Tools/bandsaw/induction

From rLab Wiki

Some of the tools at the Hackspace are potentially hazardous to use, for these tools members are required to have an induction before they can use them. Inductions provide the most basic information on how to safely and effectively use the simpler functions of the tools, we appreciate that some members may have professional experience on some of these tools and in this case please tell your induction provider and the induction may be very reduced and just cover any risks or procedures specific to rLab. Some tools have multiple levels of induction in order to cover more advanced uses of that tool without making the basic induction take too long, higher induction levels will introduce some of the more advanced features of the tools but as with all inductions are only intended to provide basic information on the capabilities of the tools and how to use them safely. Some members of rLab may be willing to offer more detailed tuition beyond basic induction level or offer guided practice sessions in exchange for beer money or assistance on their own projects.

For all tools you are only required to take level-1 induction before use, after that you may perform any task that you feel confident you can do safely, higher levels of induction may be useful to you in performing more advanced operations but are not required before doing tasks covered in them so long as you're confident of your ability to handle those tasks without risk to yourself, others, or the tool.

PLEASE NOTE : All induction providers are volunteers who are providing inductions to the best of their ability but are NOT qualified instructors. Inductions are provided on a best-effort basis but you and you alone are responsible for your safety while using the tools and for satisfying yourself that you can operate the tools safely. There are professional training courses available from various providers in Reading and the surrounding area if you feel they are appropriate for the level of work you intend to undertake. Reading these notes is NOT a substitute for an in-person induction.

Note for wiki editors : Please do not edit induction pages unless you are one of of the people that gives that induction

There are two levels of band saw induction, level 1 covers the basic setup and use of the machine for easier to process materials such as wood and composite materials; level 2 covers changing the band saw blade to facilitate a wider range of cuts, and metal cutting.

Band saw – level 1

This band saw is designed to be a wood and metal cutting band saw, 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).

Topic Detailed contents Rationale
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.
What's this tool intended to do so people know when to choose this tool and when to pick something else.
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.
Basics of how the bandsaw works, need to know how it does what it does in order to understand what might go wrong.
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.
Basic safety information on PPE and dust control
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!
Stopping and starting! Turning off when unattended and making sure the area is clear which is a safety issue
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.
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.
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
    • Don't press too hard against the fence, it's not very strong and will deflect leading to blade lead
    • 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.
Getting set up so you can perform the cut safely, what to look for when setting up and cutting to stay safe
Operation
  • Check if the welder is in use, they share a power connection and will trip out if both are used at once
  • When making the cut, hold the work piece securely against the table, and guide work into the blade. If you can't get the work securely held flat against the table, you can't cut it. Loose work not firmly against the table with snatch and break 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)
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
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
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
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
Leave the saw cleaner than you found it, cleanliness is a safety issue when working around others.
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
Other information

Bandsaw - Level 2

Level-2 induction in intended to cover some of the more advanced uses of the bandsaw as well as some of the maintenance and adjustment procedures.

Topic Detailed contents Rationale
Cleaning the Bandsaw
  • Checking and emptying dust traps
  • Where dust collects around the mechanisms, around the bearings, near the guard adjuster, around the wheels.
  • Wiping down the table
  • Lubricating the bearing sideways and guard mechanism with graphite
    • Why not to use oil here
  • Checking and emptying dust collection
    • Checking for good airflow
    • Changing filters if needed and where the filters are kept; how to know if a filter needs changing
Keeping it clean and lubricated makes it operate much easier
Checking blade tension

Using the guides on the inside and outside to verify the blade tension

  • Measuring the blade width if you don't know it
  • Making sure you're on the proper scale
  • When the scales disagree
  • Adjusting the scales, using zero reference to get them to match
Wrong blade tension will give misleading results on the rest of the tests
Checking the blade condition

Visual examination of the blade, looking for oscillations, twists or missing teeth

  • Releasing all the guide bearings
  • Using a reference stick to check for front-to-back and side-to-side oscillations
  • Checking for twists
  • Spinning the blade and checking for missing teeth or residues
  • Examining the weld for cracks
  • If needed then cleaning the blade with acetone or a wire brush
    • For wire brush cleaning using the drill, keep the blade moving and the brush angled
  • If you've discarded a blade, where to put it and who to tell.
Checking if the blade is still fit for use
Removing the blade
  • The bandsaw blade that's normally fitted is intended for course rip cutting in wood, but when the blade is changed it can be used to produce much finer cuts in wood, curved cuts, and cutting metals.
  • Blade changing does require basic safety equipment as the blades are razor sharp and can whip around during the procedure so the use of gloves and eye protection is wise.
    • Putting the saw into neutral
    • Open the door and leave it open throughout the procedure because that will cause the interlocks to inhibit the saw for an extra layer of safety
    • Release all the blade guide bearings
    • Remove the aluminium guide plate and open the blade access door
    • Clean the saw thoroughly, dust will make it much harder to handle the blade safely
    • Take the tension off the blade, being careful as once the tension is released the blade won't be held to the tires anymore and can drop or whip around.
    • Remove the table alignment pin. This pin is critical to keeping the table level and must be out for the shortest period possible
    • Carefully wiggle the blade free, the difficult parts will be getting it out of the lower dust brush mounting, slipping it out of the blade guard, and getting it past the back of the fence guide. Throughout this part of the blade change care must be taken not to bend or twist the blade too much or it will be ruined.
    • The double-turn procedure for stowing the blades, being sure not to kink the blade.
    • Cleaning any areas you couldn't get to with the blade installed, this is a good moment to clean the tyres if needed (see below)
Getting the old blade off so maintenance can be done
Cleaning Tyres

