World's Oldest Micrometer - 1776! Who made this thing??

I'm in the basement of the London Science Museum with Ben Russell mechanical engineering curator and we're about to take a part which just could be the world's oldest micrometer and look at things very few people have ever seen we're trying to answer the question who made this and when I've been obsessed with this object for a few years now the very first video I ever made for this channel was an introduction of the problems in history of precision and measurement the video thumbnail is even a rendering of a CAD bottle I made for this micrometer from largely just guessing at dimensions from a few old photographs I found and then I started to make my own replica if you watch that video you'll get a better idea of how insanely important this may be micrometers can measure repeatedly to pretty high precision well below the thickness of a sheet of paper and this very device is likely to be the world's first micrometer for measuring physical objects at that kind of precision if you had told me a few years ago I'd be holding the micrometer allegedly made by James Watt in my hands and taking it apart it would have completely blown my mind in my view this is very possibly the first device to add a second or possibly a third decimal place to precision which has mind-numbing implications to be able to consistently work to that level precision gives you the modern world almost everything in your life is dependent on the ability to measure very very small distances you'll notice I'm using a lot of weasel words implying we don't know if this is the first end measurement micrometer or who made it for sure but our investigation today is to try to answer that question and it's been a mystery for well over a hundred years even the Science Museum themselves say in their display reputedly for a good reason Ben Russell who also wrote a book on Wat says the same so let's do some forensic investigation and see what we can find out firstly where did it come from and why does the museum have it the museum came to have this object when they held a gigantic scientific conference of sorts called the special loan collection of scientific apparatus in 1876 this was a gigantic affair when the museum brought together vast numbers of scientific instruments from around the world and had them all in one place for all to see scientists from everywhere could see what others were doing and it was incredibly influential much to the amusement of me their stated goal was to be more like the Conservatoire the Arts at MIT ta in Paris a place we have visited several times on this channel the massive catalogue for the exhibition is over a thousand pages long the exhibition showed over 20,000 artifacts at once even more than the museum has on display today over a quarter of a million people came to see it was a major cultural event in that special alone collection there were some special groups of objects some of which came from the company descended from Boulton and watt and this micrometer is one of those objects and was presented as being made by James Watt now just the dust off your history braincells James Watt is not the guy who invented the steam engine but instead made it much more efficient but also perhaps more importantly with a wealthy partner founded a company to produce the engines for sale why does a giant of the Industrial Revolution as he was able to put the actual power behind the huge explosion of wealth the new industries gave us we all know that time is money but power is money too he's super famous and important and there are statues of him everywhere all over Britain not to mention being on the 50-pound note with his business partner Bolton the problem is that there are about a hundred years between when watts supposedly made it and it coming to public light and even though there's extensive documentation on watt in his businesses if he did make it he didn't tell anyone or write anything down about it so why bring it to light at the special loan collection one thought is what made it never did much with it and just forgot about it he was a prolific inventor so perhaps this was just something he played with and was left with his company continued to get passed down to the new owners but there's another theory I've heard that's a little less generous James Watt is undoubtedly one of the Giants of his age by the time the special loan collection happened u-shaped micrometer that they independently invented by a Frenchman Palmer about 30 years prior to the collection Palmer's patent was bought by the Americans brown and sharp and now a similar handheld version was being sold and these micrometer --zz were making big waves if you look through the catalogue there's dozens of devices which used screws for measuring small distances and all kinds of scientific devices so was this an attempt by someone to dig up wide as it were and show that watt had invented yet another triumph well before anyone else that's the question we're trying to answer today is there's no prominence connecting it directly to watt does it look like something invented and made in the 1770s does it look like Watts hand could it have been made with the tools we knew he had we don't know let's dig in so how does it work if you turn the small crank on the big back dial it is fixed to a screw that runs along the middle writing on top of that is an anvil which can slide also the screw drives a worm gear which turns the small dial the back has 50 divisions the small one 19 I've also seen pictures of the worm gear and I know it has 23 divisions and the lead screw is about 18 threads per inch so the first thing we can notice is that it's not decimal what about this possibly being a forgery for the special loan collection first I'm going to say everything I say here is my opinion only on by no manner a pro we have a special training to say anything definitive about this but I do think having made project for many years I can start to infer some patterns so first off in my opinion the object shows too much we're to likely have been constructed specifically for the exhibition and we passed off as watts we'll look into some of those areas in a moment does this look like the hand of why this is where I get out of my depth very quickly but that's not gonna stop me from having some opinions I think it shows areas where someone had both a lot of skill putting it together in areas where was not someone's finest work was this someone messing around was it just a prototype what was an instrument maker before making steam engines so he definitely was able to make gear to high standards but did he always make everything to that standard in no particular order here are some of the things we noticed when taking a closer look over about an hour and a half firstly I'd never seen the back and I don't think others had either because another replicas I've seen everybody gets it wrong what you see here are the three posts which hold the small dial and come all the way through and that are pinned on the back there's also what looks like a lot of hammer marks which don't seem to have anything to do at this part I'm guessing those were from another