What Did You Buy Today?

Aaron David said:
Hitting the garage sales this weekend, I found this at one of my stops:

Well, I couldn't pass that up for $5! I wasn't sure what all was in this, but I had a chance to go through it last night:

all sorted out, sort of. I still need to check the sizes of everything, but there looks to be a set of taper pin reamers, drill bits, chucking reamers, center drills, end mills, and so on, most of it in very small sizes. The Starrett box and a small pill container had these in them:

I will be tucking all of this in with my Unimat, and these should be great for working on tiny jobs.
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Nice assortment, and an interesting juxtaposition of the small center drills next to the "economy" size one.
 
Picked up this 24x36 surface plate at an auction last week. It wasn't a burning need, but I'm a BidSpotter noob and wanted to go thru the buying process on something cheap. Couple of neighbor kids (both football players home from college) helped me move it. Just need to add leveling feet and give it a little cleaning.

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I dunno, 32ndths of a RCH is pretty good. 64ths is way down in the weeds, but millionths might be "TMI". Whenever you need to correct for the ripples in the magnetic field or absolute translocation in space time, your measurement becomes more theoretical than actual.

In fact, you should become familiar with how NIST deals with measurement uncertainty by reading the bible (Guide to the Uncertainty of Measurement) attached here in case one of you finds this stuff interesting. I have authored a few papers where I needed to apply measurement uncertainty, and the exercise was a mind opener.
 

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aliva said:
What would a hobby machinist use this for? If you look at it the wrong way it will probably move. I've got a difficulty measuring in tenths of an inch let alone 2 ten millionths.
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Precision measuring can be a hobby too! ;) How good you make something can only be as good as your measurement tools!

For some relative measurements it can be pretty easy to run out of resolution. For example, on a rainy day cylinder square project the 10ths indicator is lacking. Remember that half a tenth is 50 millionths, 20 millionths is only splitting that tenth into 5.
In this case, the square gets checked, then lapped, and rechecked. It's easily near 20 millionths of square over 5 inches.

Yes, temperature is certainly a concern. But for quick relative measurements and being somewhat observant of temperature, you can still gauge a lot. No, the surface plate isn't in a temperature controlled room, yet...
 
dkemppai said:
Precision measuring can be a hobby too! ;) How good you make something can only be as good as your measurement tools!

For some relative measurements it can be pretty easy to run out of resolution. For example, on a rainy day cylinder square project the 10ths indicator is lacking. Remember that half a tenth is 50 millionths, 20 millionths is only splitting that tenth into 5.
In this case, the square gets checked, then lapped, and rechecked. It's easily near 20 millionths of square over 5 inches.

Yes, temperature is certainly a concern. But for quick relative measurements and being somewhat observant of temperature, you can still gauge a lot. No, the surface plate isn't in a temperature controlled room, yet...
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I have a couple of granite plates. A “good” one for high precision measurement and another for setup. I also have a several small cast iron plates. I use them all regularly. I couldn’t imagine being without at least one 2x3 plate. Definitely can be used outside the metrology lab. Especially if you are doing much surface grinding.
 
Picked up another compressor. This now makes my fifth 80 gallon unit, along with two sixty gallon units, and a few smaller ones. Seems I may have a problem. This one is a Saylor Beall unit, went to look at it mostly for the motor, but when I checked it out it ran so nice and quiet, and pumped right up I immediately fell in love. Hauled it home and gave it a bath. The only thing I'm going to do to this one is check out the electrical, and replace the crank seal. Pretty happy for $250. Mike

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FOMOGO said:
Picked up another compressor. This now makes my fifth 80 gallon unit, along with two sixty gallon units, and a few smaller ones. Seems I may have a problem. This one is a Saylor Beall unit, went to look at it mostly for the motor, but when I checked it out it ran so nice and quiet, and pumped right up I immediately fell in love. Hauled it home and gave it a bath. The only thing I'm going to do to this one is check out the electrical, and replace the crank seal. Pretty happy for $250. Mike

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I am supremely envious of your glut of compressors!
 
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