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
- 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
- Tracking adjustment will now be needed
|
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
- Using the guide tool and a ruler
- How accurate it needs to be depends on what you're doing, within a millimeter or so is typical
- If you're fitting the old blade back and leaving it for others, be as accurate as you reasonably can
- Stop the saw and re-fit all bearing guides and adjust them properly
- Close doors and put the gearbox into the proper gear
- Once you are done with this job, the coarse ripping blade must be re-fitted.
|
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
- Precise tracking adjustment is very challenging on thin blades, so it's normally to just center it on the wheels and leave it at that
- Greater accuracy is required with setting the bearing guides, a tighter fit will give you more control for freehand cuts but don't leave it like that when you're done as it'll wear out the bearings
- 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, cleaning table |
- Cleaning and waxing the table
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
- 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
|