Stair Handrail Fixing advice please.

[Vegable]

I have 2 newel posts at the top and bottom of my stairs. They are fixed solid and are finished in stain and varnish. I cannot remove them with dismantelling the whole stairs.
I want to install a wooden handrail, which will also be stained and varnished, between the two posts but want to use concealed fixings. How do I do it? Handrail length is about 3.5 metres.
I would normally use mortice and tennon joints but as there is no movement between the posts I woudn't be able to insert the handrail.
I have been advised to use "mitrebond" glue but don't know it's suitability in a stair handrail where people are likely to put their full weight on it.
(I'll also be installing parallel wood "strip" sections between the handrail and riser so that it complies with building Regs, also using whatever method is recomended)
What is the best way of going about this, and if glue and pinning is best, what kind of glue is most suitable.
Thanks for your thoughts
Mike

 

[JWP]

B & Q do the Richard Burbidge Bracket Fix Sytem. I did my stairs a few years back.
Effectively you use the base of your current newel posts, cut to a given height. You then prep it as per their instructions (usually a 50mm diameter hole, to "x" depth).
The replacement newel post is then fitted in the hole with a wedge in the centre that expands to make a tight fit (and glued of course).
The hidden bracket system then allows you to cut the rail to size and fit it.
It may be possible to make the holes for the bracket system in your current newel posts, but you would have to way up the work involved against the time it takes to cut 2 old newel posts, prep & fit the new.

Hope this helps,
JWP

 

[JWP]

(I'll also be installing parallel wood "strip" sections between the handrail and riser so that it complies with building Regs, also using whatever method is recomended)

Missed this part when I read first time around... the system I was describing in my case, were for a handrail with spindles. I'm not sure if they do parrallel fixing holes in their range of newel posts.
JWP

 

[foxhole]

You could simply screw thru newel and plug to make good.
Or fit an 'L' bracket [bent to required angle] to newel which is hidden by end of handrail and secured below the handrail .

 

[big-all]

you could do a false tenon either end glued screwed and plugged [plugs from offcuts just remember to stop the mortice 9to 12mm short off the top surface