There are rubber tyres on the steel wheels of the bandsaw that the blade runs on, they tend to get sawdust embedded in them over time

  • They can only be cleaned while the blade is removed
  • Some sawdust stuck to them is normal and expected, but if it's thick enough to change their shape or make the blade ride unevenly then that's a problem
  • Loose sawdust can be hoovered off
  • Any large lumps should be pried off with a screwdriver, being careful not to dig into the tyre as it's a fairly brittle material
  • Generally heavy deposits of sawdust can be removed with a wire brush, but be careful not to work too hard on any one area as it will dig into the tyre
  • Using a wire wheel in a portable drill can be effective but the wheel must be kept moving AT ALL TIMES or the wire wheel will dig into the tyre, so it's a 2-man job to do it this way. This only works because our tyres are quite hard rubber, other bandsaws with softer tyres will be damaged if you try this!
  • UNDER NO CIRCUMSTANCES try to use the bandsaw's own power to rotate wheels while cleaning tyres
  • Post on the maintenance section of the bandsaw's wiki page if you've done this
Blade will ride poorly over dirty tyres resulting in bad cuts and shortened blade life.
Checking belt tension

Tension on the drive belt should be checked now and then, especially after changing gear

  • How to unlock the adjustment
  • Examining belt condition, who to tell if there's an issue
  • Choosing suitable gears
  • What proper adjustment feels like
  • Locking it off when done
Belts will stretch with time
Fitting a new blade
  • Selecting a new blade according to job
    • Fine-tooth blade for finish cuts
    • Thin blades for tighter curves
    • Metal-rated blades for aluminium/brass/steel/stainless, hardened or chromed steels cannot be cut with this tool, annealed tool steels can be
  • We'll use the metal blade this time
  • Examine the belt carefully for kinks or twists
  • Selecting a suitable gear for the new blade, changing pulleys is easier done without the blade in position.
  • Uncoiling or throwing out the new blade after warning anyone else in the area! Use the metal cutting blade this time.
    • Untwisting the blade by hand sometimes results in it whipping out and maybe cutting you, take care! wear gloves!
  • Slide the blade into place, fitting is reverse of removal.
  • Reinstall the table alignment pin and aluminium blade guide as soon as possible.
  • Tension the blade lightly to get it stable before making adjustments
  • Spin the blade by hand and adjust the blade tracking to seat it into proper position
  • Bring the blade up to the normal tension for that thickness
  • Set the blade guide bearings
  • Close doors and put the gearbox into the proper gear
  • Tracking and blade lead correction will be needed (see below)
  • Once you are done with this job, the coarse ripping blade must be re-fitted.
Different blades are used to get access to the full capacities of the saw
Checking Blade tracking

How the adjustments work, positioning the blade properly on the tyres

  • Checking for proper position, the teeth of the blade should be a little in front of the crown of the wheel and the back of the blade well clear of the edge of the tyre
  • If it needs adjustment then unlock the adjustment handle and move all bearing guides well away from the blade, results will be poor if the blade is touching anything other than the tyres
  • Check and if necessary adjust blade tension
  • Start the saw and move the adjuster slowly, noting which way the blade moves
  • Get the correct position
  • Stop the saw and re-fit all bearing guides
Blade will tend to twist if not tracked properly
Using sliding metal vice
  • Suitable only for use with metal cutting blades
  • This is not a preferred technique as the horizontal bandsaw is usually more suitable
  • Tight clamping essential, if the material moves during a cut the blade is likely to be destroyed
    • Sheet materials cannot be used
    • Material must be long enough for the vice to grip it full-width of the jaws
    • Good for round/square/hex stock
  • More risk of blade lead as it's keeping the work up off the table
We have this so might as well know how to use it, even if it is superseded
Switching in a very fine blade
  • Far more care is required when using finer blade
  • But owing to the fine tooth pitch they'll give neater, tighter cuts on thinner materials
  • Inductee takes the metal blade off, coils it and returns to storage
  • After using metal the tyres and dust traps should be cleaned more carefully than normal as metal swarf can easily deflect the course of a thinner wood blade
  • Taking care throwing out the new blade, thinner blades are much more prone to twisting
  • Inductees fit new blade
  • Take care with the tension, it's easy to snap a thin blade. If you've not adjusted the tension gauges and they're out, now is a good time to do so
  • Greater accuracy is required with setting the bearing guides
  • Very thin blades are most often used for fine curved work, not usually against the fence or mitre gauge
  • If you need to cut something even finer than these blades can do, consider the laser or scroll saw.
  • <Demonstrate thin material free-hand cuts, then inductees practice>
  • Switching back to ripping blade.
Using the fine blade for detailed work
Nulling blade lead

Blades will tend not to cut accurately against the fence when first fitted so there's a need to adjust the fence to be parallel to the blade. If it's not set correctly then the blade will tend to push/pull the work towards/away from the fence and give wonky cuts. The blade lead also drifts over time as the blade wears because the wear is seldom perfectly symmetric, so if you notice that the saw is pulling to one side while cutting then the lead probably needs adjusting.

