Table Saw

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Bitraf provides a Bosch GTS10XC table saw for members to use, upon completion of a safety course. The only requirement is to provide your own dust mask, these can be purchased from Bitmart from 35kr if you do not have your own. 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, and to instill confidence in your ability to use the table saw. This knowledge you absolutely must know, and put into use every time you use the table saw. Always remember, there is no such thing as a minor table saw accident. If you are uncomfortable making any kind of cut, then DO NOT DO IT. It's that simple.


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

Access

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' of users who can 'checkout' the key to the machine. Your usage is logged and once you have checked out the machine key 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 repeatedly not thoroughly cleaned or left in proper order after use.

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 (store it under the table saw surface on the right hand side) and it MUST be put back on 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 24tooth 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.

Questions? Problems?

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

Stock

Stock is the piece of material you are cutting. There are a few things to check before cutting your 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

- If using the 'Grr ripper' ensure the stock is dust free (to make sure there's no slipping on the stock)

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 are hand injuries - where the stock pulls the users hand across the moving saw blade - 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


Do's and don'ts of table saw usage

Before using the table saw

- FIRST THING TO CHECK - Everything in the 'Before plugging in the table saw' section above

- Check the Power Switch is OFF before plugging in (Just hit the red power switch cover to make sure)

- Adjust height of blade (half a tooth above stock, max 6mm)

- Adjust fence, check it is parallel to runners or toe-out a tad to reduce chance of kick-back. To align the fence correctly, mark one tooth, rotate it to the fore, and measure its distance from the fence. Next, rotate the tooth aft, and perform the same measurement. (Using the same tooth as reference removes blade warp from the equation.) Adjust the fence until the measurements match and lock down securely

- Check push-stick is within easy reach and check the condition

- NEVER turn on saw while the blade is touching stock

- Check no-one is behind you

- NEVER use the table saw if tired or under the influence

- Prepare the space in the carpenters workshop, cutting a 1.5m long sheet of plywood requires at least 1.5m behind the blade and over 1.5m in front of the blade to be able to safely make a cut. Don’t realise half way through a cut you don’t have the space

- ALWAYS prepare additional support at infeed and outfeed areas for longer/wider stock. If you cut a large piece of stock that’s not fully supported underneath, it may twist or bow, causing the timber to twist against the blade which may result in kickback and possibly cause stock to split or break. If the table is not big enough for the stock you are cutting it is advisable to ask someone experienced to assist you or build a platform of some kind to help support it. The Bosch GTS10XC has 300mm extra of crosscut support and 480mm extra outfeed support available.


Using the table saw

- Concentrate! Keep full attention at all times on kick-back zone, blade, stock, fence and where your hands are

- ALWAYS use the guard when possible, if you do remove the guard store it under the table saw on the right hand side in the designated area (so it is not lost or damaged). When finished using the table saw you MUST replace it when finished working for the next user and to complete your responsibilities

- NEVER freehand cut, always use mitre/crosscut sled for crosscuts and rip fence for ripping. Freehand cuts cause crooked cuts and potential kickback

- Wherever possible, avoid standing with your body in line with the blade. (because of the possibility of kick-back) Normally, stock wider than 20cm stand to right of the blade, less than 20cm wide stand to the left and use push-stick.

- NEVER put your hands in line with the saw blade, or reach over or behind the saw blade until it has stopped turning.

- ALWAYS use a push stick/push saw when making a rip less than 300mm in length or feeding the last 300mm of longer stock.

- NEVER cut more than one piece of stock at a time

- Avoid awkward positions such as crossing arms/ overreaching/unbalanced feet

- Feed stock only as fast as it will go with ease, maintaining a firm grip

- Don't overload the motor by trying to cut material that is too thick, heavy, or dense. If the blade extends 79mm above the table doesn't mean the motor can handle cutting 79mm solid wood, especially if the cut is long. Make deeper cuts with multiple passes, raising the blade a little more with each pass. Make each pass at a cutting depth that the saw can handle. When the blade is buried in the stock the saw must work harder to evacuate waste. So even though the saw will cut 2cm easily don’t cut 2cm out of a 3cm piece of wood.

