Universal Table Saw & Router Depth Gauge

Why a Different Depth Gauge

Do you have a number of those cheap digital micrometers around the shop. I do in fact I have one in each major station of my shop; table saw, router, main bench, lathe and drill press.

A popular hack is to use these same micrometers as a shop made depth gauge.
This article inspired me to make a version of my own.
I wanted the same gauge to be able to set depth and also to accurately set the fence relative to the cutting blade .... measuring from either side of the blade.

Setting the fence is easy if you have an accurate glide on the fence and you are measuring from the fence side of the blade. However when you need to measure the distance to the fence including the kerf of the blade the process can be less accurate. Sure you can do the math to account for the blade kerf but sometimes the blade is not exactly the width you might think and if you change blades a lot you have to remember what exact kerf goes with what blade. Yes, I am talking about getting close to 1/32 accuracy.

The design

An L shaped frame is fabricated from MDF to firmly hold the mic (micrometer). This design captures the mic at the top of the frame and at the bottom of its sliding arm providing a large depth measuring ability. For me this is the highest position my table saw can achieve.

The L shaped frame is made so that it can lay flat on the table of the saw for accurate fence positioning.

The mic is held in place by a miter miter cut in the frame and by a second holding piece that sandwiches the mic between itself and the frame.

You will have to cut the miter to fit your particular mic as they all have different means of securing the spline (the moving rod) at the end of the slide. Cut the miter depth just short of the thickness of the mic's slide so the holding piece can grip the mic's slide when the wing screw is tightened. Make the miter to shallow to start and the pare away with a chisel until the slide and the holding piece have an interference fit.

The holder is fastened to the first frame by a wing screw (1/4-20 in my case) which is screwed into a pronged Tnut that is inserted into the opposite side of the first frame. The Tnut is countersunk so that the frame will lay flat on the table. I had to grind the wing screw flush with the Tnut so the tool would lay flat.

Frame [3/4 MDF]

Back side

Miter in top right of frame

Measurement

This tool can measure blade height or fence position accurately.

Blade Height Measurement

The height of the blade can be measure easily:

TURN OFF THE SAW!

1. Position the tool on the table with the foot of the frame flat on the table. Make sure your blade insert plate is flush to the table and not biasing the tool.
2. Move the mic's body until the spline touches the table, zero the gauge.
3. Move the gauge to the value that matches the depth * you want the blade to cut. 
4. Position the tool next to and perpendicular to the blade.
5. Move the blade up to touch the spline

*Note: the gauge will read negative values. Ignore the - sign

Fence Position Measurement

Setting and measuring the distance from the blade to the fence is easy;

TURN OFF THE SAW!

1. Lay the tool face up on the surface of the table an perpendicular to the blade
2. Push the foot of the tool up against the fence
3. Move the gauges body until the spline touches the fence
4. Zero the mic.
5. Move the body of the gauge until it reads the distance* you want the fence from the blade, lock the gauges body
6. Move the tool up to and perpendicular to the blade with the spline touching the side of the blade you want to make the cut from.
7. Hold the tool firmly down on the table and move the fence over until it touches the foot of the tools frame [adding a magnet on the back side of the frame may be a good improvement]
8. Lock the fence and check the position again by holding the foot against the fence and observing the position of the spline in reference to the blades teeth.

Zero the mic

Set the desired cut width

Position the spline on either side of blade and move the fence over to touch the foot of the tool.

Enjoy and comment,

Don

Thin Strip Cutter

Cutting Thin Strips Simply & Safely

Its not uncommon to need thin strips of wood and plastic materials for embellishments to various projects.

This is my version of a thin strip cutting jig that focuses on safety and simplicity.
This jig takes between 30 minutes to 1 hr to complete.

This jig will cut 1/16 thick materials without getting caught below the jigs stop block. Shown in the photo is a 1/16 x 1/16 strip cut from fiberboard.

Parts of the Jig

The jig consists of a MDF base, a sliding arm, a retaining knob, a miter slot guide and a bearing assembly. 

