Got an email request for details of a spline jig I'd posted awhile ago. Tried to attach pictures of the assembly, but couldn't, so I'm posting them here. Here is the request and the written response:
Originally Posted by JFPNCM
I would appreciate the dimensions for the spline jig if you would care to share them.
Mine was designed to run along the fence but adding the runners would make the cuts easier to replicate. Several other features on yours are of interest as well.
Thanks in advance.
Hi, I didn't have a plan and the exact dimensions were determined by the size of the scrap material I used. For example, the two boards that make up the V shape were actually one piece, about 18 inches long. I cut it on a 45 so one side was wider than the other. The 2 45 cuts make an automatic 90 when the two were glued down. I used the table saw with a flat top blade to cut the dado for the aluminum T slot bar.
There are two supports that hold the V segments in place. I laid the bottom piece on the saw, lined it up with the blade, then drew a centerline at 90 to the blade. I took the two V pieces, and placed the tips of the mitered cut together on the line. I held them in place and then measured the approximate height of support piece for the larger side of the V., which also gave me the position of that support on the base. I cut a long miter on a piece that height and screwed and glued it into place (Screws go to the far outside edges, not in the center where the blade will go through.
I lined the wide V leg up by laying the miter as flat as possible against the base, then pushed it toward the support until it formed the first 45. I used the triangle in the picture to make sure the wide V piece was exactly 45 to the base, then glued it in place to the base. I used the drawn center line as a guide for placement. Turned out to be right on because I'd held the pieces in place while measuring.
Putting the shorter piece in place was nearly a repeat of the process, but this time I used the 90 on the draftsman square to make sure the parts that hold frames or boxes for splines was 90. I cut the shorter support to an approximate correct height and slid it into place until it supported the short V piece while it was at 90. Drew a positioning line on the base and then lined the support piece up, clamped it in place (tricky) and glued and screwed it in place, then installed the short V Piece with glue only. Lots of glue, by the way because I was gluing edges.
The slider is made of 3 pieces of 1/2 inch Baltic Birch ply. 2 glued and pinned together form the V shape. The front piece searted out as a square piece, and was carefully lined up to support the V of the slider. I marked the edges of the base V on the square, then cut the piece on a sled at 45 degrees, which is why it has a slightly odd shape. The vertical piece is 90 to the base, and is used to to clamp the work piece in place for the cut. I marked the position of the slot on the back of the V slider and extended it with a carpenter's square, drilled a slightly oversized hole and put a 5/16th T bolt through it and a knurled knop on that to lock it in place.
It didn't take long. Look closely at the end of the jig, all the base parts are showing so you can see exactly how everything lines up. Also notice that the screws that hold the T-slot bar in place also attache it firmly to the taller vertical support
The slider portion was really simple to make with glue and a pinner, which is ok since it never gets cut by the blade. The pinner cost me about $20 on Amazon.
The double runners were fit perfectly to the miter slots on the saw, and I took a lot of trouble to make certain the base was square to the blade. I have seen many plans for sleds like this in web searches for spline jigs.
It is quite an exercise in writing to describe a process like this. I have tried to attach pictures of the assembly process to this email, but failed. I will post it with pictures for the group.
After looking at the pictures again, I realized that I put the long supporting piece in place with screws and glue first. Because of the twin runners, the blade always goes through the same spot, so the screws will never hit the blade.