Monthly Archive for August, 2010

Doorbell: Making the motor housing -1

Published on August 26, 2010 in Bending. Closed Tags: .

Cutting .060" mahogany slices with Laguna Tools' Resaw King blade.

The doorbell motor sticks out from the feature panel like a 4″ wart. It’s semi-circular end supports a circular arrangement of tubular bells. That, and the fact that it’s just under the arched top of the cabinet, suggested a curved motor housing.

I wanted the same Honduran Mahogany used in the mouldings, but I had to curve it around a 4″ diameter curve. I could kerf it (like the cabinet top), steam bend it, or laminate it. I was afraid the kerf cuts would show in the motor opening, and steam bending involved springback, which makes precise sizing difficult. Since I wanted a snug fit on the motor, I opted for laminating a sheaf of veneer slices.

Four .060" veneer slices would give me a finished housing wall thickness of about 1/4".

I glued up a bending form out of particle board, then tried bending various thicknesses of the mahogany. I could bend .060″ thick slices around the form. Four of these would give me a 1/4″ wall thickness—perfect for the housing.

I wanted very clean and accurate slices, since any irregularities would be multiplied by four. So I mounted a Laguna Tools Resaw King blade on the bandsaw and cut slowly. The slices were clean enough to need no sanding.

I pre-bent each veneer sheet around a form after dipping it in boiling water.

I could have bent them directly around the form, but then I’d have to fight the springiness of the leaves, slippery with glue, during the crucial clamp-up. Life’s too short. So I pre-bent the sheets first.

I just wanted a bend in the middle, with straight sections on either side. So I forced the middle of each leaf down into a pan of boiling water. In a few seconds, I could easily bend it around the form. Once bent, I clamped the ends of the (now U-shaped) leaves and let them dry.

Next—the glue-up and trimming.

Doorbell: Finishing up the feature panel

Published on August 23, 2010 in Finishing and Routing. Closed Tags: , .

Here's the feature panel, all inlaid and with the lines flushed to the surface, ready to finish.

I probably should have added these pics to the previous post. The first pic is of the panel after all the grooves have been cut and filled with cherry veneer slices. I leveled them and sanded the whole panel, then pre-finished it with shellac before adding the frame. I did this because the frame projects out a little from the surface of the panel, and it’s easier to rub out something that doesn’t have those little “walls” to stop your hand on each stroke.

Here's the panel wearing its mahogany frame.

The second picture shows the panel wearing its mahogany frame. The frame was moulded from flat stock with a router, using the same techniques as the larger mouldings I blogged about earlier. I masked the edges of the panel before gluing on the frame pieces, then finished them with shellac and rubbed them out to a satin finish with 0000 steel wool and wax.

Doorbell: Making the feature panel

Published on August 20, 2010 in Routing and Uncategorized. Closed Tags: , .

The most eye-catching feature of this project is a panel veneered with curly maple veneer, with a cherry cross-hatch pattern inlaid over it. I blogged back on June 22nd about having to bleach the maple veneer because it arrived too red. Here’s how I did the inlay.

I vacuum bag veneered the maple onto one side of an MDF panel, and put a backer veneer on the other side. Then I sealed the maple veneer with a coat of shellac. Once the panel was ready to work on, I wanted to create a pattern that referenced the floor where the project would be installed. That floor is 20″ limestone squares, separated by 1/4″ grout lines. I scaled down by a factor of ten, and wanted to produce 2″ diamonds in a pattern, separated by .025″ lines of inlaid cherry.

Here you see the special router base screwed onto my Dremel tool. In front is a router guide.

The essential tools came from Stewart McDonald Co. They included a very precise fixed router base, shown attached to the Dremel tool at left; and a six-pack of .030″ straight router bits (I needed several because they break easily). With these tools, I could route a line just wide enough to accept the thickness of a sheet of cherry veneer.

Next, I attached a sacrificial hardboard sheet to a straightedge and cut it off with the router bit in the Dremel tool. You see the results in the first photo. This would tell me exactly where the bit was going to cut. Finally, I cut a 2″ spacer from another piece of hardboard.

