Japanese finds

[Toolmaker51]

I have no issue buying Japanese products, especially those related to general engineering and machine work, including a facsimile of that square level.
It is disappointing to see buyers here equate Japan with "import", which is never equivalent grade. Singly, a portion are good, but takes very careful examination. Won't measure up in comparison.
Related earlier exposure in depth to Japanese tools and the people themselves working in Reno. Absolute top 5 of my most unforgettable work experiences.

 

[Toolmaker51]

Someone out there knows what stone that is, and someone else knows that person and will someday read this. They say the best way to solve a quandary on the internet is not to ask the question, but to give the wrong answer. I'm sure someone will correct my ignorance.

This strikes me at most dives into the 'net; more so when a naysayer pipes up "Good job responding to an old thread, bucko".
Confident an honest query outweigh weak insults.

 

[Bakafish]

So not a lot of love for the Gepy stuff, a little too niche I guess. So today I'll show something a bit more mundane, the humble and ubiquitous Optical Flat.



This example is is an ~80mm LapMaster single sided 1/8th wavelength unit I picked up for ~$20. In the picture above you can actually just make out some colorful fringes in normal light, but ideally you want to use a monochromatic light source. Forgive me for nerdsplaining if you already know all this, but the fringes are created by the light constructively and destructively interacting as it is reflected back on itself. Kind of like how noise canceling headphones work, a waveform of the same frequency, but opposite phase cancels out the sound. When the tiny air gap between the glass and the reflective surface is a multiple of the frequency of the light itself it either amplifies or dampens the light, creating the fringes seen. Knowing the frequency of light (He is mostly 587.6nm) you can actually calculate the distance between two bands, this amount is usually quite small, and if the flat is properly seated you can count the bands across the object and calculate the overall flatness.

Why would anyone want to do that, and what does this piece of glass have to do with anything? Well the glass of an optical flat has been ground to an extreme amount of flatness and using the light and these fringe patterns, one can determine the flatness and contours of a secondary reflective surface with extreme accuracy.

As mentioned above, to get the best results requires using a monochromatic light source, typically low pressure sodium or helium, powered by a ballasted high voltage supply. Other than low pressure Sodium, these light sources are not really monochromatic, they actually have several frequencies of light they emit due to the different electron band gaps, but an overwhelming amount of output is usually at one frequency making it essentially monochromatic for our purposes. Secondary filters can be used in professional settings to get even cleaner results. Partially due to advancements in solid state lighting, and the limited use of such things, these lights have become a lot harder to find than the optical flats themselves, and I've been searching for some time.



Today's the day! I finally got a hit for an Electro Technic Products experimental light source here in Japan with a helium tube for a reasonable price. There are some people using laser diodes and ping pong balls as a diffuser, but I have enough projects and just wanted to have something that worked.

Our test subject today is a Mitutoyo base plate that is included in their square gauge block accessory set, these square gauge blocks are not as common (especially over here) so I've been able to build up quite a collection as they are not as desirable, but they can be really useful as they can be fastened together thanks to having a hole through their center (also super useful for calibrating depth gauges!) This unit was shiny and a similar size to the flat, so a good first light candidate.



What you want to see is nice straight lines, from edge to edge, and honestly the fewer bands the closer the fit between the optical flat and the surface to be measured. I didn't attempt to optimize the fringe count, and I didn't make a lot of effort to get a good photo either. The light needs a diffuser and to be better positioned for photography as the picture induced some curvature to the lines that actually isn't there, as with many things this looks better in real life.

So other than verifying that your Mitutoyo accessories are properly made (a waste of time, of course they are!) what's the use for this? Well, hand lapping has come into vogue again in the YouTube community, and along with scraping for flatness the idea of lapping in some of my harder surfaced items is really appealing. This equipment allows one to do so and be assured that you have achieved the desired results. It's also just kind of neat.

