Face frame attachment with biscuits

[Chuck Miller]

I'm about to biscuit-attach a face frame for a bookcase, and it occurs to me that if I don't get the rail lengths exactly right, the stile slots won't mate with the carcase slots. I guess if they don't, I'll have to adjust the position of the slots and re-biscuit-joint--not the type of experimentation I am looking forward to. It just seems that working with biscuits in two-dimensions is tricky business.

So, could anyone share their strategies for applying a precision fit to a face frame/carcase attachment. Do only rails (or stiles) get the biscuits? Do you first dry-fit the stiles, the cut (and attach with pocket screws) the rails, then attach with biscuits.

What about overhanging the FF by a bit then using a flush-cutting router bit? Would one cut the FF a bit proud, then adjust the slot on the FF accordingly. Rather than doing this, I would prefer a flush fit, however.

Thanks for any discussion/war stories.

Chuck Colorado

[George]

I'm not sure I understand what you're asking. Biscuit slots are normally marked across dry-fitted joints, and are precise in only one dimension, distance from the reference surface. Lots of adjustment laterally.

I clamp the components in place, check the fit (proud on the edges I must scribe or plane), mark, and remove to make the slots. It has to fit wet as it did on dry assembly. Doesn't really have another choice.

[Leon]

Yes that can be tricky.

If painting the face frame I glue and finish nail. For a natural wood finish, I build the face frames with dados on the back side to accept the carcass. Pocket hole the face frame together. Build the carcass to fit into the exiting face frame slots.

[Joe Barta]

I've never done any face frame construction, but I believe I understand your question and have a thought on how I would tackle it.

I'd assemble the face frame, then make biscuit slots on both stiles. Then make slots on the LEFT side of the carcass. I would hook a tape into a slot on the face frame and measure precisely to the inside edge of the opposing slot on the face frame. I would then transfer that measurement to the carcass making a fine mark with a pencil. Then, adjust the slot cutter to cut the carcass exactly on that line.

I'd say that if you're careful measuring, it should be a plenty accurate fit.

Joe Barta

[Rumpty]

You don't have to measure anything!

Place your face frame face down on your assembly table, position your carcase onto the face frame in correct position.. Reach down into the case from the carcase "top side" and draw a line onto the face frame where it meets the carcase side. Now draw line onto the face frame where it meets the outside of the carcase. Do this for the other side.

Mark 3 locations on the outside of the carcase and face frame where you want your biscuits located.

Now slide your carcase left until the inside of the carcase meets the line you drew on the outside. Go over to the right side of the carcase and cut the biscuit slots into the face frame where you marked it. When done slide the case to the right side and cut the biscuit slots on the left side.

Now turn your carcase over onto one side and place on a flat surface, cut the biscuit slots into the case front, flip over and cut the remainder slots. You will have to scribe your locations around the edge for this operation.

This is a typical offset method of cutting biscuits and we use this system for all sorts of project.

R

[Larry Bud]

So you're just using the offset amount of the biscuit cutter to get the cutting position right?

When you slide the carcass left until the inside meets the line on the outside, you're just using the carcass as a support for the cutter, right?

[Rumpty]

Yup Larry, exactly. This is only one variation of the offset method. Keep in mind "most" biscuit joiners won't cut the the exact center of a 3/4" piece of wood, so you need some way to reference a point so both pieces of wood have the biscuit aligned.

R

[George]

Use the touch gage you used to reference the face frame overhang from the carcass to cut the slots in the sides, then remove to cut in the face frame.

[David]

Keep

I think that's referred to as a "shim".

Dave

[Rumpty]

George,

I don't understand what you are saying here.

R

[Rumpty]

Nope, you don't "shim" anything, cut your slots from the same reference point and they will match.

[George]

You overlay the face frame, on the thinner carcass, and it comes "X" distance from the reference side. You establish "X" with a piece of wood that you lay up against the carcass, which you flush up with your fingers. After marking for your locations, put the thickness gage on the depth fence of your cutter and leave it for the carcass cuts. When you remove it, you will be able to make the corresponding cuts in the face frame with the proper distance.

I'm almost sure it's in my DeWalt instructions.

Fence Shim Blade Cut is X+Y distance from face frame edge, Y from carcass edge. X Y

[David]

He's already rejected the idea of shims.

Dave

[George]

Then call it an offset block!

[David]

or a jig

Dave

[Rumpty]

But but but but but.......you don't need shims (unless you are doubling a joint) or gauge blocks, learn how to offset the Parts in relation to each other.

R