how to cut a very wide rabbet

[Ken Klingman]

I have 60' of 1" thick by 12" wide red oak stair treads with one bullnosed edge which I'll cut down to make 15 treads for my new stairs. Each tread will be about 40" long. I rough framed the stairs assuming 3/4" thick material. I could use the treads at the full 1" thickness and only be 1/4" off at the top and bottom step, and code allows for a 3/8" step-to-step difference. But I'd like it to be closer than that.

I was thinking of cutting a very wide rabbet in the tread material such that it's 3/4" thick, but leaving the original 1" thickness on the leading 1 1/2" where the bullnose is. That would end up looking like a very wide version of red oak flooring bullnose without the groove, which would have the additional benefit of overlapping the top of riser making for a very tight joint. Sketchup image of the original and the desired attached.

I have a table saw, 12" combination jointer/planer, and a router table. I've considered doing it with multiple passes of a dado blade, or on the router table with multiple passes of a 1" router bit, but I'd have to somehow do it as a dado so I'd have support on both edges and then maybe finish it off by turning it 90 degrees for the final pass. I was wondering if anybody had a better idea. Someone mentioned to me a technique using the jointer, but for the life of me I can't imagine how I'd do it on the jointer. It's the Hammer A31 if it makes any difference.

298586

[pat warner]

You'll spoil the equilibrium of the tread, taking that much stock from one face.
Creak/freak/twist city.
Would do a glue-up.

[Tom Welch]

Easy, route your round over, rip it off, then plane the board, then reattach with glue. Use Dowels, biscuits or domino if you think you need some more reinforcement.

[Alan Schwabacher]

I'd try to find a way to use it full thickness. I think there's a reason stair treads are thicker than 3/4". If you do cut a rabbet or dado, can you restrict it to where the tread is supported?

[Anthony Whitesell]

Does you joiner have the ability to make a rabbet? I can rabbet on my Grizzly G0490, up to 8" wide. Can you do the same?

Once up on a time I had a similar issue and asked a similar question. I need to make a 1/2" deep rabbet, 6" wide in a piece of 8" wide wood. I don't recall what the solution was. I will think about it more and get back if I remember. I do know that it was before I owned the jointer, so that wasn't the first answer.

[Floyd Mah]

Any chance of pulling the stringers out and resetting them 1/4" lower? Alternatively, maybe rout or saw the stringers at each step by 1/4". I think HF sells a toe-kick saw that might work in that space. Reminds me of the old days when I had to use a typewriter for school. Hit the wrong key and I had to think of a new word to use, just to avoid having to erase the letter by using brute force (this was in the old, old days before Mike Nesmith's mother invented White-out). Seems that all that cutting to reconfigure the treads is too much work.

[Rich Engelhardt]

I'd have to somehow do it as a dado so I'd have support on both edges and then maybe finish it off by turning it 90 degrees for the final pass. I was wondering if anybody had a better idea.That's more or less how I plan to do it.
I have to remove 1/4" to 3/8" from four bullnose stair treads that are 1" thick.
Mine are going to be glued to some existing concrete steps so I'm not too concerned about support.

My plan is to hog out most of the tread with a dado blade and keep about two inches on the back end for support.
When I get done with the dado part, then I plan on flipping the board up on end - setting the fence so it's the same distance as the dado is deep - and rip off the small 2 inch section on the back end. I have a ten inch high sacrificial fence so I have plenty of support.

I'd thought about using the router table, but, I'd have to go out and spend $35. on a 1 1/4" bottom cleanout bit, which I don't mind doing - but - the router generates too many chips. The table saw is set up to be less messy.

[jack forsberg]

if bottom finish does not mater this is what i do to keep the front edge thick and top surface clean. mind you yours is just straight across and would be way easier that my tapered door sill.


https://www.youtube.com/watch?v=DbNw7I7iHFI&list=UUI6jpIs2zjN9DmVvK2ZAWXA

[Dave Richards]

What about cutting front to back stopped dadoes for the stringers and leaving the rest of the tread full thickness? The dadoes could be slightly wider than the thickness of the stringers but you wouldn't need to hog out all the material on the bottom of the tread.

[David L Morse]

Would 1/8" be too much difference for you? If you can tolerate that then just take 1/8" off the first and last treads. Then you have two steps that are 1/8" higher and two 1/8" lower with only two treads to machine to 7/8" thickness. I'd cut that with multiple passes across a dado blade. With the right order I would only need support for the last pass.

[Peter Quinn]

It rarely goes well when you take 1/4" off one face like that. I used to make a lot of nosings, landings, and treads at my last job, lots of contractors get in the same position, and they can't envision how to make a seamless glue joint at the nose, so they demand a one piece tread hogged out just like you are suggesting....then they get a pile of oak pringles that can barely be installed and require boatloads of screws and PL to get flat. Don't do it. Cut off the nose with a thin kerf blade, label everything well, plane down your treads, glue the nosing back on each tread just as it came off, use a spline or biscuits for alignment. Stays flatter, much quicker than 10 million dado passes. Or do as David M suggest above. I wouldn't want the 1/4" difference at the top and bottom, but 1/8" I could live with.

[Jim Matthews]

Easy, route your round over, rip it off, then plane the board, then reattach with glue.

+1

Beat me to it.
Best grain match, this way.

[jack forsberg]

Is there some reason you could not plane the treads down as is and just go to a smaller bull nose bit and no rip the nose off and not re-glue?

[Bill Orbine]

I'm confused....do you really need to rabbit out the entire bottom of the tread not including the nosing? I'm having a little trouble exactly what you are installing these new treads into.... So I was wondering if you can only dado and or rabbit only there areas you need to rather than scoop off the entire with of the treads less the nosing.... Am I making sense??? Or am I way off base???

[Ken Klingman]

Thanks for all the suggestions!

To clarify a bit, the existing stair was framed with OSB treads to give something to walk on until finish treads could be installed. Being somewhat anal I screwed & construction adhesived them in place. Only an act of god is going to move them now. So yes, I'd have to rabbet out the entire surface as the finish oak treads sit on the immobile OSB treads. Unless someone has a way to undo 3/4" OSB stuck to LVL risers with PL400 construction adhesive...

Making a lot of dado passes with the table saw or multiple passes on the router tables is just too painful to consider.

1/8" of an inch would be OK, but I'd like to tuck the tops of the risers behind the nosing and 1/8" is a bit too small.

Finally, the bullnose is already cut - tread material came that way.

Think I'll cut off the noses, plane down the flat piece, and glue the nose back on with a domino as suggested.
Might limit the planing to 3/16's as I am indeed nervous about twists, cupping, and the like.

[jack forsberg]

Finally, the bullnose is already cut - tread material came that way.


cuting again with a smaller bit will negate nothing . every one has a 3/8 round over just saying and if not are less than $16