Layout

Back in the old days, when I was learning to shoot in service rifle competition, I found out a very interesting factoid.  The human eye can line up circles concentrically with very good precision.  Very VERY good precision.  I was shooting a stone stock M1 Garand from the DCM (Department of Civilian Marksmanship).  She was service grade, and worked as advertised.  But she wasn't too good in my hands at hitting what I wanted to hit.  

I found out about that circle magic, and I thought, "walp, the bullseye is round, the peep sight is round.... I wonder if they make a round front sight?"  Enter the Alley Globe Front Sight.  I saved up some coin for that, and it made a big difference in my ability to hit "with two or five rounds...... load!!"

I don't remember what I paid for it.  $25.00 maybe?  

 

Layout on the Pantograph Parts

I don't have a lot of experience laying out on castings.  That being said, and the aforementioned "trick" of lining up circles, I thought using a drawing guide would be the way to layout the hole locations for the pivot points and adjustment locations on the pantograph.  Didn't work as I thought it would.  Reason??  The outside of the casting boss is not very visible through the drawing guide.  I double checked with the Lufkin radius gauges, to be sure I knew the diameter of the boss, but I'm not happy with the result.  Some of the other holes are referenced from the location of that hole, so it has to be accurate.  That's why I'm going to the trouble to center them on the boss.  Makes it look good, and work better.

What to do?  Did I hear 'use a washer!' from the back somewhere?  Yeah, I'm gonna use a washer.

The parts are in fine fettle and have been primed with bbq paint.  Good to a thousand degrees.  It's what I had at hand.  I haven't settled on a color for the finished project.  It'll probably be Ford Tractor Gray.  I can get that at Tractor Supply.  I may just settle on primer gray.  Not a worry at this point.

The original document (Model Engineer 2 Oct 1970) showed a sewing machine motor as the spindle drive.  I thought that would work okay, but then I saw this on a website.  It was a complete unit, even has the collets.  So, I'm going to see if it this will work.  This here's the link¹.

 Glenn Makes a Request

Over at the Thundermug, Glen asked me to mention what I got the other day.  Back in the dark ages, I did some archery in college.  I didn't excel at it.  But it was fun and I surprised myself at what I could do with a bow.  I found out I have left eye dominate and I'm right handed.... very right handed.  So I had to learn to shoot with my left hand.  It was crazy difficult.  I can't pick my own nose left handed.  But I learned to shoot arrows as a southpaw and it worked pretty well.  I need an excuse to get some outdoor exercise, and I figured why not give this a try.  I bought my own birthday present. 

I went cheap, but well recommended.

Chinese import, but had good reviews

carbon fiber and had excellent reviews

saw it on sale and it started this whole fiasco

68" left hand, takedown model, 35# pull, 31 inch arrows.  I figure I can get longer limbs if needed and also ramp up the power if I can learn to handle what I've got.  I need to find a curtain to hang behind the bag target.

 

Trails Plowed Under

It is really weird when a family fractures....

¹  Added link to spindle motor 11-18 @ 1308 CST.

Pantograph

I decided to take a few minutes and start on the pantograph castings.  My normal method, honed so many years ago on the only other casting I started  (and haven't finished yet) I painted it before I started milling it down.  Made sense to me then.  I decided to do it again and see if it works.

All my primer spray cans were plugged or empty...  So I blew on some high temp bbq pit paint.  I traded off my pit so no need for it any more.

 

Beautiful

The black parts were not in need of fettling.  But the spindle arm was.  I spent 20 minutes or so smoothing out the flash.  Some spots, it was really proud and I had to tap it down a bit so the file would cut easily.

That spindle arm still has a big gate / sprue on it that will be ground down tomorrow or Friday, then filed flat to match the rest of it.

I haven't decided on the final color.  I have some gray and some blue.  I may even have hammered green.  I need to dig in the stash and see what's available. Man this is starting to get exciting!!  

What can a pantograph do?  Well, it reduces or expands whatever you run the stylus over.  This one can shrink by a few different amounts depending on where you put the holes.  1/2, 1/4, 3/8 IIRC.  I could engrave letters and numbers, or make torx holes, or whatever I can make a template of.  Pretty cool machine.

Here's a good overhead view of one running.  

I have some leeway on making the base for it.  I'm not sure quite which way I'm gonna go on that.  Maybe an aluminum plate or maybe dig for an old cast iron drill press table.

The original used a sewing machine motor to run a spindle.  I  found a spindle motor that runs at 12K rpm.  It has a built in ER11 collet and comes complete with a DC driver, a few cutters, ER11 collets in multiple sizes and the two mounting holes will work perfectly on the spindle arm.

I can hardly wait to get started machining on it.  The heat broke a week or so ago.  Shop isn't bad at all unless it's really humid.  It's only in the mid 90's now.  Cool edge to the breeze most days.  This evening reminded me of summer nights in Lubbock county 40 plus years ago.  Nights were cool on the caprock.  Even in the middle of summer, getting into the mid 60's at night was not uncommon.