So here's the last in a series of posts on how I made this trestle table. 3 previous threads were:
1. General: http://www.ncwoodworker.net/forums/showthread.php?t=37044
2. Table top process: http://www.ncwoodworker.net/forums/showthread.php?t=37048
3. Trestle Base process: http://www.ncwoodworker.net/forums/showthread.php?t=37064
This thread deals with the final shaping of the base beams on the trestle, as well as the saddle joints on the top of the posts.
The shaping of the ends of the beams was an exercise in pattern routing. Initially my idea was to define the pattern with a 1/4" bit and a template, use a BS to rough cut the waste away, and then sand to final shape. My first attempt at this showed me that I could not control the BS cut well enough to create the general shape. I was attempting to cut through about 6" of material, and so needed a 3 TPI blade or less. But the curves I was wanting to cut just seemed too sharp to get a decent cut with my only 3 TPI blade (1/2" blade?). I maybe should have tried a finer blade in the BS (1/4"?) but all of the fine blade I had were 6 or more TPI. I did not expect that to cut well through a 6" piece of heartwood pine.
What i did was to use a 1/4" router bit and template to define the shape (on both sides of the beam, and both ends = 4 cuts). Here's the template
Here's the piece with the templated router cut 1/4" bit
Here's the piece after rough cut shaping on the BS
More template routing with template guide in router base
THis gave me a pretty well defined shape, except that this piece was 8" wide; while I had a pretty long router bit (4" I think, 1/2" shank and either 1/2" or 5/8" diameter), I could only cut somewhere between 2.5-3" of depth. That left a 2-3" swath in the middle that I had to sand away.
I used the end of my stationary (6" belt) sander to define the inside curve (top view here, looking down on the piece leaned against the end of the sander)
and a combination of my 6" RO sander and a detail sander to finish the shaping and sanding.
The joy of sanding resinous woods like heartwood pine (cuts and sanding results in distinct turpentine smell) is that the sandpaper clogs with materials that crepe sanding blocks can not remove. I went though 3 belts and several disks - of course I was really shaping here (material removal) not sanding (smoothing).
The final step in shaping the base beams was to excavate a curve along most of the bottom edge, leaving a large pad on the end of each beam. I used the largest radius cove bit I had (initially used to cut large flutes in an exterior architectural post replacement). I clamped a board in place on the beam to define the cut, and I double-side taped a notched board to the bottom of my router base - that would ride against the clamped board. Here is a top view of that setup, obviously no router motor in place.
Another view
and another. this time with the "large" radius fluting bit
Having defined the curves on each end, the only thing left was to waste away the material in between. Again a could have used a BS to cut most of this way (maybe should have) but the theme here is that I do not have much confidence in my ability to make accurate cuts on the BS through the 8" width of these heavy pieces.
Here is the cut being made, using a 3/4" wide bit and nibbling way at the cut. Note that I am using the table router plate as a large area base to span the width of this beam, and leaving the very edge in tact so that I can keep a defined depth of cut.
Here is the setup of the router to make the fianl cut to get rid of the edges - a flush cutting (bottom bearing) bit that will ride on the bottom of the previous cut. THis pic shows it before any part of cut was made, and if you look closely you can see in the dark that the right hand piece has had the field cut away already.
Here is a pic with that edge partially cut away. The left hand piece is there to provide a platform to stabilize the router.
Here is a pic with base base beams completely shaped, and the posts set on top of but not in their mortises.
The final joinery task was to cut the saddle joint in the top of the posts. The slot to be cut across the post would be cut with the router and a jig. Here is the jig, upside down, showing the three bracket pieces that locate it on top of the post.
Here's the piece with the slot cut across it:
In order to accomplish the cut with my top bearing bit, I had to elevate the jig above the post with some spacers on the first cut. I recall reading the in general you don't want to hog out more than 1/4 x 1/4" with a router bit. I did more cut than that with a 3/4" wide bit (1/2" shank), but I tried to limit my cut depth to much less than the full 1" bit length that I had. Here it is with spacers in place before the first cut.
I do not have any pictures of cutting the top stretchers to fit into these saddle joints - I defined the edges with a partial depth cut on the TS, rough cut the bulk away on the BS, and the used a shoulder plane to fine tune. This joint was fairly crudely cut quite frankly (bottom side of table and not visible unless you are completely under the table. If I had to do this over again I would take more time and fit these together so that they would fit more smoothly.
Staining and polyurethane procedure was noted in the end of the original post - then final assembly and delivery (in pieces!)!
