full fitting instructions

smartHinge full installation instructions:

setting the cutter height:

First fit a sharp 8mm [5/16” for US] cutter [downcut spiral for cleanest cut] to a table mounted router and set the height to exactly half the thickness of the hinge at the knuckle. You should perform the following test: first take a couple of pieces of scrap 4 or 5 inches long, 1/2 x 1/2 or so, and do a ‘freehand’ test cut at the end of each by holding it flush on the table and stroking the end of the piece right to left across the cutter. To do this safely you will need to do a few successive cuts to less than 1/4 of the diameter of the cutter, otherwise it might grab. Once you’ve done this enough to accommodate the knuckle well past the pin, remove any burr and hold the hinge knuckle between the two pieces as shown.

If the cut is just right, the hinge will be held as in the top image and there will be a cigarette paper’s thickness between the pieces of scrap. If the cut is too shallow the hinge will also be held but there will be a gap between the pieces of scrap that’s too large as in the second image down. If the cut is too deep the hinge will not be held and will drop out as in the bottom image. The direction and amount of the adjustment necessary should be obvious.

If there is any give/spring in your [plastic?] router plate then you might have to add a couple of tenths to the height – it’s likely that the cut will be very slightly less deep on the box than on the test pieces due to its larger size.

TIP: if in doubt, cut in very slightly DEEPER than you need – it’s a great deal easier to shim one or more of the hinge leaves with paper [most is pretty reliably 0.1mm thick] than it is to remove more material to that sort of accuracy.

setting the fence:

The fence [preferably faced with slick-tape or similar low-friction material] should be set at a distance from the cutter so that it will cut the grooves to take the hinges in the centre of the sides of the box. The distance from cutter to fence should therefore be 1/2 x (X-8) where X is the thickness of the sides of the box. If the wall thickness is less than 12mm you might consider fitting the hinge flush with the inside edge of the side of the box. This will avoid the outer edge of the hinge being too close to the outer edge of the box. The inside edge of the hinge would then usually be covered with whatever lining material is fitted.

NB: When setting the fence the cutter must be rotated so that the cutting tips are in a line exactly at right angles to the fence, otherwise the positioning will be inaccurate.

NB: A LOW fence is best for this sort of work. I use a piece of 25mm mdf, about 100mm wide for strength, and faced with a low friction plastic strip.

setting the stop:

The smartHinge measures 42mm from the centre of the pin to the end of the leaf – you will need to make an accurate spacer this value LESS 8mm, so 34mm wide. This will mean that the smartHinge protrudes from the back of your box by the traditional amount, the centre of the pin being in a line vertically with the back.

Set the stop 34mm from the cutter as shown and you’re ready to go.

NB: when positioning the stop using the spacer the cutter must be rotated so that the cutting tips are in a line exactly parallel with the fence, otherwise the positioning will be inaccurate.

doing the cuts:

NB: The router should be set to MAXIMUM SPEED for this, and incidentally for most other operations as well – you should consider maximum as the default setting and only consider reducing it for very large cutters.

The setup described above will produce the top right and bottom left cuts. But first do a test cut in a piece of scrap: with a sharp cutter the hinge leaf should fit like a glove – if the cutter is worn [you shouldn’t be using it!] you might need to make a second pass with a piece of tape along the fence. Make these cuts moving the box elements from right to left onto the cutter and backing off again, all the time ensuring a firm registration with the fence.

Now place the stop on the opposite side of the cutter for the other two cuts. These two cuts need care as you will be moving the work from left to right and the action of the cutter will tend to push the work AWAY from the fence. It’s important that you compensate for this tendancy by keeping the work firmly againt the fence at all times. It might be helpful to do a couple of practice cuts on scrap.**

It’s important to follow standard router ‘hygiene’ and ensure that the area is always clear of chips and dust. If chips get between the work and the stop you may well have to do a second pass to ensure that you are going the full distance – and of course it’s CRUCIAL that no chips get between the fence and the work otherwise the lid and base will not line up!

Good dust/chip extraction helps, of course.

** For this second pair of cuts some have suggested it might be better to either drop the work onto the cutter, or raise the cutter into the work from below, thus enabling the work to be moved in the ‘correct’ direction. I don’t believe this is necessary and in fact could cause inaccuracies. This is a light cut and with a firm registration against a low friction fence it’s perfectly possible to do it without any problem. As I say above – if you have any doubts, practise on scrap first.

screwing in place:

Now allow yourself a few pleasurable moments rest while you remember that you don’t need to do all that fussy excavating under the hinge flaps to accommodate the stays.

