Turner’s Cube
1.
Introduction
This
document is intended to explain the manufacturing sequence for a Turner’s
Cube.
Important Notes [RETURN TO TOP]
1.
Material Selection : Use
¾" AL rod from the material rack. Look
for the piece which has been cut to roughly 30" for making the Turner’s
Cube Bases to minimize waste.
2.
Parting Off: Since
a flat base is required and the part is too small to effectively clamp in the
lathe chuck jaws, the part should be parted-off
on the lathe. Review the linked document
and ask questions before you attempt the parting operation.
1.
Measure raw
material to ensure it is suitable for the part
(1.000 ± 0.010")
2.
Cut a piece
of 1" x 1" AL rectangular bar stock roughly 1-1/8" long (± 0.062")
in the bandsaw
3.
Gently debur edges using file
4.
Clamp
workpiece in milling machine using parallels (workpiece surface should extend
roughly 1/4" above top of vise jaws)
a.
NOTE:
Parallels should normally be removed prior to cutting the workpiece, however,
due to the precision required, leave the parallels in the vise
5.
Set part
datum (zero) in Z direction using an 1-1/4"
end mill
a.
Load the 1-1/4"
endmill in a collet (refer to proper rules for changing tools:
machine off; spindle positioned over plastic cover; quill raised and locked in
its upper-most position)
b.
Carefully zero z-axis (~ 800 rpm; remember to adjust speed
with spindle running)
6.
Face
workpiece (~ 800 rpm) by removing as little material as possible (typ. 0.003 –
0.005")
7.
Zero and
face remaining 5 sides
a.
Make each
edge the same length (to within ± 0.003" if possible)
b.
CAUTION:
When using calipers, ensure machine is off and spindle has ceased rotating
8.
Install vise-stop
on rear vise jaw with machine off and use it when clamping part henceforth
9.
Set part
datums (zeros) in X and Y directions using the cylindrical
edge finder
a.
Load the drill
chuck (refer to proper rules for changing tools:
machine off; spindle positioned over plastic cover; quill raised and locked in
its upper-most position)
b.
Load
cylindrical edge finder and adjust to proper spindle speed (~ 1000 rpm)
c.
Zero to
centerline of part along x-axis and y-axis
10. Center drill part (~ 1600 rpm; remember to adjust speed with spindle running)
a.
Drill until about
half of the SMALL cylindrical portion of the center drill is in the part. Stop drilling if the center drill’s chamfer
begins to cut.
11. Drill the Ø0.250" hole thru (~ 800 rpm; remember to adjust speed with spindle running)
a.
Apply oil
and peck drill with pecks approximately equal to the drill radius
12. Center drill and drill the Ø0.250" hole
thru (size: ¼) on remaining two sides
13. Counterbore ¾" holes on all 6 faces
a.
Load the
¾" cbore in a collet (refer to
proper rules for changing tools: machine off; spindle positioned over plastic
cover; quill raised and locked in its upper-most position)
b.
Lower the
depth stop (spring loaded spindle lock) to ~ ¾" without touching part
c.
Carefully zero z-axis with spindle locked against the depth stop (~ 250 rpm;
ask a TA to place the mill in LOW RANGE and remember to rotate
the power switch to LOW RANGE and adjust speed with spindle running)
d.
Raise
spindle fully
e.
Raise Z-axis
the depth of the ¾" cbore (0.188")
f.
Cbore hole using
quill handle, cutting oil, and GENTLE cutting force
g.
Lightly debur
and rotate part to new face and repeat cbore for
remaining faces
14. Counterbore ½" holes on all 6 faces
a.
Load the
½" cbore in a collet (refer to
proper rules for changing tools: machine off; spindle positioned over plastic
cover; quill raised and locked in its upper-most position)
b.
Lower the
depth stop (spring loaded spindle lock) to ~ ¾" without touching part
c.
Carefully zero z-axis with spindle locked against the depth stop (~ 500 rpm;
ask a TA to place the mill back in HI RANGE and adjust speed
with spindle running)
d.
Raise
spindle fully
e.
