Round part present special challenges in the workshop. How to we safely machine them on the table saw, drill press, or other machines when their is no flat side to put against the fence and table? The best solution is usually to build a simple box jig which, as the name implies, is nothing more than a simple box made out of scraps to hold the part. While the video above uses woodworking examples, box jigs are also handy to hold round or irregularly shaped metal parts for work with machines like mills and shapers.
Basic box jigs come in two types. Open ended jigs, as shown in the first part of the video, are useful with parts that have one flat face that can be screwed to one of the faces of the box. They are very especially useful for making cuts in the round part on the table saw or band saw. Closed end jigs are used with spindles and curved parts which need to be secured from the ends and are especially useful for routing or drilling operations. While simple versions like the one in the animation at the end of the video usually just use screws to secure the ends of the work, it is also possible to build in lathe-style centers and a shop-built or store-bought indexing head to hold the piece at certain precise angles. Professional indexing heads are complicated and expensive, but a simple pivoting disk of wood with holes for a pin is often adequate for one-off jobs. Many furniture makers build simple indexing box jigs to so they can route the mortises in table pedestals to attach the legs.
While they are very simple, box jigs are one of the most useful and common families of jigs in the handyman's workshop.
Finishing is a complex subject which can seem a tad bewildering to beginning woodworkers. There are a multitude of products on the market, and numerous special finishes for particular applications or visual effects. The following, however, is a good general purpose finish that should give good results for most indoor projects regardless of the type of wood used. It doesn't require any special tools or knowledge and the supplies are available at any hardware store.
Supplies Needed
Several Lint-Free Rags - Scraps from a worn-out t-shirt are ideal. Heavy-duty paper towels will also work.
Cotton Swabs or Small Cheap Brush - For getting into tight spaces.
Disposable Rubber Gloves - Unless you don't mind staining your hands brown.
Oil Based Stain - All of the brands give similar results. The shade is a matter of personal preference; when in doubt go with any of the "medium" brown colors.
Premixed Shellac - I use Zinser brand, which is widely sold here in the States.
Denatured Alcohol - For thinning and cleaning up after the Shellac. This is just high-concentration rubbing alcohol.
It is often a good idea to sand and finish a scrap first to see what a finish will look like when it's done. If you write notes on the back of the scrap you can save it and start building a "library" to help remember what different finishes look like on different kinds of wood. If you're satisfied then go ahead and finish your project.
Step-by-Step
Sand everything to 180-grit. Try to sand hard-to reach spots before you glue together your project.
Thin shellac about half-and-half with alcohol to make a sanding sealer. Rub this over your whole project and allow it to dry for at least half an hour. The sealer will fill in the pores of the wood keep the stain from streaking--a particular problem with pines and maples.
Lightly hand-sand with 220-grit.
Stir up your stain and wipe it onto your project with a rag. You can put it on fairly thick. Use cotton swabs or a brush to push stain into corners and small details.
Give the stain about 15 minutes to soak in then wipe off the excess with a clean rag.
Optional: If the stain is uneven or you missed some spots, repeat the last two steps for a second coat.
Let the stain dry completely. Depending on how dry the air is, this can take up to 18 hours.
Use a clean rag to wipe on two coats of premixed shellac, waiting at least 20 minutes between coats.
That's it, you should now have a beautiful finish that looks professional and shows off the grain of your wood. With basic dusting and occasional polishing with a good (non silicone) paste wax, the piece should last for generations.
Safety Concerns
Neither shellac nor wood stain is particularly nasty stuff--certainly not compared to most modern lacquer or epoxy finishes. It's still a good idea to do your work in a well ventilated area, however. The biggest safety concern is properly disposing of the oily rags. Stain-soaked rags are highly flammable and can spontaneously combust if they get too warm before they are totally dry. It is not safe to through wet oily rags directly in the trash. Back when I had a wood stove in my shop I used to just burn them there. Nowadays I hang them on an old coat hanger until they are dry enough to throw away.
A Variation for "High Abuse" Applications
Shellac is a good general purpose finish, besides being economical and environmentally friendly. Unfortunately it isn't tough enough for surfaces like kitchen tables that see heavy daily use, including spilled liquids and coffee rings. For these sorts of surfaces you can follow the steps above, but substitute wipe on Polyurethane for the Shellac, which will give you a thicker, more liquid resistant top coat. Minwax makes a wipe-on Polyurethane that I've used several times with good results. You can also make your own by thinning regular polyurethane with mineral spirits.
