How to Make a Depth Stop for a Forstner Bit

Using a Forstner Bit Depth Stop for Precision Drilling

Forstner bits are excellent for drilling flat-bottomed holes. When drilling multiple holes that need to be the same depth, such as for a candle holder, it’s useful to have a depth stop. However, ready-made depth stops can be quite expensive. In this tutorial, I demonstrate how to make a depth stop for a Forstner bit using readily available materials which are a bit less expensive!

For this project, we’ll make two different sizes of depth stops that can be used for multiple bit sizes.

Materials:

• 2″ fender washer
• 1/2 x 1 x 7/16 shaft collar (<– affiliate link!)
• 1-3/4″ fender washer
• 1″ washer
• 3/8 x 3/4 x 3/8 shaft collar (<– affiliate link!)
• Adhesive for metal (I used Starbond CA Glue <– affiliate link)

Notes About the Project:

I used CA glue with an accelerator because I knew it would dry quickly and I could place the pieces accurately. An adhesive such as E6000 can also be used but it has a much slower dry time though it does give additional time to reposition the pieces.

Pro Tip:

When purchasing the shaft collars, make sure they will fit over the shaft of your Forstner bits! 

For the Larger Depth Stop:

Place the larger shaft collar on a flat surface and apply glue to the outer edge. Position the 2 inch fender washer on top and let the adhesive dry.

For the Smaller Depth Stop:

I wanted to use a fender washer with the same surface area as the larger stop but the shaft collar was almost too small for the center hole. I had to double-layer the washers so there was more surface area to attach the collar to the larger washer.

How to Use the Depth Stop on a Forstner Bit:

I have several large Forstner bits that I use when making candleholders. My favorite sizes are 1-7/8″ (which is the size of most tealight candle holders), and I used in this example (a hardwood incense holder!).

Using an Allyn wrench to fit, loosen the set screw on the shaft collar. Thread the depth stop onto the shaft of the Forstner bit, and position the stop as needed. Tighten the set screw.

Insert the Forstner bit in the chuck of a drill press or regular drill, then drill the holes. Once the washer portion of the depth stop makes contact with the work surface, stop drilling. Don’t try to force it because it could damage the bit, the depth stop and your drill!

One thing I did notice is that the sawdust collects between the stop and the bit. Having a small paintbrush handy to clean out the dust might be helpful!

What do you think? Did you find the tutorial on how to make a depth stop for a Forstner bit useful? Leave a comment below!