Bandsaws

Why You Want a Bandsaw

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:

1. Disconnect the power cord.
2. Remove the cover
3. 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.
4. Remove the old blade
5. Put on the new blade, making sure the teeth face down towards the table.
6. 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.
7. 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!
8. If neccesary, adjust the blade guides.
9. Replace the cover.
10. 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.