So here I am, building an oak cabinet to house a 19-inch rack.
In the first part of this story, I talked about making a design, buying the oak and preparing it for use. In part two I cut pieces to size, and assembled the side parts of the cabinet. Now it’s time to put the cabinet together.
Most of the frame will be fixed using biscuit joints, for which I have a special biscuit cutter that makes the job easy and accurate. At this point however, I need to use a different technique. The wood strips I have for the top of the frame are too narrow to host these biscuits, so instead I will use dowels. The trouble is, I don’t really know how to measure the locations for the dowel holes… My abilities with hinges have proven poor to date (see the stories of the Cold Frame and the Pottery Store) so I don’t rate my skills at getting drill holes in two separate pieces of wood to line up first go. Anyway, let’s see what happens.
My plan is to make a template. When cutting the wood to length, I had a small block left over from the top cross pieces. I could use this as a guide for positioning dowel holes. I began by drilling two holes into this block to mark where dowels should go.
I then secured this block on top of the side frame at the place where the wood strip would go, and drilled through the holes in the block into the side frame.
I then repeated this process, securing the block onto the end of the wood strip itself, and drilling into the wood strip through the holes in the block. I remembered to turn the block over so that these holes were the right way round and not mirrored.
With the guide holes in place, I could drill larger holes to accommodate the dowels. (Seen here with the bottom cross pieces, which were wide enough to use biscuit joints.)
(After finishing this project, I learned of another, simpler and more reliable way of marking positions for dowels. Start by banging nail pins half-way into one of the pieces of wood at the locations where you want dowels to go. Then use a pair of wire cutters to cut off the tops of the nails, leaving short, sharp points. Next, bring the two bits of wood together to be in the desired positions, and squeeze them tight. This will push the cut nail ends into the other piece of wood at points where the dowels need to be. Taking the wood apart again and removing the nails will leave you with guide marks in both pieces of wood. I shall try that next time…)
One other thing to note here is that I decided to recess the front and back strips a little way in from the edge of the frame. I had earlier made the side joints to be flush both inside and outside. However, I wanted the front panels of the equipment in the rack to line up flush with the top and bottom cross pieces, and I knew that the equipment would be secured using screws that were raised in front of their front panels. I did not want these screw heads to stick out noticeably in front of the frame. I accommodated this in the top pieces by measuring an offset in the position of the template block when drilling the dowel holes. For the biscuit joints in the bottom pieces, I made an adjustment to the top guide on the biscuit cutter so that the holes in the side frame were offset by the same amount.
While doing all this drilling, I took the opportunity to drill holes for Cam Locks that will be used to secure the cabinet’s tabletop to the top of the frame. I talked a little about cam locks when I wrote about building my Son’s Desk, and I used them in the Hobby Board Shelves and CD Shelves and other projects I’ve covered in this blog. They’re metal widgets that you put into one piece of wood that rotate and lock onto metal widgets fixed into another piece of wood. You’ll have seen them in just about every flat pack furniture kit you can get. Very useful things. I used them here as I thought there was always a chance I would need to disassemble the tabletop from the cabinet frame, and these can be tightened and removed as often as you like.
One thing I didn’t do this time was to round off the edges of the cross pieces. When I made the sides of the frame, I put a rounded curve into the external edges. This gives a nice feel to the wood and takes off the sharp corners. I didn’t do this for the front and back cross pieces however, because these would eventually have equipment front panels mounted flush to their faces. Rounded edges would’ve resulted in gaps between the wood and the equipment in the rack.
Now to join the front and back cross pieces into the sides to make the frame. I realised at this point that I was down to my last four biscuits! I had just enough to complete this project before having to go out and buy a new pack. Packs of biscuits are quite big, so this make me realise just how many things I have put together around the house using this technique. I’m very grateful to my friend Barry for initially lending me his biscuit cutter (for the very first project I wrote up in this blog) and I think that buying my own cutter has been a really good investment. I now have plenty of biscuits for future projects (in two sizes too.)
Anyway, I digress. Assembly. I begin by testing the dowel joints to make sure the positioning is good. I dry-assemble each piece in turn using dowels and biscuits that I have sanded down a little to allow them to be fitted and removed easily without damaging the holes. First check is to make sure the cross pieces are in the right positions and square to the sides. Testament to my great skill and precision (ok, I got lucky…) everything seemed to line up nicely.
Next, I checked the critical measure, the gap between the bottom and top cross pieces. This has to accommodate the rack rail. I have a certain amount of leeway here as the bottom cross pieces can be adjusted a little – the biscuit hole is slightly wider than a biscuit and the shape of the hole is such that you can move the join a couple of millimetres when assembling. As it happens I have just the right gaps for the rails with each of the bottom cross pieces positioned flush to the ends of the upright pieces. It all seems to have worked, so now I can get gluing.
I begin by gluing one pair of cross pieces into one of the side frames. The most significant thing here is to get the cross pieces to be exactly perpendicular to the side rectangles. You would think this would happen naturally given the care taken to get the ends of the cross pieces nice and square. However, the joints need to be clamped while the glue sets, and an incorrectly applied clamp can pull the wood out of alignment if it does not apply pressure evenly. So, lots of fine tuning of clamp positions, and double-checking alignments with the set square, I eventually have the back cross-pieces in place.
Then when those joints were dry, I could repeat the process on the front cross pieces.
With the four cross pieces fixed correctly to one side, I now need to add the other side. First, I secure the partially assembled frame to a workbench, such that I can attach sash clamps to each corner.
Then glue the dowels and biscuits into the slots in the second frame.
A bit of excess glue appearing out of the holes doesn’t hurt – it shows that the dowels and biscuits will be properly and fully coated with glue. Also, the dowels and biscuits are not driven all the way in at this stage. They will be pushed further into both bits of wood when they are clamped up.
With glue similarly applied to the remaining holes in the cross pieces I can begin to fix the second side onto the frame. First I get everything lined up.
Then I can gradually tap the joints with a wooden mallet to close the gaps.
Each corner gets clamped to apply pressure down the lengths of the cross pieces and gradually drive home the dowels.
Excess glue can get wiped off as the joints are all closed up.
One trick I have learned here is to always use bits of scrap wood next to every metal clamp jaw. The metal of the clamp will dig into the wood and leave marks, so it’s best to have those marks in the scrap wood than the finished piece. It also helps to tape these scrap pieces down so that you’re not continually picking them up off the floor every time you have to adjust the clamp…
And with that, I have a frame!
A bit of sanding and polishing to do to get everything nice and smooth to touch, but so far, everything is good and square, and all the key dimensions are correct.
Next time, I’ll make the tabletop…