wefalck

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Thanks, gentlemen, for the encouraging comments 
 
**********
 
Milling the trunnion seats and the lock
For drilling holes for the trunnions and milling the seat of the lock the diving head was set up on the slide-rest. I could have done this operation on the milling machine, but on the lathe the dividing head (http://www.maritima-et-mechanika.org/tools/dividinghead/dividinghead.html) is centred automatically. The outer end of the barrel was supported by the arm with an appropriate centre fitted. The resulting shape from the milling operation looks like a keyhole, but something like a mushroom shape with sharp edges is required. This was achieved by hand filing.
 

Set-up showing for milling the seat for the lock
 

Close-up of the milling operation in the dividing head with support
 

Working drawing and files used to finish the lock seat
 
For the next operation the set-up had to be transferred to the mill anyway: milling the seats for the square trunnions. The trunnions merge in a concave curve with the barrel. The trunnions were turned up on the lathe as disk with two round stubs protruding from either end. In the dividing head on the mill the disk was milled square to the size of the seat (or rather the other way round). These parts then were soft-soldered to the barrel. Back on the mill the concave curves of the square part of the trunnion were milled using a miniature ball-head cutter, rotating the barrel in the dividing head.
 

Milling the square part of the trunnions
 

Milling the seat for the trunnions
 

Trying the trunnion
 

Milling the concave transition between trunnion and barrel
 
Aiming a gun in these days was a rather primitive affair, using just simple sights. The sights (two of them on either side of the barrel) consisted essentially of a round bar with a sliding rod to give the elevation. The beads (mounted near the trunnions) were observed through a ring of inverted U-shape on top of the rod. The bar was screwed into a notch in the barrel. Now, drilling into a round at a tangent is nearly impossible without deflection and breaking the drill (0.3 mm!). Therefore, I ground flat a broken drill bit to make a make-shift micro-mill and sunk a start hole. This was finished with an ordinary drill.
 

Milling the seat for the sights
 

Drilling the seats for the sights
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Thanks, gentlemen, for the encouraging comments 
 
**********
 
Milling the trunnion seats and the lock
For drilling holes for the trunnions and milling the seat of the lock the diving head was set up on the slide-rest. I could have done this operation on the milling machine, but on the lathe the dividing head (http://www.maritima-et-mechanika.org/tools/dividinghead/dividinghead.html) is centred automatically. The outer end of the barrel was supported by the arm with an appropriate centre fitted. The resulting shape from the milling operation looks like a keyhole, but something like a mushroom shape with sharp edges is required. This was achieved by hand filing.
 

Set-up showing for milling the seat for the lock
 

Close-up of the milling operation in the dividing head with support
 

Working drawing and files used to finish the lock seat
 
For the next operation the set-up had to be transferred to the mill anyway: milling the seats for the square trunnions. The trunnions merge in a concave curve with the barrel. The trunnions were turned up on the lathe as disk with two round stubs protruding from either end. In the dividing head on the mill the disk was milled square to the size of the seat (or rather the other way round). These parts then were soft-soldered to the barrel. Back on the mill the concave curves of the square part of the trunnion were milled using a miniature ball-head cutter, rotating the barrel in the dividing head.
 

Milling the square part of the trunnions
 

Milling the seat for the trunnions
 

Trying the trunnion
 

Milling the concave transition between trunnion and barrel
 
Aiming a gun in these days was a rather primitive affair, using just simple sights. The sights (two of them on either side of the barrel) consisted essentially of a round bar with a sliding rod to give the elevation. The beads (mounted near the trunnions) were observed through a ring of inverted U-shape on top of the rod. The bar was screwed into a notch in the barrel. Now, drilling into a round at a tangent is nearly impossible without deflection and breaking the drill (0.3 mm!). Therefore, I ground flat a broken drill bit to make a make-shift micro-mill and sunk a start hole. This was finished with an ordinary drill.
 

Milling the seat for the sights
 

Drilling the seats for the sights
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Thanks, gentlemen, for the encouraging comments 
 
**********
 
Milling the trunnion seats and the lock
For drilling holes for the trunnions and milling the seat of the lock the diving head was set up on the slide-rest. I could have done this operation on the milling machine, but on the lathe the dividing head (http://www.maritima-et-mechanika.org/tools/dividinghead/dividinghead.html) is centred automatically. The outer end of the barrel was supported by the arm with an appropriate centre fitted. The resulting shape from the milling operation looks like a keyhole, but something like a mushroom shape with sharp edges is required. This was achieved by hand filing.
 

