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View Full Version : Biscuit cutter or reversible glue joint?



Larry Palanuk
12-05-2007, 9:52 AM
I have used biscuits when I edge glue up a panel, and to my knowledge I have never had any issue.

However when I look at furniture from the REALLY high end stores I notice that all their large flat panels use a reversible glue joint. It looks kind of neat. Do they do that for strength? If so is it really necessary? Or do they do that because in high volume you can "dail in" the process and work faster.

I worry that if I tried it (I don't have a power feeder or a shaper just a hand fed router table) that I would forever fight getting things lined up perfect. Then end up having to take my panel somewhere that has a giant drum sander to fix my mistakes.

I know I could pay the $50 and try it out, but I would like to hear from the experienced folks before I considered whether to try it.

George Bregar
12-05-2007, 10:02 AM
I'm sure that it is for speed and accurate glue up. Edge glued boards require nothing for strength with modern glues. The wood will fail before the glue joint.

I have used biscuits but now just edge glue...saves having to remember where those damn biscuits are when trimming to length. Small panels get the performax...or if they are large or I have a bunch I take them to my wood supplier. They have a 36" sander and for a few bucks I have saved a lot of time...I hate sanding panels.

john tomljenovic
12-05-2007, 11:30 AM
most likely an automation/speed thing. and those boards are not going though a router table, nor a shaper w/ power feed either. but a 3 to 6 sided moulder. raw wood goes in - a completely machined component comes out, and one that doesnt require fumbling with biscuits for registering alignment. A quick trip to the clamping tables; and a quicker pass though the widebelt. and there you go, a top that was prolly created in minutes.

That saying, working by yourself, it would be quicker using biscuits than moulding an edge w/ a router. you would save more wood too.

I always have to remind myself that the factory "methods" don't always transfer to a low production one man shop. Hell, I just recently realized that most of your knock down/Ikea style furniture is not sized/proportioned to what the aesthetics/ergo dynamics of the design requires but to the limitations of the 5x10 sheet of particle board.

Chris Padilla
12-05-2007, 12:50 PM
Biscuits are nice for alignment purposes...I don't look at them as adding strength.

A reversible glue joint router bit will provide more glue area than a standard jointed edge to jointed edge glue-up so it should be stronger. No clue how much stronger, but it should be stronger. That said, is the hassle of the set-up worth it? If you have a lot of stock all the exact same thickness, it might make sense to do it.

This reversible glue joint is also self-aligning like a biscuit and it won't slip on you.

Lottsa things to consider.

Randal Stevenson
12-06-2007, 3:00 PM
most likely an automation/speed thing. and those boards are not going though a router table, nor a shaper w/ power feed either. but a 3 to 6 sided moulder. raw wood goes in - a completely machined component comes out, and one that doesnt require fumbling with biscuits for registering alignment. A quick trip to the clamping tables; and a quicker pass though the widebelt. and there you go, a top that was prolly created in minutes.

That saying, working by yourself, it would be quicker using biscuits than moulding an edge w/ a router. you would save more wood too.

I always have to remind myself that the factory "methods" don't always transfer to a low production one man shop. Hell, I just recently realized that most of your knock down/Ikea style furniture is not sized/proportioned to what the aesthetics/ergo dynamics of the design requires but to the limitations of the 5x10 sheet of particle board.

Besides methods, the cost of machines don't transfer so well to a one man shop. Otherwise I think we would all have jet hangers, with every tool in the shop.:rolleyes:

Norman Pyles
12-06-2007, 3:19 PM
most likely an automation/speed thing. and those boards are not going though a router table, nor a shaper w/ power feed either. but a 3 to 6 sided moulder. raw wood goes in - a completely machined component comes out, and one that doesnt require fumbling with biscuits for registering alignment. A quick trip to the clamping tables; and a quicker pass though the widebelt. and there you go, a top that was prolly created in minutes.

That saying, working by yourself, it would be quicker using biscuits than moulding an edge w/ a router. you would save more wood too.

I always have to remind myself that the factory "methods" don't always transfer to a low production one man shop. Hell, I just recently realized that most of your knock down/Ikea style furniture is not sized/proportioned to what the aesthetics/ergo dynamics of the design requires but to the limitations of the 5x10 sheet of particle board.

I think John hit it right on the head. I like my projects to look handmade. Shaker and arts & crafts styles. Solid wood as much as possible, mortise & tenon. Nothing fancy, but that's what I like. If you want to try something new, nothing wrong with that.:cool:

Larry Palanuk
12-06-2007, 3:54 PM
With no real reason to make the switch, I think I will save the $50 and potentially a lot of frustration

Thanks for the feedback all

Rod Sheridan
12-06-2007, 4:14 PM
Larry if your material isn't absolutely flat, you'll find that a router table will make a mess of it.

The reversible joint is referenced from the face side, and we normally ran it in a sticker. Then we sent the material to glue up, where the trained monkeys (sorry, Valued Contributors) found it almost impossible to assemble the pieces incorrectly.

You can also run it in a shaper with a power feeder, as the feeder will force the material flat if it has a slight bow.

If you cut that joint on a router table, and the material wasn't flat, your joint would be out of alignment and there is nothing you can do about it. (Same problem as biscuits or dowels).

For flat panel glue up at home, I mill the material flat, glue and clamp it, and a light tap with the side of your hand will align the pieces properly. If you use dowels, biscuits, glue joints or splines, you cannot move anything so it has to be perfect at the machining stage.

Too much work for no gain when you are only making a few panels.

Regards, Rod.