Saturday, March 24, 2018

Broken Computer Desk Door Replacement

Broken Computer Desk Door

Accidentally hit this door on the right pedestal of my computer desk. It's made out of pressed wood with a thin laminated fake wood veneer. When the door went past the hinge limit it broke the upper and lower corners with the hinge pins off. Didn't take much force; not with 1/2-inch pressed wood. I hate the stuff and wouldn't have bought a desk made of it (someone who shall not be named bought it). I'd have built my own. Nevertheless, the broken door sat leaning up against the desk for a while. Photo shows the old door with the handle hardware removed.

Got tired of looking at it after a few weeks. Time to replace it with 1/2-inch birch plywood, about the same natural color as the rest of the desk. I've got all the tools required to quickly fabricate the new door. Birch plywood is frequently used for simple cabinetry and craft projects. It's not a hardwood, but it's not a soft wood like pine or fir either. Has seven layers, not counting the two birch layers, one on each side. Its pale color is easy to stain to a desired shade. The large number of layers makes it extremely stable and quite strong, resisting warping, even under load when used in shelving, if it's the proper thickness. I've used oak and birch plywood in furniture where the edges would be concealed for that reason. A 12" x 24" piece was a couple inches larger than the ~11" x ~20"original door and it was cheap on Amazon, with free shipping. Arrived on my doorstep in two days.

Panel Cutting With 10-inch Table Saw

The first step was cutting it down to proper size. A table saw with the proper fence and fixtures is the perfect tool for making precision rectangular panels with perfect right angle corners. This was my father's 1954 Craftsman 10-inch table saw. As far back as I can remember, this saw sat in our garage. Dad used it for just about ever project involving wood and lumber, including dressers, desks and a hobby horse to ride on when I was 3 years old. Those that know vintage Craftsman shop tools will recognize the "Craftsman Gray" color. They don't make them like this any more. Has a heavy cast iron bed and the blade is belt drive. The blade arbor can be raised to within a fraction of an inch of the table top. A 10" diameter blade can cut through 4" rough cut lumber. Many saws are direct drive with the motor severely limiting how much of the blade can protrude through the top. First step is ensuring the blade is at a right angle to the table using a small square. The rip fence isn't original. Left a lot to be desired in making furniture. It was made from cast aluminum and part of it had cracked from clamping stress over the years. Replaced it about fifteen years ago with a heavy-duty precision fence.

Ripping the Long Sides Parallel

Ripping the long sides and getting them perfectly parallel is done by setting the fence for the first cut about a half-inch or so more than the width needed. The second cut on the opposite edge is done with the fence set at the exact finished width. With a fine finishing blade (has more teeth than a rough cut) you get very smooth finished edges that are exactly parallel to each other. The two grooves in the saw table on each side of the blade are called miter grooves for use with a miter fence (which I won't be using for this). The yellow device with thin fingers clamped into the left miter fence groove is a device to prevent kickback of the work piece as it's slowly fed through the saw. The edge of the work piece displaces the fingers slightly which allow it to move forward, but prevent the saw blade from pushing it backward. These work extremely well. Anyone who's witnessed a table saw kickback in which the saw teeth grab onto a work piece, hurling it back at the saw operator, can attest to never, ever wanting to have that happen. It can cause very serious injury and a narrow piece of wood can impale you. The stick with the yellow tip is a "push stick". Keeps your fingers away from the whirring blade, which can lop off fingers in the blink of an eye.

Crosscutting the Short Sides Square

After the long sides are parallel, the short sides can be cut at precise right angles to them. The aluminum table extension on the left could be used as it's able to slide and can be fitted with a miter fence for making crosscuts at any desired angle. It's locked down and won't be used in this project. Neither will the crosscut miter fence be used. It's better for narrower pieces such as 2x4 lumber and I've got a miter saw for that. When making many right angle crosscuts on panels, it's easier to use a crosscut sled that's permanently set to a right angle. I fabricated one from birch plywood nearly twenty years ago.

It has an aluminum U-channel the same width as the miter groove on the bottom. The U-channel used is a special type, the width of which can be tweaked with some adjusting screws and wedges. It's exactly the same width as the miter fence groove in the saw table. To make it, I bolted the channel to the bottom of then plywood panel and ran the piece through the saw, which gave it a perfect edge precisely at the side of the saw blade.

For the sled fence, I added a door threshold made of ash (the poor man's oak) at a precise right angle to the sled edge that had just been cut, with the end protruding slightly over the edge. Properly kiln dried ash is very hardy and stable. Ran it through the saw again to trim the sled fence off. I've used this homemade crosscut sled for countless panels over the years. Easy to make if you know how, and worth its weight in gold when cutting furniture and cabinetry panels. Due care and time taken to ensure the sled fence is exactly at a right angle to the edge is the secret to repeatedly getting precise right angle crosscuts reliably on panels every time.

As with ripping the long edge, the first cut is made trimming a bit off one edge. The second cut is the precise one for the desired length from the other edge. With the work piece on the sled up against its fence, it gives a precise right angle on the panel. The piece trimmed off goes into the bin of wood "scraps" that can be used for something in the future. That bin has saved untold dollars and trips to the lumber store for a small, quick project.

Any doubts about whether it's square? Measure the two diagonals. If it's square, they'll be exactly the same length.

Adding the Hardware

A quick trip to the drill press for the door hardware holes. Took the measurements off of the old door for the new one. What better use as a backstop for the through holes than the old door. :-) A small Forstner bit was used to countersink the door handle screw on the inside to keep its head flush with the inside surface. Instead of the original wood screws, I used pan head machine screws through the door panel on the hinge pins. This will prevent them from being pulled out if there's stress on the pins.

Back side of the old door on the left, and the finished new door on the right with all the hardware attached. The small black rectangle in the upper right corner is the steel plate for the door latch magnet to hold the door closed. There are a few extraneous holes in the old door are from using it as a backstop on the drill press when drilling the holes in the new door. :-)

Front side of the old door on the left, and the new door on the right with all the hardware attached. Project almost finished.

Installing the Door

New door installed on the computer desk pedestal. It's very nearly the same color as the desk's pressed wood laminate. Fits perfectly with an even gap all the way around. Measure twice and sometimes thrice. Cut and drill once. I may take the door out at some time in the future and add some clear semi-gloss urethane to it. It's in a very benign environment, so it doesn't need much protection from moisture or humidity.

Bonus Photo

If you thought the table saw was vintage, this was my Dad's 1936 vintage 13-inch band saw. I remember when he bought it used in the mid-1960's. For those familiar with vintage Craftsman, it's in pre-WWII "Craftsman Blue" livery. Although not used for this project, it still works quite well. The bed is thick cast iron. The wheels are heavy cast iron, and you can see where they drilled out material in the rims to balance them when it was manufactured. Once it spins up, the upper and lower wheels are like flywheels. The energy in them allows plowing through tough spots in lumber without bogging the saw down. They don't make them like this any more. The aluminum angle piece on the left is used as a fence, and the C-clamps on the right are used to clamp it to the saw's work table.

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