I have not included a drawing or dimensions as yours may be different based on your type of saw and what scrap you have available.
You need base material to be thick enough to accept a dado and still be stable. I used a 3/4" piece of scrap MDF.

Base

The base is a scrap of MDF about 6" wide and 3/4" thick with a dado slot that is cut on its top surface 90 degrees to the table.

The bottom of the base has a miter slot guide screwed/glued to its underside that runs the length of the base and parallel to the blade. Its important that this guide be perpendicular to the blade when the guide is in the miter track of your saw.
Optionally you can glue a ruler to the base near the sliding arm so that the gap from the bearing to the blade can be set or observed. The gap is the thickness of the strip being cut.
There is a 1/4" bolt hole drilled in the center of both the dado slot and the width of the base. The bolt in stalled in this hole accepts a 1/4" knob which serves to lock the sliding arm in place.

Sliding arm

The sliding arm is a piece of scrap whose width is cut to fit the width of the dado and long enough to reach the saw blade when its it deployed. 

The sliding arm has a slot routed long enough to reach the blade when installed in the miter slot of the saw.

Bearing Assembly

One end of the sliding arm has a 1/4" hole drilled as close a practical to its end and in the center of the arm.

In that 1/4" hole a bearing is mounted using a, washer and wing nut. 

The sliding arm is sanded in an arc as to give the bearing as much exposure as possible.

Any bearing will work as long as it fits between the sliding arm and surface of the saw. You may also need to adjust the placement of the hole in the end of the sliding arm accordingly. 

The head of the 1/4-20 bolt was ground to its minimum thickness in order to keep the bearing as close to the tables surface as possible.
There is a plastic washer on either side of the sliding arm to keep the bearing from binding when the wing nut is tightened.
On the bearing, check that the shoulder on the bore for the shaft is proud of the bearings sides so that when a surface is pulled tight against the bearing it will not bind against the bearings race.
This bearing [from my stash] has a retaining boss (see bottom ridge) that nicely reduces the area that the wood being cut sees, reducing error and friction.

Using the Jig

Using the jig is simple. Insure that you use a zero clearance blade. It will keep the thin strip from falling into down the side of the blade and also minimize tear out.

Slide the jig forward in the miter slot so that it is positioned directly across and perpendicular to the starting teeth of the blade.
Release the knob and deploy the sliding arm until the bearing contacts (tangent to) the side of the blades teeth.

Move the sliding arm away from the blade equal to the desired width of the cut strip.
Tighten the knob on the sliding arm.

Adjusting the fence to hold the wood against the bearing. Note the wood is not touching the blade!

• Pull the base back toward the front of the saw well away from the blade.
• Insert a piece of wood against the bearing and bring the fence over to touch its opposite side.
• Adjust the fence such that the wood is captured between the fence and the bearing.
• Now your fence is set such that a thin strip will be cut from the side of the wood opposite the fence.  

• **Start the saw with the wood pulled back from the blade
• Using a push stick, push the wood through the blade-fence slot cutting off a thin slice.
• After turning off the saw and waiting for the blade to stop, make subsequent cuts by pulling the wood backward until its clear of the blade. 
• Release the fence and move it and the wood toward the bearing until the side opposite the fence touches the bearing. 
• Lock the fence and go to step **....

Safety note: to avoid a kickback do not pull wood backward through the blade while it is running.

Improvements

Lock the Jig

The jig's position could be locked into the miter track by drilling a hole through the base and miter guide. A flat head tapered shoulder screw is inserted in that hole from the bottom. When a knob on that screw is tightened the head of the tapered screw will cause the wood to swell in the track and lock it.

Note: I have never seen the need to lock the jig in place as there is little friction between the bearing when rotating and the wood being cut. Even if the jig moves forward and back that does not create an error in the cut.

Example locking technique and gcode: https://www.youtube.com/watch?v=G3-3x9qNXws

Or you can buy these clamping tracks: https://www.rockler.com/miter-slot-hardware-kit

Other Jigs and Approaches

WoodWorkWeb (I do not like the potential to kickback with this approach).

Shop Notes

Woodsmith


Enjoy and comment,

Don