Henry W
1. General: http://www.ncwoodworker.net/forums/showthread.php?t=37044
2. Table top process: http://www.ncwoodworker.net/forums/showthread.php?t=37048
3. Trestle Base process: http://www.ncwoodworker.net/forums/showthread.php?t=37064
This thread deals with the final shaping of the base beams on the trestle, as well as the saddle joints on the top of the posts.
The shaping of the ends of the beams was an exercise in pattern routing. Initially my idea was to define the pattern with a 1/4" bit and a template, use a BS to rough cut the waste away, and then sand to final shape. My first attempt at this showed me that I could not control the BS cut well enough to create the general shape. I was attempting to cut through about 6" of material, and so needed a 3 TPI blade or less. But the curves I was wanting to cut just seemed too sharp to get a decent cut with my only 3 TPI blade (1/2" blade?). I maybe should have tried a finer blade in the BS (1/4"?) but all of the fine blade I had were 6 or more TPI. I did not expect that to cut well through a 6" piece of heartwood pine.
What i did was to use a 1/4" router bit and template to define the shape (on both sides of the beam, and both ends = 4 cuts). Here's the template
Here's the piece with the templated router cut 1/4" bit
Here's the piece after rough cut shaping on the BS
More template routing with template guide in router base
THis gave me a pretty well defined shape, except that this piece was 8" wide; while I had a pretty long router bit (4" I think, 1/2" shank and either 1/2" or 5/8" diameter), I could only cut somewhere between 2.5-3" of depth. That left a 2-3" swath in the middle that I had to sand away.
I used the end of my stationary (6" belt) sander to define the inside curve (top view here, looking down on the piece leaned against the end of the sander)
and a combination of my 6" RO sander and a detail sander to finish the shaping and sanding.
The joy of sanding resinous woods like heartwood pine (cuts and sanding results in distinct turpentine smell) is that the sandpaper clogs with materials that crepe sanding blocks can not remove. I went though 3 belts and several disks - of course I was really shaping here (material removal) not sanding (smoothing).
The final step in shaping the base beams was to excavate a curve along most of the bottom edge, leaving a large pad on the end of each beam. I used the largest radius cove bit I had (initially used to cut large flutes in an exterior architectural post replacement). I clamped a board in place on the beam to define the cut, and I double-side taped a notched board to the bottom of my router base - that would ride against the clamped board. Here is a top view of that setup, obviously no router motor in place.
Another view
and another. this time with the "large" radius fluting bit
Having defined the curves on each end, the only thing left was to waste away the material in between. Again a could have used a BS to cut most of this way (maybe should have) but the theme here is that I do not have much confidence in my ability to make accurate cuts on the BS through the 8" width of these heavy pieces.
Here is the cut being made, using a 3/4" wide bit and nibbling way at the cut. Note that I am using the table router plate as a large area base to span the width of this beam, and leaving the very edge in tact so that I can keep a defined depth of cut.
Here is the setup of the router to make the fianl cut to get rid of the edges - a flush cutting (bottom bearing) bit that will ride on the bottom of the previous cut. THis pic shows it before any part of cut was made, and if you look closely you can see in the dark that the right hand piece has had the field cut away already.
Here is a pic with that edge partially cut away. The left hand piece is there to provide a platform to stabilize the router.
Here is a pic with base base beams completely shaped, and the posts set on top of but not in their mortises.
The final joinery task was to cut the saddle joint in the top of the posts. The slot to be cut across the post would be cut with the router and a jig. Here is the jig, upside down, showing the three bracket pieces that locate it on top of the post.
Here's the piece with the slot cut across it:
In order to accomplish the cut with my top bearing bit, I had to elevate the jig above the post with some spacers on the first cut. I recall reading the in general you don't want to hog out more than 1/4 x 1/4" with a router bit. I did more cut than that with a 3/4" wide bit (1/2" shank), but I tried to limit my cut depth to much less than the full 1" bit length that I had. Here it is with spacers in place before the first cut.
I do not have any pictures of cutting the top stretchers to fit into these saddle joints - I defined the edges with a partial depth cut on the TS, rough cut the bulk away on the BS, and the used a shoulder plane to fine tune. This joint was fairly crudely cut quite frankly (bottom side of table and not visible unless you are completely under the table. If I had to do this over again I would take more time and fit these together so that they would fit more smoothly.
Staining and polyurethane procedure was noted in the end of the original post - then final assembly and delivery (in pieces!)!
Henry W
ccasion1