Set-up showing for milling the seat for the lock
 

Close-up of the milling operation in the dividing head with support
 

Working drawing and files used to finish the lock seat
 
For the next operation the set-up had to be transferred to the mill anyway: milling the seats for the square trunnions. The trunnions merge in a concave curve with the barrel. The trunnions were turned up on the lathe as disk with two round stubs protruding from either end. In the dividing head on the mill the disk was milled square to the size of the seat (or rather the other way round). These parts then were soft-soldered to the barrel. Back on the mill the concave curves of the square part of the trunnion were milled using a miniature ball-head cutter, rotating the barrel in the dividing head.
 

Milling the square part of the trunnions
 

Milling the seat for the trunnions
 

Trying the trunnion
 

Milling the concave transition between trunnion and barrel
 
Aiming a gun in these days was a rather primitive affair, using just simple sights. The sights (two of them on either side of the barrel) consisted essentially of a round bar with a sliding rod to give the elevation. The beads (mounted near the trunnions) were observed through a ring of inverted U-shape on top of the rod. The bar was screwed into a notch in the barrel. Now, drilling into a round at a tangent is nearly impossible without deflection and breaking the drill (0.3 mm!). Therefore, I ground flat a broken drill bit to make a make-shift micro-mill and sunk a start hole. This was finished with an ordinary drill.
 

Milling the seat for the sights
 

Drilling the seats for the sights
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

Thanks, gentlemen, for the encouraging comments 
 
**********
 
Milling the trunnion seats and the lock
For drilling holes for the trunnions and milling the seat of the lock the diving head was set up on the slide-rest. I could have done this operation on the milling machine, but on the lathe the dividing head (http://www.maritima-et-mechanika.org/tools/dividinghead/dividinghead.html) is centred automatically. The outer end of the barrel was supported by the arm with an appropriate centre fitted. The resulting shape from the milling operation looks like a keyhole, but something like a mushroom shape with sharp edges is required. This was achieved by hand filing.
 

Set-up showing for milling the seat for the lock
 

Close-up of the milling operation in the dividing head with support
 

Working drawing and files used to finish the lock seat
 
For the next operation the set-up had to be transferred to the mill anyway: milling the seats for the square trunnions. The trunnions merge in a concave curve with the barrel. The trunnions were turned up on the lathe as disk with two round stubs protruding from either end. In the dividing head on the mill the disk was milled square to the size of the seat (or rather the other way round). These parts then were soft-soldered to the barrel. Back on the mill the concave curves of the square part of the trunnion were milled using a miniature ball-head cutter, rotating the barrel in the dividing head.
 

Milling the square part of the trunnions
 

Milling the seat for the trunnions
 

Trying the trunnion
 

Milling the concave transition between trunnion and barrel
 
Aiming a gun in these days was a rather primitive affair, using just simple sights. The sights (two of them on either side of the barrel) consisted essentially of a round bar with a sliding rod to give the elevation. The beads (mounted near the trunnions) were observed through a ring of inverted U-shape on top of the rod. The bar was screwed into a notch in the barrel. Now, drilling into a round at a tangent is nearly impossible without deflection and breaking the drill (0.3 mm!). Therefore, I ground flat a broken drill bit to make a make-shift micro-mill and sunk a start hole. This was finished with an ordinary drill.
 

Milling the seat for the sights
 

Drilling the seats for the sights
 
To be continued ...

And the show goes on ...
 
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The gun barrel and lock
Turning the barrel
Because there will various visible areas of bare metal, the material of the original, that is steel, was chosen.  A piece of round bar was faced, centred and rough drilled for the bore. This hole served as a protective counter bore for the tailstock centre during the following turning operations. In order to get a good finish the automatic longitudinal feed for the lathe was set up with the change gears. Unfortunately the minimum feed per revolution on the watchmaking lathe is still too high to get a 'mirror' finish. One day I have to construct some sort of reduction gear. The outer part of the barrel has a slight taper (1 degree included angle) and the top-slide was off-set accordingly for this operation.
 