The history of the lathe is a microcosm for the entire history of technology. The first literary mention of a lathe that I am aware of is in Plato's unfinished Critias, in which Critias describes the island of Atlantis as being perfectly circular with the capital places "as if at the pivot of a lathe" (113d). There is little information on what Hellenistic lathes actually looked like but a certain degree of sophistication would have been required to create some of the mechanisms attributed to Greek inventors. Certainly the Greeks, with their great reverence for geometry, would have seen the potential of a simple tool that makes perfectly circular objects. Simple lathes of some sort (probably based on the Greek models) were around throughout the Roman period--just look at the turned wooden grips on the hilts of late Roman short swords.
In the dark ages everyone got much poorer and tools became simpler. Round objects were more likely to be carved with a draw-knife than turned. Even so, lathes probably never completely went away. By the High Middle Ages wood turners, using simple spring pole lathes, were in business throughout Europe, often unpacking their lathes and setting up in the middle of forests so as to be near a steady source of green wood. Spring pole lathes are deceptively simple. A rope or thong is wrapped around the work. One end is tied to a springy rod (often a handy tree branch) while the other is attached to a pedal, or just tied to the turner's foot. When he steps down the work rotates and he takes a cut. When he raises his foot the spring pole rotates backwards. As primitive as spring-pole lathes are, however, they can potentially do every operation that a modern store-bought electric wood lathe can.
Spring Pole Lathe [Flickr user Mark, CC-BY 2.0]
Spring pole lathes do have one big drawback, though: they you can only cut for half the cycle. This problem was solved with the invention of the treadle lathe, which uses a crank rod attached to the treadle to rotate a flywheel which in turn rotates a drive center through a belt and pulleys. This style of lathe was also easy to connect to an external power source--initially a water wheel, but later a steam engine or electric motor. Many turners actually preferred treadle power, however, because of the fine-grained speed control it gave for delicate operations like threading.
The first treadle lathes were made of wood, as the spring pole lathes had been before. The advent of iron casting, however, allowed for the mass production of lathes in various standard sizes. In the 19th century cast iron treadle lathes were ubiquitous in every kind of shop or factory as well as in home workshops. In his 1869 book on lathe work (definitely recommended reading), Egbert Pomeroy Watson extols the virtues of the lathe as a must-have DIY tool,
There is no family in this country that would not find it economy to have a foot lathe in the house, where the members have mechanical tastes—not necessarily the male members, for ladies use foot lathes, in Europe, with the greatest dexterity. Some of the most beautiful work ever made, was by Miss Holtzapfel, a relative of the celebrated mechanist of the same name. If there are shovels to be mended, the lathe will drill the holes and turn the rivets. If the handle of the saucepan is loose, it will do the same. If scissors or knives want grinding, there is the lathe; if the castors on the sofa break down, there is the lathe; if skates need repairs, either of grinding or of any other kind, there is the lathe. In short, it ought to be as much a part of domestic economy as the sewing machine, for it takes the odd stitches in the mechanical department that save money.
The first lathe I ever used was a Victorian treadle mini-lathe that lived in my Grandfather's basement. He used to use it to make knobs and handles for kitchenware and toys for us grandchildren.
Most of these lathes looked very much like a modern wood lathe, with a simple iron tool rest which was used with various hand tools, but turners used them to work metal as well as wood. The cylinders and threaded parts for the first few generations of steam engines were turned by hand, as were most gun barrels prior to the civil war. Precision metalworking on a simple lathe is absolutely possible!
The mid-19th century saw the next major step in the evolution of the lathe: the engine lathe. These machines used tools clamped in a holder which was attached to a carriage that was moved with hand wheels, allowing for more precision in less time. A further addition of a lead screw (providing a power feed for the carriage) and change gears (for automatic threading in standard pitches) led to the direct ancestors of modern metal lathes.
The standard wood lathe and engine lathe have remained relatively unchanged since then and are still a basic part of well-equipped woodworking and metalworking shops, but the late 19th and 20th centuries saw the emergence of a profusion of special purpose lathes optimized for particular jobs: bowl lathes, metal spinning lathes, brake drum lathes, pipe machines (a lathe designed to cut and thread pipe on job sites), and many others. In the second half of the 20th century the focus was on automation. Production wood lathes gained duplicator attachments to rapidly copy table legs and similar pieces by following a template. Metal lathes gained turrets which held several different tools for rapid selection. With the advent of CNC technology the turret lathe became fully computer controlled.
At the same time that production lathe technology was heading towards specialization and automation, however, there was a growing interest in simple lathe designs which could be built cheaply and used for a wide variety of tasks. One of the first to publicize this sort of lathe was hand tool woodworking guru Roy Underhill, who has built and demonstrated several simple foot-powered lathes on his PBS show The Woodwright's Shop and currently teaches a class in how to build your own spring-pole lathe. Prior to becoming a TV personality Roy toured the craft-fair circuit with a treadle lathe built mostly out of construction lumber, doing spindle turning while playing the harmonica. All of his lathes are built out of wood with only a few metal parts.
