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Replacing a pane in Lewmar Old-Standard Opener

Updated: Oct 14, 2022

So last weekend I thought I’d treat my 1990 Halmatic 30 to some newly machined panes for the Size 1b Lewmar Portlights. Note that there are two versions for this size (and for size 4 too).

For 1b, the centres of the hinge and handle holes are in line; for 1a the hinge holes are slightly inward of the handle hole centre. The new panes are machined on our CNC in 8mm CLEAR cast acrylic (Perspex brand) with the edges beveled after.

Tools needed

The hinge machine screw has a 4mm hex fitting. The hinge inner nut requires a 10mm socket or similar. The handle screw has a large cross head. You will also need a Stanley knife or similar to remove the screw caps. A tub of Vaseline or silicone grease is useful.


Working alone, I found it easiest to remove the window from the inside as you can then get a socket on the inner hinge nut at the same time as the 4mm hex into the outer machine screw.

Mine released easily and were then easy to undo by hand. Take care as you get to the point of final release as there are two washers to catch; one under the machine screw head and the other under the captive nut. Repeat for the other hinge and then remove the pane.

Now is a good time to clean the closing seal and inner frame.

My closing seal was in good reusable condition but was a little green in places so I gave it a good wipe with a cloth and bathroom cleaner.

Back to the pane. You can of course just take a photo with your phone to remind you of the orientation, but I found it as easy to just do one at a time.

The handle screws from the inside into the outer part.

The torque on the screw determines how easy or otherwise the handle moves. To access the screw you need to remove the push fit cover. This requires a very fine blade (I tried screw drivers but these were all to wide). I used the blade of a Stanley Knife to tease up each side until it popped out.

With the cover of you can now unscrew the handle. With the inner handle removed, the outer part pushes through. This has a small rubber O-ring which holds the fitting off the pane. Again, mine were in good condition so I cleaned and reused these but generally we would supply new ones with each pane.

I now cleaned all the handle components as well as the hinge fastenings. My fittings were black plastic (some may be grey) and I was impressed that even the outer fittings didn’t appear to have faded. If yours have, these can be primed and resprayed using the matt paint from PlastiKote; the grey is a very close match to Lewmar original.

Reassembly is straight forward. I recommend putting a whisper of Vaseline or similar on the O’ring but other than that it’s just a case or reversing the process above.

Adjust the torque on the handle screw to ensure they operate correctly.

When tightening the hinge screws I found that it best to push the pane towards the hinge to ensure the pane is located as high as possible. This is only because by default the holes position the pane quite low in the frame (not unreasonably as this is the area most likely to leak).

All done, it probably took 30 minutes for both of mine.

Eagle Boat Windows can machine replacements for all Lewmar Old-Standard (<1997) openers, including custom sizes, in either CLEAR or GREY tint cast acrylic.


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