Tools/bandsaw/induction

From rLab
Revision as of 08:59, 8 December 2018 by imported>Stever (→‎Band saw – level 1: metricize)

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 table 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
What's this tool intended to do.
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 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
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.
Basic safety information
Start-up/Shutdown
  • Location of main power switch and how to turn on the dust extract
  • How to use the card reader
  • 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 and the crown guard 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
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 confusion.
  • Check that the upper and lower bearing assemblies are properly set. Each of the upper and lower bearing assemblies consists of two guide bearings, and one thrust bearing. Each bearing should be positioned about 0.4mm from the blade – the thickness of a piece of paper folded 2 or 3 times, they should not normally touch the blade while it's not under any load.
  • The blade guard that supports the bearings is not necessarily co-planar 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 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, 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.
      • Set the blade guard so that the bottom of the guide bearings are approximately 5mm above the top of the work piece
      • 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
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.
  • 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 it, ask someone else for advice.
  • If the cut you intend to make is important, always do a test cut first to ensure you will get the results you want.
  • 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 – see the manual for more details.
  • It is possible the laser cutter, or router table with a laser cut template, will give better results. Cutting curves too tight for a given blade will damage the blade and your work.
Getting set up so you can perform the cut safely
Operation
  • When making the cut, hold the work piece securely against the table, and guide work into the blade.
  • 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
Actually making the cut
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
  • Check the extractor to make sure it's not full and empty it if it is
Leave the saw cleaner than you found it
Making test cuts to get a feel for it

For the induction, I 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.

Making test cuts
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