In the 1980's Dave Gingery came on the scene with a series of books about how to build a machine shop from scratch. The core of his program was a simple but versatile engine lathe built from pot metal and aluminum castings. Many thousands of hobbyists have since built and used Gingery lathes.
More recently, there has been an upsurge in interest in a WW I-era engine lathe design by Lucien Yeoman which was created to rapidly tool up munitions factories. Yeoman lathes are built mostly out of concrete with pipe ways. They require no foundry work and only minor welding. Yeoman lathes can typically be scaled up larger than Gingery lathes because the latter are limited by the amount of metal you can heat in a single pour.
My own lathe design incorporates elements from the Underhill, Gingery, and Yeoman designs, and was largely dictated by the tools and materials I happened to have on hand. I don't have a foundry or a welder, but I did have a box of old bicycle parts and plenty of wood. Also, I have pretty complete sets of woodworking and bicycle tools (I'm a journeyman in both those trades) but only basic metalworking tools. So I built a lathe mostly out of wood, like Roy Underhill, but with pipe ways like Yeoman. The headstock bearings and spindle are a bicycle bottom bracket and I used bicycle quick-release levers to lock down the tool rest and tailstock. Gingery's book was constantly at hand as I designed, machined, and assembled the various pieces.
Roy Underhill with one of his lathes
A Yeoman Lathe [courtesy of opensourcemachinetools.org]
Since completing the Handy Lathe six month ago I have used it for numerous projects in wood, plastic, and metal, and it works pretty well. The biggest problem I have is that the headstock spindle occasionally gets bent and I have to realign it (a fairly easy process involving a surface gauge and a big Crescent wrench.
I am in the process of setting up a small foundry which will allow me to sand-cast parts. When it is done I plan to build a Gingery-stylr carriage and tool-holder to make the Handy Lathe into a true engine lathe. I also plan to turn a beefier spindle as soon as I find a big enough chunk of steel. My long term plan is to use the Handy Lathe to machine the parts for my dream lathe, the Handy Lathe Mk. II, which will be a full size machine with a geared transmission. For now, though, the Mk. I suits my needs quite nicely and I also think it would be a good first machine for someone who wanted to learn turning.
The bandsaw is one of the most versatile tools in the shop, able to rip and resaw lumber, cut curved sections in thick material, and make make dovetails without a jig. With appropriate blades it can cut wood, plastic, metal, leather, foam, or composite materials. if you are an aspiring furniture maker or boat builder then a bandsaw is probably one of the first stationary tools you will want to acquire, but even if you don't do much of either, a properly set-up bandsaw is useful in any workshop.
Compared to the other big saws in the shop, like table and radial arm saws, bandsaws require much less horsepower to cut a given thickness of material. This makes them cost effective for resawing (cutting thin slices the long way across a piece of board to make veneers and such) since the motor is usually the single most expensive part of a saw. It also means that you can run a relatively large bandsaw without needing to install a 220V and/or three phase electrical circuit, which is usually an absolute necessity for any of the 12 inch and large table and radial arm saws. Also, unlike circular saws, band saws are not prone to "kick back", the dreaded phenomenon in which a saw launches a piece of wood backwards at hundreds of miles per hour. Finally, many operations which require complicated jig-work on a circular saw, such as cutting tendons or circles, can be done free-hand on bandsaw.
The main drawbacks to bandsaws, versus circular saws are that they do not cut as smoothly and that they have very limited cross-cutting capacity. This makes them a less used tool in the dedicated cabinet shop, where the ability to make smooth cross-cuts in large plywood panels makes the tablesaw king.
Choosing a Bandsaw
The first decision you need to make is what size machine to get. Bandaws are sized by the diameter of the wheels. A 10" or smaller machine is intended for hobby and modeling work but won't have the capacity for serious woodworking. Still, if your space or funds are limited it will serve better than no bandsaw at all. At 12"-15" saw will meet nearly all the needs of a home woodworker or cabinet shop. People who plan to do serious resawing probably want at least a 17" machine. Those who are creating corbels and other architectural woodwork, ripping structural timbers, restoring wooden ships, or doing similar heavy work will simply want the biggest machine they can find.
The next choice is whether to buy a woodworking bandsaw or a metalworking bandsaw. While both are really general purpose machines you should probably get the one for the type of work you do more often. Woodworking bandsaws usually have the blade running vertically and have a larger table which can accept a fence and/or a miter gauge. Metalworking bandsaws have a much smaller table, usually run horizontally, and have a cross-cutting mode which is very handy for cutting pipe and sectional steel.