- When ripping, apply feed pressure to stock between blade and fence. Hook your thumb behind the board and keep your little finger in contact with the fence to rip boards 15cm and wider. Concentrate on keeping the edge of the board in full contact with the fence while you push it through the blade at a slow, steady rate. Push the stock completely past the blade and riving knife

- NEVER release the stock until it is past the saw blade. Doing so is an invitation for kick-back as it is possible for the blade to grab the part of stock that has not yet gone by

- NEVER reach behind the blade and pull the stock, if someone is assisting you with large stock make sure they only support the weight of the stock and NOT pull or lift the stock

- NEVER back a board out of a cut. If you misfeed stock you will probably hear a change in the saw noise and can act accordingly

- NEVER remove pieces in or around the blade while it's in motion

- NEVER adjust the height or angle of blade or the fence while the table saw is running, switch off the machine first

- NEVER leave the saw running unattended If you no longer use it, you have to unplug it and check the key back into the p2k16 tool system

- If you use your own blade you MUST put back the original Bitraf blade to complete your responsibilities

- NEVER place the workpiece on top of a moving blade.

After you have used the table saw

If you have removed the guard, changed the blade or in any other way modified the machine for your use it is imperative to return the table saw to the default configuration - standard Bitraf blade, riving knife and blade aligned and in place, all accessories put back and checked in (if needs be) and properly cleaned.

You MUST clean up thoroughly after yourself, not only to ensure safety, also to show a good example to other members and to complete your responsibilities. Creating a culture like this transfers to all aspects and areas of Bitraf making a better place for everyone.

'Check in' the tool in p2k16 for the next user to check out.

Repeated failure to demonstrate the required responsibility of using the table saw will result in table saw access being revoked.

Report any problems or breakages to Thomas Winther, Nikolai Kolstad or Yoshi

Glossary of terms

This section contains a glossary of terms relevant to this subject.

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.
Crosscut sled 
A crosscut sled has a fence that's mounted exactly 90° to the blade. Because both the stock and the offcut move with the sled and are backed by a fence perpendicular to the blade, there is a much smaller chance of kickback than with a miter gauge, and neither the workpiece nor the offcut will have tearout as the blade exits the piece.
Dado 
A rectangular or square 'slot' cut in the side of one board so that another board may be fitted into it - usually at right angles. Very similar to grooves - the difference between the two is that a dado is milled across grain, while a groove is milled with the grain
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.
Groove 
A rectangular or square 'slot' cut in the side of one board so that another board may be fitted into it - usually at right angles. Very similar to dado - the difference between the two is that a groove is milled with grain, while a dado is milled across the grain
Grr Ripper 
A pushblock that helps when ripping long stock, cutting small parts, preventing kickback, protecting hands and enabling cleaner cutting. It is very important to clean the rubber gripping pads with denatured alcohol after every use to keep the material clean and sticky. Swabs and bin are in the workshop for this purpose. You must dust off the stock to ensure there is no slipping of the Grr Ripper. The Grr Ripper has to be checked out with the 'tool checkout system' and can be used with the router table, the table saw and the band saw.

https://www.youtube.com/watch?v=C6yx8fZaIEw

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.
Mitre 
A mitre refers to an angled cut on the face of a piece of stock, usually for two structures that will be joined to create a corner, which would then be called a mitre joint. A true mitre joint requires two pieces to be cut at 45 degree angles, so when they are joined the corner created will be 90 degrees. However, a mitre joint can also be created from other angles. To safely cut mitres you should use the mitre gauge, which is stored on the right hand side of the table saw underneath the cutting surface. This slides in the runners either side of the blade and can adjusted +/- 60°.
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/Push Saw/Push block 
A safety device used when working with the table saw. The purpose of a push stick/saw/block 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 it as the cut depth is changed. The arched shape closely mirrors the blade curve to minimise the gap between the two. It's 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 guard may be removed and the riving knife pushed down to the same height height as the blade - for example to cut grooves or dados. This is achieved by raising the blade height to maximum, then pushing down on the riving knife. Simply pull upwards on the riving knife to raise it above the height of the blade to reattach the guard. Alignment of the riving knife should be checked before and after use to ensure proper stock feed and to check whether the bolts holding it in place are still tight. It is natural for these to loosen over time.

The riving knife MUST NOT be removed in any circumstances - as removal of this safety device SIGNIFICANTLY increases the risk of kickback, as well as there being no good reason too.

Runners 
The grooves either side of the blade sunk into the table saw surface that the mitre guide/sleds run in. They are perfectly parallel to the blade so are perfect with which to check the alignment of the fence.
Sled 
A sled rides in the runner grooves, and is used to add versatility and repeatability to cuts. You can build sleds for many different angle or jig operations. You can also add stops and clamps to a sled - for example, to cut other angles or even to rip small parts. You can also quickly crosscut many parts of the same length simply by clamping a stop block (any small scrap piece of wood) to the sled's fence. A sled can ride in a single runner like a miter gauge, but many designs use two runner tracks.
Stock 
The piece of material you are cutting.
True edge 
A perfectly straight side of stock.