Installing hardwood trim on Pre Veneered Ply?

[Will Blick]

I am considering a ply veenered top 3/4". I wanted to use some hardwood for trim to cover the plywood edges. I am aware the cut edges on the ply.... the center portion wants to expand outward more than the top/bottom of the ply.

This router bit is designed to create a slight indent into the center area of the ply edge, so when it expands, it won't create a gap between the veneer top and the molding. How big of a problem is this? I would think if this problem is very commonplace, many router bit makers would have had these made for years now? How big of a problem is it? I would think there would be a lot of ruined pieces out there if this issue was very common?

http://www.collinstool.com/images/ply_prep_router_bit_both_sizes.JPG


http://tinyurl.com/2epsus

[Joe Chritz]

Never heard of such a thing.

All I have ever done was rip on a tablesaw and glue on a piece of hardwood. Trim with a flush trim bit and scraper then sandpaper.

Joe

[Karl Brogger]

I've built hundreds of wood tops using mdf that has a veneer. I pocket screw my edging on, belt sand it flush, then use a orbital to finish it off. I'm not sure I would recomend plywood. The veneer is typically much thinner than what they put on mdf and can be easily burned through while sanding. Sometimes the core layers will show through the veneer, and it can be hard to get a really flat plywood top. Undilations that aren't seen vertically can really be seen while laying flat.

[Dave MacArthur]

I've also seen a router bit set that puts a slightly angled tongue in groove setup in the plywood edge and hardwood band.

[Will Blick]

For MDF, this is rounding process is not required, its for Ply only, as its center tends to expand more than its top / bottom, obviously not the case with MDF. In many cases this is why MDF makes a better base for the veneers...

Also, you only use this bit on the Ply, not the hardwood trim.... after trimming the Ply center, over time, its suppose to expand out, and meet the trim, vs. forcing a gap between Ply and trim.... but from the sounds of this thread, the entire problem may be "overstated" by the bit maker?

[David DeCristoforo]

This is one of those things that, IMMHO, falls into the category of "hair splitting". The phenomenon is real but insignificant. As with the other responders, I have glued thousands of feet of hardwood trim to plywood edges and have never had a failure caused by the center of the plywood expanding and breaking the glue line. It is a nifty bit tho....

YM

[Will Blick]

> I have glued thousands of feet of hardwood trim to plywood edges and have never had a failure caused by the center of the plywood expanding and breaking the glue line.

yep, this is what I suspected.....thanks

[Craig Feuerzeig]

The body of the bit has a registration mark to align with the center ply and insure a square edge.

So if your not exactly on center (plywood is not that consistant) your edge won't be square??

and never have to putty a seam again.:confused::confused: Putty a seam??:confused::confused:

This bit sounds like a solution in search of a problem...that never existed. Save for maybe a lack of clamps (maybe it's just me:rolleyes:).

[jud dinsmore]

i've got one and used it on a twenty or so bookcase shelves for a built-in. the shelves were standard shop-grade ply with hardwood edging. the edging was shot on with 18g brads and glued. everything was painted.

using it vs not using it (on the first twenty shelves) provided a tighten joint between the two materials. after it was painted you could barely tell where the edging began. the same could not be said for the shelves where i didn't use the bit. i don't know if it is designed to provided a stronger joint but it will definately provide a tighter joint. i'm pretty sure whiteside makes the bit.

good luck,

jud

[Bill Huber]

This the router bit I have and works very well.
I have only used it on one project but it did a very nice job.

http://pricecutter.com/2-piece-edge-banding-bit-sets/p/P16%2D4040/


85390

[Will Blick]

Bill, I have a similar bit, from Eagle America.... However, these only add glue surface area and assist with alignment... (not suggesting we need anything more after this thread)

I am planning a big kitchen table, and would hate to have the hardwood trim on its circumference be the spoiler, hence why I was curious just "how big" of a problem the excessive center ply expansion is. Like many so called problems....they do exist, but not enough to cause a problem for the intended task.

BTW, my big problem with that Collins bit is...by hollowing out the center of the ply, you lessened the ply to hardwood glue surface area.... that too has disadvantages.