Facing and centring a piece of steel rod for the gun barrel
 

Rough drilling of the gun barrel
 

Turning the barrel using the automatic fine feed
 

Taper-turning with slide rest off-set
 
For rounding off the ends of the rings the lathe’s hand tool rest came to good use. The work was finished off with fine wet-and-dry paper (remember to cover ways!) and steel wool. The bore was bored to diameter using the slide-rest and a micro-boring tool. I had originally envisaged to also show the rifling, but a quick calculation told me that for a 1 mm bore and 72 rifled fields I would need a tool edge tha is just over 0.04 mm wide ...
 

Rounding the 'rings' using a hand turning rest
 

Boring the barrel using a micro boring tool
 
To be continued ...

The 30.5 cm Rk/l22 gun
 
The main armament of the WESPE-Class was a massive 30.5 cm (12”) Krupp breech-loading rifled gun (Ringkanone, abrev. Rk). This caliber stayed the bigges in the German Imperial Navy for many decades and well into the Dreadnought-era. It is this gun that essentailly made the boats in floating batteries, rather than ‘real’ ships.
 
http://www.dreadnoughtproject.org)
 
A few years ago a detailed dtawing of gun-mount originating in the adminralty archives in Berlin surfaced on the site ‘dreadnought’. The arrangements for all the heavy Krupp guns of the time were similar, so that a visit to the Finnish fortress Suomenlinna (http://www.maritima-et-mechanika.org/maritime/models/wespe/suomenlinna/suomenlinna.html) off Helsinki was helpful; here a number of Russian clones of 28 cm coastal Krupp guns are still in place since the time, when Finnland was part of the Russian Empire.
 

28 cm Krupp-clone coastal guns in the Suomenlinna-fortress off Helsinki
 
Rails for the Lower Carriage
The lower carriage of the gun is supported on four races that run on semicirucular cast-iron rails bolted to the deck inside the barbette.
These rails need to go into their place in the barbette early during the construction. The same applies to the semi-circular toothed rack that is part of the gun-training machinery. I decided to make the rails from steel, even though ferrous metals in model construction are frowned upon by many. My justifications were that it is difficult to represent cast iron or steel by paint and that there hundreds of models in museums around the world that contain iron. I have used steel in models some twenty years ago and presumably due to the lacquering they shows no signs of rust.
 

Roughing out the rails from a metal disc with the backing of a wooden disc
 

Grooving the races with a specially ground bit
 
Cutting thin disks from round stock of large diameter is a pain I wanted to avoid. Against my better knowledge I picked a suitably sized steel washer as starting material. Unfortunately, the steel used did not machine very well and lot effort was spent to avoid chatter marks while turning and to obtain a reasonably good finish. The various types of wheel collets and chucks available for the watchmaking lathe came into good use for working on inside and outside diameters of these discs. The rails were shaped using a specially ground forming tool.
 

Cutting out the inside of the large ring for the tail-races of the lower carriage, while holding it in a so-called bezel-chuck
 

Trimming the outside of the smaller forward ring holding the material in a so-called wheel-chuck
 

The rails laid out in the barbette
 
To be continued ...

Engine-room skylight
 
The frame of the engine room skylight consists of a an etched brass part, folded up and soldered together. On the inside, grooves have been etched that will serve to locate the protective bars to made from thin copper wire. The lower frame was constructed from Pertinax. The ‘wooden’ gratings on both sides of the lower frame are again etched parts.
 

Unglazed framework for the engine-room skylight
 
Once this structure was complete, a square block of the size of the footprint of the skylight was milled from a piece of Plexiglas.
 

Squaring up a Plexiglas block for the skylight
 
In the next step the roof-shaped faces were milled on. To this end, a small insert vice was set to the appropriate angle of 40° in a larger vice bolted to the mill table. The fixed jaw of the insert vice pointed upward and the side of the block to be milled rested against it. This ensured that all four inclined faces would have the same angle and would start from the same height with respect to the reference (bottom) face of the block.
 

Milling the sloping faces
 

Polishing the sloping faces  
 
A very smooth surface with little tool marks can be achieved on Plexiglas. The final polishing of the surfaces was done using CRATEX-type drum polishers followed by a felt drum loaded with polishing paste. All in the same vice setting to ensure a flat surface. I was lucky the Plexiglas 'house' fitted like a plug into the skylight frame.
 

Finished Plexiglas 'glazing' block
 

Glazed engine room skylight
 
To be continued ...

