Concealed hinges for floor trap

[JohnD]

I want to have a liftable trap in the floor. Will be 18mm ply. I have had a look at the way kitchen unit door hinges work, and it looks to me like I could use them, as they have no "knuckle" showing on the room side and the door seems to lift away from the next panel so it should not bind.

I would want the trap to close down firmly against the joists and trimmers so that it can be walked on without wobbling.

The kitchen unit doors with these hinges appear to be 16mm thick.

Is there anything I haven't thought of?

 

[big-all]

dont think they will work personaly due to the weight and loading the hinges in a different way to desighned

you would also need the hinges to open beyond 90 degrees [possibly flat ]

i would look at these
http://www.ironmongerydirect.co.uk/Products.aspx?Pcode=12-066-C&Grp1Code=47895&ID=17210

you will also need a surface or stop all the way round to support the trapdoor and possibly aditional central support dependent on trap door size

 

[ColJack]

you can get kitchen hinges that open to about 165 degrees.. they are generally spring loaded and will hold the door down..
http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A326397&ts=86737&id=16131

make the door fit across 2 joist about half way and then add nogins along the other edges to hold those edges..

 

[JohnD]

thanks, I like that idea, as counter flap hinges would be too visible.

the josts are at 18" centres and the trap will probably be square, so not all that heavy, but I take big-all's point about the weight and not being used as designed. However I don't know a better "invisible" hinge.

I have a couple of 165degree hinges, they look very complicated in construction. What does "Use hinge screw on the back plate only" mean?

 

[ColJack]

special fat stubby screws to screw the small plate to the carcas, the round recessed side being held with regular countersunks..

 

[big-all]

the main point i was making about the hinges beyond 90% was the door would need full suport as the weight of the door would be to much for the hinge in the fully open position [would probably pull the hinge of the flap with leverage]

another point why have hinges at all!!!
a loose trapdoor dosn't need the hinges adjusted because its out of line

also what are your plans to lift the trapdoor as yopu cant have a handle unless its flush

 

[Jasonb]

The other problem with using consealed hinges is that the door needs to be spaced away from the carcase(joists) otherwise it will run when opened and wont close properly. This will mean that if someone stands on the door they will be putting a lot of weight onto the hinge in a direction its not intended for.

You could use soss hinges byt not easy to fit, knife of center hinges would not show and are a bit easier to fit. But as BA says at 18" sq why bother with hinges.

Jason