# Threaded corner blocks / "L" brackets



## Doug E (Nov 18, 2015)

I need to join two pieces of plywood to form a "T", and be able to repeatedly assemble / disassemble the joint. After initial fabrication, I will only have access to the "top" surface of the "T". Thus, reassembly will be a blind operation.

I have tried using threaded inserts in the vertical piece of plywood, attaching the top piece using through-hole allen wrench head connector bolts. However, repeated tightening of the connector bolt eventually pulls the inserts from the vertical plywood.

I have also tried using barrel nuts in the vertical piece, but with repeated use they become sloppy and rotate, making blind reassembly very difficult.

I am now on a quest for something like a metal "L" with an integral nut that I can screw into the vertical piece of plywood near the top, and then access the nut through a hole in the "top" piece of plywood.

Can anyone here point me towards such a connector?

Thank you,

Doug


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## woodnthings (Jan 24, 2009)

*it's not clear to me ....*

I can't quite figure out what your arrangement is. Can you post a photo of the joint as you have it now? 
Or a sketch showing the two pieces and the access hole....


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## GeorgeC (Jul 30, 2008)

Just go to one of your local hardware stores and buy the "L" brackets that you want. Or have a local machine shop make the size you want.

If the brackets are thick enough you can thread the bracket to accept a bolt. If not then weld a nut to the back of the bracket. You can even make two bolt holes per bracket. Make the hole in the top plywood slightly oversize so that you have a little leeway in lining the bolts up with the brackets/nuts. Use two brackets, one on each side of the bottom piece of plywood.

The brackets will be fastened to the bottom ply wood with through bolts. That is bolts long enough to go through both brackets and the plywood.

This whole assembly will be very secure and you will not have to worry about any screws pulling out of end grain of plywood.

George


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## Doug E (Nov 18, 2015)

GeorgeC said:


> If the brackets are thick enough you can thread the bracket to accept a bolt.


George - Thanks. I was hoping to buy something ready made and not have to tap or weld the bracket. Especially since I need a dozen or so such brackets. But that may be what I end up doing!

Doug


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## shoot summ (Feb 21, 2014)

Doug E said:


> George - Thanks. I was hoping to buy something ready made and not have to tap or weld the bracket. Especially since I need a dozen or so such brackets. But that may be what I end up doing!
> 
> Doug


Time is time, if the time invested in making these saves you time, then it all works out. Sometimes there isn't just an easy magic wand fix...

That said, I find some interesting hardware at JW Winco:

http://www.jwwinco.com/

Not really following your requirement either, but perhaps you could search for aluminum extrusions that may accomplish what you want.


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## epicfail48 (Mar 27, 2014)

Im assuming that the threaded inserts were just screwed edgewise into the plywood, but have you tried epoxying them in place? Should keep them from pulling out, and the simplest solution is always the best


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## Hammer1 (Aug 1, 2010)

With plywood,you can drill a pass hole in the end grain but don't expect enough structure for things like a threaded insert. You can use a cross dowel bolt. http://www.woodcraft.com/product/06K70/cross-dowels.aspx

There are tons of knock down hardware fasteners that might fit your needs. https://www.google.com/search?q=kno...EMQsARqFQoTCNb6j7-_nckCFYWVHgoddNAE6A#imgrc=_


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## NickB (Sep 24, 2013)

Is this what you're looking for?









Apparently they're called "Nut Plates" - in this case, "Right Angle Nut Plates". There's even a whole website dedicated to them - http://www.nutplates.com/.


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## Doug E (Nov 18, 2015)

Thanks to all for your suggestions. The right angle nut plates are exactly the kind of thing I was looking for. It's a bit surprising that the nut-plate website is focused on aircraft restoration!

What I finally settled on doing was essentially building my own using angle iron, and then tapping the iron rather than have a backing nut. Because the structure is rather large (a raised platform in the back of a cargo van) with integral storage compartments below the platform, the angle iron will provide additional support. I will will still use 3/4" baltic birch plywood for both the vertical supports as well as the platform itself, but because of the odd sheet sizes (60" by 60"), the angle iron can span the boundaries between the sheets. 

Again, thanks so much. Your suggestions and comments were most helpful in pointing me toward my final approach. When I'm done (perhaps a month from now - mainly because I don't have a proper shop and have to work outside in between snow storms, with preference always given to hitting the ski slopes if it's a powder day), I'll post pictures if anyone is interested.

Doug


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