Securing bannister, threaded rod into seasoned oak

I have a handmade oak bannister in the bedroom, which is a bit wobbly. I used the normal modern method of securing bannisters (a hole up through the bottom and a nut which tightens through a hole in the side) and I guess what I was securing it to wasn't 100% flat, so it rocks a little from side to side.

Recently this thread about repairing doors suggested a method of drilling and securing either hardwood dowel or threaded rod, and I am wondering if I could use that method here.
http://www.periodproperty.co.uk/forum/viewtopic.php?f=1&t=16870

The bannister is directly above a main beam. I am thinking of drilling diagonally down through the bannister into the beam and inserting threaded rod which would bite into the timber of both. Presumably I wouldn't need to go more than a cm or two into the main beam, if the rod bites well. I don't think hardwood dowel would work, if it didn't adhere well to the beam then it would slide in and out of its hole and the bannister would still rock.

Here is the area from diametrically opposite viewpoints. The chalk marks on the top stair show where the beam is.

I realise using threaded rod makes it tricky to finish the job if you want to recess it below flush. If I ran it in and out several times and greased it, would it go smoothly enough to cut a slot in the end and do the last few turns with a screwdriver? Unlikely perhaps in very old oak.

Any other ideas? A steel angle buried beneath the top stair is an idea, although beneath the top stair there is 6mm ply, then the original boards, before you get to the beam. Also then you'd have to cover the bit that sticks up.

Thanks for any input!

I think you could do it with fluted beech dowel, but I wonder if it will be strong enough for that application.

You can get 1m long lengths of beech dowel on Amazon:-

https://www.amazon.co.uk/Beech-Wood...eywords=beech+dowel+1m&qid=1597526911&sr=8-11

Other diameters are available. Drill it through, at least a few inches into your beam I'd propose, then tap the dowel in after having squirted some decent PVA down the hole as well as smearing some all round the dowel - the PVA makes the dowel expand and grip in the hole. Don't use smooth dowel, the fluted stuff is made by compression so it expands back out again better than the smooth. I see no reason why it won't grip in the oak.

Or - if you wanted to go with metal, I think on further thought I would use smooth stainless rod rather than threaded, and insert it into the hole having pushed epoxy down there first and smeared some on the rod - much less likely to get smooth rod stuck - it doesn't really need to grip as such, so long as it's well surrounded with epoxy and can't move in the hole it will resist the bending movement.

Perhaps a good option is to do it with beech dowel, putting at least 2 dowels in - and if they aren't strong enough and snap in service, it's easy to drill back down the same holes and replace with stainless rod in epoxy instead.

I've had another idea..... (it doesn't do to rush these things, so I've been carefully considering options - not procrastinating - since August....)
The idea is to lift the top step, thus.......

Then to have welded up a thing that looks like this......

Then to coach bolt the horizontal piece to the beam which is directly underneath - a bit like in the position shown here.....

And chisel a T-shaped groove in the bannister for the upright and the end of the horizontal, and screw or dowel it to the oak bannister.
The dilemma is this - the floor constructions is made up of very old, very fragile original floorboards, then 6mm ply, then reclaimed pine boards. Do I cut through the ply and the original boards to fit the horizontal steel directly onto the beam? or do I place it on top and hope that the fixing is rigid enough to prevent movement.
To be honest, I doubt that the original boards and the ply would be strong enough. I think if I leave the ply and the original boards in place, the horizontal steel will not be secure. and the whole thing will move, creating even more damage than currently. But I don't really want to make a great big rectangular hole in the original boards.
Would it be possible - I think I've seen a type of coach bolt that has a wood screw on the bottom and a 10mm thread (or similar) on the top so I could just make a couple of holes through the original boards and the ply, stick a couple of these into the beam beneath, then put a nut and washer above and below the steel, thereby only needing to make a couple of holes through the original floor. I can't find them online, does anyone know what I mean or have any other ideas?

