Monday 9 July 2018
Router tables and spindle moulders, or shapers, work in much the same way, and here I shall be analysing both to help you decide which is best for your needs.
Routers are well liked by most woodworkers because they are versatile power tools for channelling, edging and joint cutting, but they are rowdy, with a mind of their own unless you keep them under tight control.
Turn the router upside down so the cutter protrudes through a large baseplate and you have a router table. This way up the router is less deafening because of the tabletop between the motor and your ears. It is also easier to control because it is no longer top-heavy and you can see what is going on.
The spindle moulder is a heavy, hardworking machine from a different background altogether. Until a few years ago you would be lucky to find one away from large joinery workshops.
The cost range of moulders is comparable with tablesaws and planers – obviously much more expensive than fitting a router to a table, while the footprint is also large. Perhaps equally significantly the spindle moulder used to have a scary reputation.
In recent years high-end routers and router tables have become bigger and more sophisticated while small spindle moulders made in the Far East have become more affordable.
All about router tables
Small router tables tend to be dismissed by makers as amateurish, not so much because of their size but because of their lack of weight and stiffness. The main feature to look for in a good router table is rigidity, both in the support stand and in the top itself.
The tabletop provides a large reference surface so it must not deflect under load. If it did, the cutting action would be distorted and the cutter could bounce against the work, producing a wavy, rough finish.
Phenolic resin is a dense, stiff material used for the top of many better-quality tables, normally braced by alloy ribs. Metal tabletops need to be cast to avoid flexing. Tables that are stamped out of sheet steel, pressed and folded are unlikely to provide enough vibration resistance and need plenty of supporting ribs for stiffness.
The stand must be sturdy and heavy so the table cannot move with pressure or vibration and there is no risk of it toppling, while small tables should be screwed down.
One thing to consider when buying a router, a table and possibly a lift separately is that there can be fitting problems and there is no manual covering the lot, so you are on your own sorting them out.
Routers used for tables are larger models with a half inch chuck and a motor power normally of 1500W or more. The router must have variable speed control for safe use with large-diameter cutters – not a problem for new machines but some old routers are single speed. The plastic guards and dust collectors supplied with the router often do not work when fitted to a table.
Router tables invariably add depth to the router base and reduce the effective plunge distance. This, coupled with the fact that cutter shanks are very short, means you should look for a router with as much plunge depth as possible.
Like any machine, the router table needs an accessible no-volt release (NVR) switch with emergency stop pushbutton. Sometimes these come with the table or they may need to be bought separately. The router power switch must be lockable in the on position so that control is from the NVR switch.
Reaching the chuck from above can be awkward, generally necessitating having to bend down to reach under the router table, where side access may be restricted. Alternatively, a removable baseplate can be lifted out of a recess in the table, flipped over and stood upside-down for access.
The router table allows much larger-diameter cutters to be fitted than could safely be used in a handheld router. These require a large-diameter hole in the tabletop, which also improves access to the chuck. When a smaller cutter is used insert-rings are fitted to close the gap.
You will need to vary the height of cutter protruding above the table. The normal plunge mechanism of the router is not helpful because it has springs that push down making it difficult to raise. Some routers have a hand-screw-driven plunge system to wind the plunge up and down, or a Router-Raizer can be fitted.
Lift Platforms provide another means of adjusting height. The router base is screwed to a platform which is raised by a calibrated crank handle accessible from above the table. Be aware that the platform will reduce the rigidity of the router support so it must be well constructed. It can also make removal of the router base more awkward.
The gap between platform and table provides a ready escape path for chips and dust so you may need to enclose the stand for effective extraction.
On balance a good router lift extends the total travel greatly, allowing precise adjustment. It also removes the need to fumble about underneath, greatly adding to the usefulness of the table.
On the tabletop
A vertical fence across the router table provides a long reference edge to guide shaping work. The fence, which is split to run each side of the cutter, must be stable and easily adjustable. Some have crude clamping arrangements while others have micro-adjustments for precise positioning.
A sliding fence running along the main fence adjustable to any angle opens up possibilities to use the router table for crosscut work such as tenoning and cutting housings on narrow boards.
