|
MACHINING OPERATIONS, (CONT.)
Drilling
Drilling niobium and its alloys is
accomplished using standard high-speed drills. It is necessary
to check the peripheral lands of the drill often for excessive
wear; this will prevent drilling undersized holes. A rigid
setup and good drill design will give the best results. Operating
recommendations for drilling niobium and its alloys are listed
in Tables 11 Ð 14.
TABLE 11: DRILLING OF NIOBIUM
| |
|
FEED
|
| |
|
ipr
|
| TOOL
|
SPEED
|
(mm/r)
|
| |
|
Nominal
Hole Diameter |
| AISI
or C |
fpm
|
1/16
in |
1/8
in |
1/4
in |
1/2
in |
3/4
in |
1
in |
1-1/2
in |
2
in |
| (ISO)
|
(mm/min)
|
(1.5mm)
|
(3mm)
|
(6mm)
|
(12mm)
|
(18mm)
|
(25mm)
|
(35mm)
|
(50mm)
|
| T15,
M42 |
50
|
0.001
|
---
|
---
|
---
|
---
|
---
|
---
|
---
|
| T15,
M42 |
80
|
---
|
0.003
|
0.005
|
0.007
|
---
|
---
|
---
|
---
|
| (S9,
S11) |
(15)
|
(.025)
|
---
|
---
|
---
|
---
|
---
|
---
|
---
|
| (S9,
S11) |
(24)
|
---
|
(.075)
|
(0.13)
|
(0.18)
|
---
|
---
|
---
|
---
|
TABLE 12: TAPPING OF NIOBIUM
| |
SPEED
|
| TOOL
|
fpm
(m/min) |
| MATERIAL
|
Threads
per inch |
| |
7
or less |
8-15
|
16-24
|
over
24 |
| AISI
|
(Pitch
— mm) |
| (ISO)
|
(over
3) |
(1.5-3)
|
(1-1.5)
|
(1
or less) |
| M10,
M7, M1 |
3
|
7
|
9
|
10
|
| (S2,
S3) |
(0.9)
|
(2.1)
|
(2.7)
|
(3.0)
|
Six of Eleven 1
2 3
4 5
6 7 8
9 10
11
|