Place the lid upside down and position the hinges in their grooves. The knuckle of the smartHinge has three ‘fingers’, the two narrow outer ones and a thicker central one that incorporates the flat that creates the stop. The leaf with the single finger is fitted to the lid – this means that the flat will be down, and therefore not seen when the back of the box is viewed. Using a scribe or similar pointed implement mark for the screw holes with a very slight tendency to mark forward of their true centres – this will ensure that the hinges register accurately into the front ends of their grooves. Don’t do it too much or you will cause the screws to go in at an angle and that will spoil the final effect.

When marked, remove the hinges and drill the holes. You might like to do this with a drill press if you have one – I usually don’t bother and do the job lo-tech using a light 12v battery drill with a bit of masking tape on the bit to mark the depth. The size of the drill bit is important, of course, but there’s no hard and fast rule to choosing the correct size as it depends on the wood you’re drilling in to. The right solution is arrived at by experimenting with scraps of the wood your carcass is made from. In order to achieve the best possible result it’s important to have a set of high speed drill bits in 0.1mm increments – this ensures that you don’t compromise on size and end up with the screws too loose [will loosen and pull out over time] or too tight [risk of shearing while screwing home]. Use a tapered scribe to gently open up the top of the hole – this helps to guide the screw into place and get it started, and also makes the fit slightly looser where there’s no thread on the screws.

I always polish brass screw heads to a level that matches the hinges before I fit them. I do this by rubbing the heads on 1,000 grit, then 1,500 grit wet and dry. I usually use ths dry – less messy! – but if you have a lot to do wet is better as the abrasive will last longer. I usually finish off on a duster with a bit or jeweller’s rouge on it for a final shine.

Now fit the screws. A little beeswax or similar will help them go in place smoothly and minimise the risk of them shearing. And savour screwing in those back screws without having to work around a quadrant stay!

With the hinges screwed in place, put the lid in place on the box – the leaves of the hinges should slide easily into the grooves cut for them. Now ‘close’ the lid and you should already be able to feel that everything lines up perfectly. Place the lid in the open position supported behind with something padded so as not to damage the surface and ensure that the leaves are orientated snugly at the fronts of their grooves. Mark very slightly forward as before, drill, and fit the screws, enjoying again the lack of a quadrant stay!

NB: the screwdriver you use for this is important – in order to preserve a clean head on the screws use a screwdriver that precisely fits the slot in the screw, both in width and thickness. Any play will lead to damage to the slot – easily done on a small brass screw.

to line ‘em up, or not to line ‘em up?!

… that is the question. Referring to the slots in the screw heads, of course – a contentious subject if ever there was one. Purists will argue that when inserting a woodscrew there is ONE position at which the screw ‘bites’. That is, the screw will have entered far enough into the hole drilled for it to bring its head into firm contact with the countersink in the hinge. Rotating the screw any more than this won’t take it further down because the bottom of the hinge leaf is already in contact with the bottom of the groove. It will instead begin to loosen because continuing to rotate a screw after the biting point has been reached means it starts to act like a drill, actually stripping the thread that the screw has cut for itself …

But it does look nice to line them up … this is up to you to follow your judgment/conscience!

… if you don’t have a table-mounted router:

… you should have! If you work small scale, boxes or whatever, and you don’t already use a table-mounted router, now is the time to switch. It simply makes no sense to be using a big, heavy machine on a small box which you have to hold firm is some way. Not only will a table-mounted router enable you to fit these hinges incredibly easily, but you will also find that a whole host of other jobs that were a nightmare with a hand-held router suddenly become extremely easy, safe and controllable. Just try it … trust me, you will never go back!

For those stubborn enough to want to try this process using a hand-held router [ex Brusso-users, for instance!] I will eventually be developing a safe method for this and will post this on this website. But don’t hold your breath – and in any case my advice will ALWAYS be to go the table-mounted route. And perhaps if you’re still not convinced [and haven’t fitted Brusso hinges before] you might like to compare the above method with Brusso’s instructions on their website [www.brusso.com] for fitting their HD-680 quadrant hinge. This uses their own dedicated TJ-680 jig and a hand-held router. Also, browse any number of woodwork forums to read the problems many, many people regularly have fitting these and other similar quadrant hinges.