All about spindle moulders
The spindle moulder provides extra capacity, power and continuous cutting ability. Unlike the router table, a new spindle moulder is designed as a complete machine and comes with a comprehensive manual. It is important to read this and understand the guides, stops and hold-downs essential for many tasks. It also pays to read up on any cutting procedure that is new to you or it could bring unwelcome surprises.
Larger machines have 3-phase drive motors which are harder to stall and more efficient, hence they run cooler, so consuming less electricity. Single phase is an option on small moulders with a power of 2000W or 3000W.
Speed must be varied to accommodate different-diameter cutters. The maximum speed should be engraved on the block. This procedure is achieved by changing pulley combinations, typical settings ranging between 1500rpm and 8000rpm. The standard spindle is 30mm diameter and most common tooling is designed for this.
There is usually enough power to remove the full depth in a single pass, but making a final cut with a shallow pass will reduce vibration of the wood, hence improving the surface finish.
The hum of the induction motor is much quieter than the screeching brush and commutator in a router motor, but once the cutters have engaged in wood the difference is less significant.
Heavy cast iron is invariably used for the tables on larger spindle moulders while cast-aluminium alloy tables with ribs beneath are sometimes fitted to small ones. The split fence design is combined with a heavy rear guard and chip collector, left and right fences being individually adjustable or they can be moved together.
Moulding operations on small material benefits from using a false fence to eliminate gaps. This is a sacrificial board that you fit across the whole fence width, and then push back so the cutter sticks through.
Spindle moulders commonly incorporate a sliding table fitted with a fence to carry wood smoothly past the cutter at any angle without frictional judder.
Old designs of moulder cutters carried hidden hazards, like uncontrolled cutting depth or insecure blades flying out. These deservedly earned them a bad reputation. The modern moulder has these problems designed out, but still needs to be treated with respect.
The cutter block is bolted to the spindle and packed out with shims while the height is adjusted by moving the spindle itself up and down with a hand-wheel on the cabinet.
Straight cutters are used for rebating and jointing while profiling cutters come in many shapes for coving, beading, ogees, flutes etc. Narrow cutters stacked up can make a combination cutter, or matched pairs of cutters are made for specific tasks like cope jointing.
Chip-limiting cutters incorporate a profile to match the blade. This prevents kickback by limiting the depth of cut that can be made in a single rotation. It is still possible to remove deep profiles in a single pass through the machine but only with a slow feed rate. As well as avoiding some serious injuries this improves the quality of the resultant finish.
Insert-tooling uses individual pairs of knives clamped in a cutter block. The chip limiters for insert-knives consist of matching-profile limiter plates wedged into the block behind each knife. Insert-knives with matching limiters can be made and drilled, filed or ground to shape in the workshop for special jobs. They are easily removed for sharpening.
Cutter blocks can be reversed by turning them over and the motors can be reversed accordingly on most spindle moulders. This increases the versatility but also introduces a potential hazard as the cutter will snatch severely if accidentally worked in the wrong direction.
Panel-raising cutters tend to be large diameter hence they are set to spin at a slow speed, but even so the tip velocity is high.
Choosing the machine for your needs
The larger spindle moulder cutter sweeps a much straighter path than the router so results are smoother. Although the rotational speed of the moulder is lower than the router, the larger diameter more than makes up for this, providing higher cutting-edge speeds. These can shape deeply into contours where a router bit would never reach.
The depth of the spindle moulder cutter can remove wide profiles in one cut without the need for multiple passes. While there are plenty of router cutters on the market, the range of cutter shapes and designs to fit the spindle moulder is vast, and when you add profiles you can shape yourself, the possibilities become infinite.
On the other hand, the small diameter of a router bit will follow a template in a tight inside curve which could never be reached by the larger moulder cutter.
Fine grooving jobs like fitting spline joints are also better done with router cutters. Some spindles will accept a router cutter but the rotational speed is too low to work well.
The router table can be incorporated into bench space used for other work and some can be folded out of the way when not in use, while a good spindle moulder takes up a lot of workshop space.
Space and budget might be the first considerations in deciding which machines to buy. On balance, a spindle moulder works faster and smoother for tackling bigger jobs, but if most of your furniture is small scale and detailed, then a good-quality router and table will give you a better return on investment than a small-scale moulder.