Lost count of how many of these I have made for various joinery's and individuals over the years however current renovations on my own place require some new windows so the decision has been made to make some round ones. Firstly cause I can, secondly it'd be nice to have some for prospective clients to see so they get an idea of what they might hopefully be buying.
This thread will explain how to go about making them.
So the mission is 2 window frames of 1 metre dia, made from western red cedar....a proven weather hardy timber.
First step is to draw an accurate section.
DSCF3725.JPG
You might want to click on picture to get a better view. The window frame will be made up of 4 rows of segments, each row with 8 segments. For smaller windows you can get away with 6 segments per row but as western red cedar is generally available in 150mm x 45mm boards we are going with 8 segments per row.
Once the drawing is done the next step is to make a template so the segments can be cut out. A trammel set is the ideal tool for this, its sort of like a big pair of dividers on a stick. I am marking it out on a 3mm bit of MDF. 3mm has been added to the finished outside diameter and subtracted from the inside diameter so that there is a turning and construction allowance to achieve the 1metre final diameter.
DSCF3727.JPG
The template is cut out and then disc sanded as accurately as possible.
Since the final width of the window frame is 140mm the cedar boards have been machined to 35.5mm thick (35.5 x 4 rows of segments=142mm). This will give a turning allowance of approx 2mm.
DSCF3729.JPG
Template is then used to mark out the 64 segments required for each window.2 segments fit comfortably across a 150mm wide board.
Then it's a matter of bandsawing each segment out cutting as close to the line as you can on the inside and outside diameters.
DSCF3731.JPG
The ends of each segment are cut slightly oversize....say 1-2mm.This leaves room for fitting together later.
DSCF3732.JPG
Here are the 64 segments eagerly awaiting construction
DSCF3734.JPG
Next step is to select a suitable sized faceplate. I have several for different sized windows
DSCF3735.JPG
ranging from 1200mm to about 600mm dia. This one is a tad over 1 metre so its ideal.
DSCF3736.JPG
It's good practice to true up the face so its nice and flat. Faceplates like these tend to warp a bit over time when unused. No need to true up the whole face, just where you will be working. A straight edge confirms its true.
DSCF3737.JPG
Then the diameters of the segment are marked on the faceplate while the lathe is spinning with the trammels.This gives a precise marking of where the segments will be built up.
DSCF3738.JPG
Now we are ready to build up the segments. As each segment end is disc sanded to fit its a good idea to set up the faceplate in a horizontal position near the disc sander. (saves on walking).
DSCF3740.JPG
Note the pack of pinchdogs on faceplate centre. The first row of segments are disc sanded on the ends for a good fit and then skew nailed with panel pins on the inside diameter only. This first row will have the rebate for the glass turned out of it so the nail holes will disappear on the end job.
DSCF3744.JPG
This picture shows first segment skew nailed to the face plate smack bang in the diameter lines that were marked previously. The second segment is then disc sanded on the end so that it fits the first one (thats where the 1-2mm allowance when bandsawing the segment ends works a treat). A good old pinchdog is then hammered in to clamp the first segment to the next so that the second one can be skew nailed in place. Then its just a matter of continuing on. When you get to the last segment of the row one end is disc sanded so that it corresponds nicely to the first segment.
DSCF3745.JPG
OOPS Righty ho! seems I have reached the limit of how many pictures you can up load here. Will post this and continue shortly.
This thread will explain how to go about making them.
So the mission is 2 window frames of 1 metre dia, made from western red cedar....a proven weather hardy timber.
First step is to draw an accurate section.
DSCF3725.JPG
You might want to click on picture to get a better view. The window frame will be made up of 4 rows of segments, each row with 8 segments. For smaller windows you can get away with 6 segments per row but as western red cedar is generally available in 150mm x 45mm boards we are going with 8 segments per row.
Once the drawing is done the next step is to make a template so the segments can be cut out. A trammel set is the ideal tool for this, its sort of like a big pair of dividers on a stick. I am marking it out on a 3mm bit of MDF. 3mm has been added to the finished outside diameter and subtracted from the inside diameter so that there is a turning and construction allowance to achieve the 1metre final diameter.
DSCF3727.JPG
The template is cut out and then disc sanded as accurately as possible.
Since the final width of the window frame is 140mm the cedar boards have been machined to 35.5mm thick (35.5 x 4 rows of segments=142mm). This will give a turning allowance of approx 2mm.
DSCF3729.JPG
Template is then used to mark out the 64 segments required for each window.2 segments fit comfortably across a 150mm wide board.
Then it's a matter of bandsawing each segment out cutting as close to the line as you can on the inside and outside diameters.
DSCF3731.JPG
The ends of each segment are cut slightly oversize....say 1-2mm.This leaves room for fitting together later.
DSCF3732.JPG
Here are the 64 segments eagerly awaiting construction
DSCF3734.JPG
Next step is to select a suitable sized faceplate. I have several for different sized windows
DSCF3735.JPG
ranging from 1200mm to about 600mm dia. This one is a tad over 1 metre so its ideal.
DSCF3736.JPG
It's good practice to true up the face so its nice and flat. Faceplates like these tend to warp a bit over time when unused. No need to true up the whole face, just where you will be working. A straight edge confirms its true.
DSCF3737.JPG
Then the diameters of the segment are marked on the faceplate while the lathe is spinning with the trammels.This gives a precise marking of where the segments will be built up.
DSCF3738.JPG
Now we are ready to build up the segments. As each segment end is disc sanded to fit its a good idea to set up the faceplate in a horizontal position near the disc sander. (saves on walking).
DSCF3740.JPG
Note the pack of pinchdogs on faceplate centre. The first row of segments are disc sanded on the ends for a good fit and then skew nailed with panel pins on the inside diameter only. This first row will have the rebate for the glass turned out of it so the nail holes will disappear on the end job.
DSCF3744.JPG
This picture shows first segment skew nailed to the face plate smack bang in the diameter lines that were marked previously. The second segment is then disc sanded on the end so that it fits the first one (thats where the 1-2mm allowance when bandsawing the segment ends works a treat). A good old pinchdog is then hammered in to clamp the first segment to the next so that the second one can be skew nailed in place. Then its just a matter of continuing on. When you get to the last segment of the row one end is disc sanded so that it corresponds nicely to the first segment.
DSCF3745.JPG
OOPS Righty ho! seems I have reached the limit of how many pictures you can up load here. Will post this and continue shortly.
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