Fingerjoint Fit Questions

[Rob Luter]

Greetings to all -

Following my success at my first fingerjointed box (http://www.sawmillcreek.org/showthread.php?t=89332) I got pretty fired up to do something bigger. An old Gerstner tool box I found at an estate sale inspired me to try a three drawer tool box out of some Black Walnut harvested from my Dad's yard. All seemed to be going well until the glue up. The finger joints fit together very precisely with the heel of my hand when dry fit, but as soon as I put the glue on them and attempted assembly the wheels fell off. As soon as the fingers touched one another the glue seemed to set up. Even though this was "slow set" Titebond I literally had to beat the thing together using a combination of a leather coated mallet and bar clamps to draw the joints together. In the end I got it together, but it's not quite square and will likely need to be redone. Time will tell.

Even though it seemed the glue set up I don't think that really occured. From what I can tell either the glue swelled the wood or just made up a thick enough film that the fit tightened up. When I make my next fingerjointed box (probably the replacement for this one) I'll need to consider making the joints with a little more space between the fingers. I made a decent sled for fingerjointing and can make some adjustments, but I'm wondering if there's any rule of thumb for how tight the fit should be based on the size of the finger or the total length of the fingerjoint. I want a decent looking joint without huge glue lines. I'm sure I'll get there with trial and error (emphasis on the error part) but I'd sure welcome input from anyone who's already been down this road.

Thanks in advance for any pearls of wisdom.

- Rob

[John Thompson]

I prefer them tight after I have assured myself that the stock being used was the right moisture % and acclimated before I cut them. I use a Freud Box Cutter set and have my jig set for relatively tight. I apply glue with a squeeze bottle that has a 2" needle and spread it evenly with a 1/4 acid brush. Don't need much glue with a tight fit, IMO.

Sarge..

[glenn bradley]

Snug works for me. To quote Sam Maloof "Leave some room for the glue!".

[Mike Malott]

The issue is using a water based glue, which causes the fingers to swell.

Try using Gorilla Glue or some other non-water based glue.

Mike

[Ted Shrader]

Snug works for me. To quote Sam Maloof "Leave some room for the glue!".What Glenn said - or really what Sam Maloof said.

Regards,
Ted

[Joe Scharle]

Not saying that your problem was too long open time, but I've seen folks put glue on fingers and DTs with great care (and of course, great time) and not realize that they've spent 10 minutes doing so.
I put blue tape on the inside edges, wipe the glue on with an acid brush and sand it all flush later. On sides with a lot of fingers, I'll clamp one corner at a time just to draw the joint tight. I cut the fingers a little proud, so I have to sand anyway.

[Harley Reasons]

Another solution is too assembly joint and use CA glue on joint line and let bleed into the joint. Plane away excess after dry.

[John Bush]

A bit OT but similar ????. I am making a Morris recliner and the fit of the thru tenons and the mortises is 1/32 or so open in a few spots. I planned on the sanded oil finish to "fill in/hide" the gaps. Would CA and sanding dust fill in and absorb the oil finish without significant color difference?? I have only used CA for cracking turning blanks and haven't considered or noticed any color matching issues. Thanks for the insight. JCB.

[Will Blick]

Harley, have you successfuly employed this technique?

Doesn't the CA glue rough up the wood in the exposed areas? When you finish it, isn't it obvious where the glue is?

Sure sounds appealing vs. the long Urea glues...

[Rob Luter]

Thanks to all for the suggestions. I'll be experimenting with different amounts of clearance and see what seems to work best.

Sarge - I use the Freud set as well. The squeeze bottle with needle as an applicator sounds like a real timesaver. I was using a saucer full of glue and an acid brush. I guess I need to make another trip to the toy store :D.

[Harley Reasons]

Harley, have you successfuly employed this technique?

Doesn't the CA glue rough up the wood in the exposed areas? When you finish it, isn't it obvious where the glue is?

Sure sounds appealing vs. the long Urea glues...

I've used it successfully on some box drawers that I made. I learned of the technique from an article in the 2008 Summer edition of Woodworking magazine by Robert W. Lang entitled "Better Finger Joints". The CA won't dry instantly so you have to set the item aside and give it a few hours to setup deep in the joints. According to the article and IMHO it is as strong as a conventionally glued joint