Here the Dremel "router" is ready to cut a .030" inlay channel, once a new bit is inserted. The black strips are shims to let me cut to final depth in three passes.

I made the first cut on one corner of the panel at 45º. Then it was a simple matter to run a stop up to the straightedge, remove same, drop in my 2″ spacer, and re-clamp the straightedge for the next pass.

Actually, it wasn’t quite that simple, because the router bit wasn’t stout enough to cut to final depth in one pass. So I cut a couple of plastic shims from a .012″ thick sheet. On the first pass, I stacked both pieces under the router base. Next pass, I removed one. Finally, I made a pass with no shims to get sufficient depth.

When I reached the end of the panel, I ripped my cherry veneer into roughly 1/8″ strips with a newly-sharpened paper cutter, and glued them in place. After the glue set, I leveled them with a hand plane before making the intersecting cuts.

When the inlay was complete, I leveled everything carefully with a sharp plane and card scrapers, sanded and vacuumed the surface, and applied five coats of shellac. After a few days, I rubbed out the surface with 0000 steel wool and wax.

Doorbell: Precision cutting moulding parts

Published on August 18, 2010 in Jigs and Fixtures and Joinery. 1 Comment Tags: , .

The router bit made the top bead of the moulding. Beside it you can see the smallest of the three parts comprising the assembly.

The trim mouldings have to fit just right, and have to wrap around and return to the wall. I needed three partassemblies to wrap from the inside of the cabinet, across the face, and return to the wall with a tiny mitered piece. That means precise cutting. It’s no time for hand clamping to a miter gauge. Here’s my approach.

I build a small bandsaw sled for cutting the 45º miters. You see it  in the picture below.

I used the sled to cut a stop block with one mitered end, which you see held in the “F” clamp near the front of the sled. I backed that up with a second stop block, held in a spring clamp.

I used this sled on the bandsaw (with a new blade) to cut the mitered moulding sections to precise lengths.

To cut the longest moulding pieces, which have one 90º end, I squared the end of a strip of moulding and set the second stop block to cut it a little too long. Then I measured how much too long it was (compared to the cabinet sides), and inserted feeler gauge spacers between the stop block and the cut-off piece to get it to the right length before cutting it to final size.

Doorbell: making trim moulding

Published on August 10, 2010 in Routing. 4 Comments Tags: .

I thought six bits had promising profiles. Here you see the shape each makes, and how it contributes to a moulding.

I wanted moulding above and below the fluted trim pieces which make up the sides of the case, so I pulled out the most promising router bits and cut sample profiles to consider.

I needed two mouldings: one about an inch tall, and the second about 2″ tall. The picture at left shows how I combined the shapes made by two of the bits to create the 1″ moulding.

The lower moulding (next photo down) used the broad curve from the same (top left) router bit to shape its lowest part, followed by a straight section and a small bead from the bit on the top right.

The bottom component is from the same router bit used above. The top bead is from this bit.

The point is, you’re not restricted to store-bought mouldings for your projects. In fact, it’s often difficult to incorporate them into something. First, they’re rarely made from a matching wood. Even if it’s nominally the same species as the rest of your project, differences from tree to tree may keep it from matching. But often you can’t find the shape you want in the right wood at all. Second, you have to plan around the available mouldings. If you make your own, you can pick a piece of this profile, a piece of that, and combine them into something that’s just the size you need. I don’t have a large number of profile bits, but I can combine them to make an incredible number of shapes.

Review: Lessons in Segmented Woodturning

Published on August 8, 2010 in Reviews. 5 Comments Tags: , , .

Segmented Turner Malcolm Tibbetts shows one of his incredible segmented turnings from this DVD.

I recently watched Vol. 3 of Malcolm Tibbetts‘ Lessons on Segmented Woodturning DVD series.

Malcolm does things most people would consider impossible on a lathe. (He’s also a personable and entertaining presenter.) He spent a day at my woodturning club, Silicon Valley Woodturners, and the pieces he brought along to show were absolutely amazing. Here’s a review of this DVD (stored in the Q&A section), which I will also publish this month in the club’s newsletter.