Delta 20-330 Instruction Manual page 16

When changing speeds, release belt tension and open
belt and pulley guard cover (D) Fig. 30. Speed rates
of 80, 120, and 200 feet per minute are available with
your band saw. When the belt is on the largest step of
the motor pulley (A) Fig. 30, and the smallest step of
the gear box pulley (B) the blade speed will be 200 feet
per minute. When the belt is on the smallest step of the
motor pulley (A) and the largest step of the gear box
pulley (B) the blade speed will be 80 feet per minute.
When changing speeds, first release belt tension. After
the desired speed is obtained, adjust belt tension and
close belt and pulley guard cover (D).
SPEED AND MATERIAL CHART
Fig. 31 illustrates the correct speeds and the position
of the belt on the motor and gear box pulleys for most
common materials cut on the band saw.
BLADE SELECTION
1. Your band saw uses blades 1/2" wide, 64½" long
and .020-.025 thick. Accessory blades with a pitch
(number of teeth per. inch of the blade) of 10 and 14
are available from Delta.
2. Never use a blade so coarse that less than three
consecutive teeth are engaged in the workpiece at
one time. (Too few teeth will cause the teeth to strip
out).
3. Never use a blade finer than required to obtain a
satisfactory surface finish or satisfactory flatness
(Too many teeth engaged in the workpiece will
prevent attainment of a satisfactory sawing rate;
frequently produce "dished" cuts or cuts which are
neither square or parallel).
4. When thin rectangular solid bar is to be sawed, the
work should, whenever possible, be loaded with the
thinnest cross section exposed to the blade teeth.
The pitch (number of teeth per. inch of the blade)
selected must provide engagement of at least
three consecutive teeth in the workpiece. Should
application of this rule not be possible because the
thinnest cross section is too thin, the piece must
be loaded with the wider dimension exposed to the
saw teeth and a coarser blade selected.
5. When thin wall pipe or tubing or channel iron are
cut, a 14 pitch (number of teeth per inch) blade is
used. Fewer than 14 teeth per inch will almost never
be satisfactory.For standard wall pipe or tubing 10
teeth per inch is satisfactory.
D
A
Material To Be Cut
Tool Steel
Stainless Steel
Alloy Steel
Hard Bronze
Mild Steel
Medium Hard Brass
Medium Hard
Bronze
Soft Brass
Aluminum
Plastic
Other Light
Materials
16 - English
B
C
Fig. 30
Speed Belt Position
Motor Gear
80 FPM Small Large
120 FPM Middle Middle
200 FPM Large Small
Fig. 31