Couple of common sense points.
1). You need to develop the skill to saw accurately to but not over the gage lines! If you need practice do it. I even do it as a warm up if I haven’t done it in a while.
2). Your chisels have to be BRUTAL sharp. The softer the wood the sharper the chisel. When parring, take light cuts to insure control and clean cuts. Don’t get greedy.
3). When you begin a chop, remember the chisel will want to move backwards. Begin 1 or 2 mm forward to get started. Once you open it up you can work towards a chisel wall to complete the chop. This gage line is critical. You don’t want to go over it. Period!
There are many ways to excavate the waste and many use drills, fretsaws and other techniques. Whatever works for you. I personally love chisels. A super sharp chisel is more carving tool than can opener!
All excellent points!
Especially point #3. There are many recommendations to "place the chisel in the knife line". Now this can work, but not before almost all the waste is first cleared. If there is much waste (more than 3 or 4mm), a chisel struck downwards will travel backwards ... and over the base line (gage line). If there is just 1-2mm, of waste the chisel will travel straight down. This is one reason to either fretsaw away as much of the waste as possible, or to chop it out, leaving just 1-2mm to pare away.
But there is a better way ...
After sawing either the tails or pins,
before removing the waste, create a chisel wall along the baselines ...
Now saw away the waste. Aim to leave 1mm above the line.
Here is a very short video I made (a strong coffee will keep you awake) ...
This is now easy to chop out, especially with the chisel wall to prevent the chisel being forced back over the line ...
Regards from Perth
Derek