Thanks 
 
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Skylights, Companionways etc.   I have used two basic techniques for the construction of skylights, companioways etc., depending of the type and purpose. Skylights particularly were constructed around small blocks of Plexiglas milled to shape. Other types were constructed from strips of Pertinax. More intricate parts were etched from brass. For some of the skylights a combination of the techniques were used.   Etched parts for skylights   Boiler-room skylight The prototype construction of the boiler-room skylight is not completely clear from the drawings I had, so that I had to 'fudge' it a bit. First the central piece that supports the chimney was shaped from a piece of Plexiglas. The PROXXON drilling machine was abused as a milling machine to this end: a diamond-cut milling bit was taken up into a collet and the height of the machine set so that the bit reached just below the table. Now the Plexiglas part was passed free-hand along the mill. The form to be cut out was printed on a piece of paper that was stuck to the Plexiglas. It was tested against the shape of the etched grilles in order ensure a snug fit. The box around the skylight was constructed again from Pertinax.   Shaping a Plexiglas-core for the boiler-room skylight   The assembled boiler-room skylight   To be continued ...

Yes, the squares on the cutting mat are 10 x 10 mm ...
 
*******
 
Anchor capstan
One component that always has puzzled me somewhat as to their manufacture in a model has been the sprocket on capstans. While the geometry on horizontal windlasses is quite simple, with suitable depressions for the chain links around the circumference, the sprocket on a capstan is a complex affair. In any case the capstan head cannot be manufactured in one piece. So I broke it down into three pieces: the spill head, the sprocket and the base drum with the pawls. The whole capstan has more pieces including four guiding rollers and a finger to pull the chain off the sprocket. The cast base on the prototype will be reproduced as a surface-etched part.
 

Milling the sprocket, 1st step
 

Milling the sprocket, 2nd step
 
The sprocket started out as a 2.5 mm brass rod taken into the dividing head and five notches were milled to produce something like a five-pointed star (these sprockets typically have five or six arms). The notches for the horizontal links were cut on the lathe with a forming tool. The sprocket then was faced and drilled to fit onto the capstan stem. The next step is cutting it off. This produces some burrs that need to be taken off. Luckily I have collected over the years almost every type of work-holding device that was ever made for the watchmakers lathe. Here the insert jewel chucks came handy to hold the 2.2 mm by 0.6 mm sprocket for facing-off.
 

Cutting with a forming tool
 

Facing-off the sprocket in a jewel chuck
 
The capstan head is a simple turning job. The curved surfaces are pre-cut with appropriate lathe tools and then finished with very fine files. Incidentally, the implement shown on the appropriate picture is a rare miniature micrometer, also coming from the watchmakers toolbox and very handy for measuring narrow recesses and the likes. They came in sets of three, the other two are a depth-micrometer and one for measuring the width of notches respectively.
Finally, the three parts are soft-soldered together.
 

Assembled capstan head
 
To be continued ...

The base for the double bollards were intended to be a surface-etched parts, but I was not happy with the results I produced in my simple home-etching arrangement. So I decided to make them from solid brass. Solid brass was easier to handle for machining than brass sheet. Nevertheless the envisaged machining operations prompted me to make a couple of gadgets, fixtures, for the mill and the lathe.
 

Drilling of the bollard-bases in the work-holding block
 
Milling around the edges or on top of flat material always presents work-holding problems. Worse, if several identical parts have to be produced. Hence I divined a work-holding block with several clamps and stops running in a T-slot.
 

Milling a bevel to the bollard-bases
 
Similarly holding small parts for cutting off on the circular saw is tricky and best done on the lathe with a special saw table clamped to the top-slide. This saw table allows parts to be safely clamped down for cutting.
 

Cutting-off individual bollard-bases
 

The three parts for each bollard (apologies for the poor picture)
 
The three parts of each bollards were soft-soldered together.
 

Work-holding for soldering
 

The finished bollards on the top-left (the other parts will be discussed later)
 
To be continued ...

Deck Fittings
The hull taking shape, at least in its rough outline, I turned my attention to some pieces of deck fittings. I know, many modellers more or less complete the hulls etc. including the paintwork first, but as many pieces may require repeated handling and fitting on the hull, I leave these finishing touches to the end.
 
Bollards
The ships were fitted with four pairs of bollards of square cross section; two at the rear and two on the raised quarterdeck. Luckily a good, rather close-up photograph of the real specimen is available.
 

