where's Kevin Kostner when you need him?

 Regarding that elusive milling cutter which is allegedly on its way to me... it turns out that SpeedPak*, the carrier service used to ship my cutter, hands off their shipments to... the United States Postal Service.

 Now, it really wasn't all that long ago when this would have been happy news indeed because for my entire life, since I was a child in the 1960s until just about two weeks ago, I knew I could rely upon the USPS to do a good job.

 But of course, thanks to our Fearless (Brainless) Leader, the speed and reliability of the US Postal Service is out the window.

 So naturally I doubled down instead of being cautious -- just like our president would!

  Yesterday I ordered, via eBay, a Noga style (Shars, in this case) dial indicator holder, like this one:

 

 This is the second indicator holder I've ever owned, and I bought the first one - even cheaper, a HF PoS, at Charlie's Second-Hand tools for nearly nothing. Before this month, I've gone without, or rather, I've made my own ways and means on the spot as needed. And it's been a pain in the ass, too.

 What makes this style of holder pleasant to use is that the one knob in the middle locks up all three joints.  So you have fastened the magnetic base to something, you can hold the indicator where you want it, use the knob to move the arms to a reasonable position, and then with a twist of that same knob, lock everything up. It's like having a third hand. Another convenience is a fine-adjustment built into the indicator holder, making setup a little easier.

 The other item I picked up is a simple bracket assembly...

 which lets me mount a cheap DRO, or Digital ReadOut, like this one...

 

 to the spindle feed of my Bridgeport mill, like this:

 

...sorta, except the above photos show a method which requires drilling a bunch of holes in the mill, whereas the Shars bracket mounts using the scale screws on the left, and tracks the movement of the quill by picking up that great big round hole in the front of the quill stop. Gotta love this guy's quill feed wheel tho... 

EDIT: I'd quite forgotten, but both these items came from the same seller, who shipped them via FedEx, and they are guaranteed to be delivered by the 20th. Huzzah!

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* a partnership between eBay.cn and OCL and the default shipping option for sellers in China

wild hair

 I'm pondering how much it would cost me to convert my shop from inch to metric.

 It might not be as bad as I at first thought. For example, the mill switches over with the press of one button because I have a DRO on it and I never use the dials. The parallels I use for it have labels on them in inches, but it doesn't matter because I never look at those numbers.  The end mills I have are sized in inches, but that does matter a LOT, so long as I know what their dimensions are, and even that I don't usually need to know with any precision at all - just enough to calculate cutting speed.  Gradually I would probably convert them to mm just to make math easier... since that's kinda the whole point.

 Likewise my calipers switch with a press of a button, and feeler gauges and rulers are cheap...

The dials on the lathe would be a PITA however.

And worse, I have a lifetime of instincts and judgment built on measurement system which, while it may be stupid, is now thoroughly entrenched in my technical thinking and my visual and physical interactions with the world; I would have a lot of habits to un-learn, and until I re-adapted, I would not reap the benefits of being metric.

Hmmm... America... so advanced... >_<

whither video?

 I realized that all the video channels I watch - including the folks I called out in a previous post - are using nice cameras on tripods, and that shakycam BS taken with a phone is going to annoy ME, never mind be unacceptably amateur-hour for my tastes.

SO...

 I'm going to wait until I have the dough to spare for a tripod and a Go-Pro or similar (or I figure out the video recording issue with my SLR), before I attempt to make actual, long, lecture-y, talking sorts of videos.

IN THE MEAN TIME, sometimes a picture is worth a thousand words, and a video is worth, um, mumble frame rate times minutes of running time... well, you get the picture.*

So I'll occasionally use my phone to shoot shorts bits of video, like this one:

Oh crud, sorry about the background music, I forgot to mute the mic.

 That piece of steel which is floating across my surface plate is one of three pieces of scrap low-carbon steel I've been working on to make flat and parallel.  I'm trying to prove that I can make gauge blocks effectively out of junk, and without owning a surface grinder.

 With one proviso: I'm not planning to finish them to any particular dimension. So if they come out = .17278xx but reasonably flat and reasonably parallel, I'll be pretty darn content. (the xx's are values I care about, but won't be able to measure with any accuracy any time soon because my name ain't Tom Lipton)

 I do however, intend to make all three equal, otherwise they'd really be useless.  The point is to prove the process, but I need better measuring tools - some actual gauge blocks, say - before I'll be ready to try making any to a specific dimension.  Even so, with almost minimal effort, they are flat enough to float, which means they are trapping a layer of air - thinner than .001 in / .025 mm - between the block and the plate.

 To do that means that the microscopic features of both surfaces have to be very low in height - the surface has to be very flat and very smooth - for this to work. Realize there is no lubricant present but air - the surfaces must be very clean and free of finger prints, etc.

 This is actually already more flat and more smooth than I'm even ready for; the three blocks need more work on parallelism before they are ready for lapping; they are more like small angle blocks†... and they are not supposed to be...

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* sorry not sorry
† .0382º if you're curious, or 138 seconds of arc, or .00067 radians...

shop tour - one station at a time, but first...

I've decided the way to do the shop tour is to break it into chunks of short videos. I'll write up a blog post to go with each one which I'll probably end up using as a script so I don't feel nervous.

Because the first "station" in my shop is going to be the surface plate, I thought it might be worth while to prime the newcomer with some thinking - or education - about the origins of precision measuring instruments and precision machinery which made possible the machine tools of today.

And because I'm lazy, and there are other people who are better at researching and talking about this stuff than I am, I'm just going to provide interested parties with the videos I have in mind, right here...

The Machine Thinking channel decided to build his own micrometer just for the hell of it, and he has a great set of videos about that project, as well as some of the history which lead up to the creation of the first micrometer.

The same channel's video, "the 1751 Machine That Made Everything" is also educational and interesting:

With those as fundamental history behind metrology and mechanical precision, we are prepared to talk about the granite surface plate. For anyone who isn't already familiar with what they are and why they are useful, here's yet another video: