This is an attachment for a commonly sold knife sharpening angle guide as used on a 1x30 belt sander (Harbor Freight/WEN/Grizzly etc).

It was primarily designed for a guide designed to sharpen as the belt moves INTO the blade (which would go on the side of the motor opposite the cover for a Harbor Freight sander). However, a version was also supplied for a guide where the belt moves AWAY. You will want to print the version that applies to your guide which is still used as the base for this.

This aims to correct certain issues I had with the guide I purchased. Primarily:

• allows the guide to be closer to the belt than the stock guide
• allows the belt to be removed without removing the guide itself (problem if using a guide on the side of the cover)
• allows both edge leading and edge trailing on the same guide
• has cutouts for a bolster to allow you to get closer to the belt
• allows easy removal from base without having to unscrew completely

Place a spacer of your desired thickness (ie credit card) between sanding belt and this guide to ensure it is flat to the platen and the amount of space you desire.
This object was made in Tinkercad and found here: https://www.tinkercad.com/things/dXXcInkfw0b

This is fixed at a 17degree angle, however other angles should be able to be recreated easily as necessary. I used a random online calculator for the math where the two angles were known to be 17 and my base length was fixed at 60mm. This gave the calculated height for the roof object that I used.

I used a fixed base length

known:
Side c = 60
Angle ∠A = 17° = 0.29671 rad
Angle ∠B = 17° = 0.29671 rad

Calculated:
Side a = 31.37075
Side b = 31.37075
Angle ∠C = 146° = 2.54818 rad
Height hc = 9.17192

https://www.calculator.net/triangle-calculator.html?vc=&vx=&vy=&va=17&vz=60&vb=17&angleunits=d&x=Calculate