project and this makes me think this was originally a scrap piece of material though I can only imagine for the time this would have been rather diable on the front the small dial is soldered onto those stand offs which are pinned on the back speaking of the small dial the hands have a brass bushing soldered into it and it's rotated off-center I bet that happened during the soldering process on the big dial and back this astray hole it doesn't seem to have any purpose again it makes me wonder if this came from something else on both dials there is neural or reading like on a coin around the outside edge why if the rest of this is somewhat rough would somebody put a decorative touch on this probably practice also on the large dial there are what looks like extra circles cutter edged on both the front and back that serve no purpose not really decorative again this makes me think that maybe this was practice or possibly this piece was repurposed from another device there's also a lot of faint circular marks that makes it look like this dials been turned many times if you look at the graduated marks on the large dial it appears they were made with some kind of IDing engine at least at first but if you look a little closer you can see how there is variation in their size so I believe this was likely indexed by hand also it's hard to see in the photos but sometimes the small in-between marks extend a little too far but they are very straight which suggests to me they were made in some kind of crossing out device like clock makers use when we remove the hand from the large dial we immediately notice the large hands have some brass stock soldered into them which sits proud of the hands themselves long before we got here someone tried to remove the large back dial but the screws wouldn't move much and the big dial is loose we didn't dare try to remove them further we then discovered something neither of us had noticed before the main body dials and stand are all of brass but the rest is made of wrought iron if you look carefully you can see this strata where the iron has been hammered over this is especially true on the small fixed handle where it's actually curved a bit does this suggest more 1770s than later maybe one of the problems with trying to date things from this period is that it took technology sometimes decades to become ubiquitous and like today people with different skill or wealth levels have accessed the different methods but personally I think the wrought iron speaks this being older than newer relatively speaking let's flip it over and look at the bottom we can see the accession number the year of the collection when the micrometer was added at the Museum collections 1876 and the item number 1370 but we can also see the screws holding the base on and they are terrible I know this is a bad photo but both slots are way off center you can also barely see there's an extra hole just ahead of the rear one which was never used that looks like a transfer punch mark was made on the main micrometer by to locate a hole that was never drilled but also look at the quality of the outside base holes where the mounting screws would have been their terrible again not even close to round and very rough it also looks like the holes are intentionally hand countersunk from the bottom and top which is odd there are countersunk screws on the back of the big dial they are much better done does this suggest to makers when the micrometer is right-side-up the base is actually a little shorter than the bottom of the use so it sits a little crooked unless something is placed under it or it's off the edge of a table was it made later and someone screwed up the height or was it intentionally made to sit off the side of a table but either way if we flip it over and look at the top wouldn't we expect to see some evidence of screws that had held it down to something even if washers had been between a screw holding it down in the micrometer or even countersunk screws I would expect to see some marks but we don't what does this mean was this ever actually mounted on something so now looking at the anvils that actually do the measuring when we take them apart we start to see some really interesting stuff I presume this is something only a handful have ever seen over the last couple hundred years first we noticed the moving anvil has what looks like to me where on the top and it's pretty uneven this suggests that the bottom dovetail is not very flat or parallel in my highly in expert opinion it seems to me like this item has actually been used a fair amount though you can also see some straight file marks from the makers still back of the fixed anvil shows some hammer marks what are those mean bottom of the moving anvil is very interesting too we can see it's pretty rough with lots of file marks but also notice how the threads seem wider in the middle less at the ends this says to me it's bowed also notice that the area above the thread is filed down to clear the screw threads this is obviously filed not drilled which to me suggests someone with older tools than something more modern comparing the flatness of the dovetail services on a reasonably flat tabletop does show that indeed they are far from flat the same with the bottom looking at the lead screw itself though it's fairly rough but perhaps not too bad for the suppose a time it was made one thing that's really interesting to me is that there are what looked like marks at either end that suggests it was held between centers on a lathe could many lathes the 1770s cut wrought iron like this what kind of skill level did it take I know there were small clock making lays but I don't know if they were cutting iron though I'm far from expert here I'm not sure how common metal cutting lathes were with tail stalks on them and then all you had was foot power I think it suggests the threads were likely chased which makes sense but I still have so many questions here so after looking at all this detail what do you think was this made by James Watt in the 1770s was it made later who do you think made it I want to hear what you think in the comments personally I'm not yet drawing any conclusions I think the evidence could go any number of directions and more work needs to be done and again anything I've said here is my opinion that has only begun his investigation of this micrometer and he's far and away the expert here he has an article coming out later this year and it should have much more detailed based on closer inspection and doing much more advanced things like examining the metallurgy plus he's going to compare this to other objects which are known to have been made by watt so perhaps we get a better idea of who's handmade this if you haven't already please subscribe and stick around this story is far from over and I can't wait to get more into the history of machine tools and then actually making them thanks for watching I'll see you next time

Channel: Machine Thinking

Views: 608,157

Keywords: science museum london, science museum, micrometer, mill, lathe, james watt, watt, machine, machining, science education

Id: 1K_NQlmOwqM

Length: 13min 3sec (783 seconds)

Published: Thu Oct 04 2018