1/4" Finger joints in plywood

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jaysg
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1/4" Finger joints in plywood

Post by jaysg »

Mostly I'm testing the attachment thing. I've already done it wrong once...where did it go? Anyway, this was a treat to figure out how to not let end up with shattered fingers and then get it all together. The rear panel is attached with biscuits.
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GlennG

Post by GlennG »

Nice job that looks great. Evertime I try finger joints or dovetails in plywood I get so much tearout that I`ve just about given up on using using the stuff :? . Care to share your secrets? I like biscuits too, I made some cabs using biscuits on all sides and they turned out very nice...very strong too.

Glenn Gertis
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Gabi
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Post by Gabi »

Awsome work over there Jay! You have tons of slots over there for the finger-joining. Did you used a jig? Or the table saw?

Glenn,

Try using back-up pieces (scraps) of wood (1/2" thick is quite enough) in front of the board you are routing. I usually clamp it in with the jig clamps. This is if you are talking about the dovetail jig.

This way the router won't chip off the edges.

I'll post some pictures once of my dovetails jigging...

Take care,
Gabi.

PS: here is an example of my work on a 2 x 12 extension cabinet.
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Post by EBE »

If I use plywood with dovetails I only use it for the top and bottom. For the sides with the fingers I use solid pine. I had some half inch plywood that was nine plys and really held up well. I bought a nice sheet of 3/4 inch birch plywood and it does not hold up when cutting the fingers. I thought maybe my bit was getting a bit dull but when I used the solid pine the fingers came out just fine.

Norm
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jaysg
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Post by jaysg »

GlennG wrote:Evertime I try finger joints or dovetails in plywood I get so much tearout that I`ve just about given up on using using the stuff :? . Care to share your secrets?
Like Gabi said - backer board and fronter board. I had a jig made, based on posts by Jeff Suits over on the weber Enclosures board. It has 1/8" tynes spaced 3/8" apart. A 1/4" spiral bit with a 3/8" bearing goes in the slots. Thanks for the kind words.
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SpentMusic
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Dovetails

Post by SpentMusic »

The dovetails work very well with 1/2 inch 9-ply baltic birch. The 3/4 requires so much removal of wood that it is very very difficult. A backing piece as Gabi said and very sharp bits. Go slow will all of it. The pine is a dream as it is such a soft wood but not a personnel favorite of mine (I grew up with a pine bed and it broke in the middle of the night, may have some issues to deal with LOL :mrgreen: )

I'm about to invest in a big Porter Cable omni jig so I can make the 3/4 inch hiwatt style cabs with dovetails. As I get some more experience (successful!!!) on the 3/4 I'll pass it on. One note is if your jig is loose or vibrates a lot it will create problems. A lot of the smaller jibs you see just can't hold up.

Jeff Swanson
SpentMusic, Inc.
www.swansoncabinets.com
Last edited by SpentMusic on Fri 04/11/03 11:38 pm, edited 1 time in total.
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EBE
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Post by EBE »

I bought the 24 inch porter cable jig for myself for Christmas :) I got a deal I couldn't pass up.
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jaysg
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Post by jaysg »

here's my jig:
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