how to clamp railing miter joint

I'm about to attach a stair railing to the wall. It's 12 feet long and has a circular cross section except for a flat bit along the bottom where it attaches to the brackets.
I was thinking of cutting off the end of the railing (A) at 22.5 degrees and then putting in a little piece (B) that is cut 22.5 at each end, and then another piece (C) also cut off at 22.5 that goes to the wall (see crude diagram below). This is a sort of miter joint with an extra piece in the corner. But I'm not sure about the best way to assemble it.
---------------------.\ A . \ . B .\ ------------------. .. | |.. | | C | |_____|
Ideas about assembly I have had:
1) put a flat board against the railing, mount a 22.5 degree wedge on the board, and use a clamp to hold B onto A. This didn't seem to work when I tried it.
2) use pinch dogs. Never used these. I'm not sure I'll be able to get the parts properly aligned with them. Are they likely to work?
3) use hot melt glue or maybe super glue or double stick tape to hold it in position so I can drill holes for screws
Have I missed the perfect assembly technique?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Lowe's (and other woodworking stores such as Rockler) sell special nut/bolt kits used to attached railings to the newels or other posts. I recently completed several sections of handrail and attached them in this manner. It requires that you attach the bolt to the post, then slide the rail over the bolt (through a hole), then drill a hole in the bottom of the handrail to attach the nut to the bolt. The kits usually offer a plug (or you could make your own).
With a little glue, the joint is very strong and simple. No clamping is required or special miters.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I am talking about a railing on the wall. It is attached to brackets that are attached to the wall. There are no posts involved. The miter is necessary because code requires a railing on the wall to have a "return" to the wall. (It could just be a simple miter, but I thought the joint above would look better and it fits the space a bit better.)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I did something similar in my house. I don't know about your house, but here, a "return" is code. I guess the idea is that you don't want someone coming by and catching clothing on the handrail. The only difference is that I only had parts A and C that came together at a 45. In my case, I did basically what you were talking about in #1. I clamped part A down and force part C into place, keeping its movement constrained as well. Alternately (this would be easier for you since you have smaller angles to deal with), you could clamp A & B together long enough to drill a pilot hole and use a screw to (at least temporarily hold the parts together "just until the glue dries". Then repeat with B & C. You could even remove the first screw if you thought it would interfere with the second assembly. The only potentially visible hole will be against the wall, so there's no worries about that.
And oh, yeah. It's probably hard to screw up, but there is a code requirement for handrail height. Make sure you meet it.
todd
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

But how can I clamp A & B together well enough to drill the pilot hole? I'm perfectly willing to use screws. When I tried to clamp A and B together as in (1) above the parts seemed to slip around and I couldn't get them to align even well enough to drill a pilot hole.

There are some parts of the stair code that I cannot meet (like head room and tread size), but this one, at least, is easy. :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.