3” Allchin Project

Steel Boiler Preparation Prior to Welding

1. Shell

   1. Cut to length

   2. Cut out for firebox

   3. Drill and chamfer two top firebox stay holes

   4. Drill and Tap sightglass hole (or bushes)

   5. Drill hole for steam manifold and weld prep strengthening plate

   6. Drill and bush cylinder steam holes

   7. Drill and tap (or bush) water filler hole

   8. Drill and tap (or bush) injector feed water inlet

   9. Openings into Smokebox (easier to do before welding))

      1. Chimney hole

      2. Holes for two rings of rivets

      3. Perch bracket holes

      4. Blower bush (if not through chimney saddle)

2. Compensation Plate

   1. Drill and tap cylinder holes

3. Smokebox tubeplate

   1. Weld Prep circumference

   2. Drill and ream tubeplate holes

4. Inner Wrapper

   1. Bend to shape

   2. Drill stay holes in sides and top (6)

   3. Chamfer inside of holes

   4. Drill and tap hole for fusible plug

5. Firebox tubeplate

   1. Weld prep top and sides (outer edge)

   2. Drill and ream tubeplate holes

   3. Drill and inside chamfer stay hole

6. Backplate

   1. Cut hole for door ring

   2. Weld prep door ring hole (inside)

   3. Drill and internal chamfer stay hole

7. Backhead

   1. Cut hole for door ring

   2. Weld Prep door hole (outer edge)

   3. Weld prep sides, bottom and curved top of backhead (outer edge)

   4. Drill and external chamfer stay hole

   5. Drill and tap 4 steam ports plus sightglass holes

8. ThroatPlate

   1. Weld prep bottom and curved top (outer edge)

   2. Drill and chamfer stay hole (outside)

   3. Drill and tap IP holes

9. Right Side Outer Wrapper

   1. Weld prep top, bottom and front edges (outside)

   2. Drill and external chamfer 2 stay holes

   3. Drill and tap any IP or drain holes

10. Left Side Outer Wrapper

    1. Weld prep top, bottom and front edge (outside)

    2. Drill and external chamfer 2 stay holes

    3. Drill and tap any IP or drain holes

11. Foundation Ring

    1. Weld prep bottom inside edge

12. Stays

    1. Cut to length

    2. Drill tell-tale holes

13. Firebox door ring

    1. Nil

14. Tubes

    1. Cut to length

    2. Prepare ends

Revised 15 May 2006