Scriber/Height Gauge Construction

 

    

  I decided a new scriber was needed with more capability than to just scratch lines and needed to be more precise than the junk box unit of before. After much study of commercial units available, I decided on a twin column type with a digital scale provided by cutting the tangs off a Homier digital caliper ($14.95). I have found these calipers to be very accurate and repeatable. Some may disagree with the materials or dimensions I used, but I evaluated all aspects based on weight, useability and my hand size (small).

Here are some photos of the work in progress:

 

 

 Some of the parts shortly after cutting out.
 

Several of the parts on the assembly bench. Yeah, yeah. Let he who is without clutter throw the first end mill

 

The fine adjust mechanism and column rods. 
 

 Modified caliper scale.

 

Folded piece of .010 brass shim stock, Gorilla glued to back of scale. When glued to the moving block it provides a bit of flex to allow for imperfect alignment of the scale shaft to the columns.  

The top mount bracket holds the rods rigidly while providing a clamp for the top of the scale shaft.

 

The lock knobs are brass caps pressed onto socket head machine screws. Don't ask how the locks operate. It is a shop secret.   This is an interim assembly to check the fit of most parts and do final adjustments for smooth movement up and down the rods. Finishing has not yet begun.

 

 The main parts are 6061-T6 aluminum, the fine adjust knob and lock knobs are brass and the column rods are 3/8 inch W-1 drill rod. The scriber point is a commercially available one (about $12) and the mount and holder bale are CRS finished in black oxide. Careful examination will reveal a small slot milled in the base. The end of the scale column sits in it rather than having a clamped bottom end. This allowed the scale body to hit bottom. Originally, the aluminum finish was to be a kind of satin chrome look achieved by buffing on a floppy wheel using emory, but I fly cut the top surface of the base block and liked the appearance so much I decided not to buff it. Mounting for the rods is achieved by drilling and tapping the bottom end of each to 10-32 and running socket head machine screws up through the base block. The screw heads are in a counterbore and the rods sit .125 into a counterbore on top. This holds them in rigid alignment. Finally it was time and the assemblies were carefully aligned and tightened and the scale Gorilla glued to the slider block. It works beautifully. I figure I have less than $35 invested in this. Check the price of a Starrett or Mitutoyo. Besides, I have the pleasure of knowing that I crafted this scriber entirely on my own.