Chisels - Essential Woodworking Tools

Chisels:
No matter how many power tools you have at your disposal, one hand tool you'll always want to keep around (in varying shapes and sizes) is the chisel. It can likely trace its origins back to the sharp rocks used to carve wood in prehistoric times, yet the chisel still remains one of the most versatile tools in the wood shop today. While there are literally hundreds of different types, shapes and uses for chisels, they all operate on the same basic premise: a sharp cutting edge that can be guided through the stock with a handle that is built specifically to aid the chisel's intended cutting task,
Types of Chisels:
Different types of chisels include gouges designed to be used with a lathe, as hooks, and with square, round-nosed or curved cutting edges. However, for this article, we're going to stick to the most commonly used type of chisel, the bevel-edged chisel. These chisels have a blade that is typically 4 to 7 inches in length, with about a 20-25 degree bevel on three edges, but only on the top side of the chisel (the bottom side of the chisel is flat).
Chisel Construction:
The blade of a bevel-edged chisel narrows at the top to connect to the handle, which is typically made of either hardwood or plastic. Chisel handles come in various shapes and sizes, but in the case of the bevel-edged chisel, the choice of handle is a matter of preference rather than function. The butt, or back end of the chisel is sometimes reinforced for strength, as certain circumstances call for the chisel to be tapped with a mallet to guide the blade through the stock.
Using a Chisel:
The term for cutting with a chisel is "paring". To pare with a chisel horizontally, you should place the flat side of the chisel against the stock. Hold the handle of the chisel firmly with one hand with your index finger steadying the blade. Use your off hand to steady the chisel by holding the blade between your thumb and index finger. Stand in front of the work piece with your weight evenly distributed and the chisel parallel to the floor. Use your body weight to ease the chisel through the stock. If extra force is needed, use the heel of your main hand to strike the butt of the chisel.When paring vertically, hold the handle of the chisel with your thumb on the butt, steadying the blade with your off hand. As before, use your body weight to ease the chisel through the stock, this time in a downward manner. Should extra force be needed, you can always use a wooden mallet to tap the butt of the chisel. However, avoid using a steel-head hammer, as it can damage the chisel.
Taking Care of Your Chisels:
Avoid storing your chisels loosely in a drawer, where they can bang into one another, thus dulling the cutting edge(s). A better option is to hang your chisels on a rack or in a drawer with individual dividers (for each chisel) where you lessen the chance of the tip getting banged up. Proper use of a chisel requires that the cutting edge remain sharp. To properly sharpen a chisel, use sharpening stones of progressive grades. You may need to touch up your chisels regularly by honing the flat side to keep them at their best.
Using Your Chisels Safely:
The number one rule of chisel safety is to keep them sharp. A dull chisel is a dangerous chisel, as it will require more effort to push the chisel through the stock. However, if keeping the chisel sharp is safety rule #1, then rule #1a is to always pare away from your body and keep your hands behind the cutting edge. And of course, as with all woodworking tasks, never use a chisel without your safety glasses.
Woodworking Chisels
No tool in the shop is more important, or more heavily used, than the chisel. Just look in any good old tool chest and what do you find, a few saws, some miscellaneous tools, and lots and lots of planes and chisels. I am glad my birthday and Christmas are just around the corner.

Other Tools

All about Rasp's File's and Riffler's
A rasp is a piece of steel with little teeth cut in all over the surface of the tool. Rasps superficially resemble files, which have long teeth running the width of the file. Files are very useful and popular tools, but their woodworking use is mostly restricted to sharpening woodworking tools. They're basically used for metalwork, whereas rasps are used on wood and stone.
In woodworking the word Rasp is used to denote the entire family of the tool when are talking generally aobut the use of the tool. When the particular details matter we rasps to mean a rasp with a handle at one end. The term riffler rasp or riffler is used to describe a type of rasp with teeth cit in both ends with an area to hold onto the middle. Rifflers can be either file cut with long lines of teeth or rasp cut with pointy teeth. Riffler rasp might be the better term to use.
Tools for a Basic Layout Kit
As we have already mentioned a try square, a ruler and a marking knife are essential layout tools. To complete our layout kit we will add a marking gauge, a mortising gauge, a bevel gauge, a protractor, a set of dividers and trammels used for circles. As our instructor told us "Flawed measurements will plague a project at every stage.

