Lapping Tools - GE Baker Hughes 2900-40 Series Maintenance Manual

XXIII. Maintenance Tools and Supplies (Cont.)
C. Lapping Tools
The following tools are required for proper maintenance of
Pilot Operated Safety Relief Valve metal seats, and may be
purchased from BHGE.
1. Ring Lap: The ring lap is used for lapping the disc seat and
finish lapping of the nozzle seat.
2. Lapping Plate: The lapping plate is used for reconditioning
the ring lap. It may also be used for lapping the disc. One
11" (279.40 mm) diameter plate is required for the entire
line of valves (Part No. 0439004).
3. Lapping Compound: Lapping compound is used as
a cutting medium when lapping the valve seats, as
specified in Table 14.
Table 14: Lapping Compound Types
Brand Grade Grit
Clover 1A 320
Clover 3A 500
- 1000
Kwik-Ak-
Shun
4. Drift Pins: Two drift pins are required for the removal of
the disc from the disc holder. Refer to Figure 59 and Table
15 for Drift Pin specifications.
Orifice
D
E
F
G
H
J
K
M
N
P
Q
R
T
Note 1: Ring Laps: One set of three (3) ring laps is recommended for each orifice to assure ample
64 | BHGE
Lapping Size Part
Function Container No.
General 4 oz 199-3
Finishing 4 oz 199-4
Polishing 1 lb 199-11
2 lb 199-12
Table 16: Nozzle Lap Dimensions
Nozzle Bore
min.
in mm
.404 10.26
.539 13.69
.674 17.12
.863 21.92
1.078 27.38
1.380 35.05
1.650 41.91
2.309 58.65
2.535 64.39
3.073 78.05
4.045 102.74
4.867 123.62
6.037 153.34
flat laps are available at all times.
Figure 59: Drift Pin Specifications
Orifice
D, E, F, G, H, J, K
L, M, N, P
Q, R
T
5. Nozzle Lap: The nozzle lap is used for lapping the nozzle
seat and has one flat side and one side with a 5° angle.
This lap guides in the bore of the nozzle; therefore, a
different size lap is required for each valve orifice (Table
16).
6. Lifting Tools: Lifting tools are used for the removal of
upper internal parts of larger valves, as specified in Table
17.
Nozzle
max.
Lap
in mm
.409 10.39 4451501
.544 13.82 4451502
.679 17.25 4451503
.868 22.05 4451504
1.083 27.51 4451505
1.385 35.18 4451506
1.655 42.04 4451507
2.314 58.78 4451602
2.540 64.52 4451603
3.078 78.18 4451604
4.050 102.87 4451605
4.872 123.75 4451606
6.043 153.49 4451607
A
B Diameter
45°
Table 15: Drift Pin Types
A B
in. mm in. mm
1.75 44.5 .219 5.55
2.50 63.5 .375 9.53
3.00 76.2 .625 15.88
3.50 88.9 .875 22.23
Nozzle
Lap Ring Lap 1
Handle
544603 1672805
544601 1672805
544601 1672805
544601 1672805
544601 1672805
544601 1672805
544601 1672807
544601 1672809
544601 1672809
544602 1672810
544602 1672812
544602 1672812
544602 1672813
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