| Topic |
Detailed contents |
Rationale
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| Bandsaw's capabilities |
- It is high powered, single phase bandsaw that can cut wood and some metals and so can be used to machine a range of materials, including but not limited to softwoods, hardwoods, composite materials (such as plywood, MDF, OSB), some plastics, and a range of metals (not hardened).
- Some plastics can be cut on the band saw, but you should check before cutting plastics, as not all behave well. Some plastics will chip badly, others will turn into a gummy, melt-y mess.
- To cut metals the bandsaw blade needs to be changed for the special metal cutting one, which is a level-2 operation
- The saw has the ability to cut material up to 300mm thick and 460mm width of cut
- It can make straight cuts using the fence, but so can some of our other tools that may do it better depending on just what you're doing. It takes less set-up than most other tools though and it really excels at cutting curves.
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What's this tool intended to do so people know when to choose this tool and when to pick something else.
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| Machine overview |
- The band saw is a simple machine, consisting of a motor, connected to a lower wheel via a drive belt and pulleys. The band saw blade is a large circle of hardened and tempered steel with cutting teeth ground into it which is fitted around the lower and upper wheels, with the upper wheel being adjusted vertically to tension the band saw blade.
- The two gears on the gearbox, and three different ratio pulleys, give six possible speeds of the band saw, which are used to facilitate different kinds of cuts in materials of different hardness and dimensions. However, the machine should by left in the higher (wood) gear, and highest ratio pulley, so that the saw runs with the highest speed, as this is generally most useful.
- The work piece is then machined by passing it over the band saw table, though the blade. The band saw is the most versatile of the wood cutting machinery, being able to dimension stock (crosscut, rip, and resaw), as well as cut joinery such as tenons, dovetails, bridle joints, and also detailing work like chamfers, bevels, and curves. It is also very useful for preparing stock for the lathe.
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Basics of how the bandsaw works, need to know how it does what it does in order to understand what might go wrong.
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| Suitable clothing & PPE |
- Sleeves tied back, no loose or flowing clothing, long hair tied back as the blade can is fast moving and can pull things in
- Always use eye protection
- Ear protection is sensible for extended use mostly because the dust extraction is very loud
- The inbuilt dust extraction is fairly effective, but for extended use, or for wood/material dust known to be an irritant or hazardous, it is a good idea to put the air cleaner, and wear a respirator or dust mask.
- When cutting metals the dust extraction system MUST NOT be used because of the risk of sparks setting fire to the vacuum.
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Basic safety information on PPE and dust control
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| Start-up/Shutdown |
- Location of main power switch and how to turn on the dust extract, mention the stiffness of the off button
- How to use the card reader, the card needs to stay in the reader while you're using the saw
- Clean the Bandsaw off if it's noticeably dirty and check the dust traps aren't overfilled
- Check the dust extractor is connected to the main extraction hose
- Make sure that the bandsaw isn't obstructed, the table needs to be empty and there should be nothing around you that will prevent you moving material through the saw and completing your cut.
- The saw must NEVER be left unattended when turned on
- When you're done with your work make sure the machine is left at least as clean as when you started and all material put away
- Make sure you take your card out when you're done!
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Stopping and starting! Turning off when unattended and making sure the area is clear which is a safety issue
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| Machine setup |
- Some interlocks in the door frame prevent the machine from starting when the doors are open. Therefore, when checking and adjusting the saw setup, it is sensible to begin by opening the doors, as this provides some additional security that the machine won’t start while you are setting it up.
- Check the motor is in the correct gear and the drive belt is on the right ratio pulley.
- Check that a suitable blade is fitted for the job you intend to undertake, ideally between 6 and 12 teeth on the blade should be in the work at any given time. Less than this is likely to result in a rough cut, more than this may result in clogging and excessive heat production
- Check that the blade is centered on the upper wheel. This is important, so that the blade runs true, and the set of the teeth don’t chew up the tires on the wheels, if it's not correctly centered then post on the list or ask someone with level-2 induction to adjust it.
- Check that the blade is appropriately tensioned, using either the guide inside the saw, or on the back of the saw. The numbers correspond to the blade depth in mm, which is measured from the back of the blade to the bottom of the gullet. Make sure you are looking at the appropriate side of the guide, for wood or metal as the scales are quite confusing.
- Check that the upper and lower bearing assemblies are properly set. Each of the upper and lower bearing assemblies consists of two guide bearings which stops the blade wandering sideways and one thrust bearing at the back to push on the blade. Each bearing should be positioned about 0.4mm from the blade which is about the thickness of 4 sheets of normal printer paper (or one sheet folded in half twice), they should not normally touch the blade while it's not under any load.
- The lower guide bearings are likely to be correct as they only normally need adjusting on blade change, but they can work loose so check them anyway.
- The blade guard that supports the upper bearings doesn't accurately move with the blade, and so it is important that bearings are set with the blade guard at the appropriate height for the work piece before checking the bearings. Adjusting the blade guard height after setting the bearings may degrade the setup. If you're making very approximate cuts then it's probably fine just to check that they're positioned about right but if it's an accurate cut you WILL need to adjust them.
- If the bearings need adjusting, the process is as follows; See figures 25, 26, and 27 in the manual for more details.
- Free all bearing assemblies from the blade and release all the adjustment locks so you can be sure the blade is free and not being pushed by any bearing.
