Bench Grinders & Polishers
Last updated on Tuesday, September 19, 2023 08:44:48 PM Mountain US Time Zone

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Bench Grinder, Grinder Chuck,
Polishers, Jigs, Pedestal Feet,
Wheel Dressers, Diamond Carbide Grinder,
2x42-inch Belt 6-inch Disk Combo Sander

WARNING: Grinders are Dangerous. Grinding wheels
can break apart while turning at high speeds.
Always use appropriate eye, breathing &
clothing protection. Read, understand &
follow all of the manufacturer's instructions.
Dust from grinding tool bits is dangerous if inhaled.

Never use a taper-mounted chuck without a
drawbar if side forces are being applied.
Side forces can cause a taper-mounted chuck to loosen &
spin-off at dangerously high speeds causing injury. 

Always wear ANSI (Z87.1) approved safety eye protection,
breathing protection, & gloves during machine & tool use.
Refer to the Material Safety Data Sheet, or MSDS, for
info regarding the properties of a particular substance.

See Tool Post Grinder Section.

Bench Grinder

Stock bench grinders can be modified to make them
more useful for tool bit grinding & general shop use.
Often, a grinding wheel has a 1" hole but is used on a
1/2" shaft & is usually adapted using concentric plastic
spacer rings. Took a 1.000" aluminum dowel, centered it
in the 9x20 4-jaw, faced it, centered drilled, then drilled a
31/64" hole. Chamfer the opening & then used a well-
lubricated 0.500" reamer at the lowest RPM. When the
reamer is all the way through, stopped turning the part &
then withdrew it to keep a tight tolerance. The spacer is a
tight, concentric fit to both the wheel & the grinder shaft.
The wheel is now held very precisely on the grinder. As
needed, use a star dresser followed by a carborundum
dressing stick to make the surface smooth.


Aluminum shaft spacer for grinding wheel
(1.000" OD,  0.500" ID, about 0.75" long).
Note: left-hand nut & thread on the left side of the grinder.

The next mod was the tool rest. Most grinders
have inadequate rests & mine was no different.
Replaced it with the Veritas tool rest (tool rest manual).
It is a great improvement over the OEM rest. 
It has a wide range of adjustment. Its best feature
is the 1/2" x 1/2" channel on the tool rest platform
that is used to guide jigs. There are several jigs
available but custom jigs may be fabricated to suit
any need. Shown is a jig that allows me to precisely
grind tool bits at 60 deg for threading. The rest
mounts onto the bench. Tapped holes into the
grinder mounting plate & used 1/4-20 socket head
cap screws with nylon washers. Note the 1/2" x 1/2"
channel to guide jigs. The rest's center hole is for
(Veritas) pivoting jigs. The locking handles can
be pulled & rotated to any detent position.

WARNING: DO NOT permanently remove the
shrouds that covers the grinding wheel stone.

Grinder Chuck



Measuring total indicated runout (TIR)
of the chuck using a dowel pin.

My Father, a civilain aircraft mechanic for the USAF at WPAFB,
always had a bench motor with an adapted, keyed drill chuck.
One of the most useful modifications is to mount a
drill chuck onto right-hand side of a modern grinder motor.
A taper-mounted chuck is not recommended since sideway
forces could easily cause it to come loose at speed.
The arbors usually have only two, 1/4-28 set screws.
Drilled & tapped for three more set screws (as referenced
 from the center of the pre-existing set screw); one
every 90 deg. Used hardened, USA made set screws.
This set screw arrangement allows adjusting the runout
in the same manner as a 4-jaw chuck.
 Most any keyed chuck can be used. Pictured is a
Jacob's (USA) medium-duty 5/64" to 1/2" chuck.
This example is mounted onto a 1/2-20 threaded
arbor. One could use a keyless chuck
(not recommended) but keyed chucks grip so much
tighter. Hack-sawed the shaft threads off
 to place more motor shaft into the arbor.
Install the drill chuck on the right side of the
 grinder since most accessories (arbors, sanding
drums, etc.) are threaded for that turning direction.
 Use a full-face visor for eye protection. The
reflexive tape is for use with a laser tachometer.

This grinder & its mounting plate were moved off the
bench to make way for the carbide grinder. It is now
on a free-standing, cast-iron pedestal having rubber feet
(manual). A drill-bit sharpener can also be mounted.

Mounted grinding stones.

Polishing wheel with different compounds. A given
wheel should only have one type of compound on it.
White Rouge (White): gives a bright, shiny luster to
stainless steel, aluminum, iron, chrome, & nickel.
Emery Cake (Black): emery abrasive, gives sharp, fast
cutting action to remove scale, rust from iron & steel.
Red Rouge (Red): buffing gold, silver, sterling, platinum,
etc. Increases luster of already buffed surfaces.
Tripoli (Brown): for buffing aluminum, brass, copper,
pewter, bone, plastics, wood, & painted surfaces.

Abrasive disks of varying coarseness that
screw onto the rubber-backed arbor.

Low-cost, all metal drill bit sharpener that uses a bench grinder.
Dress the grinder wheel before use. Grinding attachment manual.

Jigs
 

Top & bottom view of a jig used to grind tool bits for threading.
It is rotated 180 deg to grind both angles.
The guide bar is 1/2" x 1/2" x 2". As an alternative,
use a lower temperature diamond grinder with its miter.

Pedestal Feet

Pedestal foot detail.

Bench Grinder, Grinder Chuck,
Polishers, Jigs, Pedestal Feet,
Wheel Dressers, Diamond Carbide Grinder,
2x42-inch Belt 6-inch Disk Combo Sander

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