Having made an Adirondack camping chair (see this instructable Adirondack Deck Chair) and planning to camping in a couple of weeks I needed to make myself somewhere to put my drinks without them falling over on uneven ground!
My friend had brought me some hardwood offcuts round a week or two ago and one of the pieces was a small planned board which seemed like a perfect bit to make this out of. I got out my vernier calipers and measured the thickness of the board and the arm of my chair. As luck would have it they were pretty much the same thickness.....nice. I'm not sure what species of wood it is, my knowledge is limited to timber I have bought and know what it is. I know its not walnut and that's about it!
The dimensions of the older came about by the width of the board and the type of drinks I will be drinking while camping. For good measure I wanted to allow for a half litre bottle and a stein mug, this would pretty much allow for any type of receptacle to be used on the holder.
Timber - if you have some largish offcuts these should do.
Glue - I used Titebond III for its waterproof properties
Finish - I used Osmo 420 which has UV protection so should be good for this
Step 1: Prepare the Router
I designed my holder to hold different types of drinks in different way. If I was drinking some tea I would want to put my cup in a fairly shallow recess as the handle would get in the way with a deep recess. If I then wanted a beer I would want to put the bottle in a deeper recess to reduce the risk of spillage - this becomes increasing more important the later in to the night it gets. Therefore I decided to have a top section with a recess and a hole and a lower solid section these would be separated with pieces of timber the same width as the chair arm.
I find one of the best ways to cut circles in wood is to use a router. I have a small laminate trimmer which I have added a plywood base to. In the ply I have drilled holes at certain distances away from the router bit to give me different size holes. After measuring my bottle and stein I determined that I needed a 100mm diameter recess and a 75mm diameter hole. I already had a hole on the router base for 100mm so I added another to give me 75mm.
Step 2: Cut the Wood
After marking the centres of the circles I drilled a hole through the wood using the same drill bit that was used for the router base holes. Once they are drilled take the drill bit out of the drill and insert it in to one of the holes, this ensures a snug fit. As the circles are fairly small the holes in my router base ended up under the router so the drill bit could only stick up 6mm.
Once you are ready start the router using a shallow cutting depth and lower it on to the pin and in to the wood. All you have to do now is rotate the router until you have a circle. For the hole just keep lowering the router cutter bit by bit until you have cut through the entire wood. Do remember to rest your wood on a piece of scrap so you don't end up with circles on your workbench!
The process for the recess is pretty much the same apart from you stop once you are at a nice looking depth. Once you have done this you need to remove the waste from the centre which I do freehand. Again do this in several passes and be careful not to go too far and start cutting in to the edge of the recess.
Once this has been done go and check the hole and recess with your cups etc. I did, and neither were the correct size so I had to go back and enlarge the recess and the hole. Making the recess bigger was easy as the centre hole for the drill was still there. The hole was much more difficult. I had to clamp the wood on to another piece and estimate where the centre was, drill a hole in to the lower piece, insert the drill bit and cut the hole. Unfortunately the router kicked back a little when I was doing one of my passes and it took a small chunk out of the top...grrr. This also caused the top bit of wood to move and the hole ended up uneven throughout its depth. This was easily rectified by using a straight router bit with a bearing and following the larger of the two circles.
I then routered a profile to the top of the hole to give the top a slightly better finish and make the chip a bit smaller.
Step 3: Assemble
Once the top part had been finished I cut it to the correct width and cut the bottom part the same size as the top. I wanted the edge of the holder to be in line with the edge of the chair arm so I positioned the bottom bit of the holder on the arm and marked out the position of what would be essentially be the 'stop'.
After cutting three small bits of wood I glued them to the bottom part and secured them with a couple of brad nails. This makes clamping a little easier as you don't need to worry about the middle bits moving. The top bit was secured only with glue and the whole thing was clamped for a couple of hours.
Step 4: Sand and Finish
Once the glue had set I sanded the whole piece using a random orbital sander and hand sanding the parts the sander could not reach. I also added a some chamfers to each corner to remove the sharp corners. I then rubbed a couple of coats of UV protective oil on the finished holder. Once it had dried I tested it out to make sure it fit on the arm correctly which thankfully if did.
The proper test will be in a couple of weeks when I go camping......brilliant!!