Friday, November 15, 2019

Always Read the Fine Print

LittleMachineShop.com offered this 3" screwless vise marked down to $74.95 on closeout:
This high precision toolmakers screwless vise has a one-piece body. The body and jaws are hardened to Rc 58-62. All sides are flat, square and parallel to 0.0002". There are horizontal and vertical vees on the inside face of the movable jaw to hold round objects.This screwless vise has slots along the sides so you can clamp it to the mill table with a clamping kit.
The jaws are 1.357" deep and open to 3.94" capacity.
The vise is 7.72" long, 2.76" tall and 2.875" wide.
but:
These vises have blemishes, cosmetic defects, and/or light rust, but function normally 
What I received:

They appear flawless to me.  There is some light protecting oil of course.

Frankenvise is fine for the largest projects where the extra fractions of an inch in jaw opening matters, but this will be what I use most of the time.  It is like a bigger, easier to use version of Sherline's 2" vise.

Thursday, November 14, 2019

Nuclear Stress Test

I am likely still emitting gamma rays, but my heart is fine.  This is likely cold-induced asthma.  Back to my GP for a solution.  This indicates breathing through my nose, not mouth, will help; the opposite of what I have been doing.

Baby Telescope

I moved the primary mirror .5" closer to the diagonal and it is now a decently functioning telescope.  Most of the work on this rebuild was making sure that I could collimate it.  (The previous diagonal holder was a stalk that was held in the eyepiece focuser by a screw.  There was no practical way to adjust the diagonal's position relative to the primary mirror.)  I was able to collimate it to a level that it has never seen before!  I will need the primary and diagonal recoated.  From using it this evening on Bogus Basin, I have some confidence that it will make a fine scope for the Moon, the Orion Nebula, and other low magnification objects.  (I never had any delusions that my first mirror was great.)

How to mount it is the next issue.  I had originally put a 1/4"-20 hole in the bottom of the tube, but this is unsatisfactory.  The first time I mounted it on a camera tripod, it barely attached at first.  I did this 25 years ago.  Now I know that you should chamfer threaded holes.  So I did so, and perhaps too aggressively; this is not a very thick PVC tube.  It seemed to thread on, then rolled off into my fortunately present hands.  I have some 4 5/8" ID rings which I will turn into 4.5" rings with a layer of foam rubber.  These rings have 1/4"-20 holes in the bases.  I just need to make an assembly on which to mount these rings.

This will have to wait.  My mill is at Sherline getting fitted with limit switches, and trying to figure out why Axis X on the controller keeps blowing its fuse.

I turned on the TV and put the baby telescope (telescopette?) on the table.  Even at 50x (a 7mm eyepiece) it was nicely sharp.  Maybe I did a better job on this mirror than I realized.

Fortunately, This Was in California

Background checks on all firearms transfers; gun storage law to keep guns from kids; limits on magazine capacity; a "roster" of legal handguns that can be sold; assault weapon ban.  11/14/19 ABC News:
Two 14-year-old boys and a 16-year-old girl are dead and two other students are injured after a classmate opened fire at a high school in Southern California Thursday morning, sheriff's officials said.
The 16-year-old male suspect was taken into custody and is in the hospital in "grave condition" from a self-inflicted gunshot wound, authorities said.
Detectives reviewed video from the scene which showed the gunman in the quad of Saugus High School in Santa Clarita when he took a gun from his backpack, shot five people and then shot himself in the head, authorities said. The early morning school shooting was on the suspect's birthday, authorities said.
Helluva a birthday present. 

First Jaguar Repair

The "Check Engine" light came on.  One of the six oxygen sensors had failed. I am glad that I bought the 7 year, 100,000 mile extended warranty.  Although because these are emissions related, I suspect that they would have been covered anyway.

I saw the new Jaguar EV400 in the service driveway awaiting delivery to the owner.  All electric, pretty four door sedan.  0-60 in 4.5 seconds, and priced as you might expect.  Range about 240 miles between charges.  I think I am going to stay a gasoline man for another generation or two.  $70,000

Wednesday, November 13, 2019

Forgot I Did This

Why the Dickey Amendment Was Passed

It appears from this article that this article in NEJM provoked it. While there is no direct statement: "guns should be banned," this quote conveys some of the language that is pretty clearly intended for that purpose: "Despite the widely held belief that guns are effective for protection, our results suggest that they actually pose a substantial threat to members of the household. People who keep guns in their homes appear to be at greater risk of homicide in the home than people who do not. Most of this risk is due to a substantially greater risk of homicide at the hands of a family member or intimate acquaintance. We did not find evidence of a protective effect of keeping a gun in the home, even in the small subgroup of cases that involved forced entry."

That they excluded lawful uses is pretty indicative of cherry-picking the data: "Although our case definition excluded the rare instances in which a nonresident intruder was killed by a homeowner, our methodology was capable of demonstrating significant protective effects of gun ownership as readily as any evidence of increased risk." They assume that "a nonresident intruder was killed by a homeowner" is rare, and exclude defensive uses that do not lead to death of an intruder. Here are 1155 gun defensive uses involving home invasions. And 492 residential burglary cases. And 326 residence robbery incidents. Many did not leave a bad guy dead. Excluding such cases is misleading.

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