Door Latches are falling apart -- upgrade required

[smr547]

My Yacht have latches, check they fit

[smr547]

• Ongoing problem owing to poor design of latch mechanism.
• Latches will be difficult to replace and very costly
• Suggest we treat these as working bee maintenance item and
• Encourage skippers to perform routine maintenance on the latches

[smr547]

Locksmith for a new springs and replace nylon washer between handle and face plate.

[smr547]

Replacement Door locks are available at SVB24

Inventory of doors

1. Port aft cabin door -- DIN LEFT
2. Port aft cabin bathroom door - DIN Right
3. Starboard aft cabin door -- DIN Right
4. Starboard aft cabin bathroom door - DIN Left
5. Saloon/Galley door forward -- DIN Right
6. Shower Room forward - DIN Left
7. Forward heads - DIN Right
8. Forward Starboard Cabin -- DIN Right
9. Forward Port Cabin -- DIN Left

Total of 9 Doors, 4 x DIN LEFT, 5 x DIN RIGHT

9 Replacement locks will cost 1200 euros including shipping #budget=$2000

[smr547]

Assuming all the handles are in tact we could save about $800 by purchasing the lock without handles

[smr547]

Hi @SamMcDonald2538

SVB can supply door latch mechanisms for Euro 54 plus shipping from Germany -- this might be the way to go

See this link

The can also supply the complete lock assembly at about Euro 114. We may need one or two of these to augment any missing/broken parts -- of which there are a few.

I'd also suggest:

1. Replacing several of the grub screws with high quality equivalents -- many have stripped hex slots owing to the use of poorly sized (i.e. Chinese) Alan Keys
2. Use a mill to produce complementary / opposing key-way slots on the brass hand bar. This will allow the grub screw to seat with a positive grip
3. Use "Loctite" to secure the grub screws in place
4. installing the handles in an "opposing" vertical orientation -- this will dramatically reduce the turning moment on the closure spring and extend it's life.

I'm on board at the moment and will prepare an assessment of what we need.

[smr547]

To aid reporting of this problem here is a diagram of the components involved in the lock

Legend

A | Locking Pin -- | -- B | Screw disc C | Face disc D | Mounting plate E | Mounting plate F | Machine screws G | Grub screw H | Handle bar I | Handles J | Washers K | Lock body (Right) L | Lock body (Left) M | Locking spring N | Wood screws @SamMcDonald2538 and @CORCpete will be interested

[smr547]

Summary of problems

Summary of problems with Namadgi's door locks

1. Pins in screw disk (B) have sheared away on all locks (spot welding failure)
2. Handles (I) are too heavy for the spring in the lock body (K)
3. Grub screw (G) all damaged due to use of "cheap" Alan Keys
4. Milled channel in Handle Bar (H) poorly designed -- does not "capture" grub screw adequately
5. Nylon washers missing (J)
6. Lock pin (A) missing on some doors

The good news is that the lock body (K/L) appear to be OK on each door.

I'll do an inventory of each door and work out what needs to be ordered.

Possible repairs

• Replace handles with light-weight cylindrical nob
• Mill Handle Bar (H) grub tracks
• New grub screws
• Spot weld screw posts to mounting disc (B)

@CORCpete @SamMcDonald2538

[smr547]

Failed spot welding on Screw Disk (B)

[smr547]

Milled channel in Handle Bar (H) is inadequate to capture grub screw

[smr547]

Proposed solution:

1. Use existing handle and lock mechanism
2. replace worn grub screws with new s/steel screws -- 5mm OD 6mm long 2.5mm allen key head -- 20 purchased from Industrial Replacement Batemans Bay
3. mill slots in brass handle bar so that grub screws fit snugly -- Industrial Replacement will do the machining for about $200 --- bars are 8mm square brass stock, 67mm long -- required slot 3mm wide and 1mm deep (or 2mm deep with V profile)
4. turn up new washes to replace missing washes - I can do this with my lathe using nylon stock -- 20mm OD, 16mm dia hole, 2mm thick) -16 off
5. remove all security locks -- they are a danger, not an asset -- people should knock if doors are closed
6. reassemble with handles in vertical orientation (see photo) -- this will prevent the doors opening under the weight of the heavy brass handles
7. Replace missing face discs (C) -- 49mm OD, 16.4mm dia central hole, 2mm thick -- machine from brass stock or use stainless steel washers?
8. Ignore broken weld points on screw disk B -- these form no practical purpose except to align the safety release holes for the lock mechanism -- but we are removing the lock so no drama

These repairs should give us another 10 years of life from the latches

@SamMcDonald2538 and @CORCpete will be interested

[smr547]

Some progress notes:

• By aligning the handles vertically each pointing in the same direction (up or down) we can avoid the milling operation (step 3 above)
• The grub screw thread in the handle holes are damaged. I purchased an M5 tap and wrench to clean these out -- locktite will be necessary

We could tighten up the whole latch assembly by by rejoining screw posts to disc B using a machine screw. The screw posts were welded to disc B but have separated. Screw posts are 18.3mm long with a M4 tapped hole to a depth of 16.5mm. Suggest

1. Drilling a hole through the remaining length of the post (2.5mm)
2. Tap this through with a M4 tap to continue the existing thread
3. Drill two 4mm holes in disc B to align with the posts
4. Fix disc B to the posts with 2 x 4mm hex head machine screws (stainless steel)

It's a fiddly job but quite straight forward -- we will eliminate a lot of rattles in the latches

@SamMcDonald2538