Shop Made Digital Height Gauge

[gee-dub]

I was asked for more detail about this item in this thread.  Rather than take that thread too far afield I dropped this one here real quick-like.  This was a second version of this helper and I'm afraid I didn't keep track of the build too well.  Essentially I took a piece of 3/4" BB ply that was 7-3/4" wide by 8-1/2" tall.  I drew a center-line along the tall dimension for reference and ran a 3/4" dado lengthwise to a depth that suited the digital unit.  You want to watch for your battery access door requirements and not set the unit too deep (DAMHIKT).

I had scrounged the unit from an iGaging product that functioned poorly as designed.  Seems they figured this out as the unit is no longer offered. You could certainly cannibalize any digital caliper.  As a matter of fact, my original version of this was made from a Harbor Freight caliper that I picked up for a few bucks.

The overall width on the first version was 6" which seemed like it should do all I wanted to do.  In practice the "feet" often ended up on a seam between a throat insert and the cutter or be just not quite wide enough for what I was doing.  Your mileage on this will vary with your tools and your use.  The inner arc is about a 3" radius on the larger unit.

Sorry. Rambling.  I then positioned the digital unit in the dado and traced around the body.  I free-hand routed this cavity with a 1/4" upcut spiral and chiseled the corners square with a "beater" chisel I keep around for such things.  Again, these pics are all following completion but, I hope they will help anyone wanting to make one of these.

The position of the readout along the blank is subjective.  I placed it low which allows deeper readings.  The upper limit is dictated by the arc's radii.  The arc on mine was measured from the aforementioned center-line with a simple compass and cut out on the bandsaw.  The other waste material was also cut away on the bandsaw leaving the final shape.

I have some 3/4" O.D. stainless steel washers from somewhere.  I epoxy one to the tip to give me a bearing surface.  I place the unit on it's back and press the shaft/washer against a 90* reference.  I also make sure the washer is offset so that when the unit is on it's back I can measure to something like a router bit that is only 1/16" high.

I sanded the "feet" and washer (primarily to remove the epoxy that squeezed out of the center hole) on an edge sander with a 320 grit belt to assure an even plane and shellac'd the BB ply.

I attached the readout into the cavity with a thin film of silicone rubber glue.  I learned from my days making speaker cabinets that a thin continuous film of this stuff provides a tenacious grip but, can be released with care.  I used double-stik tape till I was satisfied with the way the thing was going to work, then I siliconed it and left it over night.

Here's an overall shot for size and a comparison shot with version 1.

[Just Bob]

Very nice! Thanks.

[CandorLush]

Thanks!!!!!!

[Isaac]

This is really cool, but wondering, in general, won't you be better off just cutting a test groove and adjusting accordingly?

[gee-dub]

7 hours ago, Isaac Gaetz said:

This is really cool, but wondering, in general, won't you be better off just cutting a test groove and adjusting accordingly?

That's the point; don't have to .  Also handy for setting a delta; zero at current height and move up or down by "so much".  It is just another gun in the arsenal.  Setup blocks and a pocket rule handle most of my setups.  When things get touchy the readout is "nice to have".

[Isaac]

13 hours ago, gee-dub said:

That's the point; don't have to .  Also handy for setting a delta; zero at current height and move up or down by "so much".  It is just another gun in the arsenal.  Setup blocks and a pocket rule handle most of my setups.  When things get touchy the readout is "nice to have".

I guess I'm just thinking that in general, if I have the option of cutting and creeping up on the exact fit, that will be more accurate than trying to do it via measurement. Then again, I've never had a tool to measure with this sort of accuracy.

[gee-dub]

I'm going to start measuring my saved time in "KA's";

Pre-finish interior of carcass prior to attaching back, saved 12 KA's. 

Run a dado prior to large sliding dovetail slot, saved 2 KA's