Draw | Solid from Curves | Cut Out Solid

This tool imprints a profile through a solid to create a cutout, automatically subtracting material.

The cutout takes the shape of the imprinted profile.

Turn the view to Top, then draw a rectangular profile, similar to that shown below using the Rectangle from Center tool, making sure the Smart Polygon option is set in the edit bar.

Use the center of the top face of the new part as the center of the rectangle.

Select Cut Out Solid from the toolbar or use Draw > Solid from Curves > Cut Out Solid.

Set the Distance in the edit fields to -1.5 then select the solid shape. Select the newly drawn rectangle as the closed curve. The result is shown below.

Rectangle used as cut-out for top of fixing

The rectangle, after the completion of the Cut Out Solid process is no longer required and can be deleted. The result, when the layer for Part 1 is reactivated, is shown below.

New part in context drawn and assembled