Rabbets when joining 3/4 plywood

[Joe]

Hi 

I wish to joining 3/4 inch baltic birch plywood to make an 18 inch square box. If I rabbet one piece  3/8 inch deep for gluing purposes what size screw should I use and will i get a stronger joint? 

Thanks 

Joe

[Gary V Morris]

I am glad that you were able to get the advice you needed and then found an adaptation of your own in using the Kreg screws as well. Wood working brings such joy in seeing such resolutions go from abstract to product in hand. Thanks for sharing your experiences with us. Down the road, when you have absolutely nothing to do, and plenty of time to do it - conduct a small scale box setup with just the screws and glue and see how much time you could have saved for other things, e.g. napping! ;-)

On the note about tear out - this occurs more so on cross cut as opposed to with-the-grain cuts in plywood. So you could just score across the grain with a sharp razor knife as suggested and not have to deal with scoring the with-the-grain cuts. Saves you time and effort.

[Joe]

Thanks Gary , I'll do that.

Joe

[Ken Darga]

Re avoid chipping and tear-out

Masking tape firmly applied over the end of the work-piece, where the saw blade exits, is effective.

Just wrap a 2'' wide strip of tape, starting the on the top side, wrapping it around over the edge and then back underneath the work-piece.

Another method---

use a backer board (strip of wood), the same thickness as the work-piece, affixed onto the trailing edge of the work-piece, is also effective.

This is akin to using a backer-board on the trailing edge of the work-piece, when making cuts with a router bit.

The board keeps the fibers compressed into the work-piece.

[Joe]

Thanks Ken , the wrapping the whole way around is something I did not think of. 

Joe

[Ken Darga]

Joe,

You don't need to wrap it ''the whole way around''---

start about 3'' from the edge---

then wrap it over the edge---

then continue on the underside, about 3''.

Adhesive residue will be on the wood surface, after removing the tape, and

needs to be removed---using a damped cloth with ''mineral spirits'', should do the trick.

 

Joe said:

Thanks Ken , the wrapping the whole way around is something I did not think of. 

Joe

[Rick]

Another method I have used to prevent tear out is to only raise the blade 1/16 inch to cut the bottom veneer.  Then raise the blade to normal height, and cut completely through the plywood.  Sometimes this works better than taping.

Gary V Morris said:

On the note about tear out - this occurs more so on cross cut as opposed to with-the-grain cuts in plywood. So you could just score across the grain with a sharp razor knife as suggested and not have to deal with scoring the with-the-grain cuts. Saves you time and effort.

[Joe]

Thanks Rick.

[Gary roofner]

Here is sample joint John was talking about made with dado head newly upgraded radial arm saw.

[Joe]

 You get a square assembly with these joints. 

[Ed Pellerin]

basic draw making

[Ed Pellerin]

I'm new at woodworking and I'm planning to make draws with 1/2" wood 5" X L20"X W16"