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Making a Depth & Distance Measuring Jig

measuring gauge jigI love making woodworking jigs, it's fun and intereting to see what improvements of adaptions can be made to suite every different woodworker's needs. This jig has been around for many, many years and has changed little during that time. Rather than follow one of the plans that are readily available on-line, I decided I needed to make this jig to fit my own needs that may or may not be available in the plans someone else has created. My main objective was to ensure that both legs of the jig would straddle the insert throat plate in my saw, after all, that was the whole purpose ... to build a jig that would accurately set or measure the distance from the top of a table saw blade to the top deck of my table saw and not to a measurement from the top of the blade to base of the throat plate, which is often the case.

To start off with I would need something thicker than 3/4 inch material for the main body of the jig because I wanted to use one of my plastic off-cuts of mitre slot material. I wanted something harder than many woods as this jig will be used a lot and I don't want the measuring arm to get dinted and chewed up by the table saw blades over time.

I started off with a block of wood that was 8 inches wide, 5 inches high and 1.25 inches deep. From this block, the first thing I did was to carefully cut a dado slot that would fit the plastic mitre slot material I wanted to use as the center measuring post. ...


Once I hand that, the next thing was to start removing some of the excess wood on the jig. I used a 1-3/8 holde saw to cut the inside arches, making sure that the legs on each side remaind about 1.5 inches wide and the inside height ended up at around 3 inches.

I also took some time to carefully trim the top of the jig to 45 degrees on each side, again, just to reduce all the excess wood. Remember ... working with small pieces of wood CAN BE HAZARDOUS so make sure your wood is supported properly and that you hands are well away from the cutting wheels and that they cannot get pulled in by unsecured wood you are cutting, drilling or sanding.

I have seen some plan versions of this jig that use a wooden center measuring post and even have a tongue and grove type sliding cut in the post and in the body of the jig. I do not like wood on wood for moveable jigs. My experience, at least in my part of the world, is that the wood expands and contracts enough that the wood expands large enough to prevent any movement. My wooden measuring gauge is the case in point.

Before cutting the hole for the tightening bolt in the back of the jig, I first got some clear 1/16 Inch clear plexigass to use as the scale. I drilled 4 countersunk holes in the plexi and while I was at it, I cut 2 other pieces of plexi that would be used to shim out the side of the gauge in case I wanted to use that side. I hind sight, cutting my original dado deeper and recessing the plastic gauge piece would have been more elegant, but I thought of that after ... something any of you who read this article can benefit from my mistake.

The next thing I did was to figure out where the positioning of the clear plastic gauge part would be, then I carefully, with a 3/4 inch forstner bit, drilled a very shallow recess in the front of the jig, in the middle of the dado slot. This recess wold used to accomodate the lip of the T-nut so that it would sit flush in the dado slot. Another idea I saw after this, was to drill that recess a bit deeper and that way you could use a penny as the stopper to prevent the steel bolt from maring the plastic (or if you use wood) center measuring post. I decided to use a small round piece cut from a plastic shelf bracket insert.

After the plastic gauge part is aligned, now is the time to apply the stick-on measuring tape if you wish. I purposely positioned mine a bit high so that I could trim it down very accurately on my sliding mitre saw so that when the bottom post was on the table top the gauge would measure perfectly at zero on the gauge ... and it does.

And that's pretty much it .. the jig is complete and ready to use. I think one of the best parts about this gauge is that in many cases you don't even need to set the gauge, if you have exisitng material you can often just measure it with the jig and transfer that info to your table saw, bandsaw, router table or what ever you are using it for.

I mus say I was pretty impressed with how accurate and how versatile this little jig was ... I know it will soon be one of those jig I should have made years ago ... oh well, another lesson you can learn from delay in making this ...

Copyright Colin Knecht