Incra Ibox Question

[Roy Payne]

Hi there

Ive been making simple box joint type jigs to cut a keyboard part for a melodeon and as I'm a novice at woodwork its very time consuming to get it right.
for example if I'm cutting 10 x 8mm Trench at 18mm centres with a stacked Dado blade by the 10th cut it could be .8mm or 1.5mm out then I unclamp move it, cut
etc till I get it spot on. if I screw it off to use again as I make different centred jigs when I use the jig again sometimes its out by .6mm see photo.
I came across the incra Ibox jig and as it does Dental moulding Im hoping someone on this Forum could let me know if its possible to use it to cut this part.
the largest centre measurement and thickest keyboard part would be 32mm thick 8mm trench at 20mm centres.

any advice greatly appreciated

Best regards

Roy

[Carl Beckett]

I have one. It works great. Run the first cut then adjust the 'finger' to fit that slot size. Then simply move it down and cut the next and so on. I found it to be accurate and repeatable.

Am sure you can do 10mm trenches.

[Carl Beckett]

Was thinking about this some more, to better understand your question.

It may be that you are asking too much of an 'incremental' type jig. No matter what style you use, even small errors will add up over repeated increments (in the absolute position sense).

So if you need to cut say, 20 trenches and you need the 20th trench exactly positioned a certain distance from the first - it is going to be hard with any incremental positioning device.

The only really option in that case is a fixture that does the entire length. So that the 20th position is fixed to the first position, not building up through 19 other trenches.

In that case you may just have to build a full length jig that guides each trench .... not universal, but gets the 20th one in exact location.

A wood rat, a milling machine, cnc, or other measurement device is great for this type of work. But a home made fixture can work.

[Gary Ragatz]

A box joint template on a dovetail jig would address the repeatability of the spacing, but the template would have only a limited choice of center-to-center measurements. Are the center-to-center distances your own design choice, or are they dictated by something/someone else (I don't know anything about melodeons)?

[Bert McMahan]

If you're really hankering to make something, Matthias Wandel's screw advance box joint jig won't compound errors over time like an incremental one would. It'll be as accurate as the threaded rod you use (which will be very accurate). It'll let you make basically whatever box joint you want, but it's far from a simple jig

[Tony Joyce]

Based on my rudimentary understanding of what you are doing my suggestion is the Incra Tools Positioner.
https://www.incra.com/table_saw_fences-tsls_fences.html
While not cheap it is accurate, fast and repeatable.
No affiliation just a satisfied customer wondering why, every time I use it, I didn't get one sooner.

[Rick Potter]

It is quite possible I do not fully understand the problem, but if you need the piece to be 'X' long, with 'Y' number of slots....why not just cut the 'X' piece extra long, cut the slots, and trim the piece on both ends to be even?

[John Stankus]

Having started down the rabbit hole of trying to follow a sheaf of old photocopies of "How to build your own Accordion" (approximate title) I have some thoughts. (my father plays Accordion and wantedto try to build one). Note: I never did get all that far on the project.

One thought I had was building a pin router and using a template. You could build an initial template by planning pieces to your spacing widths and building a stack . Use this intial template to make a user template in one piece of MDF.

template.jpg


John

[Roy Payne]

A box joint template on a dovetail jig would address the repeatability of the spacing, but the template would have only a limited choice of center-to-center measurements. Are the center-to-center distances your own design choice, or are they dictated by something/someone else (I don't know anything about melodeons)?

centre to centre is dictated by the 10 button Melodeon face plate.

[Roy Payne]

Thanks everyone for your replies I'm going to make another jig as I've purchased a couple of incra mitre sliders rather than making my own out of timber,
the jig in question is in the first 20 seconds of the video link. I sent a question to incra help desk about 8mm trench at 20mm centres with the ibox using it like dental moulding
they said yes you can. next time I've got a spare $300 I could find out.


https://vimeo.com/38078671

cheers

Roy

[Carl Beckett]

Fun video to watch, thanks for posting!

I am not sure it is long enough, but I have a couple of the early incra positioning sets. Nothing more than a plastic piece which they fastened the positioning teeth/gear strip onto. That would give absolute positioning capability of your fixture, and in those days at least cost about $20 and could be bolted to whatever you like.

Dont know if they still sell the simple version.

[glenn bradley]

I'll offer another method. When I make long-ish grooves, dados, whatever, that have to match-up, I make the groove in an oversized piece of stock and then rip it to width. The resulting strips have grooves that line up perfectly.

The i-Box is made for finger-joints. Using it for longer cuts will have much of the same problem you already face. Support of the stock beyond the "stock ledge" could be problematic.