Raise Z-axis
the depth of the ½" cbore (0.300 - 0.188 = 0.112")
f.
Cbore hole using
quill handle, cutting oil, and GENTLE cutting force
g.
Lightly debur
and rotate part to new face and repeat cbore for
remaining faces
15. Remove the counterbore
from the spindle (refer to proper rules for changing tools: machine
off; spindle positioned over plastic cover; quill raised and locked in its
upper-most position)
16. Remove part from mill vise
17. Lightly debur holes using hand-held
countersink tool
18. Clean up milling machine
a.
Always have
a TA or instructor inspect your machine for cleanliness before leaving
b.
CAUTION:
PLEASE DO NOT wipe off machine guideways (the oil on these surfaces is
essential for proper machine function)
c.
Check
the machine has been returned to HI RANGE, and if not, ask a TA to please do so
for the next student who uses it
Turner’s Cube Base [RETURN TO TOP]
1.
Measure raw
material diameter to ensure it is suitable for the part (Ø0.75 ± 0.020")
2.
Cut a piece
of ¾" diameter AL round bar stock in the bandsaw (if there isn’t a piece
< 30" already on the material rack
3.
Debur edges
using file
4.
Clamp
workpiece in lathe chuck with 2" of material protruding from chuck jaws
a.
CAUTION:
NEVER leave the chuck key in the chuck
5.
Install
turning/facing tool onto tool post
a.
Use the tool
with a silver colored insert (not gold)
b.
Ensure the
tool is aligned vertically with the part centerline using the ruler or lathe
gage
c.
Check for
proper relief angles (~5°) and adjust as necessary
6.
Touch off
and set zeros in X and Z directions
a.
CAUTION:
any time you interact with anything on the left side of the machine (like the
DRO), use your left hand; NEVER reach over the spindle
7.
Face end of
workpiece and re-zero Z axis (~ 600 rpm)
a.
Remove 0.020"
of material using the automatic feed
b.
After removing
the material and before moving the cutting tool away from the part, re-zero the
DRO using your left hand; although not specified as requiring a finished
surface, precise measurements must be made from this surface, so it should be
finished
8.
Finish turn
part OD
9.
Cut chamfer
(~ 600 rpm)
a.
Use the tool
with a silver colored insert (not black or gold)
b.
Gently touch
off on corner to be chamfered and zero the Z-axis
c.
Move 0.030"
along Z-axis
10. Remove chamfer tool
a.
Turn machine
off
b.
Clean and
inspect tool prior to putting it away
11. Center drill hole using tailstock (~ 600 rpm)
a.
Drill until
about half of the SMALL cylindrical portion of the center drill is in the
part. Stop drilling if the center
drill’s chamfer begins to cut.
12. Drill hole thru with ¼" drill to a depth
between 0.568" and 0.630" (~ 600 rpm)
a.
Use oil and
peck drill with pecks equal to the tool radius
b.
Zero the
tailstock when the drill begins to cut at its full diameter
13. Countersink to a diameter of 0.55" using
the special 110° csink tool with the purple stripe (~200
rpm)
a.
Use oil and
peck
b.
CAUTION:
turn the machine off prior to measuring part
14. Part-off workpiece
a.
Begin the
part-off
b.
Stop and
file the back-side chamfer
c.
Complete the
part-off
15. Remove material from lathe chuck (remember to be careful with the chuck key)
16. Debur holes using hand-held countersink tool
17. Clean up lathe
a.
Always have
a TA or instructor inspect your machine for cleanliness before leaving
b.
CAUTION:
DO NOT wipe metal surfaces! Only wipe
painted and plastic surfaces (the oil on the metal surfaces is essential for
proper machine function)
1.
If you
enjoyed making this part, try making one out of brass or titanium.
a.
When cutting
brass, use
the same tools and cutting parameters as aluminum.
b.
When cutting
titanium, use the same drills and counterbore tools, but reduce the speeds by 10X and use the dark thread
cutting oil in the chemical cabinet to resist the higher cutting zone pressures
and temperatures. You should use the 2” indexable facemill in the endmill
cabinet when facing the cube down to size, using a maximum depth cut of 0.020”.
