9x20 Lathe Ball Turners & Knurlers
Last updated on Tuesday, September 19, 2023 04:30:13 PM Mountain US Time Zone

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Ball Turning, Ball-turning Fixture, Material Setup,
Part Removal, Micro Ball Turner, Knurlers, Mini Knurler

Ball Turning

CAUTION: The sphere is very hot after
turning, especially when cutting SS.

Aluminum base, SS cylinder, steel tool bit holder.
Pivots on a bolt with a shoulder. A fabricated
Teflon washer is under the bolt head. The bolt
is held in place with a set screw entering from
the top (centered inside the 1/2" x 1/2" groove). 
High viscous grease increases control during turning.

Ball-turning Fixture

Ball turner with HSS tool bit
holder for aluminum & brass.

Turning a concave contour for a wine stopper.

Material Setup

Set cutter at each end. Keep it close to the
collet or chuck. This is a steel 1/4-20 arbor with a
recess for the tool bit inset. The arbor is held
by an ER-40 collet in a MT3 to ER-40 chuck.


A finished aluminum ball. Sanding & polishing
easily done on the lathe. Stainless steel takes
a lot longer to make but looks & wears great.

Part Removal

After letting it cool, a strap wrench easily
removes the sphere from the 1/4-20 threaded arbor
without marring the finish. This example shows
a completed 1.2" diameter stainless steel sphere.

Micro Ball Turner

Micro-ball turner for the Taig.

Taig ball turner with rounded corners & cap-head screws
replaced with set screws to provide more clearance.

Knurlers

Scissor-type knurler works very well. All the pressure
is in-between the cutters as it floats on the pivot.
 Modified the pivot bolt head & added a lock nut.
The knurlers are held in via friction pins.

Left, right & bottom views shown
as mounted in an AXA tool holder.

Knurling aluminum in the Jet BD-920N
lathe. I knurl at low speeds feeding it
by hand using the rack & pinion.

A standard knurler with interchangeable cutters.
Also holds a tool bit for facing cuts. Really need a rigid machine &
setup for this type of knurler since it exerts high side forces.

An AXA-mount knurler with an indexed, multi-knurler
(fine, medium, coarse) head that allows it to float.

A smaller, clamping-type knurler.
Good for light knurling in soft materials.
The larger scissors-type can exert the
needed higher pressures to form a true,
high-grip, pyramidal pattern.

Replaced pivots with 10-24, 1/4" x 3/4" shoulder
bolts with lock nuts for ease of knurl pair changes.
The two bolt heads on the left have flats milled
into them to engage the steps to prevent rotation.

Exploded view showing how the shoulder-bolt head
has a milled flat that engages the knurler arm recess.
The shoulder is a fraction too long so a
nylon washer is used to take-up the extra length.

Pairs of different patterned knurlers.
Left to right patterns: fine, medium, course, straight.

Mini Knurler

A knurler for the Taig Micro Lathe closely patterned
after the Sherline design, but stronger. Standard-sized
knurls pivot on 1/4" diameter hardened dowel pins.
They are held in place by 10-24 set screws. The pin holes
were precision reamed. Knurl pockets (1" L x 3/8" W x 0.7" D)
were made using a 3/8", 2-flute, carbide end mill.
Used the RF-25 mill with its DRO-350 tool diameter offset
feature. Two, 1/4-20 cap-head cross-bolts easily exert
all the knurling force. The two supports have keys that
ride in a carriage T-slot. 10-32 threaded rods are used
 for the hold-down bolts. First, finger tighten the hold-
down bolts, adjust cross-bolts for desired knurl depth,
 then wrench tighten the hold-down bolts. Turn the spindle
by hand for smaller jobs & use the low, 178 RPM
for larger jobs. Put light pressure on the right to left
carriage travel while knurling. This design exerts all the
pressure in-between the knurling posts, not
on the lathe carriage as some other designs.

Ball Turning, Ball-turning Fixture, Material Setup,
Part Removal, Micro Ball Turner, Knurlers, Mini Knurler

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