 

[Bakafish]

Like many of you, I'm very much a completionist. When I get something, I want to get all the optional attachments, often with no clear need identified. As a big fan of Nakanishi stuff I picked up the smaller Emax Evolution and have been collecting all the various tool heads for it when I see them come up cheaply. But that's for another time. A while back I picked up an old NEWS BS-1 dividing head, it being a licenced clone of the ubiquitous Brown and Sharpe units. It came with all the plates and was in good shape and the right price, but didn't include the chuck or the tail stock. An appropriate 6" NEWS chuck was easily obtained for $20, and I've seen a number of the tail stocks in fair condition listed, but as the same unit is still being manufactured in Taiwan and China I've been a little bit picky about the condition of a used unit and have been waiting for the 'right one' to show up. (It's not like I'm actually using any of this stuff yet... )



Well, today's the day. $80 delivered, it came (double packed) with the original oiled box and still coated in many spots with the original cosmoline. Seems to have been used once, then put back in the box. After giving it a good scrub, she's ready to go.

For some bonus content, I picked up this pair of "Junk" Haimer's (one branded in local Big Daishawa livery) for $300. Nothing significantly wrong with them, a few new set screws, plastic polish for one of the lenses and a simple recalibration couldn't solve.



I have a couple of the shorter probes for these, but they are packed safe in their boxes. I can already picture clutching the pink shards of ceramic in my hands with tears in my eyes.

 

[eKretz]

Nice. I've got a NEWS/Yuasa BS-2. I like mine very much. Mine came with everything but the gears for compound indexing, in great shape.

 

[Bakafish]

Nice. I've got a NEWS/Yuasa BS-2. I like mine very much. Mine came with everything but the gears for compound indexing, in great shape.

Oh, very cool! Whenever I see NEWS items come up, I'm always tempted. The BS-1 is already too big for my current machines, if it hadn't been an impulse buy because it was cheap I would have maybe tried for a BS-0, but I envy that helical cut ability and fine feed the big ones like yours has. I'm sure I'd never use it, but I love capabilities, even if they are never tapped.

 

[Bakafish]

One of my original purchases that kicked off my metrology 'collection' was a Mitutoyo granite block square. I bought it assuming the price of ~$50 was good (I think it was) and at the time I had no reference surface, so I thought it could be used as a little surface plate (kind of awkward for that, but the infected do what we have to to convince ourselves of utility...)

I just love the look and feel of granite, and the fact it doesn't rust makes it a less stressful material for me as most of my stuff just gets packed away. Last weekend, a largish (450x250) Mitutoyo square was listed at auction for about $250, but I was going to be away skiing in Hokkaido (★★★★☆) so I wouldn't be able to camp it. I threw an auto-bid on it and was happy to find I was the only bidder, but being remote I wasn't able to encourage the seller to package it carefully. When it arrived I was disappointed to find that one of the (non-critical) corners of the otherwise pristine square had been chipped and I recovered a few fragments from the box.



This sort of thing hits me harder than it should, and after sending a restrained complaint to the shipper, I immediately started thinking about how to repair the damage. As this was a non-critical surface, and on the back side as well, I didn't want to go overboard. I collected a bit of baking soda out of the refrigerator and overnight ordered some Loctite 380 (Black Max over in the US.) By doing a layer a day, and embedding the chips I recovered, I was able to stabilize and build up the area enough that I could then use the Nakanishi with a right angle head and a set of sanding discs to reshape the corner close enough to the original that it wouldn't haunt me. Shortly after finishing the repair, the vendor credited me %20 bringing the cost down to under $200, so I think it worked out okay.



This bigger square had a hand made sheet that mapped it's accuracy included in the box, it wasn't the original calibration or something from a lab, it was clearly from the original owner who was compensating for any errors, but if I choose to trust it, it showed it was under 2 microns out across the length. The two reference surfaces on it seem pristine with the subtle silky frost that differentiates them from the highly polished surfaces of the rest of the instrument.



Long lost siblings reunited.

 

[M.B. Naegle]

Optical flats are cool. Years ago I ended up with an old 1940's Van Keuren catalog that in addition to having their metrology tools listed had some good documentation on the how and why of optical flats. We have a a couple flats but no calibration documentation for parallelism. Building a nice wood monochromatic light cabinet is still on my to-do list.

Yuasa News stuff isn't uncommon over here, but I don't think I've ever seen a piece from the "News" generation that was in that good of shape! We have a couple of News lever action 5C collet indexers that are 90% stripped of paint and the tags are beaten pretty bad. One needs parts but they're still affordably available from OEM.