Rear deck with emergency steering stand and other pieces of deck fittings
 
The bollards are milled from round brass stock. Round stock was chosen as a starting point rather than e.g. flat stock, because it can be held easily in the lathe for turning on a spigot, by which the part can be held for further machining. Otherwise it would be difficult to mount such a small part on the miller for machining on five sides. The spigot is a convenient reference for machining and for fastening the part on the model eventually.
 

Indexing head on the milling machine
 

Before the milling operations
 
From the lathe the raw part is transferred to an indexing head mounted on the milling machine. After each pass with the cutting tool, the part is turned by 90º or 180º depending on requirements. Thus a square and symmetric part is produced.
 

Milling nearly completed
 
For a final machining step, the part is transferred back to the lathe and the dome shaped head formed using a very fine file on a roller-filing rest.
 

The nearly finished bollard with the roller-filing rest in the foreground
 
The job is completed by rounding off the corners using a not-too-hard rubber-bonded abrasive wheel (CRATEX) in the mini-drill. Remaining machining burrs are removed by offering the part to wire brush wheel.
 

The bollards on part of the working drawing
 
To be continued with the bases for the bollards ...

The Barbette for the 30.5 cm Gun
The barbette mainly consists of a semi-circular breastwork armour, backed by hardwood and by an open space covered with thin plate. The latter presumably to retain splintering wood in case of an impact. Since no tube of suitable dimensions for the breastwork was to hand, I made a short, laminated one from Bristol board layers glued together with white glue. The edges were soaked in thinned white glue before being trimmed down on the lathe. The tube then was varnished with wood-filler before the edges were sanded. Finally the tube was cut into half on the fret-saw. More wood-filler was applied before final sanding. The other inside wall of the barbette were lined with Pertinax to provide a smooth surface.
 

Trimming the laminated tube on the lathe
 
The fore-deck has been covered in a sheet of thin Bristol board and the camber of the wooden decking built up with an additional piece of board and putty (I am using fast drying bodywork putty from car repair suppliers). The anchor pockets have also been lined with thin Bristol board, but Pertinax would have been better for this.
 

Tube for the barbette armour made from laminated Bristol board
 
All surfaces that would have been iron plating, will be covered in thin sheets of Pertinax. The necessary holes for portholes and other opening will be drilled or cut before the sheets are fixed.
In between, I had also improvised a disc-sander from a PROXXON router. In think in the meantime this manufacturer offers a small disc-sander.
 

Smoothing the hull on the newly constructed disc sander
 
To be continued ...

@Tadheus, thank you very much for your efforts ! However, could you please check on my Web-site first, before posting a link, whether the picture you found has not been already published there. These pictures are all well-known to me and I may want to use them later to illustrate specific points.
 
*******
 
And off we go with the actual model construction ...
 
Materials
 
I had been contemplating a variety of materials for the hull; for instance Plexiglas® layers with bulwarks made from brass foil. In the end, I choose MDF (medium-density fibre) board, which is available in thicknesses down to 1 mm from architectural model supply houses. Other parts will be constructed from or covered with Bristol board, which is also available in various thicknesses (or rather weights per square metre). The bulwarks etc.. will be made from Pertinax® (phenolic resin impregnated paper, FR-2), which is available in thicknesses down to 0.1 mm. Bristol board and Pertinax® are easily cut with a scalpel, a razor blade or scissors and will not crease or dent as metal foil might. I currently have no facilities for photo-etching large parts, but if I had, perhaps I would have made the bulwarks from brass still. The other advantage is that Bristol board can be readily and permanently glued using white glue. Bonds between large areas of metal foil and Plexiglas® might become detached. Pertinax® can be glued using cyano-acrylate or epoxy-resins.
While I have been shying away from thermoplastics, such as polystyrene, on account of it being suspicious to be not ‘permanent’, practical experience shows that my plastic models built over 40 years ago are still intact. So I may reconsider my position in this respect. Polystyrene, of course, has several advantageous properties. One has to be sure, however, that it is properly painted to exclude the deteriorating UV-radiation.
 
The hull and superstructures
 
The basic bread-and-butter construction of the hull is shown in the pictures below.
 

Cutting out layers for the hull
 

Using the drill press as a makeshift disc sander (I have since constructed one)
 

Using the drill press as an improvised miniature drum sander
 

The layers of the hull with the barbette and the anchor-pockets cut out
 

Milling a recess into which later the rubbing strake will be inserted
 
To be continued ...