Which router cutter for stair strings.

[bench_monkey]

not really, the best thing to do is try a test piece first to get yourself familiar with the equipment. do you have 2 or 3 different guide bushes with the kit? it will be trial and error to get the correct setup for your job, we are set with a routine for all our flights now, 1/2" straight, 22mm treads, 1/2" risers. dont forget you can alter the size of wedge to suit the trench and board going in it. if memory serves, the centre point when marking out does not hit the middle point between tread/rise on the jig, as i say, trial and error. its the only way we learnt im afraid

 

[tomba26]

Ok Tom, Thanks again.

 

[bench_monkey]

well heres our prize chimp and his masterpiece half way through. cack photo but our workshop isnt very photogenic!

 

[chippy1970]

The idea behind useing a dovetail cutter is so that when wedged up the treads and risers crush the strings wood fibres thus making a gap free joint between said treads/riseres and string.

For MDF treads I would not use less than 25mm thickness.
Check out the Trend catalogue for their stair housing bit, and their instructions download for the way to set up/depth of housing etc.

An accurately made jig and a straight bit will do the job just as well, after all they never dovetailed the housings in the days when all was hand cut.
This stair I made last week, 25mm mdf treads 9mm ply risers and softwood strings, using mdf jig and 1/2" straight cutter.

Rob.

Hi Rob I see youve picked up a few MUNGO systainers there, cheaper than buying Festool ones did you get them from bunnys bolts ??

 

[JoinerySolutions]

Yes Chris and it was all your fault! :lol: :lol:
I caught one of your posts about them and ended up with three sys4 and a sys3.
Sys 3 for router bits, two 4's for hand tools and one for various bits off the CMS kit.
Rob.

 

[tomba26]

All, I used the new jig today and got it working in the end but initially had some problems getting the correct thickness of nosing to fit my treads.
The spec is oak strings and in the end they wanted 25mm mdf treads so I tried every combo of bush with the 12.5mm cutters I was going to use but just couldn't get near to 25mm which would let me have a snug fit for tread thickness at the nosing. It was either a few mm over or under the 25mm I wanted.
I knew for my 25mm treads the instructions said use a 16mm dovetail cutter and bush C, I didn't have any dovetails but found a couple of 16mm straight cutters so set the router up with that and everything else as suggested in the instructions. My nosing thickness/tread thickness ended up a little over the 25mm for a snug fit, it's much slacker than I would prefer, but after being glued and with the flight being carpeted it won't be seen.

I have a few questions though if you don't mind folks:

Any problem with the nosing being not as snug as I would like or is it mainly a cosmetic thing? I was going to use an expanding glue to soak up any slack (not that much) and the flight is to be carpeted so nothing will be seen.

Anyone else had problems getting a snug fit with 25mm mdf and 16mm or 12.5mm straight cutters?

Also why would the 16mm straight cutters still end up routering the treads a little oversize, would it be because the dovetails are 16mm at the widest point but as they are plunged into the timber you end up with less than the 16mm say?

For what it's worth I could have used 22mm mdf no problem as I found
that eay to achieve with the 12.5mm cutters.

Sorry to ramble, so many questions, so little time.

 

[tomba26]

edit:duplicate post sorry. Mods feel free to delete.

 

[bench_monkey]

yeah thats just like i said earlier, thats the set up we use tomba. must be the same jig then! 1\2" cutter, 22mm tread. have you tried it on a scrap or just gone for it?

the nosing is a mix of both in my eyes, obviously its nice to get a good fit for looks, but i think its good to have a good fit to hold the tread in a consistant place on each step. saying that, provided your rise is correct from tread to tread the gap can be made up somehow

 

[JoinerySolutions]

I think most purchased jigs are designed for 1" tread material which is 25.4mm so that could be the source of the problem if you have dead on 25mm mdf boards. Pva will take up the slack, stay away from polyurethane glues they are too messy around anything that will be clear finished.

Out of interest what is the width of the jig nosing aperture the bit that would determine the tred thickness?

Rob.

