Wheel kerfing jig for T&J models
Hi all. I have been debating whether I should publishing this article regarding my “Wheel kerfing jig” for T&J destined wheels
because the jig is primarily laser cut with only the indexing pin created using conventional woodworking techniques.
“Laser cut???” you say… well join in the chorus… as not too many people have lasers or even access to one, but with the growing popularity of CNCs and their acceptance in the woodworking community, I now probably have 2 or 3 more interested people added to my captivated audience.
I finally decided to publish this article for 3 reasons:
- I made a video of using the jig that runs for far too many miles to keep viewers interested without a lot of toilet breaks and this may alleviate that burden and could use some further explanation. Here is the link to the video (suggest you grab a slab of beer and a pizza first).
- While you probably have a “snowball in hell” attitude towards such a build, I’m hoping you may get some sort of “inspiration” to use parts of my presentation/ideas in some other independent woodworking ventures.
- Hmmm? I can’t count…
The jigs suggested by T&J are boards with dowels clamped to a mitre gauge and slanted (or straight) across a table saw,
or a router table,
I have seen many great jig designs and innovative ideas, however, they all seemed to get bogged down with “advancement to the next index” and the “lock down” process while making the cut.
My intention was to devise an indexing/locking mechanism and then building a jig around that which was a complete rrrs about logic and in-keeping with this authors “mental orientation”. This exercise was more of a challenge rather than a requirement, as I had become quite familiar with the production of simple dedicated wheel kerfing jigs for each style of wheels as per the T&J instructions.
After designing a spring loaded locking/indexing pin mechanism I then proceeded to designed a base to hold the wheel.
I used a far too heavy spring in the 1st. pin mechanism I made. As it took too much of an effort to pull it out and fearing early destruction, I made another one with a much lighter spring.
As I progressed with the design, it kept gravitating to a modular MDF build suited for laser cutting.
During solution contemplation, I quickly realised that it was impractical to have the indexing wheel in line with the wheel to be cut as the indexer would need to be smaller and that would make the indexing holes impractical.
So I came upon this bright idea of gears and gearing ratios.
Unfortunately the solution was totally out of whack with my initial draft. The first design was totally screwed up as I planned on equating the number of gear’s teeth with the number of indices required.
I considered a 2:1 ratio but my logic was reversed as I had the small gear attached to the wheel with the larger gear incorporating the indexer.
This gave me a 1:2 ratio with the kerfs at every 2nd. location… DOH! I thought that I could rotate the wheel ½ a kerf and then re do but after many misalignments that idea was scrapped.
This concept required a relocatable indexer, hence the elongated pin holes (rather than just plain circles) in the index wheel that just never got update.
The only problem is that a “draft” in timber is not like paper. After making the component it was a bit difficult to erase misplaced holes and I had to redesign and re cut.
I found that such a large index wheel was an overkill and thought that to separate the two geared components and compensate for a smaller index wheel, I will need to introduce a 3rd gear… This was designed around the location of the index pin mechanism. I never considered moving the index pin… that would have been far too easy. This was already over-engineered… why stop here.
Combined with frustration and many mental blocks I somehow thought about using bearings in the jig to facilitate the introduction of this new gear.
I kept forgetting that one of the key features of SketchUp was simulation and unfortunately the laser cutting made minor modifications too easy and rather that re-evaluate the jig and do a total redesign I made quick “adjust to fit” modifications using SketchUp followed by quicker laser re-cuts.
The following is the components of the jig’s components in the “table saw” mode.
Two examples of wheels created using different indexing wheels.
After completing the jig and observing some other jig designers using routers, I considered extending I’s functionality accordingly
I designed what I affectionately refer to as the “Foredom configuration”. This configuration has the geared base with indexer mounted into a “router kerfing table” type setup. You can then use a Foredom, Dremel, trimmer or router with the appropriate following template to cut the kerf.
The kerf is controlled by following designed tracks using template followers. You can design any pattern you like and this can permit non-linear kerfs to be cut as opposed to the straight kerfs on a table saw.
To cut different shaped kerfs all you need to do is replace a template that is located by 4 dowels on the “router kerfing table”.
I prefer to use a Foredom as it is very manoeuvrable, can be operated by one hand and with the appropriate hand-piece will accept ¼” router bits. To permit ease of use of a Foredom tool I designed a 3D printed jig to hold the Foredom and permit its use with the following template. While the base of this 3D printed jig is relatively small it is large enough to provide stability.