So, the next fall, we bit the bullet and installed a wood stove. The basement has become the primo destination in the winter for every activity. We keep the thermostat upstairs at 61F during the day and let it drift down to 59F at night. Meanwhile, the basement hovers between 72F and 85F depending on what the stove is doing and what kind of wood is being burned. Maple gets nice and hot and is a good mix for burning with oak. Hickory brings aromatic bliss as does cedar kindling and cherry wood.
One thing I would really like is for the upstairs to be as pleasant as the down stairs. So, while we were having our floor replaced, I thought it would be a good time to install a floor grate common in the old houses which featured basement boilers. Usually those are cold air return vents to let the cooler air settle down into the basement where the boiler or furnace would draw it in and heat it and feed it up through an iron octopus of pipes and vents. In our case, the hope is that warm air will rise from the wood stove, almost directly through this grate to the living room while cold air falls down the stair well, making the whole house a bit more evenly heated and comfortable.
I started out looking for cast-iron antique grates but the local Habitat Re-store had sold through their small supply. I looked at local home improvement stores but all they had were standard vent sizes and I wanted something a bit larger. I decided, with time short, as we had the installers scheduled mere days away, that I would build my own from oak.
I started by sketching the idea out on a paper placemat at one of our local favorite restaurants. From there, I wanted to build a model in Sketchup to make sure it worked, but I'm old school and learned to model 3D objects in three-axis views using Lightwave back when I was working towards Film and Video special effects and Sketchup is just one long exercise in frustration for me. So, I dug out an old copy of Lightwave and built my floor grate with perfect precision. From that, I knew the design would work and what my dimensions were. Lightwave has a measure tool like Sketchup so I was able to check and recheck dimensions while I built.
- 5, 1 1/2" x 1/4" x 24" oak "planks"
- 2, 1 1/2" x 3/4" x 24" oak boards
The design would rely on interlocking pieces for strength and uniformity. First I taped the planks together in a bundle so that my cuts would be uniform, then I marked out 4, 10 3/4" lengths along with blade space for the table saw. After cutting, they were taped into two packs of 10 using the same masking tape. I wrapped the tape in a spiral down the length of each pack. This provided a nice surface to draw the cut-outs directly on the pack and also serves to limit splintering on the trailing edge that a table saw can often produce in hard wood.
One pack of ten would have 3/4" dado cuts facing up, spaced 3/4" apart and the other would have the same facing down. The ends had a 3/4" rabbit on the bottom and a 1/8" rabbit on the top. This left a 5/8" tongue that would sit in the the 1/4" x 5/8" groove cut into the perimeter rail pieces.
Cutting the slats was tedious but rewarding when they all fit together tightly. Small imperfections in spacing that occurred due to not using a fence with a key meant some pieces actually bend to fit in place, fortuitously locking the members together tightly with no glue.
One tip I picked up Woodsmith magazine was creating a custom top for my table saw. You can see it clamped down in the above picture. I used my dado blade to cut a guide slot for my perpendicular slide and placed it so the slide could run within 1/8" of the dado blade. This allowed me a greater degree of precision as the stock guide slot is a bit loose and 2" further to the left of the blade.
Once the lattice was knocked together, I started on the rails. I was concerned about the potential for structural failure though. Below you can see my area of concern in the cross section on the right, which is from the original design. The cross section on the left is a modified design I came up with, explained further below.
In the cross section on the right, I was worried the 1/4" neck would experience failure along the grain if someone put their full weight on the grate. My solution was to use a 10 degree bevel. This also alleviated my other concern, that of the wood breathing and either shrinking and falling through the hole or growing and warping against the floor boards under the pressure. My oak bench seat has a 1/2" to 3/4" bow in it owing to Ohio humidity. It is firmly jammed against the ends of the window box, which consists of 2 2x6 king studs on either side. But I digress. The point is that taught me something about oak. The slats have a 1/4" tongue but that runs along the grain so I'm not worried about a failure there.
The rails were first beveled using the table saw with the ripping fence and another plunge cut on the ply-wood table top so that I had solid alignment pushing the rails past the blade using my push stick and guide. ALWAYS use sacrificial materials to guide and push your wood through your saw. NEVER use your fingers.
Then the rails went for a ride in the compound miter saw to get 45 degree miters on each end. Finishing up involved applying a film of glue to the inside of the rails, on all three sides of the groove and on the face above and below using a 1/2" brush and Tight Bond III wood glue.
With the beveled design, any change in dimension would cause the grate to rise up out of the hole or settle down into it a bit. I cut the floor at the same angle to provide a good amount of contact and, like a cork, gently worked the grate into place with my heels on the corners.
The following day, the installers came and finished the floor (they had come just short of this location on the first day of work), and that night I applied a coat of Polyshades (tm) Pecan polyurethane. I used a 1" foam brush to get into the holes and a 1/4" fiber brush to get into the tight spots. After rubbing it down tonight with 0000 steel wool, it looks pretty good.
Total cost was about $24 if you count the stain, which I had. Materials came in at $18. Total build time was about 6 hours from design to completion, spread out over three days in my evenings and free time. Finished dimensions are 11 3/4" x 11 3/4 " x 1 1/2 ".
The finished grate looks great, and is rock solid. Thumping it with the ball of my foot feels no less solid than the floor itself. Hopefully it will last for years and help achieve the desired distribution of heat in the house this coming winter.