Saturday, June 4, 2011

A Smoothing Plane Trick and Some Amazing Dovetails

Last week I glued the small chest using Old Brown Glue. It's my first time using the stuff and I have to say I like it. One thing I don't care for is the smell however. When I warmed the glue in warm water then cracked open the lid, I had the same feeling when you start rooting through last night's leftovers first thing in the morning and mistakenly open the Tupperware of broccoli. To me it smells very little like hot hide glue. Not that I enjoy that odor, but its not off putting. In fact, when I do mix up a batch of hot glue I'm immediately taken back in time to some of the more intense sessions of luthiery work. It's an interesting sensation.

Nevertheless, I'm probably going to move towards using this glue for all my furniture making. The main reasons are convenience and conservation. The longer open time of OBG is important for gluing certain long-assembly joints like the dovetails in this chest. Even yellow glue is too quick for my tastes in this case. Yellow glue does not stick to itself, making future repairs extremely difficult. Hide glue just needs to be rehydrated to reactivate it. One thing I noticed right away about OBG that I did not expect. Once it cools and starts to cure it gets super tacky just like hot hide. I love this feature, and it instills confidence. I never experienced this with Franklin's liquid hide glue, which I've used now and then. 

After the glue cured (I let it sit overnight) I had the task of planing the joints flush. Planing large unsupported panels after assembly is always tricky. I did cut these dovetails so the joints were slightly proud, but I always find some long grain planing that needs to take place post-assembly. And that's where vibration comes into play. Not in the plane, but in the panel. There is also the issue of the panel flexing to concave under planing pressure and preventing the iron from engaging.

So I clamped the chest to the bench in the tail vise and inserted a wide board between the front and back of the chest. The board is just a tad longer than the inside width of the chest. The brace introduced a very slight convex bow to the outside of the panels, allowing my smoothing plane to ride the arch easily. No chance of the cut disengaging from the panel as it deflected away from the sole. The brace also prevented any vibration. It was as if I was working the panel directly on the bench top.

Sighting down the panel's edge the slight outward bow can be seen.

Once the corners were planed flush (the end panels were short enough not to need the brace trick) and the joints revealed, the accuracy of the Bridge City JMP became evident once again. I was simply blown away by the quality of the joints. Every one was dead on. No gaps. Simply put, the joints were as close to perfect as possible. If you're into that sort of thing (I like tight joints too, but I don't obsess about them), the JMP won't disappoint. All I did was make careful scribe lines (see that in the video in the previous "Personal Work" post) and then line up those scribe lines right the blade's edge on my zero-clearance tables on the JMP. That's it.


  1. Hey, nice work and nice tip. I've found the same problem when smoothing/fitting drawer sides, probably would work there too.


  2. Jameel

    Those joints look awesome , almost like they grew together. The JMP sure does a nice job of cutting them . Do you know of any video's that show how to cut them using the JMP?

    Thanks for the tip on planing joints and link to OBG , think I'll give a bottle a try to see how it is . His blog looks very interesting too, should be a good read. Stay well my friend . Hope to see you soon .

  3. Jerry,

    Here's the technique I used, except I didn't make the cuts in one pass since my boards were thicker.

  4. I gave Old Brown Glue a try since I was getting ready to glue a 27" deep dovetailed carcase together. And in my rather cool basement shop (68 in the summer, maybe down to 60 in the winter) it delivered a 5 minute open time. I heated the glue in water to 130 and tried to warm the wood, but it didn't make a difference. I exchanged some emails with the guy who makes it where he suggested I should heat my shop to 75.

    I subsequently encountered fish glue at Lee Valley, which advertises a 60-90 minute open time. So I gave that a try and it really does deliver a much longer open time. I think it may share those other advantages with hide glue as well. I used it to glue my project together and it all went without a hitch. It took me about 45 minutes to get everything assembled, so I'm glad I wasn't using regular PVA glue. Everyone talks about hide glue these days, it seems, but I wonder if fish glue ought to be better known.