I have finally spent a half day in the workshop
It has been a while but I have had finally been able to have a potter about and get to a task that has been on my 'to-do' list for quite some time - setting up an Incra I-box.
Most of my 'woodwork' is an off-shoot of DIY. I can fix things up, I can repair things, I can potter around the house. I have a fair selection of tools, but mostly of the decent quality but not heirlooms variety. No Festool here, but very little shed bought stuff either. For the last few weeks I have been putting shelves in an airing cupboard and stripping and refitting the hundred year old doors that had a hundred years of paint on them. Jobs like that I can take in my stride and make a pretty good fist of them.
What I never seem to have been able to get the hang of is joining two bits of wood together. In fact the butt joint is my staple joint. You see what I really like (and aspire to) is to produce quality small scale joinery. Box making. Scroll saw work. Puzzles and intricate work that takes time, skill and patience. I don't have any of those 3 things
As such, I am always on the look-out for a little help, particualrly in the skill department. I have a David Baron dovetail guide because I don't have the time to learn or practice fully hand cut dovetails. I have a pocket hole jig because it is easier and faster than half laps or mortice and tenon joints (hey - it produces tight butt joints OK!). One area I have really struggled with however, is finger joints. I just never seem to get it right. Too tight, too loose, too random. So I finally bit the bullet and bought (actually last Summer, but what the heck, this is the first time I have had to try it out) what is supposed to be the Rolls Royce of finger joint jigs - the Incra I-box. My days of sloppy joints must surely be over I thought, solid, tight, if not overly attractive, finger joints should now be mine to command.
The jig comes in a fairly weighty box, nicely packaged and protected, even has an instructional DVD (if you can put up with the irritating voice-over on it - available on youtube if you want to check it out)
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The bits are not overly numerous, and it seems fairly simple to put together, despite the strange numbering of the bolts, but it all goes together fairly easily. One feature that I was looking forward to was the 'glide'bar' mechanism - a small plastic washer that when rotated, is supposed to take any slop out of the bar in your mitre slot. Except the circular plastic washer is just that - circular. No matter how I position it, it does nothing other than sit there. It is not on a cam, it is not oval and I am stumped as to how it is supposed to work. Oh well, there is only a tiny bit of slop, so a strip of blue electrical tape on the side of the bar takes up thhe slack. Yes, I fully expect this to slough off within 10 minutes of use, but I only have an afternoon and I want to get to a perfect finger joint today!
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Onwards with the overly complicated instructions, not helped by the typical American assumption that everyone has a dado blade in a table saw. Managed to get things together and aligned, managed to get the 'kiss' calibration set-up, managed to make a test cut without running the jig into the router cutter (a definite bonus). Managed to leave off the entirely useless but incredibly irritating perspex protrusion to the front of the jig. Look - shavings as proof!
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OK, so lets see how it get's on with a full board width and a number of fingers. Now bear in mind I have not taken the time to set this up in terms of board width, I want to test the tightness of the fingers and the fit of a full width, hence the odd spacing in the photo below:
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9.5mm cutter (or thereabouts) and a first attempt - fingers are a little tight but nothing 'easing' with a rubber mallet cannot rectify. But the joint is not 'perfection' as most of the testimonials seems to indicate - forum reviewers and google-land seem to rave about the simplicity and ease of use; the perfect results first time every time that this jig provides. Probably because I am using some scrap pine that is soft and fluffy I think. Give it another go and take care this time to be as accurate as possible. One tip I note on the second use is to ensure you blow the shavings out after EVERY pass over the cutter. This affects the depth of cut and certainly evens up the finger depth. OK, lets try it on some wider board.
Dry fit and still too tight. Not a problem I say to myself - I will just look at the troubleshooting part of the instructions and be back to perfect joints in a jiffy. Except there are no troubleshooting instructions. No indication at all as to what you need to do to tweak the fit. So I play some more. Now this jig works by moving two pins to act as the spacers for one socket to register in the correct position and align the timber for the next socket. To do this you undo a black locking knob, turn a silver knob a hairs bredth to allegedly increase or decrease spacing by 1/1000th of an inch at a time. Then tighten the black locking knob and off you go. Or not as the case may be.
I now seem to be introducing incramental error into my finger joints somehow. I must have tweaked, touched or somehow otherwise introduced some slop into this that was not intended. I have no idea how. It only has 2 wheels for adjustment, how hard can it really be?! The first pin fits, but by the 10th pin, I am almost 5mm out
The 'holes' are all the same size as they are cut by a router cutter, so the spacing between them must need tweaking. OK - back to the silver knob, twist by 1/1000th of a inch and go again. Still 5mm out over 10 pins. Get irked and tweak by 3/1000th of an inch. 3mm out over 10 pins. OK, not great but getting there. Tweak by another 3/1000th of an inch. Now 2mm out in the wrong direction over 10 pins. And so on. And so on. And so on. I spent all afternoon trying to get this to work. I reset it from scratch. Twice. I checked the 'fit' on scrap multiple times. I drank coffee and calmed down then tried again. And again. And again. I then ran out of time and still do not have a consistent cut and fit I am happy with. It might be the soft pine. It might be my lack of patience. It might be my lack of skill.
One thing I do know - having the ability to adjust the fit of a piece of timber by 1/1000th of an inch at a time sounds like you should easily be able to end up with the perfect fitting joint. In reality, I should have stuck with a butt joint.
On the plus side, I am am in the workshop so infrequently that the next time I get an afternoon to try out my new Incra I-box I will have forgotten all this frustration, and tell myself quite happily that perfect finger joints are just a few cuts away given the adjustability down to 1/1000th of an inch - how hard can it be?