Need some help for a project design

[harryball]

This is so simple it's complicated, I almost overlooked coming to the board and asking for ideas... but the more I think about it I would love to see how others would approach this.

The end product is a 20" x 20" x 3/4" piece of plywood (or MDF) that breaks into 2 pieces 10x20 each. When assembled it needs to be solid. When in 2 pieces it needs to be benign (i.e. no sharp edges) The final use is a table top for a portable display unit. It will be removed, stowed and then used again at shows.

My first thought was to use a piano hinge so they fold open, then add a small lip under them like a table apron. This is not the best solution because they fold into one piece.

My other thought was to do opposing rabbits so they would lap onto each other. Then place a small fastener of somekind on the bottom. That leaves a little too much flex.

Ideas welcomed!

Robert

[Gary Campbell]

Robert.. \
Take a look at the spring loaded table flap hinge. The kind that lets a 3 or 4 ft. square table open into a 4 or 5' round. The locks are spring loaded, they are rigid, will fold back on themselves, no fasteners required. (other than the mounting screws) I get them from Hardware Imagination (MIA).
Gary

[brucehiggins]

I would take a low-tech approach and use a dowel jig to drill dowel holes and glue dowel pins in one of the pieces.

[beacon14]

If you need a more solid connection you might try these (http://fastcap.com/products.aspx?id=132)

[srwtlc]

Exactly what I was going to mention (Davids post).

Along with that, to make it level without having to play with it each time you put it together, put some biscuit slots in both edges and only glue the biscuits into one edge.

[Brady Watson]

Nice link, David. How deep do you need to go with your pocket for the bolt to be fully submerged? (what's the Z height of the bolt?)

Thanks!
-B

[beacon14]

Not sure Brady, of course the web site tells you every dimension except the one you need. I've only used them once or twice and don't have any on hand but I know they are designed for 3/4" material so I think 1/2" deep is probably OK, you might get by with a little less.

[jseiler]

Lamello duplex hinges might work if they are strong enough. Detachable, one could cut the recesses with the bot or biscuit joiner. A little pricey though. I think Lamello's simplex connectors aren't the right animal though.

[harryball]

PERFECT! I knew it was a good idea to post here... I can even use those flip bolts for a different project I've been working on.
THANKS!

I think, in this case I will cut the tops out whole with the pockets cut for the flip bolts and allow a little for the 1/8" kerf of my table saw blade. Then cut them in half with the table saw after I add the edge banding.

Robert

[bleeth]

Brady: We use these daily in our shop. The pocket is approx 1/2" deep. Our supplier sells them to us for less than $1 each. Our typical method for countertops larger than 8-10 ft is using a combination of these and biscuits for alignment. We do not count on this type of joint to support load without bracing underneath.

[Brady Watson]

Thanks Dave. I don't know why they tell you every other dim than the one you really need on the site...

-B

[harryball]

Flimsy excuse but maybe liability Brady... some poor dummy (think of me) would probably order a bunch but go ahead and cut the project before they arrived to find out another 1/32" more or less would have been better then get upset about cutting up $$$ and try to blame the MFG for not posting the exact precise to the micron dimension.

Just a thought.

These are great though, ordering a bunch today!

Robert

[harryball]

Dave or anyone... if someone would be so kind to email me a dxf of the working pocket outline I'd appreciate it. I've still not got my bolts and I can't tell how far the threads run and thus how far I need to make the circle halves from each other.

I won't actually set the depth and cut the project until I get the bolts though :-)

Robert

[wooden_innovations]

Here is my drawing using flipbolts. I was using a .5" deep pocket but I like the clearance better using a .625" pocket.

Rodney




2743 (23.3 k)

[harryball]

Thanks! It's amazing how close I got just eyeballing it from the photo but it's nice to have a known working pocket shape.

Robert