Table Saw

Bitraf provides a Bosch GTS10XC table saw for members to use, upon completion of a safety course. This course is necessary for everyone who wants access, whether a beginner or experienced user. As useful as they are, table saws are very dangerous and should always be treated with the respect they deserve. The intention of the course is to develop safe working practices for the safety of you, others in the workshop, and the machine. This knowledge you absolutely must know, putting it into use every time you use the table saw will instil confidence in your ability to use the saw and keep Bitraf great for everyone. Always remember, there is no such thing as a minor tablesaw accident. If you are uncomfortable making any kind of cut, then DO NOT DO IT. It's that simple.

Please see Glossary below for any unknown words in the following paragraphs.

Access to the table saw is via the p2k16 'Tool Checkout System' in the workshop. Once you pass the course satisfactorily your username will be added to the tablesaw 'circle'. Your usage is logged and once you have checked out the tool in your name it is YOUR responsibility. You MUST clean and return the machine to it's 'as new' original state (i.e riving knife & guard attached and aligned, original blade fitted, push stick and tools in correct location, machine as clean as it can be) once finished. If you do not have time to clean up after yourself then you should not use the machine. Even single, one-time cuts should be cleaned up as you are creating risk for the next user, as well as causing another member to use their time to clean your mess. Doing this helps to create a culture within Bitraf that benefits everybody. Table saw access can be revoked if the tool is not left in proper order or cleaned up after yourself repeatedly.

NEVER let another member use the machine while checked out in your name, irrespective of whether they have completed the safety course. You must unplug and check the machine key back in if you are not using it anymore (and obviously clean it, replace any parts you have changed and clean the floor thoroughly) ready for the next user.

BEFORE PLUGGING IN THE TABLE SAW

Things to check/consider before plugging in the table saw. Why do these before plugging in the machine? Because it's totally safe. Bitraf has no injury liability for you, so your safety is YOUR responsibility. No electricity means nothing can happen. There is always a chance of malfunction/miscommunication, no matter how small.

- Safety gear, MUST wear eye, ear and dust protection. Gloves should NOT be worn when using the table saw (loss of tactile feel, some gloves loose enough for saw to grab. Better a splinter than chopped off fingers)

- Correct clothing/hair (NO long sleeves, no ties, no jewellery, long hair tied back)

- Floor clean and free of debris (tripping or sliding into a running, or even stopped, saw blade will really hurt!

- Tabletop clean and free of dust/debris? (dirty/rough surface requires more force/increases friction to push stock through blade/lifts stock slightly (kickback possibility). Are the runners for the crosscut sled free of dust? (could become obstructed thus not slide smoothly/flat)

- Does the fence clamp down properly or is there dust obstructing the locking mechanism?

- Blade turns freely (no debris thrown into face on start up)

- Sideways movement in blade (previous user may have changed blades and not tightened etc)

- No debris in fence/blade area (could become projectiles during use)

- Check guard is in place and in proper condition. (reduces risk to you). You may remove the guard if absolutely necessary and it MUST be put back after your use ready for the next user.

- Check alignment and condition of riving knife (in line with blade)

- Check condition/correct saw blade for material, report and change if necessary. A damaged blade could result in kick-back/damage to you/machine/stock. Every blade has a purpose and should only be used for that task. Using the wrong blade will not only produce a less than premium cut, it may increase the danger level of the operation. The standard Bitraf blade is a 24T ripping blade, for wood ONLY. Members can purchase and use their own 254mm blades on the table saw, but MUST put the original Bitraf blade back on the machine once finished with their blade.

- Check blade is parallel to runners (use long metal rule) and 90° to table (use engineers square) if cutting at 90°. Adjust the angle if cutting a bevel and ensure the fence is on the right side of the blade (as the blade tilts left)

- Is it the right machine for the task? The bandsaw might be better for ripping. A router might be better for running a dado or groove. A plunge saw on a track might be better for breaking down sheet goods. Consider which tool is best for the situation before making the cut.

Any problems/reports/questions about the table saw or associated can be directed to Thomas Winther, Nikolai Kolstad or Yoshi.

STOCK

- MUST be free from nails, screws, stones, etc, as they could become projectiles and damage you or the blade, could also prevent stock from sliding flat on the table saw bed. Use a magnet to check the stock for internal broken nails/screws.

- Must have 1 true edge if ripping, if both sides of stock are not straight it will move sideways between blade and rip fence and cause potential kick-back. You can use a jointing jig (as of today 28/2/19 Bitraf does not have one - will be updated when one is made) to true one edge of the stock to use against the fence for cutting the parallel edge.

- The stock must be flat, anything warped, twisted, cupped or bent is very likely to be kicked back

- Correct blade must be used for the stock material and type of cut (ie rip or crosscut)

- Round stock should not be cut unless adequately supported and held in position with a gripping device

KICKBACK

The most common danger with table saw usage is ‘kick-back’. Kick-back is the term for stock that suddenly and without warning is propelled back towards the user at great speed. One of the reasons kick-back is so dangerous is that it happens in a split second - far too quickly to react to. Over 35,000 people are treated each year from table saw injuries in the US alone with kick-back contributing to over 70% of them. The two main causes of injury from kick-back is hand injuries where the stock pulls the users hand across the saw blade because it moves so fast and head and body trauma from stock propelled at nearly 150kph. If kick-back occurs there’s a reason for it - it’s not the saw being temperamental, it’s usually because of operator error or problems with the stock. Kick-back is not a risk you have to learn to accept when using a table saw, since you can easily prevent this. By understanding the causes, you can counter the forces involved and manoeuvre your stock with increased safety. Don’t let your saw demonstrate kick-back to you - there are many videos on Youtube showing the horrors!

