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Micro Adjuster Project

I know there are many very accomplished woodworkers. I know this because I see evidence of their work everyday and I am still in awe but what can be done with the right tools, patience and a skilled hand. I on the other hand am not an accomplished woodworker so I look for projects that even I think I can build. I ran across a DIY fence micro adjuster on Canadian Woodworking & Home Improvement magazine while surfing the web last week.

micro-adjuster-plan

Adjuster Jig – plans by Michel Theriault

Somewhere along the way I decided that the jig looked simple enough and that I should build a few of them so I purchased the hardware to make three. Additionally I thought I would have some fun and tinker with the plan a bit. It looked like the screw was off-center so that the left hand side of the block could be used for clamping. This was simple enough but I figured the block could be a bit thinner so the clamp would need to be opened quite so much, my idea was to put the adjuster screw back in the center and make cutouts for the clamp jaws.

IMG_3699

This would make the adjuster ambidextrous, allowing clamping from either side. The cut-outs are a little over an inch  (1.2″) deep and this was a compromise so as not to weaken the center, yet allow enough space for the clamp jaw. The other modification I made was to drill 3/8″ holes through the end grain so that these could be clamped using my Rockler Universal Fence Clamps. Both of these modifications seemed to work out as I planned.

IMG_3695

A third modification was to install rare earth magnets along the bottom so that I could just stick it to my table saw and band saw table without clamping. I haven’t installed these yet but my initial testing tells me I need larger magnets than those I had on hand. The adjuster screw turns without a lot of pressure but to move a heavy table saw fence the adjuster will need to be somewhat firmly affixed.

Micro-adjuster Scale

I did have an issue with the plans however which I addressed before starting the project. The scale that was to be printed and cutout for the adjuster had been messed up with the online copy of the article. After a couple of attempts at fixing it, I decided to make a new one using SketchUp. Expert I’m not but I can get around enough for simple designs and with a bit of patience I was able to knock out a scale that worked. So the way it works is as follows, using the recommended 1/4″ -20 bolt you have 20 turns for the screw to advance one inch. The scale has 50 divisions thus:

20 turns/in * 50 divisions/turn = 1000 divisions/in

So advancing the screw by one division should represent 0.001″ of throw on the adjuster. To make things simpler, the plan calls for a 1″ diameter wheel which is important because you need a scale to fit your wheel. The way this works is to find the circumference of the wheel and divide it into 50 intervals.

Circumference = pi * Diameter = 3.14 * 1 in = 3.14 in

So each interval on the scale should be about 0.063 in apart. Not easy to draw by hand but not too much trouble to make in SketchUp. Here is the scale that I drew for my project and you are welcome to use it for yours: https://3dwarehouse.sketchup.com/model.html?id=u9718b3cf-aca2-4ac5-b130-4c9ea1d2dcec

Printing things to scale requires a trick in SketchUp. First you must make sure that your model is being viewed in Parallel Projection (Camera, Parallel Projection) then when you go to print you can select your scale of 1 in drawing is 1 in printed.

SU printing to scale

So if you don’t want to fool with SketchUp you can also download this PDF version, just make sure you print it out in 1:1  scale: Micro-Adjuster Scale

What ‘s Left

As I mentioned earlier, I wanted to try a magnetic mount so I’m going to give that a bit of thought and purchase some bigger magnets! As creative as my clamping mount improvements may or may not have been I can’t think of a single place right now where the adjuster could actually be used in my shop. So there is that…. the magnet mount would change that. The 3″ bolts that were called for appear to be too short for this project. I’m considering purchasing a 3 1/2″ or 4″ bolt so that I have more room to add a second knob as called for in the plan. I made two wheels for each adjuster but the bolt isn’t long enough so for the prototype, the scale and the adjustment knob are one. Another thought I had been the cap nut coming loose during use would be bad for precision; I’ll add a spot of glue to secure it once I’m happy with the finished design. I haven’t yet made the plastic reticles for these adjusters as I ran out of shop time yesterday. Once I’m satisfied the version 1 adjuster’s are finished, I’ll rub some Danish Oil finish on them but at this point I’m still experimenting. Once I take a closer look at each of my fences and how I might use an adjuster, I might end up making a unique adjuster for each situation, I’ll let you know how things work out.

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