SMB

 I see no point battering my head against OpenSSH.  However, I have reached the point where:

 smbclient //192.168.4.42/linuxcnc -U clayton%mypassword

gives me access to the Windows directory. But

sudo mount -t cifs -o claytoncramer@192.168.4.42 /mnt/linuxcnc

 asks for the same password and rejects it.

Several syntax errors in the mount command.   Solved. I wish Linux utilities were a little more specific about where and what is the error. 

Then I discovered that I could not write in linuxcnc from Linux.   I verified permissions were wide open on Windows and 777 on linuxcnc.  It turns out the /etc/fstab entry needed file_mode=0777,dir_mode=0777 as well.  Before I forget all this, I need to reboot Linux and make sure it still works.