South Bend Tools SB1125, Owner'S Manual, Page: 29 / 56

South Bend Tools
For Machines Mfd. Since 11/21 Model SB1125
-27-
O P E R A T I O N
Calculating Spindle
Speed for Drilling
The chart shown in Figure 35 is intended as
a guide only. Always follow the manufacturer's
speed recommendations if provided with your
drill bits, cutters, or hole saws. Exceeding the
recommended speeds may be dangerous to the
operator or cause damage to the tooling.
The speeds shown here are intended to get you
started. The optimum speed will always depend
on various factors, including tool diameter,
drilling pressure, material hardness, material
quality, and desired finish.
Often, when drilling materials other than wood,
some type of lubrication is necessary.
Lubrication Suggestions
Wood ............................................................... None
Plastics ................................................Soapy Water
Brass .................................Water-Based Lubricant
Aluminum ..................... Paraffin-Based Lubricant
Mild Steel .............................. Oil-Based Lubricant
Figure 35. Drilling speed chart. Figure 35. Drilling speed chart.
Twist/Brad Point Drill Bits Soft Wood Hard Wood Plastic Brass Aluminum Mild Steel
1
⁄
16
" –
3
⁄
16
"
3000 2500 2500 2500 3000 2500
13
⁄
64
" –
3
⁄
8
"
2000 1500 2000 1250 2500 1250
25
⁄
64
" –
5
⁄
8
"
1500 750 1500 750 1500 600
11
⁄
16
" – 1"
750 500 1000 400 1000 350
Spade/Forstner Bits Soft Wood Hard Wood Plastic Brass Aluminum Mild Steel
1
⁄
4
" –
1
⁄
2
"
2000 15000
9
⁄
16
" – 1"
1500 1250
1
1
⁄
8
" – 1
7
⁄
8
"
1000 750
2" – 3"
500 350
Hole Saws Soft Wood Hard Wood Plastic Brass Aluminum Mild Steel
1
⁄
2
" –
7
⁄
8
"
500 500 600 600 600 500
1" – 1
7
⁄
8
"
400 400 500 500 500 400
2" – 2
7
⁄
8
"
300 300 400 400 400 300
3" – 3
7
⁄
8
"
200 200 300 300 300 200
4" – 5"
100 100 200 200 200 100
Rosette Cutters Soft Wood Hard Wood Plastic Brass Aluminum Mild Steel
Carbide Insert Type
350 250
One-Piece Type
1800 500
Tenon/Plug Cutters Soft Wood Hard Wood Plastic Brass Aluminum Mild Steel
3
⁄
8
" –
1
⁄
2
"
1200 1000
5
⁄
8
" – 1"
800 600
Larger bits turning at slower speeds tend to
grab the workpiece aggressively. This can
result in the operator's hand being pulled into
the bit or the workpiece being thrown with
great force. Always clamp the workpiece to
the table to prevent injuries.