Cut stringers for stairs - which cutter?

[WellsWood]

Okay, so the hall renovation saga continues apace. Circumstances, distractions and illnesses have all contrived to make this a much longer project than i would have liked, but there's nothing new there, for me at at any rate.

I've got the main staircase built, have had for a while now actually, as per Roys advice here.
so now it looks like this

instead of this

The old one really was alot more beyond repair than even I thought. After we'd ripped the old one out we discovered, for instance, that the wall-side string was split from end to end - it was pretty much only being held together by 100 years of paint and goodwill from above, along with a generous quantity of heavy duty angle brackets.

Anyway, the next stage, now that the resulting hole (I moved them back about 3 feet) has been concreted and screeded, is to replace these 3 steps from the kitchen level up to the hall/lounge.

The hall floor has been replaced with new T&G redwood and will be sanded and sealed to match the lounge, rather than our original plan of carpeting. This means that these steps will now have to be made "properly" of timber rather than the MDF/ply used on the main stairs, and sanded/sealed to match the new hall floor.
I've decided to do this with cut stringers and wedges, and a homemade jig (the small size makes this feasable for me to do singlehandedly), but I'm unsure about which cutter to use for the housings. I've seen a "router workshop" video where a straight cutter is used, but proprietry jigs like the Trend one use a large dovetail cutter.

Which is best, does anyone know? If I use a dovetail cutter what angle should it be, and do I need to match that angle on the ends of the treads and risers? (I can see the setting out getting very tricky if so).

I have a feeling this is a lot simpler than I'm making it in my mind, but I could do with some advice from someone who's actually done this.
Any takers?

 

[CNC Paul]

Mark,

For the housed string the professional would use a 95 degree cutter as it gives you a tighter joint when you wedge up the treads and risers, it is also more time consuming to set up as the offset from cutter to collar varies with the depth of cut.

As it is only a short flight I would use a straight cutter, plus you will get other uses out of a straight cutter....The dovetail cutter will just sit gathering dust unless you plan to make more staircases.

On the cut string the riser is mitred to the string with a 45 degree cutter, this is usually a rebated mitre as the string and riser will be of different thickness.


I hope this helps


Paul

 

[WellsWood]

Thanks Paul,
I have both straight cutters and dovetails already so I won't be buying anything in specially, although the dovetail cutter is 14deg (or 104, depending on how you measure) which seems to me to be too steep to allow much strength to the glue line - you do glue the ends of the treads/risers as well as the wedges I assume?
I'll use the straight cutter then, about how deep should the housings be in 36mm strings? On the old stairs I removed they looked like about 1/2", but I'd be inclined to up this to around 3/4" / 20mm unless this has implications I haven't considered.

The bit where you completely lost me is about mitreing the risers to the string, could I impose on you for a little expansion please?

 

[JonnyD]

I used to buy expensive cutters for stairs but now use the perform ones from axminster which are really good value for money. http://www.axminster.co.uk/product-Perf ... -33208.htm.

You can get at least 2 full staircases out of a cutter before it goes dull. 12mm deep is about right for the depth of the housing.

Mitred risers are used in a cut string stairscase. The string is cut out and the treads overlap the string and the riser is mitred to the string and the spindles fit on top of tread.

Jon

 

[Rich]

I know it's not my thread, but I am lost now, if the string is at 90 degs to the riser and treads and they both sit in a routered housing, where does the mitre come in?, an illustration would be very much appreciated, on my part anyway.

Regards,

Rich.

 

[JonnyD]

This is a cut string staircase

http://www.pearstairs.co.uk/pages/stair ... 8900A420C8

Usually the side against the wall is housed as normal.

jon

 

[jasonB]

Mark is it actually a cut string like jonny's pic or do you mean one where the strings are housed out unlike your main staircase where the risers & treads are just screwd to battens.

reason I ask is that you can't wedge the treads & risers on a cut riser as there is nothing to hold the top of riser ot front of tread.

Jason

 

[WellsWood]

DOH!! #-o

The confusion is all my fault for using the wrong terminology - by "cut" string I meant that the treads and risers sat in housings "cut" into the sides of the strings. All the more embarrasing 'cos I know what a cut string is, I just had a brainstorm and forgot that I knew it :?
I see it now, and the mitre-ing makes perfect sense.

No, my intention was to have closed strings like the original. But since we got here accidentally, and considering the point of moving these steps and ripping out all the built under cupboard was to open the space out, I see now that actually a cut string (and I'm using the term correctly here) on the right would achieve the look I'm after much more effectively.

Back to the drawing board then. Thanks everyone.

 

[Rich]

DOH!! #-o

The confusion is all my fault for using the wrong terminology - by "cut" string I meant that the treads and risers sat in housings "cut" into the sides of the strings. All the more embarrasing 'cos I know what a cut string is, I just had a brainstorm and forgot that I knew it :?
I see it now, and the mitre-ing makes perfect sense.

No, my intention was to have closed strings like the original. But since we got here accidentally, and considering the point of moving these steps and ripping out all the built under cupboard was to open the space out, I see now that actually a cut string (and I'm using the term correctly here) on the right would achieve the look I'm after much more effectively.

Back to the drawing board then. Thanks everyone.

Whilst you are there at the drawing board, I would be obliged if you could show me what the "mitre bit" is, as I'm more confused than before.

Rich.

 

[CNC Paul]

Whilst you are there at the drawing board, I would be obliged if you could show me what the "mitre bit" is, as I'm more confused than before.

Rich.

I hope this helps

Paul

 

[wizer]

wow that joint looks fun to cut.. :shock:

 

[CNC Paul]

Wizer,

Ther is another way with a different glue block, the cut to the string is just a 45 degree bevel.... still a pain but the end result looks really good.

Paul

 

[Rich]

Now I understand, thank you Paul, I am obliged.

Regards,

Rich.

 

[WellsWood]

Thanks Paul, beautifully illustrated. It confirms the conclusion I've been coming to ove the last 24hrs: I'm pretty sure I can't cut any of those except maybe the one with the single bevel on the string.

Instead, I think I'll take the riser out past the stringer and mitre it to a bracket laid on the outside face of the string, similar to this one: linky
- should get me round the most awkward part of the joinery and still hide the end grain on the riser. It'll be more than adequate considering you'll only be able to see it from under the main stairs anyway.

 

[JonnyD]

Hi Mark I have done a few of these staircases. Cutting the bevel is fairly straightforward with one of these cutters. http://www.wealdentool.com/acatalog/Onl ... ve_80.html

You need to get the bearing for the cutter. A piece of mdf clamped along the line of the riser will act as a guide for the bearing guided cutter. You need to work from the inside face of the string and clean up the corner with a chisel.

jon