Difference between revisions of "Workshop"

Revision as of 14:30, 18 January 2018

General Safety

As with the main area, the machines are for use by members only, for both insurance and safety reasons. It is assumed that members understand the risks inherent with power tool use - only you are responsible for your own safety. Never use a machine you have not been shown how to use. This page is a reminder and summary only, and in no way a substitute for training or common sense.

We are currently planning a more formal system for machine training & access control, documentation will follow when this is finalised.

Goggles and ear defenders are readily available, and their use is highly recommended. Restrain long hair, sleeves, ties, beards, fu manchus, or anything else that might get caught in a machine. Needless to say, keep hands well clear of all blades. Push sticks and sleds are available.

Do not distract people using machines, and again, never use a machine you have not been trained on. If you are doing something unusual or you are otherwise in any doubt, ask; people will be happy to help and advise, or supervise.

Other General Information

Where possible and within reason you are expected to clear up after yourself. Half finished projects often have nowhere to live and it's somewhat expected that they'll be lingering occasionally. Similarly nobody expects you to deep clean the place after each use to remove every speck of sawdust. Ideally though the place should be left in the same or better state as you found it; tools away, bench as clear as possible, batteries charged, wires coiled, and so forth.

The Workshop gets quite cold in winter, so dress appropriately. The British Antarctic Survey have been known to hire the room for conditioning and equipment testing.

Machines

Dust Extraction

After much work, the shop now has a dust extraction / cyclone system, and all the machines are linked up via blast boxes, which are located on the wall behind the tools on both sides. Open your tool's gate (they are labelled), turn on the hoover, and then turn on the tool. Reverse the procedure when done. If the vacuum is left on with all gates closed, or otherwise significantly impeded, there will be a release valve to stop the cyclone imploding, but ideally it should never happen in the first place. Conversely, gates that are left open for idle tools drastically reduce the effectiveness of the system.

The system is for DUST ONLY. If you block it up with rubbish you are expected to clear it out. This will probably mean removing, opening, ram-rodding, resealing and then re-laying the piping behind the woodstack and shelves, which is about as fun as it sounds. The system is earthed to prevent static buildup, and rubbish may catch and break the earthing wire, which would also then need replacing and rethreading as well.

Bandsaw

A solid workhorse, the bandsaw is the only power tool on which it's relatively safe to have your fingers near the blade (eg a couple of inches), IF and only if you are completely familiar and confident with the tool. This machine is the only exception to that rule. If the blade guard is set correctly the blade is not exposed, it produces no kicks, and is very predictable; this makes it excellent for detailed work. Whereever possible though, push sticks and guides should be used for close work, and they are always nearby.

The saw table can tilt up to 45 degrees. There is a drop-on zero clearance overlay table with a 45/90/180 guide, adjustable fence, and a mitre guide. Unless you need the table to tilt, or an extra centimeter of depth, the overlay is recommended and is usually left in place.

Some specific warnings; never reach behind the blade with your hand when the tool is on. In fact it's good practice to never do it even when off, to prevent habits forming and then absent-minded action when the tool is live. When cutting a slot without an exit cut, turn the tool off before pulling the work free of the blade - if you don't you will probably pull the blade off of the saw, which is aggravating at best and dangerous at worst. When cutting tight corners, use relief cuts to allow the saw room to move. Not doing so will pinch the blade, results of which vary from stalling the machine, removing the blade, or flat out breaking it.

Drill Press

Always align the drill with the hole in the support plate before drilling. If you do not the drill bit will be ruined, and there is a chance a wood bit may shatter if it strikes the steel.

There is also a table overlay available here, with an anchor wall to prevent 'strimming' when the drill bites the workpiece, and its use is recommended. Drill bits are in the box under the central bench, and some more are usually to the right of the press itself.

Chop Saw

This tool is quick, powerful and intuitive to use. Always keep your off-hand well clear of the cut zone; if you need more support for the stock, clamp it to the fence. There is a laser guide that will help with cut alignment, but it is not 100% accurate. The saw also does not quite cut to precisely 90 degrees, so bear that in mind if absolute perfection is required. When cutting along the work, rather than simply downwards, it's best to start the cut with the saw fully extended then move inwards against the cutting force.

There is a zero-clearance inlay currently installed, it is set for vertical / 90 degrees. Please do not ruin it by using the mitre modes without removing it first!

Table Saw

The table saw is the most dangerous tool in the shop, followed by the routers, which are deceptively safe looking but just as capable of launching workpieces or pulling fingers into the blades. Always keep your hands out of the blade line, and your body where possible. Use the guided pusher or a push stick for close cuts, and the featherboard for narrow stock. There is a crosscut sled, although it currently requires resquaring. A blade guard is also available, but it is usually not attached as it prevents several common forms of use. If your intended cut would accept it, as with all safety equipment, its use is recommended.

Note: The guided pusher uses the fence, thus neither it or your hand can be pulled into the blade, but by nature it pushes one side of the workpiece only. As with all pushers, it's best used for the latter part of the cuts. If it is used BEFORE the workpiece reaches the riving knife, e.g. with very short stock, then it could in theory cause kickback if the work turns into the saw. Use of a featherboard will prevent this.