Fractions: What woodworkers need to know.
Adding and subtracting fractions: Remember these steps.

1. Express all fractions in terms of a common denominator
2. Add or subtract the numerators to find the new numerator
3. Place the new numerator over the common denominator.

Improper fractions and mixed numbers. Remember these steps.

1. Determine the largest whole number in the improper fraction.
2. Subtract the whole number from the improper fraction to find the remaining fraction.
3. Combine the whole number and the remaining fraction for your answer.

Adding or subtracting mixed numbers: Remember these steps.

1. Multiply the fraction's denominator by the whole number.
2. Add the fraction's numerator the answer from step one.
3. Put the resulting number over the fractions denominator.

Multiplying a fraction by a whole number: Remember these steps.

1. Multiply the fraction's numerator by the whole number to find the new numerator.
2. Place the new numerator over the original denominator which remains unchanged.

Class Project: Mantel or Hanging Clock

Time to select the Project:

The class is offered four plans to select for the semester woodworking Project. The purpose of the project is to observe and learn selected skills required to build one of the four clocks. The skills will be some of the following listed below. The photo on the right is called the Arch Clock

Determine which project we want to build and select the species of wood we will use.
Complete the Bill of materials sheet to determine the quantity of wood needed for project.

Purchase wood from School

Square wood and bring to final thickness.

Layout needed parts with chalk to determine where to make cross cuts.

Cut two sides, and bottom and top of clock according to the plans for our clock.

Select boards for clock back and dial board. These boards will be cut in half and glued together.

This is often refereed to bookmatching two pieces together. The photo on the right show the back of the clock

These are just the beginning steps more steps will be added as we work on each piece for the project.

Layout Tools

Rulers:





Folding rulers have been used for years especially in carpentry. Tape measure is the more common ruler used now mainly for convenience, certainly questions of accuracy are one of the issues with today's tape measure. Bench Ruler, a metal flat ruler one foot in length and accurate to at least 1/32 of an inch. This bench ruler is usually considered the workhorse for the workbench. This ruler has clear markings and is usually a non reflective surface. It is about one inch wide and about 1/32 inch thick and slightly flexible.


Determine Square:



Framing square, why is the length and width different (we will get to that). Try Square or Tri Square is a metal and or wood tool used for marking and measuring a piece of wood. The square refers to the tool's primary use of measuring the accuracy of a right Angle (90 degrees); to try a surface is to check its straightness or correspondence to an adjoining surface. A piece is of wood that is rectangular, flat and has all edges (face, sides, and ends) 90 degrees is called four square. A board is often milled four square in preparation for using it tin building furniture.




Squaring a piece of wood: Seven Steps

• Step One: Crosscut to length plus 1 inch
• Step Two: Joint one face of the wood, this will be the reference side for planning to thickness
• Step Three: Surface or plane to thickness in our project this will be 3/4 inch
• Step Four: Joint one edge, the cleanest edge will be the easiest
• Step Five: Wood is now table saw worthy, jointed edge against the fence, rip to width
• Step Six: Square one end with a cross cut leaving some length to cross cut for final length
• Step Seven: Cross cut to length.

We will perform this procedure on all of our wood for class project.

Calipers: The tools you need when close isn't good enough.

Given that wood shrinks and and swells, most woodworkers regard 1/16 of an inch's an acceptable tolerance. So why would you need a device capable of measuring to .001 inch? Prat of the answer lies simply in the desire to fit projects together without gaps or misalignment. For example if you are working with two pieces of wood with 1/16" the total off could be 1/8. In order to get tolerance of 1/16" each piece would have to be within 1/32 of an inch. This fraction is equal to about 31 thousands of an inch. (.031). Vernier Caliper, named after a French Mathematician who devised the vernier scale. More comm om is the Dial Caliper, with this one a dial indicator provides a direct reading of subdivisions, making it easy to read. Finally a Digital Caliper show the exact measurement on a calculator-style digital readout. Though expensive it is the easiest to read.

Combination Square: A perfect name for a near-perfect tool

Use it as a depth gauge. Use it as a marking gauge. Use a Combination Square to calibrate your table saw or set up your Router. One thing we learned today is that you usually get what you pay for. If the combination square is not square it is worthless. Getting a good deal is OK but a well made square may well be worth the money.

