Fluting jig.



... or Multi-purpose tool holder !!! This was another one of those projects that I put off for way too long. The basic idea for this came from Richard Stapley's "Laymar Crafts" website but I redesigned a lot of it to better suit my needs. Some of the criteria behind my design were...

1: The ability to pivot the router to carve both convex and concave arcs.

2: The ability to follow templates attached anywhere on the baseboard.

3: The flexibility to quickly move the pivot point anywhere on the baseboard.

4: The ability to 'plunge' the tool by sliding up to limiting stops.

5: Provision for the tool to be used inside forms.


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Making the jig...

Underside of the baseboard

The base board came first - just some laminated MDF with a strip the same width as the gap in the ways attached to it to locate the baseboard. I wanted to be able to clamp the board in place from above so I came up with the catches pictured at right. Just an M8 Allen head bolt recessed into the top of the baseboard so that the head doesn't interfere with anything. When you turn the bolt, plates with a threaded hole on the underside spin until they hit the side of the cut-outs in the MDF and then begin to tighten onto the ways - works sweet!

Base-board clamp

Carrier components.

I fitted slotted aluminium tracks across the top face of the baseboard. Yes, the centre track is not exactly in the centre but it doesn't really matter - especially after you've cut the slot on the wrong mark!!! - but I can live with it.

 The components for the basic carrier are pretty simple - some 12mm threaded rod you can pick up from any building site, nuts and washers and some 25mm RHS off-cuts about 150mm long.

Basic carrier assembled.

Slide guides.

The guides for the sliding pivot bar were the only tricky bit - made trickier by the scrap flat bar I used not actually being flat, but tapering 0.5mm across its width instead - not happy - but working. You would be much better off to use the bar from one of those el-cheapo quick-clamps which is smooth and true. An easier way to make the guides would be to cut them from metal plate and mount them on the upright face of the RHS - but I didn't think of that until after I had made these. The main idea behind doing the slide this way is to allow the pivot point to be located anywhere in front OR behind the cutter to create both convex and concave arcs.

Simple tool clamp.

In it's simplest form, you could hold the tools on the carrier using wooden clamps as pictured at left but you will not be able to get inside deeper bowls and so on. I tried an assortment of methods to clamp the tools on to the carrier before settling on the "T" bar and collars which will allow me to reach inside deeper forms with the cutters.

Various clamps


Extra track for pivot.

I designed the sliding pivot bar so it is positioned high enough to allow another piece of slotted track to be clamped to the baseboard, effectively allowing me to clamp the pivot point anywhere on the board and even past the edge of the board if need be.

When looking for something to use as limiters on the slide, I stumbled onto these el-cheapo window security clamps - perfect!!!

Slide limiter.

A trial run on an old jam-chuck - everything seems to work as hoped.

Note that if the cutter clears the work when pivoting so that a 'plunge' is not required, instead of using a limiting stop, the slide is clamped in position by a small thumbscrew that runs through the RHS and onto the top face of the slide.

All painted up and ready to roll.

By turning some sleeves from ply to suit the diameter of the collars on the drill and Dremel and cutting a slot in one side, I'm able to very quickly change tools without upsetting everything.

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Using it...

Basic cut by swinging on a fixed pivot point.

The most basic operation, just swinging the router loaded with a 'V'  cutter on a pivot with this one, reducing the depth of cut for each 'notch' by locking the sliding bar in place after each cycle.

I turned this camphor bowl about 2 years earlier to help work out the rough dimensions etc for the jig, leaving it thick enough to re-turn a few times to remove the marks from my 'experiments' - but I decided I like this one so it has stayed thick. 

It was several weeks later before I realised why the pattern it created looked familiar - I'll leave it for you to work out!

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Cutting the full height slots.

Note the bearing for following templates mounted in the pivot hole of the sliding bar .

This offset sycamore bowl was a 'collaboration' piece sent to me by a member of the Inland Northwest Woodturners Club of the USA a long time ago and was one of the main reasons I wanted to build the jig. Though it didn't come out the way I had pictured it in my head, it's not all that foul either.

After turning the outside grooves so they penetrated half-way through the thick side of the bowl, I clamped a template to the baseboard so the cove-bit would start cutting just above the lowest point inside the bowl and finish half way through the wall just below the rim. I then clamped a 2nd template over the main one to cut the intermediate slots which started further up the wall of the bowl.

2nd template clamped on for intermediate grooves.

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Cutting the slots in the sphere. Note the 'G' clamps acting as limits for the arc.

Cutting the 'cages' in the finials.

Another reason for the jig was for piercing the style of pomander I like to make. After hollowing the 75mm sphere to about 3mm wall thickness, I mounted it between a couple of 'extensions' turned from scrap timber to give me clearance for the router body when swinging around to the top and bottom of the sphere.

I set the pivot point to the centre of the sphere and set a stop up on the sliding bar so I couldn't 'plunge' the cutter in too far and attached tiny 'G' clamps to the edge of the baseboard to act as stops for the arc. I used a 3mm single bladed cutter which worked well in the Huon pine.

I also used the jig to remove the bulk of the timber from the Gidgee finial 'cages' by altering the height of the cutter above and below centre as necessary. On the 1st one I set up with a pivot and limiting stops but ran the cut too far at one point and found it difficult to get the arc right. The 2nd one I removed the pivot and just moved the jig freehand on the baseboard with some limiting stops and got a pretty good result. Once the bulk was cut out this way, the final shaping was easy enough with small files and sandpaper.

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