# Reducing/Elimnating Plywood Tear-out



## Titus A Duxass (Jan 6, 2010)

The time has come for me to build a toolbox.
I am going to use 16mm BB Ply and box joint it.

Now BB Ply over here is not cheap and I know from experience that it suffers from tear-out.

Are any tips against tear-out when cutting the box joints?

I score the cut lines with a marking knife when sawing which seems to help.
Would taping the area to be cut help?

Or is going to be a case of double stick taping scrap pieces of hardboard/ply over the area?


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## Pete_Judd (Oct 19, 2010)

Don't know how you are going to cut use to cut the slots. If using the tablesaw or router, a backer board works great, even scrap MDF works great. I have used tape, but on the table saw for plywood I use a zero clearance insert.


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## Titus A Duxass (Jan 6, 2010)

Sorry I should have made it clear.
I will cutting the box joints on the RT with a 10 mm spiral cutter.


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## dutchman 46 (May 23, 2007)

The best way to do this,in My opinion , Titus is to get a down cut spiral bit wiith bearing also a fence back up board. Clamp the sacrifical fence on one side and move it into the bit as if making a zero clearence table insert for a saw , and now clamping the other side Cut the panel close to the line with a table saw, or band saw and add a template to the part Your cutting. move the piece through therouter table untill the bit is meeting the template. It shoud give You a clean cut.


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## newwoodworker (Mar 27, 2009)

I have seen people do it by cutting half way threw from the front then flipping and cutting the rest from the back it eliminates tear out completely but it is time consuming.


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## Titus A Duxass (Jan 6, 2010)

newwoodworker - my tear out problem occurs on the cutting side. If I cut a 10mm slot with a 10mm cutter the tear out occurs as the bit leaves the wood. The other side (face) of the work piece is fine.

Dutchman - I've got a downward spiral bit without a bearing and cannot afford another!
I can't quite get my head around your approach.
Have you got a sketch?


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## dutchman 46 (May 23, 2007)

Sorry, I do not. The only thing I was trying to mention is the fence used to reduce splintering. The bit is partially in bedded in the fence. The template would keep the router from taking to much off . You might be able to use a collar on the table to follow the contour if You use a spiral bit without bearing. Hopefully, that will help you . I have a very hard putting thoughts into text. I am sorry!


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## bobj3 (Jan 17, 2006)

Hi Titus

This works for me , cut 5 parts to the box at one time, than on the 2nd box pull one of the 5 out for the cut on all 4 at one time, once you have the pattern cut in one keep it on hand for a clean cut next time you want to make some box joints.
The setup block is the key to cut all the parts at the same time, and to give you support to the cut....to help with the rip out error 

YouTube - MLCS Woodworking Multi-Joint Spacing System Making a Box Joint

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Titus A Duxass said:


> The time has come for me to build a toolbox.
> I am going to use 16mm BB Ply and box joint it.
> 
> Now BB Ply over here is not cheap and I know from experience that it suffers from tear-out.
> ...


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## Titus A Duxass (Jan 6, 2010)

Cheer Bob, that solution is the easiest. So easy that I missed it.

Sandwiching them together... whoda thunk.


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## bobj3 (Jan 17, 2006)

Hi 

Your Welcome...I get lazy from time to time and in a big rush and I don't use the setup block all the time, I just clamp them as one block and just rip them to the right size after the slot in in place..  after all it's just plywood ..I snap them together like a little train cars and rip them all at one time..  big boy Toys ...  

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Titus A Duxass said:


> Cheer Bob, that solution is the easiest. So easy that I missed it.
> 
> Sandwiching them together... whoda thunk.


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