Day 2 Continued

Hardwood

Comes from deciduous trees that drop their leaves every year.

broad Leaves, enclosed nuts, higher density, Mostly deciduous

Cost: Expensive

Examples of Trees: Aspen, Poplar, Birch, Elm, Maple.

Applications: used for furniture but less frequently than softwood

Density: Higher density, which means the wood is harder

Found Where: Hardwood is found all around the world in the north and the Tropics

Softwood

Comes from Trees that are conifer and have needless, which they do not normally lose each year

Leaves are less dense and less durable, High aslorific values, evergreen

Cost: Less expensive

Applications: Widely used as a structure for building, and furniture.

Density: Lower density and most varieties are softer than hardwood.

Found: In the northern hemisphere

Hardwood Measurement

4/4 equals 1 inch

5/4 equals 1 and 1/4 inch

6/4 equals 1 and 1/2 inch

7/4 equals 1 and 3/4 inch

8/4 equals 2 inches

Bill of Materials

When we do our clock project we will complete a bill of materials. This will be used to help us calculate the amount of wood we will need to buy for our clock project. The measurement we will use will be board feet. Many will use this bill of materials to make a cut list, which determines what board we use to cut each of the project parts.

Board Feet

Calculating board feet uses a formula
thickness x length x width/divided by 144

all measurements are in inches, the 144 is the number of cubic inches in one board foot.

We will be adding about 20 to 30 percent to the number we get to account for any waste.

Our method also drops all fractions to the next full inch, so 4.5 inches is 5 in our formula.

A word about measurement and fractions
One area that has the potential for confusing new woodworking students (this student included) are fractions and what they mean. During the course we will be discussing how to understand and use fractions as our friend. (This I have to see, I am thinking I should have been born in England where they use the decimal system)

Moisture Meter

The modern moisture meter has a large Digital LCD readout. the range is 0 to 40 percent, with a plus or minus 1 percent. Use the moisture meter when purchasing different boards to make sure they are close in moisture content, or one could let them dry in the shop until they are closer to the same content. In either case we will give our purchase of new wood time to adapt to conditions in our shop by checking the moisture meter as they adapt to there new environment.

Different Types of Woodworking Joinery

Butt Joint

For this common and simple joint the end of one piece of wood is simply placed against the adjoining piece, forming a right angle. The two pieces can be fastened with screws, glued or dry dowels, or sometimes staples. see illustration 1

Cross Lap

Ina cross-lapped joint a rectangular channel is removed from both of the pieces of wood in the joint. The boards then interlock at right angles. The channels re cut to a depth that allows this joint to appear completely flush when properly constructed. The cross lapped joint is similar to the rabbet joint and uses the same general technique. see illustration 2

Dado Joint

A dado is an adjustable blade used to create this simple joinery. Dado joints connect tow pieces of wood by cutting a groove (with a dado blade) in one piece of wood which is equal to the height and width of the second piece. Dado joints are often used to insert a drawer bottom. the dado joint is similar to the traditional rabbet joint and uses the same general technique. see illustration 3
Dovetail Joint

This form of locking joint looks similar to an outspread bird's tail. thus the name. One board has a flared extension which fits into matching flared cavity in the adjoining board. Use of a single dovetail is called a French Dovetail and multiple joints in the same corner are called and English Dovetail. Better drawers often use a multi-dovetail because of it's strong holding power. see illustration 4

Doweled Joint

Two or more small holes are bored into two pieces of wood. The boards are then joined by inserting small round pegs into the holes of one board. The dowels are then inserted into the other board and the joint is glued. see illustration 5

Miter Joint

Two pieces of wood are cut at 45 degree angle and the two beveled edges are placed end to end. They are usually connected with glue, nails or screws. see illustration 6

Mortise and Tenon

In this method of joinery, the mortised part has a recess cut into it. The tenoned part has a protrusion that matches the recess in the mortise. The pieces are sometimes glued together to strengthen the connections and sometimes a hole is drilled through both the mortise and the tenon and dowel inserted to further strengthen the joint. see illustration 7

Rabbeted Joint

for this joint, a groove is cut into one piece and a section of the other board fits into this groove. Similar to the lap but joint, only one board is cut.

