Preventing veneer on plywood from chipping - tongue and groove routing

[Daniel Hillmer]

Hi,

Anyone have any suggestions as to how I can prevent veneer from chipping whilst running 3/4 inch maple plywood across the grain on a router table, along the plywood edge, over a groove bit?

I tried blue painters tape over the area I'm routing, it helped to reduce chipping a little, but not much.

[Mike Cutler]

Score the face along the trim/cut line with a straight edge and a very sharp utility knife.

[Daniel Hillmer]

Now why didn't I think of that - THANKS Mike.

[Bill Wyko]

You might also try a strip of masking tape over the edge to be routed.:D

[Jason Whelehon]

You can try this...
http://www.dm-tools.co.uk/extraimages/TS4020_Scoring1.jpg

[Rick Gooden]

I made a zci that worked well, but then went to a whiteside upcut spiral 1/4" bit for the groove and it works perfectly. I do, however, use 2 router tables for the tongue and groove so I only need to set up once for the operation. If using the Sommerfeld system with a single router table I would use the zci.

[glenn bradley]

I do what Mike does. An Xacto knife is also my marking knife so it is always handy.

[Daniel Hillmer]

Pardon my ignorance Rick, what is a zci?

[Jim Becker]

Pardon my ignorance Rick, what is a zci?

Zero Clearance Insert...a replacement throat plate for a saw that has an opening created by the blade, itself. Since there is "no" overhang of material, splintering is greatly reduced or even eliminated with the right combination of sharp blade and blade height.

[Ed Gerken]

Not sure if it would help for this particular situation or not, but perhaps you can attach sacrificial stock to the face. Sort of like a mobile ZCI!

-Ed

[Peter Quinn]

I find a straight bit with a shear angle on the carbide or a spiral up cut aids in reducing chip out on plywood. A ZCI can be a dedicated router plate insert, but it can also be as simple as a piece of 1/8" hardboard double stick taped to teh table top with the bit raised up through it. This will leave the edge of the material fully supported through the cut and less prone to tear out.

[Daniel Hillmer]

Ah, I see ok thanks. So is there a commercial product I could buy, a ZCI for this router table - fence combo which I have - the deluxe router table (below link) - something I could adapt to it? Or am I pretty much stuck with rigging up a ZCI myself?

http://www.ptreeusa.com/routerTables.htm

M not happy at all with this table but I'm stuck with it for now...

[Larry Prince]

Hi,

Anyone have any suggestions as to how I can prevent veneer from chipping whilst running 3/4 inch maple plywood across the grain on a router table, along the plywood edge, over a groove bit?

I tried blue painters tape over the area I'm routing, it helped to reduce chipping a little, but not much.

The easiest/quickest way to do this is to simply set your fence forward so the depth of cut is only 1/64th - 1/32nd deep. Run your ply at this depth to make what is essentially a "scoring cut", then set the fence back to normal depth and make the final pass at full depth to finish it off.

All this happens a lot faster than it sounds and should eliminate your problem. I've used it on both red oak and prefinished maple ply with excellent results.

[Mike Wilkins]

I use a pre-score method. After marking out the location of the dado, use a straight edge and a sharp marking knife or utility knife, and score the veneer exactly where you plan to run the router bit. I use this method for tablesaw cuts and it works great. This should eliminate all or most of any tearout.