Staircase spindle movement

[Trevanion]

As Mike Jordan said, a dovetail and return is the proper and traditional way of doing it such as below:

You can do it with a straight mortice but I would also house the full width of the spindle 1/4” deep into the tread. Alternatively morticed caps can be made that can be screwed and glued to the tread to positively and securely house the spindle without housing the tread itself.

 

[Cabinetman]

Hi Trevanian what are mortised caps, haven’t come across those unless I call them something different. Ian
Sorry got it now.

 

[Trevanion]

Sorry got it now.

Just for clarity, say you've got a 30mm square spindle, you would make a 50mm square cap with a 20-25mm or so thickness that has a 30mm square hole morticed into it about half it's thickness and this is screwed down to the tread and the spindle sits in the mortice securely. Typically the caps are decorated with a moulding or chamfer all round depending on the style.

Also, MikeG has a very excellent thread on building his own staircase with the dovetailed spindle construction for anyone interested.

 

[Jackbequick]

Thanks for the response . Its not that I'm trying to avoid going back to the job , it's more that I am interested in how long is a reasonable amount of time before you have to carry out remedial work ? . Four years is a long time in my opinion .
Also , if I did offer to repair it and I couldn't get it back to the same solid job that I originally completed , what would happen then ? .

There may be a warranty period by law...check that. That aside is it an OHS matter in which you could find yourself in expensive proceedings? if a person is injured or some kid crals through dislodging the spindles and then falls ..If not covered by warranty , claim or law then it's the balancing act. Was the timber you used certified as seasoned and fit for purpose...Have the 'doweled/turned ends come out so far that they can actually slip out of the assembly?

Could there be any thing, realistic, of their actions as 'contributory?

Did you make any claims at the times like 'good for the next 20 years mate'. Have you called around to see the situation and assess the reality as opposed to the claim? At least by seeing it, photographing and assessing you can show you took an interest in the problem and the safety aspect. even if you say..''no I am not going to fix that problem as some kind of a warranty'.....but then if you fix it anyway it's unlikely you'll be paid so better see it as a tax deduction or a charitable act possibly earning an earlier release from purgatory...

To fix...would it be possible to drop the banister enough to take up the shrinkage?...Obviously I have no idea whether it is a straight run or curved but another suggestion is to make a batten which is adequate to take up the space...cut to suit the least visible part then cramp and drill to match the spindles so as to fit and screw together essentially as a buffer.

 

[RJ Joiner]

Thanks for all your feedback . I have told the customer that I will go back and attempt a repair.
Attached is the picture they sent me .

 

[Doug71]

It looks like it's just the spindles at the front of the treads that are the problem, maybe they were cut short?

Might be possible to remove some of the infill strip from the handrail and pack the problem spindles back down on to the treads?

 

[Daniel2]

Is it possible that the string is flexing or sagging, when weight is applied
to the front of the step ?

 

[Sheffield Tony]

My thought - having never made a staircase in my life - is that there doesn't look to be much meat left where the string is cut, maybe the whole thing is moving.

 

[Cabinetman]

As trevaniom said.
Just for clarity, say you've got a 30mm square spindle, you would make a 50mm square cap with a 20-25mm or so thickness that has a 30mm square hole morticed into it about half it's thickness and this is screwed down to the tread and the spindle sits in the mortice securely. Typically the caps are decorated with a moulding or chamfer all round depending on the style.

I think this is about the only way to easily fix it with the clients permission, they would have to be made slightly differently as a letter E with another straight piece to make it into a cap as Trevanian has described. Ian

 

[Cabinetman]

Sheffield Tony, you’re right, I hadn’t noticed that. We can only hope there is at least another 2or 3 inches underneath that rail and plasterboard?

 

[Mike Jordan]

No wonder it's moving in use, as already pointed out there is very little of the string depth left. You need at least 150mm at the narrowest point. Have a look at Mike G ,s post " a cut string staircase blow by blow" posted about six months ago. If you have done others like this the customers should be forming a queue by now.

Cabinetman - it isn't standing on that wall if you look at the full size photo.

 

[Cabinetman]

No, I knew that I was just hoping there was some more string/wood behind that. Perhaps I should have said behind rather than under

 

[Doug71]

I was only looking at photo on my phone (small screen) and also thought the stair was carried by the wall underneath but now I see it's not, yeah that string is a bit on the narrow side to say the least.......Think I'd be bolting a bit of 6x2 underneath before it snaps.

 

[Trevanion]

Holy jumping Jesus on a pogo-stick!

As has already been said multiple times, that cut string is not structurally sound enough to be carrying its own weight, let alone a person going up and down daily! There must be what, only an inch and a half to two inches left of timber? Unless there's a hidden piece of 2x2 angle iron bolted on the inside to help prevent the flexing it's no wonder the spindles have come loose!

I've seen some shonky work but that really takes the cake, it is NOT safe!

 

[HOJ]

As Trevanion has quite clearly stated, that is not fit for purpose, it's a liability claim waiting to happen.

