Design Failure

My plan was to use 1/2" ID 5/8" OD bearings with little square blocks 1" square to hold then in place inside the axis housings.  The 5/8" OD bearings are actually. 5/8" OD.  To make the bearings fit requires a .704" hole.  This gives .296"/2 on either side of the bearing block into which I need to epoxy a helical thread insert.  I bored 1/4" diameter holes in each side because I thought I ordered 6-32 to 1/4"-20 inserts which were. 138" long.  They are fine inserts.  Notice where made:

They are actually for an 8-32 through hole.  This is not surprising.  I could use 8-32 screws in 1/4"-20 holes, but those inserts will not be short enough to fit in .145" deep holes.  I think the solution is to:

1. Measure each component as it arrives (bearings OD, helical thread OD).

2. Drill much smaller holes to accommodate these Down Under inserts.

Drilling the existing 1/4" holes down to .145" will require a mill that operates in a Lobashevsky space.  I cannot afford that.

Fortunately,  I only milled the 1/4" holes in one besting block.

To hold the block and grab the outer ring of the bearing will require 3/16" screws.  They are fortunately available  

.41mm Leads

I am trying to find a connector for combining .41mm leads to a wire that is considerably larger..These Harwin connector cables terminate in very fine leads, which I need to connect to a 9V battery holder.  Wire nuts usually bind wires of similar thicknesses.  I could solder the wires together and then wire nut the joint to nget an insulated, physically strong connection.

12VDC Harwin Pin Style Connector Cable

I have a Harwon type 6 pin female to female cable to connect the controller to the stepper motor.   What I am still trying to find is a cable that let's me plug into the two 12VDC pins on that cable and connect the other end to a battery source.  I will likely a 9V battery pack to see if this enough power for my application.   Is there some magic dimensions that identify it as compatible with the Harwin cable pin spacing?

Stepper Motor

I have reached the point where I am starting to fiddle with a stepper motor and controller.  The stepper motor has four inputs.  The controller has six outputs, of which two are DC- and DC+.  It appears that the four conductor cable from the motor goes on the four connectors that are not DC- or DC+.

There are 2 pin DC cables on Amazon that would be seem to fit except that I do nor think there is room to fit the 4 pin connector there as well.  There must be a six pin connector that connects the motor cable and a two pin DC connector.   Any ideas?

Climate Change

"Sun stones and the darkened sun: Neolithic miniature art from the island of Bornholm, Denmark" Antiquity 1/16/25

This article looks at the discovery of a large number of ca. 3900 BC stones with Sun representations and ties their sudden appearance and then disappeared from the record to a 3900 BC volcanic eruption that causes dramatic cooling.  No Sun  requires actions to bring it back.

Learning to Machine?

 When I received my mill, it included some "hold down" clamps.  Why would I use these when the mill came with a milling vise?  Below is an example of a workpiece that wll never fit into a milling vise that fits on the table.  It is a 6" x 6" x .5" piece of carbon fiber composite.

  The carbide endmill is cutting 1" x 1" squares, .001" per pass at 25 inches/minute.  The hold downs are clamping the workpiece to the mill's table.  You need to square the back of the workpiece to the back of the mill table to get square cuts.  This is easier than it sounds.  I can easily feel a discrepancy of .003".

G2 Code for Arcs and Circles

 I have been battling gCode's fairly complex scheme for turning arcs and cirxcles.  This bash script produces gCode to cut a circle centered in a biounding box specified byn the first four values, starting at z cutting circles at specified step size at the specified feed rate for a hole of specified size and mill diamete.  There are a lot of intermediate steps there m ostly for debugging but likely useful for understanding the process.

#!/bin/bash

# Cut an interior circle starting at xStartBB yStartBB xEndBB yEndBB zStart zStep zEnd feedRate holeDiameter endMillDiameter

# BB is short for BoundingBox

if [ "$#" -eq 0 ];

    then echo "$0 xBB yBB xEndBB yEndBB zStart stepZ endZ feedRate holeDiameter endMillDiameter"

else

xStartBB=$1

yStartBB=$2

xEndBB=$3

yEndBB=$4

startZ=$5

stepZ=$6

endZ=$7

feedRate=$8

holeDiameter=$9

endMillDiameter=${10}

millRadius=`echo "$endMillDiameter/2"|bc -l`

# Calculate starting cut points

echo $xEndBB $xStartBB $holeDiameter

center=`echo "(($xEndBB-$xStartBB)/2)"|bc -l`

offset=`echo "((($xEndBB-$xStartBB)-($holeDiameter))/2)"|bc -l`

        startXCut=`echo "$xStartBB+$offset+$millRadius"|bc -l`

startYCut=`echo "($yEndBB-$yStartBB)/2"|bc -l`

endYCut=$startYCut

endXCut=`echo "$yEndBB - $offset - $millRadius"|bc -l`

# calculate radius for i

i=`echo "($center-$startXCut)"|bc -l`

cat prolog.nc >rotate.nc

echo "g1 z1.0 f$feedRate" >>rotate.nc

echo "g1 x$startXCut y$startYCut f$feedRate" >>rotate.nc

echo "g1 z$startZ y$startYCut f$feedRate" >>rotate.nc

newstartZ=`echo "$startZ+$stepZ"|bc -l`

for curZ in `seq $newstartZ $stepZ $endZ`

do

    echo "g1 z$curZ f$feedRate" >>rotate.nc

    echo "g2 x$endXCut y$endYCut i$i j0 f$feedRate" >>rotate.nc

    echo "x$startXCut y$startYCut j0 i-$i" >>rotate.nc

done

echo "g1 z1.0 f$feedRate" >>rotate.nc

cat epilog.nc >>rotate.nc

fi

The two external files are prolog.nc

%

g17 g20 g54

and epilog.nc

 m2

%