To understand the speed, unpredictability and sheer power of kickback, watch this Youtube video. The man in question was intentionally trying to cause it and fully expecting it, was using a pushpad, and had both his body and hand out of line with the blade... and was still lucky to leave with his fingers intact.

Absolutely NEVER cut from the back of the saw. It will literally launch your work across the room, and probably your hand with it.

If you are not confident with the table saw, the chop saw and bandsaw are usually viable alternatives. When not in use, the saw must be unplugged, and the blade drawn below the table surface. This protects both users and the blade.

Belt Sander

Relatively safe to use, the main hazard is dust. It is possible for the belt to grab work and pull it, with practice you will recognise when this is likely. Always keep fingers away from the belt intake. Whilst the gap is narrow it can still pinch, and if you get something caught in there, it will be ground away in moments, whether that's your workpiece or a fingertip. Using the heel (rounded end) is likely to cost you some knuckle skin occasionally, as it is its wont to grab the work.

Bench Grinder

This has no guard attached, and is unsafe to use without a face mask. Additionally, sparks may ignite the worryingly close polystyrene on the ceiling nearby. Be Careful. It also has a narrow sanding belt, which is unsupported so is suitable for curved work. Be aware that they both activate at the same time.

Router Table

Currently pending relocation. The router is deceptively dangerous for a static tool, on par with the table saw, and as with other power tools must be treated with respect at all times.

Always feed your workpiece against the cutting direction, which is to say move it from the right towards the left. If you reverse feed (AKA 'climb cut') the router will usually grab the workpiece, pull it (and potentially your fingers) straight through the cutting bit, and shoot whatever's left off of the bed at great force. The kickback video linked above demonstrates this too.

Use of guards (and/or guide pins as applicable) is essential, and featherboards are again highly recommended whenever possible, for both safety and control. As with other tools, use push sticks to finish the pass, or scrap wood. Scrap has the added benefit of preventing chipout at the end of the cut.

Note that the router is primarily a trimming tool. As with the handheld version, it's best (and safer) to take multiple passes at a cut, getting progressively deeper per pass. Excessively deep or fast cuts risk control being lost, breaking your work, and/or the bit.

The CNC

This semisentient beast mainly eats wood, polystyrene, router bits, and the unwary. If you see it in action keep well clear of the work area, it moves quickly and erratically, and will chew through any wood or fingers it encounters without pausing for breath.

It's not yet ready for general use, but Adam & Jon are working on it heavily so that will change at some point. It's capable of 2.5 degree milling to varying degrees of accuracy - results vary wildly depending on the medium, model detail and pathing quality. There is a Wall of Shame demonstrating many projects which have fallen victim to poor pathing, misstepps, and collet catches.

Preparation of files for this is significantly more challenging than with 3D printing, and will later be an article in its own right. In short though, something flat / 2.5D or less than 3cm deep is usually millable. An article which requires two (or more) sided milling, 100% precise depth and bit changing, or over 3cm in depth is much more complicated, to the point of currently being impossible. The polystyrene blocks are for testing purposes, as they are less likely to damage the tool than with wood.

ESTLCam can perform some basic outline and finishing profiles, as can Meshcam. We are leaning towards Fusion 360 as the recommended processor, and experiments are well underway with it. The downside to that is the complexity that inevitably comes with more control; it's significantly more involved to set up pathing compared to ESTL or Mesh, as it is an industry standard tool. Again this will need to be an article in its own right later on.

Repetier-Host can visualise gcode. Once a script has been created you must always sanity check it to see that it moves as you expect, but bear in mind that this will not show cut speeds! Fusion 360 in particular specifies movement speeds in mm/ps (minimetres per second) in all places, except for one field quietly buried among them, which always uses m/ps - metres per second. This is very easy to miss and completely ruined a testpiece when the router exited stage right at warp 9. If that program had been running on wood the machine would now be thoroughly broken. Always test cuts.

Handheld Power Tools

Similar caveats apply to these as to their mounted brethren, so they will not be repeated again here, however since the handheld tools are not fixed in place it is comparatively more important to be aware of people around you. Additionally, when plugging a tool in, assume it will immediately start up, even if you believe it is off. This policy has saved many fingers.

We currently have a sabre saw, circular saw, planer, belt sander, angle grinder, drill, jigsaw and a router. Some of these are corded and others are battery operated. Always charge batteries after use, and remember to turn chargers off when leaving the Space. In winter months, note that the cold will drain the batteries quite quickly. If the tool has a dust bag or an adapter for the Cyclone system, you should use it.

The angle grinder will produce significant quantities of sparks when used on metals. The obvious general precautions applicable to all power tools don't need restating, for this tool or the others, but a less obvious hazard is the presence of polystyrene on the ceiling and by the CNC. This is very prone to catching fire, so be incredibly careful if grinding anything.

Finishes

We have an array of paints, dyes, varnishes and oils available. If using oils you must ensure that you air the rag sufficiently - oily rags have an unpleasant habit of spontaneously combusting. Ideally rinse it, then leave it unfolded on a metal surface. Just chucking it in the waste bin may well lead to a fire several hours or days later when the space is unoccupied! If in any doubt about what to do, ask.