 

[chippy1970]

Yes Chris and it was all your fault! :lol: :lol:
I caught one of your posts about them and ended up with three sys4 and a sys3.
Sys 3 for router bits, two 4's for hand tools and one for various bits off the CMS kit.
Rob.

:lol: :lol: :lol: glad to be of service :lol:

they are pretty good value, i noticed the panasonic stand at the dm tool show were selling their ones but they were about £40 each.

 

[scholar]

JoinerySolutions and katellwood both posted some interesting pictures (thankyou).

I am interested in the curved handrails you have shown on the winder staircases - something I have in (slow) progress on a staircase I have at home. I have copied the curve of the stair string for the handrails and laminated some oak strips to that curve, so I now have a curved square section handrail; I am now wondering how to machine the required profile (could be on the router table or spindle moulder).

The top profile of the handrail should be relatively straightforward using a bearing guided roundover cutter and the sides of the workpiece flat on the table. I am thinking about how to machine the side profile, so some insight from JoinerySolutions and katellwood would be very much appreciated. (One possibility I am considering is to laminate the handrails in two parts so I can machine the profiles from both top and bottom and then join the two machined profiles - hope that makes sense - I have only laminated up one full depth piece so far and would have to remake that).

Any ideas would be gratefully received.

Cheers

 

[JoinerySolutions]

JoinerySolutions and katellwood both posted some interesting pictures (thankyou).

I am interested in the curved handrails you have shown on the winder staircases - something I have in (slow) progress on a staircase I have at home. I have copied the curve of the stair string for the handrails and laminated some oak strips to that curve, so I now have a curved square section handrail; I am now wondering how to machine the required profile (could be on the router table or spindle moulder).

The top profile of the handrail should be relatively straightforward using a bearing guided roundover cutter and the sides of the workpiece flat on the table. I am thinking about how to machine the side profile, so some insight from JoinerySolutions and katellwood would be very much appreciated. (One possibility I am considering is to laminate the handrails in two parts so I can machine the profiles from both top and bottom and then join the two machined profiles - hope that makes sense - I have only laminated up one full depth piece so far and would have to remake that).

Any ideas would be gratefully received.

Cheers

A lot depends on the profile and the rake or pitch that the curved part takes. On many 'one of' handrail wreaths I machine the straight runs and turn to a bandsaw and scratch stocks with plenty of hand sanding into the bargain, it is actually quicker than trying to go the machine route.
It is possible to make a laminated straight rail (not glued up) and then machine it and bend it to a former during glue up, still requires lots of sanding but is hard to describe but leaves either end in the correct plane to joint the straight runs.
You have probably concluded that the rail twists as it curves due to the pitch of the stair; think of a rectangular length of rubber and wrap it around a tube start at the bottom and wind it upwards, the rubber has to twist so the side of it remains flat against the tube. It is this that makes machining difficult or requiring many jigs.
Much of the tooling that used to be in service for this kind of spindle work has been made illegal (with some good reasons) and now accomplished with CNC Router machines.
Post up some pics of what you want to do and a few more details (pitch/rise & going) etc and see what ideas come forward for your situation.

Rob.

 

[katellwood]

Hi

As you can see my stair has two curved handrails one curved in plan the other in elevation, both were cut from the solid i.e. no laminating.

The one in plan was easy as the setup used to machine the straight sections was used with the aid of a ring fence on the spindle (the difficult bit was that the shape required was an ellipse as opposed to a radius).

The rail in elevation was slightly more difficult as the ring fence could not be used. The majority of the waste was removed with a router then meticulously shaped with scratch stocks and scrapers. The routing was carried out first then the rail attached to the straight section, this was joined with two 3/8 pieces of ply morticed into the underside then hidden with the balustrade groove. Following being joined to the straight section the shape was completed with scrapers and scratch stocks to the final finish

One issue when utilising solid material in this way especially on the landing rail is that any tenons cut on the ends to attach to the newels are cut in extremely short grain therefore if draw bore dowels are used to pull up the joints there is a strong possibility of the tenon breaking. That being said if the joint is cut traditionally and the handrail section housed into the newel less force will be needed to pull up the shoulder as it will be hidden in the newel housing.

Hope this helps