M/L building vice......Stanley Workmate is excellent , put a section of carpet between the jaws to hold delicate stuff , like a finished rifle. I've been building m/l,s for years using one of these. I can,t stand for long periods of time any more. The Workmate is perfect for old guys ,cause ya can sit and work.
Another rig guys use is two of those cheap 4" swivel vices mounted about 24" apart on a 2x6" , or 2x8". The swivel levers can be unlocked , the work piece put in , the work piece will self align, automatically , then tighten the swivel bases on the vices . A thick piece of cow hide in each vices' jaws , for instance , can hold a gunstock on a 1/4 angle as well. I use one of these 2 vice rigs in an elevated position to hold a barrel/stock combination and install butt plate. From the shop floor the vices sit about shoulder high. Butt plates are challenging and this two vice rig makes it a lot easier.
Another positive feature , both the Workmate . and the 2 vice rig can be portable if space is a problem.
oldwood