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  • #383
    Eric
    Participant

    The otherwise voluminous hymnal is a bit brief on the subject of hinges.  This is how I did it and what I believe should be the procedure. For the doors it should be mentioned that the alignment/clamping goal (other than matching the panel 3-4 seams and shooting for uniform reveal) should be getting the panel 3 forward edge of the door flush with the corresponding shell surface (thus the door is not against the sill there)  The rear of the panel 3 section of the door should be spring clamped against the sill. One must study the picture in the hymnal closely to deduce this; it is not discussed.

    Now for even more important considerations not discussed: the hinges come with 1/4″ CNC drill holes for the pins.  The #8 pins are a good deal smaller ( 4mm), so the following can occur if one redrills the holes to 1/4″ after fiberglassing the hinges: In the procerr of filing to get the mortesses and tenons to slip fit, invariably some if not most of the mortesses get elongated and otherwise enlarged.  This slop allows at least as much misalignment of pin holes as the difference between 4 and 6mm, if not more.  Foreseeing and predicting this, I redrilled my fiberglassed hinges only to 4mm ( centered in the obvious fiberglassed- over CNC holes). Then I filed the mortesses for the slip fit (hinges assembled, doors/hatch positioned/clamped/taped). Then the hinges were glued in (epoxy/cellofil and CA). I let them cure (without filleting yet), then pulled the pins and, with everything still clamped/taped up used an 18″ long 1/4″ twist drill bit to redrill all the holes (right through each assembled hinge with hatch/doors in place) to 1/4″.  The 1/4″ bit follows the path of least resistance straight through all three hinge components. The reason for the long drill bit (actually 12″ will also do) is solely to get drill clearance beyond  the chines. The result is perfectly aligned pin holes even if some of the hinge components are slightly missalligned due to loose/elongated mortesses (though at the CA glue step every effort was made to get everything lined up).  Only after this drilling, the doors/hatch were removed and all the fillets were applied.

    Also not mentioned is the importance of coating all those pin holes twice (two coats) when the hinge edges (not fiberglassed) are coated. I coat my holes by dipping an awl in epoxy and sticking it in the hole with a circular motion.  Shine a flashlight through each hole from the other side and look through the hole to insure that the hole is uniformly coated (it will be uniformly shiny). The hole is endgrain plywood and must be sealed well (that’s the main purpose of drill fill drill).  Heat shrink will pad the hole against thread wear but an improperly sealed hole is as much kryptonite to okoume as is ultraviolet radiation to epoxy. It is not necessary or desirable to get varnish in the holes; UV is not an issue there.

    #439
    cpieper
    Participant

    Thanks for the great tips on setting the hinges. Unfortunately, too late for me… Regarding the treatment of the hinge pin holes, I did something somewhat different being concerned with having bare wood exposed which would ultimately rot/discolor… I wasn’t clever enough to think of drill/fill/drill, so I bought some nylon sleeves (3/8″ OD) and drilled out the hinge pin holes to accept these sleeves. I epoxied the sleeves in place and use long SS screws (#8 as I recall) as the hinge pins. The door action is very good. This might be overkill, but that’s what I did…

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