Once the handrail opening cap joint angle has been determined it is time to cut the cap, in this example I will show you how to make the template and jig for the turned opening cap, this will be the same process for a square cap.
I will normally do this on a blank piece of board material first, this also makes it easier to get the cut angles set before cutting the actual cap.
This is definitely worthwhile doing if this is your first go at cutting the “v” into a cap , I still use this method now.
How to get the opening cap cut angles.
The stage before this.
Marking the flat cap.
Draw the O/A cap size.
Using a square piece of board, that is just larger than the opening cap diameter, we want to draw the cap cut marks calculated in the opening cap joint angle page onto this board.
Start by drawing the circle onto the board. (Illu’ 1)
Draw the centre line.
Using a square, draw a line through the centre of the circle to the edge of the board. (Illu’ 2)
Draw the cap inner diameter.
Offset the over all cap diameter by the distance to the depth of the handrail feature being used as the narrowest profile point. Distance “A” if working from our opening cap cut angles. (Illu’ 3)
Mark the handrail width.
Measuring from the centre line, transfer the straight handrail width dimensions onto the board, then transfer these down to their corresponding diameters. (Illu’ 4)
Mark the cut angles.
Draw a line through the intersecting points until they touch the centre line. (Illu’ 5)
Cut out the disc.
With the cut angles drawn on, the template disc can be cut out. (Illu’ 6)
Carry the angle marks over.
Continue the angle cut marks from the face over the side of the disc, this is best done using a square; as accuracy at this stage is important.(Illu’ 7)
Mount onto back board.
This will vary dependant on whether the opening cap has the dowel hole drilled into it or not.
When the dowel hole is already drilled into the bottom of the opening cap, a hole the size of the dowel can be drilled through the back board andthe centre of the opening cap template disc then a dowel inserted through the back board and into the template disc. (Illu’ 8)
The holes are best drilled on a pillar drill to avoid any drifting and to ensure the holes are drilled perpendicular to the back board and disc.
When the opening cap is not drilled for the newel dowel, then it may be screwed onto the back mount, A pilot hole set in the centre of the cap template will help locate the template in the correct position.
Leave plenty of material on the mounting back board to allow room for clamping.
Mark the vertical cut position onto the back board.
The easiest and most accurate way to get the position for lineing the cap up vertically and ready to cut, is to use the drawings created for calculating the cut angle.
By extending one of the cut angle lines across to the other side of the cap. (A)
With a compass describe an arc touching the extended cut angle line. (B) (Illu’ 9)
Using distance arc (B) draw the vertical cut position, measuring from the opening cap or dowel centre, onto the mounting board.
Draw a line either side of centre at distance (B). (Illu’ 10)
Cut the template.
Set the opening cap template back onto the dowel and backboard, spin the template until one of the cut angles align with the appropriate vertical cut line drawn on the backboard.
Cut down through the backboard and template, keeping the saw to the side of the line that the sector is going to be cut out and stopping just shy of the intersect point. (Illu’ 11)
Rotate the cap template until the second cap angle joint aligns with the 2nd vertical cut line marked on the backboard.
Cut down through the backboard and template as before, stopping just shy of the intersect again. (Illu’ 12)
The reason for stopping shy is that the last bit of material will snap of easily and can be cleaned with a chisel, wheras when the cut is taken to far it will leave a gap when the handrail section is bolted into the cap “V”.
Mark the cut angle onto the backboard.
Snap the sector out of the template and mark the cut angle line onto the backboard. (Illu’ 13)
The template can be rotated back to the 1st cut position and that cut angle can also be marked onto the backboard.
Cut the cap.
Mount the cap.
Put the opening cap onto the dowel and turn it so that the grain is perpendicular to the cut angle centre line, either clamp the cap onto the backboard to stop it from spinning or put a screw through from behind the board into the underside of the cap, when using a screw ensure it is inside the newel top diameter.
Cut into the cap stopping shy of the intersect as with the template. (Illu’ 14)
setting the template over the cap and transfering the cut angles onto the top of the cap may help know where to stop cutting.
Rotate the cap as with the template, line the 1st cut face with the cut angle marked onto the backboard.
Cut through the cap again stopping just shy of the cut depth again. (Illu’ 15)
Once again either clamp or screw the cap into place while cutting.
Clean up the cut.
The last thing to do is to clean out the inside of the cut and remove the last bit of material ready to accept the handrail section. (Illu’ 16)
This will leave the cap ready for connecting onto the main handrail, the handrail coming into the cap should be quite simple to cut the angles on the end.
I will add an article on how to join the cap and fit it on to the newel post as soon as I get the chance.