Making sideplates is one of the "fun" jobs of making LRs....besides, the sideplates w/ the holes in sometimes have the front lock bolt invading the RR hole if one wants the sideplate attitude to look pleasing in the sideplate mortice.
Here's a short version of making and installing a sideplate for a LR. Locate and use a tap drill for the holes for both bolts in the lockplate . install the lockplate and use the tap drill to "spot" the holes in the stock. Remove the lockplate. Drill the bolt clearance holes through the stock....make sure the tap body isn't tight in the holes. Clamp the lockplate in its inlet , insert the tap from the sideplate side and tap the holes.
Clamp a large enough piece of 1/8" brass on the sideplate side and use the shank of the clearance drill w/ a center punch ground on the end and hit w/ a mallet so the "dimples" are deep enough.
Use a compass to scribe a diameter around both center punches that are large enough for the bolt heads plus some for the border around the bolt head. I then draw in the rear sideplate outline ensuring that the end of the sideplate end is centered w/ the point of the sideplate molding.
Then draw in the front outline.... the bottom of the sideplate outline should be parallel w/ the bottom of the sideplate outline which can be slightly changed. Hacksaw most of the brass off and then rasp and then finish file. File the bevel that's slightly more than 1/16" and file draft on the edge that's in the wood.
The clearance holes in the sideplate can now be drilled and I usually tap both holes for pulling the sideplate out w/ the lockbolts when inletting. .... oversized tap and lockbolts are used. Shown below are 2 sideplates that I made ....one a BC and one a Lancaster and both look like they belong . .....Fred
