Center vs Offset Pivot Hinge

[Ben]

Hi everyone,

I'm new to the group and an aspiring hobbyist cabinet maker.

I'll be building an installed bookcase wall in July with one segment being a hidden door to the garage. I'll be using a pivot hinge for this design and want to make sure I'm not missing something simple regarding my choice of hinge.

I'm looking at center and offset pivots capable of holding 1000lbs+ (they won't need to hold more than a ~300lbs but I prefer to err towards overkill on the hardware). The offset pivot is $150 less than the center pivot and I can install either one easily. Rough dimensions of the bookcase door are 36 x 11 x ~90. The pivot point of the hinge will sit roughly 5" from the front and 5" from the side. Is there any reason to use a center pivot hinge rather than an offset pivot?

Thanks,

-Ben

[HeyBub]

You know, of course, that the torque on that bookcase/door is going to be MASSIVE, don't you? The the hinge should be attached to a steel I-beam, anchored in the concrete and braced on its upper dimension in the extreme. The physics can be overcome somewhat by rollers or wheels at the bottom.That means the door should swing outward from the room into the garage to avoid marring the library's floor.

Of course if a car is snuggled up to the door, then you can't get it open.

When you're up to your ass in alligators, it's hard to remember you were only trying to drain the swamp.

[Ben]

I appreciate the advice to be prudent with this type of project. It would be very easy to build a bidden doorway that doesn't last, fails or worse. Fortunately I'm fairly prudent and am more likely to build something that lasts a lifetime... rather than the alternative.

There are a *lot* of good designs out there for hidden bookcase doors. I think I've only seen one design that calls for a caster--and that was from a first time builder of these things that didn't appear to be looking at what others had already done. There also a lot of interesting hardware options (from steel frames to these Reversica Hyde systems that look really neat--

any rate, I've not seen anyone discussing the pro's and con's of different pivot hinges. I'm only interested in knowing if there is any functional different (other than the obvious) between center and offset pivot hinges.

Thanks!

[Upscale]

[Gary A in KC]

I've actually got something similar in my house. About a 6 foot high bookcase in a built in wall that swings out revealing another door behind it (goes into our cedar closet and upstairs mechanical room). Uses a continuous length of piano hinge. It's actually fairly well hidden even with the piano hinge and you wouldn't notice it unless looking for it. Also uses a roller on the extreme edge of the door bottom to eliminate (or minimize) the torque on the door hinge. Think that's really the key - you have to either build the heck out of your pivot hinges and anchoring points or just eliminate the torque on the door with rollers underneath it.

Gary in KC

[Charlie Groh]

...I tore out and rebuilt a 1920's Murphy bed awhile back and was amazed at the simplicity, *and* complexity in design, of the hardware. It was really in great shape and worked well after 8 decades; we took it apart and had it powder-coated and no parts needed replacemet. Key to the design was balance, it all pivoted on a center point, springs and gravity doing the remainder of the work. It makes sense for the

*weight* part of the equation to equalize in some way...

cg