# What joint to use with plywood



## MeasureTwice (Jan 12, 2012)

Once again a novice question, so thanks for your assistance and patience.

I'm building a small, very simple bookcase out of 3/4" white birch plywood. My only concern is how to make the joint attaching the top and sides. I will put on a face frame and do not want to put any trim on the sides of the top, so the top+side joint will be exposed. I was planning to rabbit the top but that will expose a small amount of the plywood end grain. 

What is the proper joint to be used? Is exposing a small amount of end grain typical and acceptable? This is a project for my girlfriend, who just wants me to nail a couple of pieces of shelving together but I'm trying to work on proper technique with any project I do. 

I will be using some sort of stain simply to work on those skills as well.

Any thoughts?


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## TomC (Oct 27, 2008)

When I build a bookcase I make the top out of same material that I use for face frame. That way you have no plywood edge showing. The top is attached with screws in elongated holes to allow for expansion.
Tom


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## Dave Paine (May 30, 2012)

_I'm building a small, very simple bookcase out of 3/4" white birch plywood. My only concern is how to make the joint attaching the top and sides. I will put on a face frame and do not want to put any trim on the sides of the top, so the top+side joint will be exposed. I was planning to rabbit the top but that will expose a small amount of the plywood end grain_. 

I have used iron on veneer to cover the sides of plywood.

Some of this is applied with hot iron, some with glue. This will give a nice clean look.

http://www.woodcraft.com/Search2/Search.aspx?query=edge banding

_What is the proper joint to be used? Is exposing a small amount of end grain typical and acceptable? This is a project for my girlfriend, who just wants me to nail a couple of pieces of shelving together but I'm trying to work on proper technique with any project I do. _

The plywood top surface will not glue well to the top of the sides with or without a rabbet.

I would use dowels to attach the top.

I use this jig to drill my dowels in the ends or edges of boards.

http://www.leevalley.com/US/wood/page.aspx?p=32250&cat=1,180,42311,42319

After drilling the sides, I would then use these centres to mark the exact placement of the dowels in the top.

http://www.leevalley.com/US/wood/page.aspx?p=32732&cat=1,250,43217,43228

You want dowels so that they have the grooves machined into the sides to allow the glue to squeeze out. Straight rod can be difficult to use since if the hole is tight the glue can prevent the straight dowel from going all the way into the holes.

http://www.leevalley.com/US/wood/page.aspx?p=44995&cat=1,180,42288

If you have a drill press use this to drill the holes in the top. If not, you need to get the hole as vertical as possible.

Mark the drill so that you do not drill all the way through the top. I would go 3/8in into the top and then whatever length you need in the side so you do not have to cut the dowels.

If you wanted to use fasteners instead of glue, lot of quick connect hardware is available.

http://www.leevalley.com/US/hardware/page.aspx?cat=3,41306&p=45375


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## cabinetman (Jul 5, 2007)

MeasureTwice said:


> Once again a novice question, so thanks for your assistance and patience.
> 
> I'm building a small, very simple bookcase out of 3/4" white birch plywood. My only concern is how to make the joint attaching the top and sides. I will put on a face frame and do not want to put any trim on the sides of the top, so the top+side joint will be exposed. I was planning to rabbit the top but that will expose a small amount of the plywood end grain.
> 
> ...


How tall is this unit?










 







.


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## Fred Hargis (Apr 28, 2012)

I guess I wouldn't think any exposed plywood edge would be acceptable in the house (though I may do that on garage/shop/barn cabinets). I the rabbeted joint would be best, but edging that exposed end will look a lot better than leaving it exposed.


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## MeasureTwice (Jan 12, 2012)

cabinetman said:


> How tall is this unit?
> 
> 
> 
> ...


Only 27" tall and 36" wide 12" deep. sized to fit under her classroom blackboard. One adjustable shelf.


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## BigJoe16 (Feb 20, 2012)

Why don't you just cut the corners at 45 degrees like you would do with trim? I haven't worked with plywood like this but I don't see why it wouldn't work.


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## cabinetman (Jul 5, 2007)

You could use a lock miter joint, but you may get some tear out. 







.
You could just use an ordinary miter joint. 
Or, you could use a splined miter joint.
.







.
Or, you could make a modified rabbet...
















 








.​


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## MeasureTwice (Jan 12, 2012)

cabinetman said:


> You could use a lock miter joint,
> You could just use an ordinary miter joint.
> Or, you could use a splined miter joint.
> .
> Or, you could make a modified rabbet...


I'm intrigued by the locking miter, may have to get a bit and give it a shot. Not sure the splined miter matches my skill level and would the ordinary miter be as strong as the modified rabbet? The modified rabbet is close to my original thought.

I'll do some test runs tomorrow to see how they work!

Thanks!!


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## Midlandbob (Sep 5, 2011)

A dado or rebate joint is good with birch ply. Any surface is 50% or so side grain so good glue holds well. The mechanical help of dados ads strength and make assembly easier as it indexes.
You need to put a full back on in a 1/4 inch rebate or at least for one shelf height to add strength , square it up and prevent racking. Sometimes i use 1/8 inch door skins 
If you don't want that and the face frame is made of two inch or so width rails, you should end up solid. If it feels unsteady, adding a 4 inch or so piece inside the back top and/or bottom shelves to control the racking.


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## MeasureTwice (Jan 12, 2012)

I ended up using a lock miter joint and it worked out well. I did get a little tearout like cabinetman said. The joint isn't perfect but accetable for this application and I will keep practicing until I get it right.

I did put on a full back and face frame so it is rock solid.

Thanks again for all the comments and assistance :thumbsup:


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