Rosette Router Jig

[Trevor Gore]

Below, as per a request, a few photos of my precision router jig as used for rosettes.

A few things go together to make this thing accurate. First, the large diameter pivot (10mm), the stiff structure of the thing, low runout after-market router collets on the DeWalt trimmer and the anti-backlash adjustment mechanism. The anti-backlash mechanism is made from M6 threaded rod (so 1mm shift per revolution of the adjuster) with pairs of nuts sprung apart by Belleville washers. This means that when going from forward drive to reverse drive with the adjuster, the threads on the rod don't have to cross a gap to load up on the opposite side of the threads on the nut - they are already pre-loaded onto a second nut. A search on anti-backlash mechanisms should show how this works if you can't figure it from the pics. The linear bearings are over-kill, but I had them so I used them. Note the multiple holes for the pivot, so I can cut holes from ~50mm diameter (Ukes) to ~300mm diameter (speaker drivers) with rosettes anywhere in between. The bracket on the top was for a digital gauge, but it turned out to be redundant because the adjuster was so accurate. Note the inlay in the adjuster knob!

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Doing these custom deco rosettes is made a lot easier when you can trust the adjustments on your router base. All the inlays and pockets were cut with the rig above.

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[Dave M]

Thanks for that Trevor. It is maybe time to step up from the simple version you described in the book.

I have to say how much better I found the DeWalt trimmer compared to the well known UK make that I have been using.

[yakka]

hello Trevor
thanks for the pictures, does the aluminium bar closest to the adjusting knob (with fancy inlay) have a threaded hole, or is the adjustment achieved in another fashion
thanks for your time
regards
chris

[Trevor Gore]

The hole in that bar is a through hole. The nuts and Belleville washers lock the threaded rod to that bar which screws in and out of the nuts on the wide bar, causing it to move. The piece of angle (NOT the bracket that had the gauge on) captures the sprung nut at the wide bar so that it does not rotate, and so the wide centre bar (to which is attached the plate that holds the pivot) moves.

There are a few similar gadgets around, all with slightly different geometries, so don't necessarily get caught up in trying to reproduce this. It is what it is because those were the bits and pieces I had around. The important parts are the anti-backlash screw mechanism, the large diameter pivot, the rigid structure and the low runout collets.

[yakka]

thanks trevor

[yakka]

made this, and did that, very easy to use and very small adjustments quickly thanks Trevor Gore