Re : PC 557 biscuits in 1/2" stock

[Jeff MacDonald]

I want to cut biscuits in 1/2" ply (actually 12mm) with a porter cable 557. The smallest height I can set on the fence is 1/4" or 6.3 mm. I know it is not hugely important since the biscuits are hidden, but out of interest, does this mean that you can not get a perfect center (eg 15/64 or 5.9mm) with this model plate jointer?

Also the mating surfaces are perpendicular to the 1/2" plywood back (3/4" thick sides of a cabinet). To make the mating joint do I just need to put the side pieces vertically in a vise and set the set the fence on the edge with the same height as on the first cuts?

Are number 10's a good size too?

Thanks
Jeff

[Chip Lindley]

Jeff, you're on the right track. Same setting for horizontal and vertical pieces. 1/2" ply does not give you much to work with. If you use a water-based wood glue, biscuits may swell and telegraph to the surface of the 1/2" stuff. You won't know until you try.

[Richard M. Wolfe]

I've put biscuits in a number of pieces less than 3/4" and never had any problems. As long as you're not going to sand through to the biscuit it doesn't matter whether it's centered or not, as you said. If I want placement that's difficult to get using the joiner's height adjustment I have used various thickness shims under either the workpiece or the joiner, making sure everything is flat before making a cut.

[glenn bradley]

To get a perfect center, double stick tape a shim to your registration face; old credit card, half a CD, etc.

[Al Willits]

On 1/2" ply from the borgs I'd bet you'll see swelling if you use Titebond, I did anyway.
Not sure on the better stuff though

And I used a piece of plastic sheet to shim like suggested, didn't tape it, but that sounds like it'd work easier maybe.

Al

[Andrew Pitonyak]

On 1/2" ply from the borgs I'd bet you'll see swelling if you use Titebond, I did anyway.
Not sure on the better stuff though

Is that "better stuff" as in "better glue"? Dare I ask "which glue" may be "better stuff" for this task? Do you mean simply the product labeled "Titebond" and perhaps "Titebond III" would suffice?

Sorry for my naivety.

[Jeff MacDonald]

Thanks all.

I made a test joint this morning and it worked but i had to flip the 1/2" ply over to have it flush with the edge of the 3/4" edge. I see know why using the same reference is important. I won't be able to flip the carcass back over when i do the doors on the cabinet.
so i guess i will just forget the fence and use my work bench as my reference. that said is their a way to do t-joints with one piece of wood on the other...i remember hearing this somewhere.

cheers,
Jeff

[Neil Brooks]

1) For some reason, your situation sounds like one where a particular rule doesn't apply.

We're "taught" to keep our biscuits dry. Mine are in glass jars with desiccant packets in each.

We're even "taught" to microwave the steam out of them.

But ... just for future reference ... this sounds like a case where you'd want MINIMAL expansion of the biscuit, and might WANT to get it a little wet before 'bopping' it into the slot.

Does that make sense?

Does anyone buy that notion?

2) Ply? Why were you taking the biscuit route with ply?

Since this sounds like a glue-up ... I'm curious why you were taking that approach in the first place.

Was it to get a matching, "perfect" edge ... and/or to KEEP it that way?

ISTM that ply is pretty darned stable, by its nature.

I'm wondering whether the whole biscuit thing is overkill.

Did I understand your application right ??

[Jeff MacDonald]

Hi Neil,

In the picture below you can see what I am making....It is the swing out door of a tool cabinet (and a 2nd door and carcass to follow).My problem is not that the ply is not strong enough it is that i want to have something to hold the panel in the frame. It must be flush since it will be visible. I could have done a rebbate around the frame and just dropped in the panel but the " back" is actually the front when the door is closed and i had cut the ply before completing the finger joints.

Since I will be reaching in and pulling tools out when the door is open I want to make sure that I don't pull the panel with them (although unlikely with glue) hence the #10s. I could have nailed/screwed/dowelled through the sides but the 1/2 " is thin that i didn't want to split it and wanted to keep the outside clear.

My problem is that I layed out the biscuits on the inside of the dry fitted door in the picture. I was going to do the slots (using the fence @ 90 deg) in the 1/2" using the inside-side as the joiner reference and then do the 3/4' frame slots using the edge as the joiner fence reference. Which means that i am not referencing the same plane....I THINK should be cutting the slots in the 1/2 using the outside side as the reference since i know in theory tit should be flush. Is my problem as simple as flipping the panel over cutting on my marks and flipping it back for assembly provided I don't move the side frames around ( switch tp for bottom or L for R?

does this make any sense....

[Neil Brooks]

Jeff-

The description of what you're building ... and the pic ... makes perfect sense!

I had it ALL backward.

I was thinking bookshelf, and that you were gluing up either interior shelving or the back -- neither of which should have required what you were talking about.

Boy ... the quick and easy answer to you "do I just need to ....?" sure SEEMS like ... "Yeah, you got it," but ... my experience with my 557 is limited, yet.

I'd sure rather defer to those with more expertise on this one to confirm my interpretation or set BOTH of us straight

[Al Willits]

Sorry, better stuff as in Plywood, not glue.
It was Titebond 3 I was using fwiw

Al