Next, look at bandsaws in your size range and type and decide how much you are willing to spend. The most affordable saws are usually older American-made machines like the one i work on in the video. My buddy bought it off CraiglList for $10. The downside of these machines is that they often require a little elbow grease to refurbish them into working condition.
The quality of new saws has a lot to do with their country of origin. At the low end are Chinese machines like Harbor Freight's 14" model. These saws usually work well but might have strange wobbles, be underpowered for their size, or have machining defects which need to be corrected.
Most of the midrange saws are currently being build in Taiwan. Grizzly and Jet are typical brands. They each have numerous models which are mostly decently made and fairly priced.
At the top end are the European bandsaws; Laguna is an example. These saws are beautifully machined and have power to spare, but their prices make them hard to justify for a small shop.
Bandsaw Maintenance and Rehab
In this week's video I show you how to do a number of the more common maintenance tasks.
Changing the Blade
The general process for changing blades is similar on most machines:
Disconnect the power cord.
Remove the cover
Release the blade tension. Usually there is a lever provided for this purpose. On some machines you need to turn the blade tension adjuster knob.
Remove the old blade
Put on the new blade, making sure the teeth face down towards the table.
Retension the blade. A properly tensioned blade should still have a little bit of flex at the middle when you poke it with your finger.
Rotate the wheels by hand to check the blade tracking. Tracking is adjusted with either a knob or screw, but the placement varies in different machines. NEVER TRY TO TRACK A SAW MOVING UNDER POWER!
If neccesary, adjust the blade guides.
Replace the cover.
Optionally, you can hone the back of a new blade. This removes imperfections, makes the blade run cooler, and helps it turn in a shorter radius. Just take an oilstone with a few drops of oil and use the edge of it to round the back of a moving blade. A few seconds is all it takes.
Adjusting Guides
Blade guides come in various styles, from the blocks of pot-metal that come stock with most saws, to special composite materials designed to last longer and run cooler, to little ball bearing roller assemblies. I personally believe that the plain metal blocks are fine for nearly any work as long as they are adjusted properly. The four blocks that restrict the blade's side to side movement should be run all the way into the blade then backed off a couple 1000ths of an inch. That is, they should be as close as you can get them without actually touching. The guides should line up with the flat part of the blade, not the teeth. Otherwise they will be shredded by the set of the teeth.
The guide that keeps the blade from being pushed back, which is nearly always a roller, should be run forward until it just begins to rotate with the blade, then backed until it just stops rotating.
Lubrication
Use a dry lubricant (graphite, Dry-Glide, or paste wax) on parts that will come in contact with wood and metal shavings, such as the trunions and the blade guard post. On the inside, especially on the tracking/tension assembly, apply a good coating of all-purpose grease. A few saws are fitted with grease zerks so you can use a grease gun. More commonly, however, you just wipe the grease on moving parts with a rag.
Replacing a Tire
Some metalworking bandsaws are meant to run without tires on the wheels, but most woodworking and general purpose saws use soft tires. This setup lets the wheels accommodate different widths of blade without the teeth chewing into the wheel itself. You should never run one of these saws without some sort of tire, even if it is only improvised. Stock tires are basically big rubber bands. Install them by putting a little bit of contact cement and stretching them over the wheel. Urethane tires look similar but cost more. They definitely last longer and possibly run smoother. Since tires, even the rubber kind, are somewhat expensive, many people improvise their own, either by cutting them out of an inner-tube or using some sort of tape. I've heard of that bicycle rim strips work adequately, as does friction tape (look for it on the electrical aisle of the hardware store).
Maintaining the Table
The table should periodically be checked to make sure that the 90degree stop on the trunions actually places the table at right angles to the blade. It is usually easy to adjust by loosening a couple of screws.
When putting a saw into service, use a straight edge to make sure that the table is dead flat. Minor imperfections can be sanded off with a sheet of sandpaper on a surface plate or piece of plate glass. Major warping or pitting requires either hand scraping or surface grinding in a machine shop. Hand scraping is easier than it sounds, though fairly time consuming. The basic process is to coat a flat surface with layout dye (a.k.a. "machinist's blue") then rub it against the table to transfer the dye to the high points. Carefully scrape off all of these high points using a machinist's scraper (which looks a little like a blunt chisel). Repeat as many times as necessary.
Keep your top nice by scrubbing off any gunk that builds up with WD-40 or something similar. Then rub on a nice coat of paste wax to prevent rust and make work slide easily.
Building Your Own Bandsaw
I haven't done it myself, but I've seen numerous plans and videos about how to make your own bandsaw from scratch. I suspect it would usually be more cost effective to refurbish a used machine than to build your own, but it could still be an awesome DIY project.
