No where in the literature do I see mention of grinding the surfaces into one another and conceptually I don't see how that would produce a true surface, you'd just be transferring error back and forth, maybe that error gets smaller over time but it's completely uncontrolled and subject to a host of problems. It would also be completely unmanageable with larger plates and you will see reference in both documents (Moore in particular) to the problem of elastic deformation of the plate and the great care that must be taken when handling and supporting them during the marking process, obviously if one were to grind them together back and forth with the intent of removing material it would create all kinds of unwanted stresses.

I wasn't confused about anything. You can certainly lap three plates together and get them very accurate. Watch Tom Liptons video that is posted above to see it done.

partsproduction · Mar 16, 2018

I used a similar method of acid etching to make a duplicate machine makers plate for a shaper I restored. I used vinyl sign material though, which the sign people cut out for me with a sign machine.

I also used ferric chloride but didn't think of setting the 1/8" thick brass upside down, instead I made a motor driven sloshing machine out of acetal pulleys and eccentrics to slowly raise one side of the plastic tub and then the other, the motor being a 1/20th HP gear motor.

That worked pretty well though I wish I'd have thought of the inverted method.
The problem I found was that the edges of the fine cut away details would erode away at an angle, deeper in the center and rising toward the fine edges. Also the ferric chloride tended to try to seep under the vinyl sign material.
I wanted .015 depth of all text and lines which I never achieved. I think the best I got was about .007"

Oh, BTW, it took me weeks as well to get an acceptable plate, in fact I made three good examples.

One does begin to wonder if the results are worth the effort.

Precision video

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