Delta Shaper handwheel lock--won't lock

[Bob Vavricka]

I purchased a used Delta Shaper 43-454 and in getting it ready to use I discovered that the handwheel lock doesn't actually lock the handwheel. With the lock tightened, the handwheel is still easy to move. I have looked at a parts breakdown online, but I don't see how the handwheel lock works. Looking for some help in fixing the problem.
Thanks, Bob

[Dave Cav]

Depending on the vintage there are either two little brass "bullets" or two flat steel "butterflys" that are in holes/slots in the elevation shaft. The end of the lock knob shaft bears on the inner ends of the bullets or butterflys and pushes the outer ends against the housing, locking the shaft. The bullets get worn and won't bear, or they (or the butterflys) get lost during a disassembly. You should be able to get replacements, or fabricate new ones without too much trouble, but the shaft has to come out, which is kind of a pain. There is lots of info on the Wiki at vintage machinery dot com.