- Set the lower bearings first.
- Bring forward the guide bearings so that the sit just behind the gullet of the blade.
- Lock off the forward motion of the guide bearings. The thrust bearing moves relative to the guide bearings hence why it is done in this order; If you set the thrust bearing first it will likely need adjustment after the guide bearings are set.
- Use the elliptical nuts to rotate in the guide bearings so that are 0.4mm away from the blade.
- Move the thrust bearing forward so it is 0.4mm behind the back of the blade.
- Lock off all the adjustments.
- Set the upper bearings.
- Release the lock on the blade guard and set the blade guard so that the bottom of the guide bearings are approximately 5mm above the top of the work piece then lock off the adjustment.
- Set the guide and thrust bearings in the same order as for the lower bearings.
- To see if the bearings are set right, start the saw. If you see or hear any of the bearings moving when the saw is not under load, then adjustments should be made. Turn off the saw and make the adjustments. Never adjust any bearings while the saw is on.
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Getting the Bandsaw set up properly. Ideally have the inductee(s) do the bearing setup as they'll need to do this quite often to keep it cutting well.
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| Setting up for your cut |
- Consider how you will complete the cut before you make it. If you need push sticks or guide blocks, have them to hand before you start the cut because you don't want to be flailing around trying to grab them while you have the blade inside your work.
- Where possible use push sticks and guide blocks to complete a cut. It is never necessary to get any part of your person within an inch of the blade. If you cannot see a way to achieve you cut without getting close, ask someone else for advice.
- The sizes on the fence guide are approximate, if the cut you intend to make is important, always do a test cut first and measure it to ensure you will get the results you want.
- If the material is thin and the cut narrow then the fence extension will probably be needed to get proper distance to the upper guide
- If cutting curves, remember that each blade can cut a curve of a minimum radius that is proportional to the depth of the blade – tighter curves require narrower blades. This varies from radius as tight as 3.5mm from a 1.6mm wide blade, to a more normal 65mm radius using up a 13mm blade, up to a maximum of 180mm radius on a 25mm wide blade. So consider whether the curves you intend to cut are practical on this blade.
- When you are cutting curves be aware of the twisting forces on the blade, it shouldn't be visibly twisting in your cut. If it is then your curve is too tight for this blade, stop and get the blade changed or you risk snapping it.
- It is possible the laser cutter, or router table with a laser cut template, will give better results on tight curves.
- Setting up for freehand cuts
- Positioning your hands safely so you can feed material around your curve
- Consider at all times what happens if you slip, make sure you won't fall into the blade.
- Setting up for cuts against the fence
- Used for rip-cutting, when your workpiece is longer than it is wide, or generally when cutting along the grain.
- Watching out for getting hands between the fence and the blade, using push-sticks
- Using the fence extension for thin materials
- Being aware of blade-lead - Call for help if it's bad
- Setting up for cuts using the mitre guide
- Used when your workpiece is wider than it is long and for cuts across the grain.
- Holding work secure to the guide
- Be careful if you need a hand on the fence side of the blade, this is best avoided when possible
- Setting angles and cutting them.
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Getting set up so you can perform the cut safely, what to look for when setting up and cutting to stay safe
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| Operation |
- When making the cut, hold the work piece securely against the table, and guide work into the blade.
- If you're rip-cutting then you should be resting the work against the fence, if you're cross-cutting use the mitre guide or the vice, if you're cutting curves then you'll have to do it free-hand
- Do not push too hard into the blade, as you will damage the blade and get a poor quality cut.
- Feed rate and pressure depends on the materials properties and dimensions, as well as the blades specification and condition and machine setup. So it needs to be felt – rather like changing gear in a car. However, it should never be hard work to push something through; if it is, stop the cut and consider if everything is set correctly.
- Start the dust extractor, start the saw, make the cut, turn off the saw, turn off the dust extraction
- Do not try to remove off-cuts from immediately around the blade with your fingers
- Especially when taking thin shaves off materials be aware the the off-cut can fall down into the lower bearings and that's dangerous to the machine, try to find a way to prevent this if you can safely do so.
- Demonstrate the 3 main types of cut to be made (Cross, Rip, Freehand)
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Actually making the cut and getting the feel for what are suitable cut speeds in various materials, demonstrating the safety procedures so people can see how they work
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| Making test cuts to get a feel for it |
- For the induction, we normally ask people to make cuts into 3 different kinds of material (MDF, softwood, and hardwood), so they gain a sense of the different feels.
- One cut freehand
- One against the fence
- One using the mitre guide
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Making test cuts with someone around who can advise on work-holding and speeds of cut so the inductees get a good feel for things
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| Cleaning up afterwards |
- Ensure that all materials are removed from the saw and it's table
- Sweep up the saw and sawdust from the floor around it as it's a slip-hazard
- Check the dust-trap inside the saw and make sure it's not full.
- Check the extractor to make sure it's not full and empty it if it is
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Leave the saw cleaner than you found it, cleanliness is a safety issue when working around others.
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| Miscellaneous extra info |
- The manual for the band saw which provides illustrations and more details about its setup and maintenance is on the wiki here
- The HSE has also produced a fairly comprehensive document detailing safe band saw use: http://www.hse.gov.uk/pubns/wis31.pdf
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Other information
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