This page also available in Spanish Some people are intimidated at the prospect of making their own wooden gears for the screw advance box joint jig. So I figured I'd cover the topic of gear making in a bit more detail. You can click on any image in this article to get a larger view. The method I use to make the gears for the box joint jig is the same as for the gears for the wooden router lift, but I'll focus on the ones for the box joint jig in this article. It's vital to use good plywood for the gears. Start by making a template for the gear shape. Glue the paper template onto a piece of birch plywood about 10 mm (3/8") thick. Next, use an awl to punch a divot in the center between every two gear teeth. Use a 5/16 (8 mm) brad point drill to drill out a hole in every space between the teeth. 5/16" is just the right size for the tooth spacing used in the gears for the box joint jig or the router lift. The divots made with the awl help to center the point of the drill on every hole.
Jenga pistol 2The game of Jenga was possibly designed to be a more contemplative and strategic game. But sliding those blocks out carefully without knocking over the stack is just entirely too fiddly a task to perform. I figured it would be much more fun to just be able to shoot the blocks out with some sort of pistol. The animation at left was extracted from a video shot at 60 frames per second. As a precaution, I'm pulling the pistol back immediately after the shot, to avoid having the stack fall on the pistol's bolt. The pistol works by hurling a wooden captive bolt forward inside the pistol, powered by rubber bands. I actually designed the pistol so that the rubber band pulls the bolt back again from its front most position after impact. Other than the rubber band and pulley, the bolt and trigger are the only moving parts of the gun. The trigger piece is two pieces of wood glued together. When the bolt is pulled back, it automatically hooks onto the trigger.
Gear generatorThis free online gear template generator is designed for making scale accurate paper gear templates which you can glue onto wood and then cut out with a bandsaw. I recommend printing the gears with an ink jet printer. Even cheap ink jet printers print very scale accurate but Not all laser printers are accurate. You can still access the old (pre 2015) Flash based gear geberator Getting the printout to scale correctly, avoiding cropping Different browsers print at different scales depending on browser type and printer configuration. Use an ink jet printer I recommend using an ink jet printer. Printing the gear templates To print the gear template, use the 'Print' button, instead of printing the web page from the browser. The gear generator program that I created and sell doesn't need the scale calibration, and can paginate across many pages for larger gears. Some notes about gear design and this gear template generator This gear template generator generates shapes for involute spur gears.
Timber Frame ToolsPlanetary gear ratio calculationsThis article also available in Spanish A question that I often get is how to work out planetary gears using the gear template generator Working out the tooth counts for planetary gears is actually not that complicated, so I initially neglected to mention how to do it. But having received the question a number of times, I'll elaborate. For convenience, let's denote R, S, and P as the number of teeth on the gears. The first constraint for a planetary gear to work out is that all teeth have the same pitch, or tooth spacing. The second constraint is: R = 2 × P + S That is to say, the number of teeth in the ring gear is equal to the number of teeth in the middle sun gear plus twice the number of teeth in the planet gears. In the gear at left, this would be 30 = 2 × 9 + 12 This can be made more clear by imagining "gears" that just roll (no teeth), and imagine an even number of planet gears. Now imagine the wheels have teeth. Here's another planetary gear set. ... and here it is inserted. We get
Вычерчивание профиля зубца - Техническое черчениеЭвольвентный профиль зубца. Построение эвольвенты в общем виде было рассмотрено в главе „Геометрическое черчение". Рассмотрим практическое применение этой кривой при вычерчивании профиля зубцов зубчатых колёс. Пусть даны два цилиндрических зубчатых колеса с модулем m=18 и числом зубцов: первого z1 = 18, второго z2 = 12. Для вычерчивания профиля зубцов пользуемся ранее приведёнными формулами. Первое колесо: d1 = m • z1 = 18 • 18 = 324 мм; De1 = m (z1 + 2) = 18(18 + 2) = 360 мм; Di1= De1 — 2 • 2,2 m = 360 — 2 • 2,2 • 18 = 280,8 мм; t= ? Второе колесо: d2 = m • z2 = 18 • 12 = 216 мм; De2 = m (z2 + 2) = 18 (12 + 2) = 252 мм; Di2 = De2 — 2 • 2,2 m = 252 — 2 • 2,2 • 18 = 172,8 мм. Проводим из центров O1 и 02 (фиг. 358) начальные окружности, окружности выступов и окружности впадин, обращая при этом внимание на то, чтобы начальные окружности обоих колёс имели одну общую точку касания К, лежащую на линии центров O1—O2. Проводим через точки d', c', b', e', f' перпендикулярно к радиусам лучи. t = ?
The Milkman's Workbench in UseThe Milkman’s Workbench – a portable bench I built for the June 2013 issue of Popular Woodworking Magazine – is about 653 percent better than my first workbench. Thanks to the clever engineering in the portable bench, it can handle most handwork tasks when clamped to a dining room table or kitchen countertop. My first workbench – a heavy door on sawhorses – could do only a fraction of these task. To demonstrate its capabilities, I attached the portable bench to my dining room table. If you watch the accompanying video, you’ll see the tabletop move a bit under the pressure of handplaning. Likewise, when dovetailing, you can see the table vibrate a bit. When you clamp this portable bench to a kitchen countertop or a dining table with four legs (instead of two), it’s as sturdy as an old-school workbench. Check out the issue in the ShopWoodworking store here that features the plans. — Christopher Schwarz P.S.
Dovetail joints on the bandsawWhen you read a lot of "fine woodworking" style magazines, sometimes it seems woodworking is all about the hand cut dovetails. Personally, I'm not that infatuated with this type of joint, but I thought I'd play around with them a bit. Now, I don't have the kind of patience required to cut them out by hand, so I sped up the process with my bandsaw. Dovetail joints require angle cuts. The jig is clamped onto my table using two of these funny "fence clamps" shown at right. My jig also conveniently serves as a fence. After having cut both sides of the joint, I make some more cuts to start hogging out the material between the pins. I make a turn as tight as the blade allows to start cutting out the material between the fingers. I have to work from both sides. Here's my pins cut. Now to transfer my marks onto the mating pieces. Cutting the tails is easy compared to the pins. Checking the fit I used lots of glue when I put the joints together. See also: More about joinery
Wind Up Mechanics: How To Make a Wind-Up Toy Yourself | Retro ToysThey are used all over the place - in wind up toys, cam and crank toys, or even in mechanical clocks. They are used to store kinetic energy just like the batteries are used to store electrical power. Without the wind-up mechanisms we would not have any of these toys with keys, and perhaps this site would not exist. So, let's have some fun and find out how wind-up mechanics work and even how you could build one such motor yourself. How Do They Work? Let's look inside such a mechanism. Number (1) in the graphic above is the key that winds up the motor. This graphic shows a really simple toy where the rotation transfers into another rotation. Most complex mechanical wind-up toys, and the mechanical clocks use 2 or more springs and many gears to transmit the power into complex motions. How To Make One Yourself What if you are so amazed by wind-up mechanics that you want to build one such motor yourself? So, there are three main things you need to buy or make: Gears. So, that's it... Sources