Splined Joint

Grooves are cut in ends of each piece of wood so that they will line up when joined. A small strip of wood called a spline is inserted into each groove to hold the two pieces of wood.

Tongue and Groove

Two pieces are joined by cutting and edge or shape on one piece of wood which fits into a mirror groove cut int he other board. The tongue and groove must be cut in such a way that the boards fit together tightly without gaps, and the tow surfaces remain flush. see illustration 8.

Minor Setback

Well, I am sure many of you are thinking I have been skipping school. I wish that had been the case, but 2 weeks ago today I had a bike accident which has slowed me down some.

The good news is I am back to a somewhat normal life and schedule and will begin posting again. Fortunately I only missed one of my classes and had other students take great notes for me.

I will be adding to the blog every until I catch up with the actual classes.

Thanks for your patients and do give up on me yet.

John

Day 2 continued

How Dry is Dry

Water occurs in wood in two places, First, theirs the free water that fills the inside of the wood cells. That's like water in a bucket. Second, water also infiltrates the cell walls. That's called bound water. Imagine squeezing a piece of cotton Cheeses cloth until all the free water is drained away. The cloth though, remains damp because the material continues to contain moisture-the bound water.

When wood contains bound water its is said to be in its fiber saturation point. And the bound water can be eliminated completely only by drying it. Somewhere with no relative humidity, as in an air-tight oven.

Wood likes water, wood rates as a hygroscopic substance. Thai is it has ans affinity for water and readily absorbs it as a liquid and vapor. This ability directly deepens on the humidity of the surrounding atmosphere. therefore the amount of moisture is wood changes as the humidity changes.

The term Kiln-Dried means that wood moisture was removed in a chamber where air circulation, humidity and temperature were controlled.

Bow, Cup, Twist Crook

What Shrinkage does to wood

Woodworkers call the change in shape of a piece of wood warp. And it takes several common forms, all of which distort the wood.
Bow, as its name implies, describes the lengthwise curvature for board-end to end along its face. Twist, means that all of a boards corners won't lie equally flat. Crook, all the curvature runs end to end alone its edge. Cup, is when a board no longer flat from edge to edge. Cup always occurs in the opposite direction of a flatsawn board's annual growth rings. Although not a distortion like any form of warp, checking refers to the Small splits along the grain. You'll most often see checks in the ends of boards but they can occur on surfaces too. This is due to the fact that wood dries 10 times faster along it length compared to drying across the width. One of the things we will learn in our class project is to project wood movement and design and build with this in mind.

Defects in Wood

Knots are limbs separated from the tree trunk during tree growth.

Wane is bark on the edge of a board.

Pitch Pocket is an opening in a board containing pitch.

Splits is the tearing apart of wood cells due to improper storage or handling.

Checks are the lengthwise separation of wood due to shrinkage.

Measuring Wood

The standard method of measuring hardwood is given in board feet. We will be calculating the board feet we will need for class project. Including any projected waste as part of our calculations.

One board foot is described as 12 inches by 12 inches by 1 inch thick or 144 cubic inches. This is calculated by multiplying length x width x thickness.. examples of a board foot are 3x4x12 and 2x4x18 and also 1x6x24. All these measurements give 144 cubic inches of lumber. We will be using a bill of materials for the workshop to determine how much wood we will need for each project.

Grading Wood

FAS (first and Seconds) This is the best grade, boards are 6" and wider and 8' and longer. Almost clear and yeidls 8 32/3 percent clear face cuttings 4" or wider by 5' or longer and 3" or wider and 7' or longer.

Selects, The boards 4" and wider, 6' and longer. one side is FAS the is no 1 common. Yiedls 832/3 percent clear face cuttings.
No 1 common, Boards are 3" and wider, 4' and longer and yields 66 2/3 percent clear face cuttings 4" or wider by 2' or longer.

Urban Forestry in California

In 1989 the legislature passed a bill to reduce solid waste by 50% by the year 2000. One unique outcome put forward by Eric Oldar of the California Dept of Forestry was to promote the value of the lumber cut from trees in Urban locations and to promote organizations to harvest urban lumber as an economic venture and to reduce solid waste.

Palomar College Participates in Urban Forestry with a Wood=Miser portable ban saw and Kiln for drying the lumber. Student participation in the Urban Forest Program is part of the class requirements and more will be covered on this subject in future blogs.