Part of knowing how to prevent kickback is by understanding why it happens.

Causes include:

- Improperly fed stock (pressure at one corner of stock causing rotation, bottom surface of wood gets caught on saw teeth and is thrown in direction the blade is turning) Use riving knife, use correct tools (push stick/push saw) and hand position, push stock in correct place

- Fence not parallel to saw blade (fence angled inwards slightly towards blade - causes edge of stock to press against rising rear teeth of saw blade). Align rip fence parallel to blade. Some woodworkers angle the fence away from the blade a tiny amount at the rear of the blade to remove the potential for kickback without adversely affecting the workpiece.

- Cutting wood with knots (flaws are more likely to create pinching/extra friction and therefore kickback). Check stock before cutting, slow down feed rate when approaching knots, anticipate and increase downward pressure on stock to prevent stock riding up and possibly kicking back. Do not push harder. If running sound of cut changes it is a marker that there may be a knot.

- Cutting painted wood (increases friction) Sand paint off first, reduce feed speed if you feel the stock pinching or hear the running sounds change.

- Stock that is bent/warped/cupped/twisted Change stock where possible, true one edge or surface, reduce feed rate, be aware kick-back could occur

- Stock with no true edge. Use a jointing jig to true one edge, never attempt freehand cut to get a straight edge

- Damp stock Be aware that wet sawdust will increase friction and take necessary precautions

- Dull blade While it may seem counterintuitive, dull blades are more dangerous than sharp blades. It takes a little time to get a feel for. At some point, you will realise you have to push much harder than you used to for simple cuts like ripping. Friction and heat increase, resulting in more burning on woods that didn’t burn before. You will notice more tearout on your cuts. Dull blades are usually caused by a build up of sap on blade from pitch woods (Pine etc) Remove and clean blade or change blade. Never clean the blade while running

- Using a bent, broken or warped saw blade (Heat from prior misuse can warp blade) You will have discovered this from the checks you performed before even plugging in the table saw, report to Thomas, Nikolai or Yoshi and change the blade if possible

NB: There is no kickback from the cut piece on the ‘open’ side of the blade (ie the other side of the blade from the fence) - it just stops when it's loose

GLOSSARY OF TERMS

Crosscutting - crosscutting is the action of cutting wood ACROSS the grain, rather than with the grain. A blade that excels at crosscutting will be poor for ripping. A good crosscutting blade is designed to provide ultra-smooth cuts going across the grain without splintering or burning. Generally, more teeth equals a better cut. A 254mm (10 inch) cross cutting blade should have 60 to 80 teeth.

Dado - a rectangular groove cut in the side of one board so that another board may be fitted into it - usually at right angles. Great for shelves.

Feed rate - How quickly and how much pressure you are applying to the stock when pushing through the saw blade. Feed stock only as fast as it will go with ease, maintaining a firm grip with hand or push stick(s)/saw depending on width of stock.

Kick-back - Kick-back is the term for stock that suddenly and without warning is propelled back towards the user at great speed. It is the most common way to get injured using a table saw.

Pitch - A highly viscous substance of plant (or synthetic) origin. Pitch produced from plants is also known as resin. Pitch is not sap - all trees produce sap to a considerable degree, but resin exists in the domain of trees that belong to the Pinaceae family - woods like pine, fir and cedar. Over time, pitch builds up on the cutting edges of saw blades when cutting these woods. This effectively coats the edges, making the blade act as though it is dull.

Push Stick/Saw - A safety device used when working with the table saw. The purpose of a push stick is to help the user safely manoeuvre a workpiece, keeping it flat against the machine table or fence while it is being cut. Sometimes it is safer to use multiple push sticks and there are many different shapes that may be of better use for different size cuts and safety requirements.

Ripping - The action of cutting wood WITH/ALONG the grain, rather than across the grain. A blade that excels at ripping will be poor for cross cutting. A good 254mm (10inch) ripping blade will have only 20 to 30 teeth. A good ripping blade leaves ultra-smooth edges.

Riving Knife - A riving knife is a safety device that sits behind the blade and rises and falls with the blade as the cut depth is changed. The arched shape closely mirrors the blade curve to minimise the gap between the two. Its purpose is to keep the two halves of the stock, as it is cut, from springing back together and binding on the blade, allowing the saw to cut much easier due to the lack of resistance. It also keeps the stock against the fence to deny it access to the rising rear saw teeth - helping to avoid the possibility of kick-back. The guard attaches to the riving knife on this particular model of table saw, which may interfere with certain types of cut. The riving knife may be removed if absolutely necessary for these purposes - please be aware that removal of this safety device SIGNIFICANTLY increases the risk of kickback and MUST be put back and aligned correctly before checking the machine key back in for the safety of the next user and for you to demonstrate the required responsibility of using the table saw.

Stock - The piece of material you are cutting.

True edge - A perfectly straight side of stock