Model B1 - Production 20" Diamond Disc Grinder

Model B1 - Production 20" Diamond Disc Grinder

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Variable Vs. Fixed Speed


There are two models. A fixed-speed machine which is set at 1100 RPM, or a variable speed version which is adjustable from 1100 RPM to zero by just turning a knob.

1100 RPM results in a peripheral speed (in the working area on the disc) of 4500 ft/minute, which is the perfect speed for grinding glass. This can easily be changed in the field to accommodate other types of grinding media.

If the machine is going into a production beveling shop and will be used for only a single purpose, a fixed-speed model is probably the best choice.

The variable-speed model is preferable in the following situations:

1. If it is the only grinder in the shop, it should be as versatile as possible.If a polishing pad is to be used on the disc, a slower speed is preferable for polishing.A cold-glass working shop needs the ability to slow the disc for delicate pieces.

2. A lapidary shop prefers different speeds for different materials.

The B1 is designed for heavy production use.The precision-ground, one-inch mounting shaft and flange are solid stainless steel and the 1/2"-thick housing is molded fiberglass so that rust will never be a factor.The shaft ball bearings are oversized, sealed and permanently lubricated. The motor choices are the best available. The fixed-speed motor is a Baldor, with electronic starter. The variable-speed motor is a Magnetek. Its electronic speed control has current limiting to protect the motor and control.The base is 1/8"-thick steel tubing. Every aspect of this grinder is over-designed to create a machine that will last trouble-free.

Disc Size

There are primarily two diamond disc sizes used on the B1, 20" and 16". A production shop that will be grinding a good part of the week should be using 20" discs. If the usage is one day a week or less, then a 16" disc will be adequate unless, of course, the size of the work pieces require a larger disc.

Grit Size

For the rough grinding, an 80 or 100 grit is most popular, and for the smoothing step, a 360 or 600 grit. The 80 and 360 are usually used together, or the 100 and 600. As an economical first step, purchase a single B1 and switch the roughing & smoothing discs. It takes less than 30 seconds to change discs

Flush-Mount Discs

This unique mounting arrangement results in a completely flat grinding surface. This allows use of the total grinding surface without being concerned about the work piece striking a mounting nut. It also makes it very easy to turn the disc upside down so that the new adhesive-backed grinding or polishing pads can be used on the other side.


1. Glastar stocks a very large inventory of diamond discs and pads, polishing pads, natural-quarried stones, man-made stones.

2. An industrial pump is available so that coolant can be circulated over the diamonds which will improve their life by at least 10-15%. The Model B1 has a receptacle with its own on/off switch for the pump.


Drive Shaft
Mounting Diameter 1"
Hold Down Screw 5/8-11 Countersunk Allen Head
Allen Key (Supplied) 3/8"
Material 303 Stainless Steel
Rotation Counter Clockwise
Speed Setting*
Fixed Version 1100 RPM
Variable Version 1100 To Zero RPM
Fixed Speed Motor
Power 1 HP
Electrical @ 60 Hz 115V & 208V-230V
Electrical @ 50 Hz 230V
Speed @ 60 Hz 1725 RPM
Speed @ 50 Hz 1425 RPM
Manufacturer Baldor
Bearings Ball
Variable Speed Motor
Power 1 HP
Electrical @ 50 or 60 Hz 115V or 230V
Speed @ 50 or 60 Hz 1750 To Zero RPM
Type Permanent Magnet
Electronically Controlled
Manufacturer Magnatek
Bearings Ball
Weight 175 Lbs
Size 25 1/2 X 25 1/2 X 37 High
(Excluding Lamp)
*Any maximum speed between 215 and 2300 RPM can be specially ordered or easily changed in the field on either version (approx. 30 min.)