The process of drawboring has been mostly covered but I felt like giving a few tips in case this is in your mind to do on your table. The main thing is to make sure that the holes are spaced so they miss each other and are close to the middle of the tenon (mine could have been closer). Also make sure that the hole you drill is not going to be under the shoulder of one of your rails…simple mistake that makes assembly kind of hard. Your holes should be as close to the rails as they can be without being under them. I used blind drawbores…take care if you do this not to drill through the leg, the tip of the bradpoint goes farther than you think. I used a brad point to start the hole and a twist drill to finish it to get as deep as I could in the leg without poking through the other side.
Give yourself 3/16ths of clearance in case you need to clean the outside of the leg after assembly. To create several drawbore pins I took ¼ inch poplar doweling rod and cut several pieces to length on my bench hook (a small pencil mark on my hook to get the length consistent helped), and lightly chamfered the leading edge with a pencil sharpener. MAKE EXTRAS!!! You don’t want to scramble for more during a glue up, I typically make 5 pins for each 4 I need.
Glue up was…interesting. The filming did not go well so rather than show my blurry, out of frame, frantic attempts to glue up the entire assembly in one shot (against my typical recommendations…I screwed up of course) I thought it would be more beneficial to show what needs to be done for the successful glue up of this table. In short. Glue this up in three sessions; one for each of the short rail assemblies (one short rail two legs) and one gluing the longer rails into the two sub assemblies to complete the base. This means at max you only have to glue up 4 joints at a time…as opposed to 8. This will really help both your stress level and your chances of success.
My apologies for the poor editing on this clip. I tried to get the full length video (12 minutes) up several times before I chopped it down to under 10 for upload.
I go through this in the video, but in case I missed something or you want a list to take into the shop.
For the small rail assemblies here are the checks you need to run.
1. Does the top of the rail meet up with the legs eventual top line?
2. Is the joint closed?
3. Is the measurement from the corner of the bottom of the leg to top of the opposite leg (it’s final height, not the height of the horn) the same from corner to corner…if so the sub-assembly is square.
4. Check that the legs are not twisting from one to another (sight across the straight sides as though it were winding sticks)
Tweak the joints on these sub-assemblies until you are happy. Double check that large gobs of glue don’t end up in the mortises that the longer rails will go into as those will require clean up or they will interfere with your fit. I pound the drawbores in once everything looks right (note, during test fit, I had to modify the fit of one drawbore hole with a rat-tail rasp in order to have the joint come together correctly…take your time with drawbore joints since they are permanent)
On the final glue up, you will need to do these same checks (on 4 joints as opposed to two). You will also need to check for a few more things
1. Are the corner measurements from the top of the left front leg to the top of the right back leg the same as the measurement from the top of the right front leg to the top of the left back leg? Use a clamp from corner to corner on the longer measurement to squeeze this into alignment.
2. Check the rails for twist with winding sticks. Tweak the fame to avoid any twist hear since it will interfere with the top.
3. Set the who assembly on a flat surface (table saw in my case…but a well flattened workbench works too) to dry nice and flat…this saves time later when you go to level the table. If it dries a little off resist the urge to fix it now as attaching the table top may reintroduce (or fix) the issue.
Speaking of the top…
Starting the table top is very exciting to me. I have had this slab of beech waiting patiently for some time. I just needed the right project to come along. I did my layout on the table top before but left the cuts for after the base was complete…giving me time to meditate on my decisions. Invariably I change just a little bit when I do this and this top is no exception.
It’s a point of pride to show a top that looks seamless, when I looked at my layout lines a second time I realized that one of my cuts was going to fall in the smoky colored section on the beech…if I joined this to the other board as I had originally planned then I would create a line where the seam hits and the color stops. As a result I decided that it would be better to miss the smoke color completely since the creamy parts’ grain pattern is so subdued and easy to match.
I made this rip cut first and lightly jointed the edges with the stock clamped face to face, this is a nice tactic on longer pieces since any variation from square is cancelled out by orientation of the wood (if you are 5 degrees off square, one board will be 95 degrees and the other will be 85 degrees). Be careful with this technique though as it can lead to two problems:
1. If your joint planed far out of square it will try to creep on you when you apply pressure from clamps (so the more square you are the better)
2. While this technique solve minor lateral problems, it doubles any lengthwise imperfections, so take care that any lengthwise hump or hollow is removed to the point that you can press the joint together with hand pressure (a very slight hollow on the joint is OK and even aimed for by some craftsman, but avoid a hump at all costs)
Obviously, your jointer should have a straight blade if you intend to do this (any edge to edge glue joint should be done with a flat blade really).
One orientation with the grain looked great and I used big triangles to mark how I wanted to glue up the joint…then I remembered about the big crack in the bottom of one of the boards, and I rethought things a bit…the small triangles became my permanent decision for how the joint goes together. Take your time with difficult and precious wood; you can rethink a cut several times but you can only execute it once.
One change always leads to others.…by adding an extra inch to the center of the top my new cut line (marked out using two marks with a story stick then connected by chalk line) fell directly across some of the pattern I wanted to keep.
I decided here that the best approach would be to decide where the front of the desktop should be to look right and to make that cut first. I had room to play around on the back end without messing up the feel of the piece. I made my rip cut and I jointed that edge…the smoke pattern falls around the left front of the top, I did this for two reasons:
1. It looks cool and it is a clue to someone looking at this piece that this is not veneer.
2. I wanted to know about how far the color goes into the wood since it has completely disappeared on the other side.
Knowing that the pattern seems to be halfway into the board gives me some confidence but I still want to be careful and not take off too much material. When gluing up panels and working them by hand you have two choices; glue up rough material and surface/square it as one piece, or square the individual boards that make up the panel and glue those together. Both ways work if you are careful of the pitfalls that they present. The later can get you into trouble if you are not very careful aligning your glue up (some people resort to using dowels in the joint to be certain). The former presents a different challenge, if the panel is not glued up “as flat as it can be glued up” you may have to remove too much material to get the wider panel flat. This is the other reason I joint the seam with the faces clamped together…it finds the flattest configuration for you.
I decided to leave the last rip cut until after the top was glued up and flattened. This is not the best habit of mine since I will have to remove a touch more material to flatten the board. It’s pretty flat to begin with so I am not too worried, and this approach lets me test fit the top on the base to see if I like the look before I am totally committed to it. The extra few inches gives me the option to make last minute changes and I can use it as means to control tearout on the back of the cut when I traverse the top.
Next stop, getting the base in order to attach to the top, flatting smoothing, and shaping the top…and a tiny bit about finishing. We are in the home stretch…keep your tools sharp.
-- Make furniture that lasts as long as the tree - Ryan