I’ve wanted to be able to do fine adjustment to my router fence for ages. Apparently I could spend $480 + carriage on something like this
from Pat Warner. Or I could make my own. I already have a nice enough fence, which accepts hold downs and adjustable end stops.
It would be good if I could adapt this for fine adjustment. Well a while back I posted a Table Saw Fence Micro Adjuster . I suppose with everything else I was doing I never got around to adapting it for the router table. Well now I have and here it is
Yes thats it. That tiny little thing in the middle of the picture.
Shown in plan view its mounted to the left of the picture.
The bottom part of the picture shows the rear of my existing fence with its 8 mm securing knobs. The top half shows the MDF (mounting plate) that the fixed part of the mechanism is attached to (with securing knobs). In the centre is a locking attachment to lock the two jigs together, whilst the rough positioning of the fence takes place. You see as far as I can make out you are only going to want to fine adjust a fences position within about
± 1 mm. Fine adjustment over its full travel is not necessary and cumbersome.
First the making of the beast. The mounting plate is an 18 mm piece of MDF with slots milled to enable it to be bolted down to the table
The main body of the adjuster is made from a 40 mm x 35 mm x 37 mm block of Oak. I first bored a 6.5 mm hole straight through it and then a 10 mm hole down, intersecting that to accommodate a 6 mm furniture securing barrel nut into.
I then cut this block, vertically, into two pieces
Yes I know there’s two sets of blocks there. I screwed the first one up by cutting horizontally. Still its useful for the picture. Adding the adjustment screw, 6 mm threaded rod (yes its man enough for the job just wait and see), holding nuts and a 6 mm penny washer (adjustment wheel)
The small piece on top of the adjustment end carries the register mark for the adjustment wheel, which is ultimately notched ten times around its circumference.
The two halves of the adjuster were then screwed to their relative pieces of MDF. I made a locking plate from a scrap piece of 18 mm MDF with four 6 mm dowels glued into holes in it. These register in holes bored both in the router fence and the adjuster mounting plate.
How do you use it?
Before we start
If you don’t like this procedure because you consider it dangerous then don’t do it. Your safety is quite rightly your own concern. I am not forcing you to do anything you don’t want to do. So no wingeing
1. Slacken off all four securing knobs.
2. Lock the fence to the mounting plate with the locking plate.
3. Adjust the router fence to approximately the correct position to your work and router bit.
4. Tightly screw down all four locking knobs, both on the mounting plate and on the router fence.
5. Remove the locking plate.
6. Make a trial cut on some scrap. Measure your cut and assess how much adjustment is necessary.
7. Loosen both knobs on the router fence.
8. Screw down the right locking knob on the fence only (finger tight), making this a pivot point. You can leave the left one slightly loose, the adjuster is holding the fence in place.
9. Adjust the distance of the fence as necessary using the adjustment wheel (plus or minus, it works in both directions).
10. Tighten down both fence knobs tightly and cut again.
Make any further adjustments using steps 7. to 10. above. When the cut is finally correct mill away to your heart’s content.
The thread pitch of 6 mm threaded rod is 1 mm. As there are ten markings around the circumference of the adjustment wheel this means that you can adjust position to within 0.1 mm ( 0.004”). As the right locking knob of the fence is being used as a pivot point this means you are moving the fence centrally at the point of the router bit to within 0.05 mm ( 0.002”). Don’t believe me. Well here’s a section of a piece of Maple I did a step cut on (2 mm down 0.1 mm in) on. I made the step 0.1 mm so that it could be seen.
I might add that this micro adjuster was made from stuff already in the shop and would cost very little to buy.
Be seeing you.
-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com