The Jones house is the oldest brick home in Pontiac, Illinois. It is managed by the Livingston County Historical Society.
Recently, the wood thresh-hold for one of the upstairs bedrooms required replacement.
I reviewed the old thresh-hold and determined it was not really feasible to repair it. I got the ok from the Historical Society to replace it.
I removed the old thresh-hold, so I could take it home to my woodworking work shop, and use it as a pattern to make a new one.
When I got the old thresh-hold home, I taped up some sheets of 8.5x11 paper, and traced the outline with a blue ink pen (blue ink shows up when I scan it, pencil does not show up). I scanned the tracing, the imported it into Sketchup.
What I found in Sketchup was that the tracing was not accurate enough to make and exact duplicate...........because pieces were broken off and missing from the old thresh-hold. I designed one side of the thresh-hold as accurately as I could in Sketchup, then printed that piece out. I cut out the print-out with scissors, then took it back to the Jones House in Pontiac. I marked up the piece, and also put all 3 doorway width dimensions on the sheet. Then I updated Sketchup with the additional information.
The old thresh-hold appeared to be made from pine, not oak. I needed a blank that was 6 inches wide and about 36 inches long. I also wanted no knots, because they could break out when the new thresh-hold experiences usage. I checked at Menards, and they had 3/4" by 8" clear pine in 48 inch long pieces for $11. I picked up 2 boards, in case I messed up the first one.
Back in 1858, the carpenter probably just took a long plane, and then planed down a 5/8" thick board to yield a peak at the center. I own a few planes, but I am not very good at planing exact slopes like required on this thresh-hold.
I could have made a fixture for my band-saw, then sawed one 9 degree angle, then turn the board around an saw the other 9 degree angle. This would require building a special fixture, and sometimes the blade drifts on the bandsaw.
The option I chose was to table-saw the 9 degree angle, then flip the board and saw the other 9 degree angle. The blade on my table saw only cuts a thickness of about 2.75 inches, and this board requires a 3 inch depth of cut (1/2 of the 6 inch width to give a center peak). I decided to remove the stock after table sawing with a hand plane and/or a belt sander.
When you cut the 9 degree angle and only leave about 1/8" thin edge, the thin edge will want to slip down between the blade and the throat plate on the table saw. To prevent it from slipping downwards, I temporarily clamped the work piece to a scrap piece of 2x4. The scrap piece of 2x4 rode on top of the fence. This method worked well.
I then clamped the work piece on my work bench, and used a combination of hand plane and belt sander to remove the un-sawed section from the top.
Using Sketchup, I printed out a full scale paper template, to use to scroll saw each end.
I went with a Teak stain, since the old thresh-hold was a very dark brown. The old one also had a glossy varnish on it as well. After staining, I did 2 rounds of 220 grit sanding and clear gloss polyurethane.
I took the vibrating tool with me in case I needed to fine-tune the fit of the thresh-hold in the doorway..........and sure enough I had to fuzz a little off. It fit pretty good and looks pretty good.
We will see how well the pine thresh hold stands the test of time. The historical house gets relatively light traffic, so the pine should be ok. It was very hard to tell if the old piece was oak or pine, but I checked the surrounding woodwork again when I installed the new thresh hold, and everything seems to be pine versus oak.