  • The blade must be properly tracked before doing this as tracking affects blade lead
  • Preparing a suitable block of wood with parallel lines on it, block needs to be at least 300mm long, MDF is preferred owing to lack of grain so the saw can move through it without anything other than the blade lead controlling the path it takes.
  • Move the fence well away
  • Cut carefully but quickly along one of the parallel lines stopping when half-way though and being very careful not to move the wood once you stop
  • Turn off the bandsaw and if possible clamp the wood in place, all without moving it at all.
  • Bring the fence up to the wood block, release the adjusters and adjust it parallel to the wood block, lock down the adjusters
  • Repeat until the lead is reduced to an acceptable level.
  • If using a metal-cutting blade then obviously metal test blocks must be used
  • Post on the maintenance section of the bandsaw's wiki page if you've done this other than as routine at a blade change
  • Checking blade lead when making difficult/long/thick cuts
  • Using fence clamping immediately after a lead check for especially awkward cuts on large objects
Correcting blade lead will result in neater cuts and longer blade life.
Working with rough and odd shaped wood

Irregularly shaped wood, such as old twisted timber, or green wood, or bits of tree can all be cut but considerably greater care is needed.

  • Try to figure out if there's any way you can make it rest flat against the table, if yes you can cut it as normal, just be careful
  • If the shape is sufficiently odd that you can't get a flat surface resting on the table then you'll need to MAKE a flat surface so that it can be cut safely
    • If you're able to make a rip-cut along the work's length safely you might find you can prepare a flat surface that way
    • If there's a surface that's already close to flat then you may be able to use the planner to make it flat enough
    • If all else fails you can build a sled to carry your work through the saw that has a flat bottom and then screw the work onto it
      • Be very careful not to cut through the screws with the saw blade, serious damage is certain if you do.
  • Some situations are especially dangerous and should be avoided completely
    • Cutting across round stock - Cutting along round stock can often be done with care but cutting across it (for example trying to cut rounds off of a tree branch) is exceptionally risky. The saw is very likely to snatch at the timber and rotate it very fast. If you're lucky this will result in friction burns, if you're unlucky... broken bones, crushed or cut-off fingers, cuts and major blood loss.
    • Cutting anything where the blade is likely to contact the top of the work before the bottom - Unless the work is long enough to be stable then there's a serious risk that the blade catching the top edge will rotate the work and slam it down into the table extremely hard. Damage to the saw, and potentially broken bones are possible here.
  • Whenever cutting non-standard timber you need to pay special attention to how the cut is going. If you're getting snatching, erratic cutting, blade moving off to one side or excessive heating these are all warning signs that's something going wrong and you need to stop. You won't always get these warning signs before something bad happens, but if you do get any of them, DON'T IGNORE THEM!
People are doing this, might as well make it safe
Checking and changing oil

Oil in the bandsaw should be changed every 12 months, or sooner if it's looking contaminated

  • Checking the wiki to see when it was last done
  • Location of the sight glass
  • Can only be read when the gearbox is level
  • Can only be read when the Bandsaw has been off for a while
  • Oil will never look brown/black but watch for contaminants
    • Bubbles are normal if the machine has been running, "mayonaise" is not and indicates a problem
  • If you've decided an oil change is needed, which oil should be used and checking we have enough
    • Who to tell if we don't
  • Drain plug is on the bottom of the gearbox, you may need to move the gearbox back and forth to get it all out. Opening the fill port at the top will help it drain faster
  • Collect it in a tray. If you're able to dispose of it at the recycling centre yourself then please take it there, it's harder for us to get it recycled properly as trade waste is charged for.
  • Inspect the plug and O-ring for any degradation
    • If the O ring looks dry then rub a little fresh oil on it
    • If it's cracked or perished then a new O-ring will have to be used.
  • Reinstall the plug
  • Using a clean funnel add fresh oil back in
    • Wipe around the drain plug till it's dry, then leave a paper towel under it for half an hour to check for any drips
    • Refill with oil until it settles half-way up the sight glass
  • Reinstall the filling plug
  • Re-tension the belt
  • Post to the wiki page indicating you've changed the oil
Regular maintenance is required to keep the gearbox running nicely
Using the tilting table
  • Location of the locks
  • Setting an angle that you want to use, the range is -5 degrees to +45 degrees
  • There is a stop at 0 degrees, but check with a square if that's critical to your cut
  • You loose a lot of the height of the machine by tilting the table, consider if that will affect your cut
  • Material will tend to fall away from the blade, this might mean you need 2 people to handle the cut safely
  • Put the table back to flat when you're done
Making angled and mitred cuts