Shopsmith Forums

I am confused on how to attach solid wood pieces to manufactured pieces (plywood, MDF, etc.). I have read you cannot glue solid wood pieces to plywood since the solid wood expands and contracts. Would using biscuits to attach a face frame to a plywood cabinet lead to a problem? Can you satisfactorily pocket screw through the plywood to grab the solid wood frame? What have you used in the past?

Thanks, Mike

tryinhard wrote:I am confused on how to attach solid wood pieces to manufactured pieces (plywood, MDF, etc.). I have read you cannot glue solid wood pieces to plywood since the solid wood expands and contracts. Would using biscuits to attach a face frame to a plywood cabinet lead to a problem? Can you satisfactorily pocket screw through the plywood to grab the solid wood frame? What have you used in the past?

Thanks, Mike

Wood movement or knot, the standard method is to glue and nail (usually the face frame has a shallow dado that the carcass fits into).

You can use biscuits and/or pocket screws to attach face frames. With pocket screws you don't even have to glue them unless you just want to.

I've used a tongue and groove joint to attach plywood to aspen. No issues whatsoever, which is probably a good thing since my table saw is sitting on top of the cabinet I built using this method.

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Hi Mike,
Last year (the last of the new episodes - the kitchen remodel) on the New Yankee Workshop, Norm ran a groove around all of the exposed edges of his cabinets and then cut individual biscuit slots in his face frames (he used pocket screws to join the face frame rails & stiles). That way he didn't have any side-to-side alignment issues.

tryinhard wrote:I am confused on how to attach solid wood pieces to manufactured pieces (plywood, MDF, etc.). I have read you cannot glue solid wood pieces to plywood since the solid wood expands and contracts. Would using biscuits to attach a face frame to a plywood cabinet lead to a problem? Can you satisfactorily pocket screw through the plywood to grab the solid wood frame? What have you used in the past?

Thanks, Mike

You can use any method you want to attach face frames to plywood or MDF. Since the grain of the face frame stiles and rails run parallel to the cabinet edges there is no issue with wood movement.

Wood movement is mostly across the grain of flatsawn wood. movement is negligible along the long grain. Since the attachment will be in a narrow line ( usually not over 3/4") any movement in that width is also negligible. Red oak will expand or contract about 8% from water moisture saturation to bone dry. In a kitchen the wood moisture will only change a portion of those extremes. Therefore flatsawn wood will only move a fraction of that 8%. (8% X .75" = .06") So - a flatsawn face frame will only expand less than .06" across that 3/4" fastened surface.

Riftsawn or quartersawn face frames will have even less of a wood movement issue.

This reference from Nick's "Workshop Companion" will help you get a better feeling for wood movement. http://www.workshopcompanion.com/KnowHow/Design/Nature_of_Wood/2_Wood_Movement/2_Wood_Movement.htm#moisturecontent

I've made most of our bedroom furniture with cabinet grade red oak plywood and red oak lumber. I've attached all the face frames with nothing more than glue--no nails, screws, or bicsuits. My internal construction of shelves and/or dust panels glued into dados in the sides of the cases reduces the need of the face frame to bear any load.

jtomwoods wrote:I've made most of our bedroom furniture with cabinet grade red oak plywood and red oak lumber. I've attached all the face frames with nothing more than glue--no nails, screws, or bicsuits. My internal construction of shelves and/or dust panels glued into dados in the sides of the cases reduces the need of the face frame to bear any load.

Doesn't your face frame support the weight of the doors? Do you knot have people open and close (hang on and slam) the doors? Actually, glue should be strong enough by itself; the nails just hold it in place while the glue dries. I suppose if you use clamps, you do knot need the nails.

Last year I made new kitchen cabinets (actually I'm still not done - but I work full time) and used a combination of tongue and groove joint pulled together with pocket screws.

I purchased a T&G set and cut tongues on the face of the cases and grooves on the back of the rails and stiles. You'd think setting this up would be a real pain but it wasn't. The set came with a rubber gromet/washer that the instructions said to put in bottom of the sleeve of the router before adding the router bit. Just drop the shank of the bit in the sleeve until it bottoms out on the gromet/washer before tightening the collet. Once the set up is done, if you don't use the router for a different operation, it's a snap to set up and cut a tongue or groove for the next cabinet.

This process make a strong face frame, the pocket screws draw up the pieces together so they don't need to be clamped in assembly and lining up all the pieces is a snap.

Good luck with your project.