I would use a TC constructive solid geometry workflow from the start instead of trying to fit things up afterwards. Something like this: Make a cylinder 8mm diameter, random height. Select it and press D to edit the selector point, default is at geometric centre of object, tab into delta Z and move the selector point minus 1/2 cylinder height to put the reference point at its centre on the base. Still selected, tab into rotate Y, 90° and enter. Release selection, then re-select (should stop UCS axial confusion), check "make copy" in right-click or Inspector bar context menu, tab into rotate Z, 140° and enter, which should give another cylinder rotated 140° relative to the first, axes on the workplane. Draw the profile of the triangular part, the sides to be grooved along the axes of the cylinders, then simple extrude 2mm, double-sided. Select both cylinders and in selection info palette, give them any height that'll extend past the block edges, then 3D subtract the cylinders from the extrusion, checking "don't remove the subtrahend" at bottom left of the drawing window. That creates the groove along the edges. In selection info palette, you can select and specify the cylinders' height. The cylinders, which have their bases at the intersection of their grooves, can be moved anywhere. The cylinder lying along the x axis is easily moved with the delta X box of the inspector bar, vector copy for the other with distance and 140° angle as the parameters is what I used to use when I started out with TC V5 designer way back before the turn of the century, it's still good and you've got transform tools too, today (he wrote alliteratively). One thing I'd do with deluxe is set the cylinders' surface options "number of approximation lines" to 16 from 14, or to some other product of four, because otherwise you won't get consistent radiis at the quadrants.