 

[Mike Jordan]

I think the gaps beneath the balusters must be caused by the cantilever action of the treads and risers easing the wall string fixings out a little or, in the worst case, the treads and risers easing out of the sinkings. Either way that outer string needs support now! Long term an apron rail ot spandrel frame would be a solution.
I'm amazed its lasted four years.

 

[That would work]

Go back and dress it up along the lines of.... "after doing a few like this we have developed a modification to prevent the movement".
Now design in a way of widening that string, shouldn't be too difficult and it would probably look better as well.
I recon a couple of heavy people running down that could actually cause that string to start breaking in two.

 

[Cabinetman]

Oh hell, I just had another look at the photo and I had misread it completely, (Probably couldn’t believe my eyes) that really is appallingly thin. It just screams at you that it’s totally unsafe. It must bounce if you go down the outer side where it is unsupported by the wall.
If I was called in to do remedial action I think I would run a mile, adding a piece at this stage would be downright dodgy, I’m sure only a complete rebuild with the correct size stringer fitted will cure it. Several props are the only other way but they would be bloody ugly, and an admission of it’s original unfitness for purpose. Ian

 

[Max Power]

Hi everyone - this is my first post , and i start with a bit of a problem....
I fitted a set of oak turned spindles to a cut string staircase around four years ago ,

Does this read as the op fitted the spindles or he installed the staircase as well ?

 

[Jackbequick]

RJ, The general consensus is make an effort to resolve the matter even if it 'costs'. You wrote " When I installed the spindles I glued in a 12 mm dowel using pu glue and also pinned at an angle. This has always worked and I have done quite a few of these jobs without problem". It's peculiar unless the dowels have broken, if not broken by your pinning, for a gap to appear.

All things being equal it sounds like timber shrinkage. Illustrations would assist. I dislike angle-pinning although common practice these days with nail-gun fiends. If the spindles are notched-in (as in Cabinetman's illustration) it would seem to me to be not good practice. I think I'd use two dowels to spread the load. I was just thinking, my father a brilliant cabinet maker used pv glue on some jobs and hot melted horses' hoof glue on others. Maybe the horse-hoof has better binding qualities...I must look into that....

Amongst the suggestions, Max....a truly bad habit has become par-for-the-course since the battery drill was widely introduced...turning a screw through all the timber to be connected without drilling a clearance hole (similarly masonry drill bit used to drill through timber then into brick/concrete and timber to metal using HSS drill bit). While I am going...noggins no longer notched into studs even when most pacific timber is not fully seasoned and, commonly, split ....often we see expose nails or 'misses' so bad are some tradesman and so time conscious their bosses.

Another bad procedure is using the screw itself to 'hopefully' pull its head into the timber; sometimes the head shears-off.

Some tapered heads on straight-shank screws have a small extrusion supposedly to cut a countersink. It's not as good as 'the real thing'. I do think tork-head screws are an improvement, but I haven't seen any in the 'traditional' tapered wood-screw.

The result of 'no' clearance hole in a short end of timber can be/may be a split or vulnerability to a split. If doing as has been suggested or screwed or nailed as in Cabinetman's illustration a tight-clearance hole should be drilled for a screw and a slightly tighter one for the nail. I might dry-soap the nail before driving it.

The emerging of the problem at hand seems to have a general consensus of the forces and stress and strain by people in staircase use. In Cabinetman's illustration it may be possible, with access below the staircase of course, to prepare glue locate and then while glue wet, screw preferably a good quality slotted tapered screw ( i.e. not a straight-shank screw generally weak by virtue of what they are ) up from below using correct (professionally tradesman-like) clearance for the screw land. Penetration into the spindle might well be say half an inch or an inch higher than the nosing. The nosing should then keep the spindle located without splitting being a problem.

A reflection on screws, nails and eccentricity....so many stories (chuckles)

I keep very old tapered wood screws when I find them or can buy them, for use in old renovation works .....not though to the extent of (also crooked) builder 'second hand Harry' as known by his workers. I did some work at Milsons Point NSW I suppose 40 years ago. Some cottages in that highly desirable area were owned by a North Sydney school and Harry had some deal going with the school. He was not cheap...but he was a cheapskate, using sometimes good old demolition site timber which gathered 'somewhere' and would charge 'new' price.

Harry would also pick up bent nails (clean or rusty) and straighten them...unconcerned of any weakening...and use them on renovations. If Harry or one of his genius' drove a nail through or drilled through my concrete-encased conduit or inside-wall plasterboard it could take half a day to locate and more to fix. and pull-in new wiring ..back then about $600-1000 easily lost ....back then a lot of money.

Harry's view was 'these things happen...not my problem, you'd have built it into your price ....not so of course, Harry was a con-man ....I didn't go the whole hog the first time ...but It happened twice.

I refused to give up my claim the second time and was determined to 'nail' him, this old bent builder (irony) but 'conveniently' for Harry and unfortunately for me, Harry, who lived with his shrewish wife in a nice Kirribilli NSW home, looking over the Bay (so he had a 'quid') died of heart failure a few weeks after I dropped around with the invoice and told him I'd keep at him until he paid. I'm sure I have a guardian angel...but I think she'd subbie'd to a poltergeist.