I am building Cabinets with Pocket Screws. Using 3/4 oak Plywood and 25/32 face frame. I want to flush route and round over the face frame on all outside panels. I used 1 1/4 screws from inside to attach the face frame. My question is how much round over can I use without risking exposing the screw tips?
Make a test run. I would hate to guess at that.
You should be able to rout deeper if the screws come from outside the cabinet. They will be pointing in. Unless the ends are exposed then that's not an option.
Prior to using a small round over bit,
I'd use a block plane.
Make shallow cut passes and work your way around to form a rounded edge.
For close and inside corners, a fine rasp will suffice.
Sand paper fitted onto a sanding block.
The issue of screws protruding when you route the cabinets edges off with also depend on how deep did you drive the pocket screws. This can vary some depending on how deep did you bore the pocket hole. I do not know why you are routing off the face frame (flush trimming) unless you have a very large face frame hang over. It is best practice when applying the face frame to allow it to over hang the cabinet box by as much as 1/16 of an inch. The reason being is that any cabinet box that is joining another cabinet box, in a cabinet run, will install with a tighter face frame to face frame joint. This is because of the fact that you are making a seal between two face frames of which is much less of a surface than the full cabinet box and therefore much easier to obtain a tight joint. I hope you are using a hardwood face frame as it has a much better appearance than plywood.
In the cabinet run even if you have a 1/16 overhang on the face frame on both adjoining cabinet they will result is a 1/8 inch gap at the rear of which you can not see from the front anyway. The cabinets should be joined at the front of each with screws placed just behind the face frame through the door opening. This gives you a full inside cabinet side free of screws. The cabinet should be attached on the wall using a hanging strip at the back of the cabinets and not using the cabinet back for this purpose. You use a hanging strip of three to four inches in width depending on the cabinet size. I normally use the same hardwood that I make the face frame out of in the upper cabinets and 3/4 inch plywood. (in your case 25/32") for the lower cabinets. This gives you a firm and clean install of your project.
For the end cabinets and or any cabinet that you will see after it is installed I use a dedicated panel build like the doors of which I screw to the cabinet ends. This give you a rich and excellent cabinet box and much better looking than a plywood end. Not only are you enhancing your cabinet end but in today's modern plywood there is a horrid problem with thin veneers of which often delaminate and are subject of a bad eye appeal as time passes. They are too thin to sand much. In some plywoods there is a problem also of the noticeable cut of the lathe blade chatter as the veneer is produced and in not always noticeable until you apply the finish coat and light shines on the surface. This is why I apply dedicated hardwood panels on cabinet ends . I always make my measurements for cabinet runs to allow for this 3/4 inch thick panel as if you do not you are not always able to add a panel once the cabinet is built and a defective end is seen.
I like you method of applying the face frame using the pocket hole as that is my method and find that it is the strongest and most sure way of attaching a face frame.
Something to consider and something that I often do will do is to cut a fine back taper on the face frame that is going to join another face frame so that the taper will also aid you in making an invisible face frame to face frame joint. The taper will be only as little as maybe less than a degree or so but that taper will insure a very fine joint.
Good luck with your build and enjoy your work and do so safely. If you have questions feel free to contact me and I will assist you in anyway I can.