How to measure and build a new staircase...

Yep, and so many don't do this and wonder why stairs won't fit, K, now I have this I will start on the elevations etc, these will take a while and I have a bit to do tomorrow but will try and get something back over early evening. you probably don't have a stair jig for routering out the tread and riser housing, I will try and get drawings out for that early tomorrow morning, this will keep you busy for a couple of hours, easily made and a lot cheaper than buying one.

 

Here are the dims for the stair jig, I show this with a removable nosing piece, you may not need to make it removable as just doing the one staircase, If you do get the solid jig wrong you can always make it removable to correct this afterwards.
I would go with 19mm 3/4" material, so it is nice and firm.

 

Another bit for you, this is the margin piece used for marking out the rise and goings onto the stringers, this will work alongside the pitch board, I have been a bit busy today so have not had the chance to get the elevations out but hopefully give you a few bits to do while I get my finger out.

I have attached a drawing of the margin piece, a bit of 18mm MDF or anything will do for this, I have also attached a visual of the stringer, margin piece and pitch board to show where we are heading with this.

I have lowered picture quality on some, as I think I may have been upsetting the servers.

 

Yes, the straight 1/2" will do the job, using a flat bit for getting the nosing nice and round works well.
will catch up later have to dash again.

 

Yes, that will work, it doesn't matter if these are loose as the wedges will take up any space, so slightly larger is best, slightly smaller the treads and risers won't fit in.
I have added a couple more dims to help clarify, please do comment on anything I miss as I am using you as a guinea pig for training videos etc.

If not on the road by 5:30 forget going into London.

 

Bullnose - yes this does have to be precise as with all visible face edges, top of tread and riser face.

Offset distance - yes this has to be added on when making the jig, the easiest way to get this dimension accurately is to set up a straight edged piece of timber onto some scrap material and run the router along the straight edge cutting into the scrap material and then measure the distance between the edge of straight edge and edge of the cut.


Rounding over bit - as close to half the thickness of the tread as possible ideally 13.5mm but 13 or 1/2" will be close enough as this can be cheated when dressing in the nosing.

12mm fluted cutter - this is fine, just needs a few more passes and slightly slower cutting rate to prevent chatter, the dovetail cutters are not ideal as the glue contact face is removed, the reason a lot of "joiners" say use these is it allows the thin edge of timber that is left to be pushed or squashed out of the way closing any gaps that may be in the meeting faces. The only time this is really helpful is when squashing the nosing into place, as mentioned in "we can cheat this" above, for the nosing a gouge is used once the housing has been routed out and the treads are being fitted.



I bought these - Perfect.

 

By all means, reduce the jig to 5º.

The stringers ideally around 275mm +, I will do the maths on this probably tomorrow, been a mad week this week.

The easiest way to joint the treads is with a biscuit jointer, anther option is to tongue them together, dowels will work but you will have to jig up to keep the boards level. Once jointed a quick clean up with a belt sander will flatten them nicely.

Yes, let the wood acclimatise to indoor heat as much as possible, you will find it probably moves and you may get shakes appearing, these can then be cut out before glueing up for the treads.

A few sash clamps or t bar clamps will be ideal for glueing up the winders, 3 should be enough, just do one winder at a time. The clamps may also help when glueing the treads and risers into the stringers, in which case 4 will be best and wide enough for the flights, so min 1M opening.

Boards plenty big enough for the risers.

PVA Is great, just make sure it is a good one, some a thin and really runny. if not sure most places stock Evo stick, keep it indoors as the cold totally knackers it. worth buying a pot rather than a bottle, grab a 1" paint brush to apply it with, cheap and chearfull will work to this.
Incase I forget to mention it later, when glueing always glue both mating faces.

 

Question time!
you noted earlier that you would like a 20mm nosing, is this still the case? traditional is that the nosing projects by the thickness of the tread, so 27 mm thick tread, 27mm projection.

Are you having the scotia moulding to the underside of the nosing?



To answer your question with this. The nosing is not part of the calculations and purely decorative as far as building stairs is concerned, so just an add on in front of the riser line which help increase the tread size.

Do you use any sort of cad software?

 

Just to clarify, are you on about gluing the strings together to widen them for the turn, or gluing the treads together to deepen enough for the going?

 

Yes, that was the idea, I can send images though, just if I miss any dim's you want you could check if I'm not about or if you wanted to view in 3d.
I use rhino3d you can download this for free as an evaluation version, full working copy for 90 days, after that it won't save but everything else still works.

I have attached a couple of files,
1. Commode curtail, this will allow you to look at a model in a web browser.
2. Stair jig model. This is a Rhino file of the stair jig if your felling brave.

I have had to zip them to be able to upload as these file types are not permitted here.

I am working on your full model and hope to have it complete for tomorrow.

Ref: dowels, check out this company called screwfix, you may have heard of them! They do a biscuit jointing kit for routers, may be cheaper than buying the machine.

https://www.screwfix.com/p/erbauer-...eLn1dGzhxlJpgDE8aFAaAo0FEALw_wcB&gclsrc=aw.ds

 

Biscuit joint the treads or hire a festool domino jointer although that's quite top end, as SMUN mentioned you could cut a slot and fit a loose tenon, with joining the strings together you can just glue the two mating edges with Polyurethane glue and clamp together with sash clamps, as they will be housed out to accept the treads and risers they will lock together without fixings being as the treads and risers will secure to the two halves of the string, though if you have a biscuit jointer it wouldn't hurt to pop a couple in as it makes it easier to keep them flush.

 

The scotia molding is very traditional and you would have had it on your original staircase, this was originally used to give extra glueing area when fitting the risers, many people use quadrant to cover gaps! yes, used to cover bodges 90% of the time.
If you look at the commode curtail model, you will see the molding on there, these would have been made as a complete tread with the molding run around the outside, this molding plate would sit under the top tread.
But you can decide at any time to have this or not.