Zebra said:

- I think I've seen a type of coach bolt that has a wood screw on the bottom and a 10mm thread (or similar) on the top so I could just make a couple of holes through the original boards and the ply, stick a couple of these into the beam beneath, then put a nut and washer above and below the steel, thereby only needing to make a couple of holes through the original floor. I can't find them online, does anyone know what I mean or have any other ideas?

Click to expand...

That sounds like a Hanger Bolt
Yes, they sound like a good idea to me in your situation.

Me! said:

That sounds like a Hanger Bolt
Yes, they sound like a good idea to me in your situation.

Click to expand...

That's them! Thanks, I'll do some measuring and try to figure out what size I need........ eventually.

Seems like a lot of work to me and possibly problematic when it comes to cutting the recess in newel post to accept the steel bracket, and without damaging/weakening the mortice and tenon for the lower rail.

I took a simpler approach last year with my stairs after I'd levelled the bedroom floor, 200mm height variation, by fitting a large right angle bracket directly to the newel post and screwed to the floor. Solid as a rock.

Cubist said:

Seems like a lot of work to me and possibly problematic when it comes to cutting the recess in newel post to accept the steel bracket, and without damaging/weakening the mortice and tenon for the lower rail.

I took a simpler approach last year with my stairs after I'd levelled the bedroom floor, 200mm height variation, by fitting a large right angle bracket directly to the newel post and screwed to the floor. Solid as a rock.

Click to expand...

Could you show me a picture? When you say large bracket, how large are we talking? I haven't cut into the bannister yet, and you're right, getting that groove right will be tricky. I have a wood blade for my grinder, but am putting off starting, perhaps for good reason. I'm interested in considering your idea, how did you finish the steel, painted? And how was it strong enough, if it's just a right angle with no brace between the two legs?

Hi Zebra,
I'm struggling with the pictures, too big, will add them later if I can find a way. Hopefully my verbal description below will tell you enough.

The steel bracket is approx 200mm at the base and 320/30 on the upright. It is an old/antique piece used to mount the original newel post. The bracket has a 'beaten/hammered' surface on the outer faces and I've added some wax to enhance the oxidised surface.

At my place the entire rail has to be dismountable to get larger furnishings into/through the bedroom due to width and wall height/slope constraints. I used 70mm wood screws to secure the lower rail and the foot of the bracket to the floorboards and joist below. 50mm wood screws used to fix the bracket upright.

Cheers,
Cubist

Well you'll all be glad to know, I've done it! With no cutting into the newel post, and no extra bolts or screws into the main beam.

I think this is a very good example too, of when non-traditional materials can be your friend.

The issue was that the newel post and beam didn't meet perfectly, the bottom of the post being flat and the beam being bumpy. The second issue was the pathetic little curved plastic washer that came with the bannister fixing kit, and the third issue was that having cut away more material than you're supposed to in order to fit the kit (nothing in this house being straight), the area the washer was bearing onto was insufficient.

I managed to get the newel post off with much difficulty but no damage. I cut the bottom of the newel post so that is was concave, and the force was bearing on the edges not the middle. I got some mouldable plastic (can't remember what I bought it for, but it was kicking about so I thought I'd just try this crazy idea...). You heat it in water and it goes gooey and runny. Then as it cools it hardens. It doesn't stick to the timber or damage it in any way (I know this because it took me about four attempts to get this right). So carefully carrying upstairs a bowl of molten plastic from the microwave, I placed it in the hole and quickly hammered the newel post into place, making a perfect join between post and beam. I shoved more molten plastic into the hole on the side of the post under the nut, used an oversized washer, and tightened as it hardened, thus making a perfect join between the rod and the post.

It's pretty solid now. Job done!

Sounds like a great solution to me, and it works. The fastener holds it down and the plastic filling holds it firm. Very creative.
Ron

Top work, such dextrous hooves!

If it works, it works, well done!