Notching a beam - router?

[hanser]

Bit of DIY advice please....

I am going to replace a wooden beam in a ceiling and plan to route out the notches for the short joists using my Triton TRA 001. There are 20 notches each roughly 110x40x70. The beam will be some sort of pine.

What type of router bit(s) would you guys recommend? Will one do the job or do I need two types -one for the bulk removal, the other for tidying up?

Your advice is appreciated.

 

[Newbie_Neil]

Hi,

Is the depth 40 or 70mm?

To make the job easier it might be worth making an "exact width dado guide".

Thanks,
Neil

 

[hanser]

Neil
I can plunge from either the top or side on - the least depth option (side on) is 40mm.

Using a template sounds like a good plan.

Hanser

 

[chipmunk]

Could you route around the outside edge and then chisel out the middle and perhaps clean up the base of the notch if you need to which I doubt TBH - That sounds like an awful lot of routing/noise/dust.

The other thought would be to drill out as much of the waste as possible (Forstner or augers) and then clean up with router. Again this will be less airborne dust & noise. Any dimples in the base of the notch will be hidden by the joists and won't affect the structural integrity to any meaningful extent.

HTH
Jon

 

[zb1]

They are pretty big housings to be attempting with a router, would be quite a number of passes for each pocket and take an age. In my experience it would be quicker this way. I generally use a Mafell LS103 of Protool CMP150 chain mortiser with a fence jig on a plunge stand for these sorts of housings but at a couple or 3 grand you would be better off using the alternative (cheaper) method of drilling out the lowest part of the housing with say a 38mm auger to required depth, then running a circular saw up the edges followed by a series of parallel cuts between, finally chop out the waste with a nice big firmer chisel. Bish Bash Bosh, job done.

Is this just decorative of is it actually a structural floor? How deep is your beam? How deep are the floor joists?

 

[Steve Maskery]

Perhaps I'm missing something here, but wouldn't the quickest, cheapest and generally the best way be to cut these by hand? The marking out is the same for both methods, so you just have to saw to the line and chop out the waste. I really think it would be easier to do it this way than fannying about with a router and a guide - and I speak as someone who is generally in favour of using power tools and jigs.
But not in this case.
Steve

 

[Graham Orm]

Why are you notching the joist? You are reducing the load bearing capability significantly. Joist hangers are quicker and easier, and your floor wont collapse!

If you're replacing like for like, use a saw and chisel, much, much easier than a router. Make several cuts per notch with the saw and the waste will be easy to chop out.
You stand a chance of reducing the life of your router on such a large amount of heavy cuts.
Good luck :wink:

 

[hanser]

Much food for thought - thanks guys.

I am replacing like for like other than 'beefing' up the dimension of the beam. I am looking for something like 11" x 7" x 15ft in old money. If anyone knows where to get this sort of thing, please let me know.

Guess I'll have to start eating my spinach!

 

[marcros]

i dont know for certain, but Somerscales in Immingham had some huge sections of softwood in when i went, the size of which i hadn't ever seen before. They would likely be able to cut those sections for you if there is nobody local that can.

 

[WellsWood]

+1 for non use of router - it is not the tool for this job. A sliding crosscut saw with a trenching stop would be my first choice, followed by chiseling out the waste. If you don't have access to a SCMS then a sharp handsaw will be almost as quick and easy.

I would echo questions as to why the notches in the first place - definitely a last resort if they are structural, and ONLY after calculating loads and residual beam strength.

Edit: just re-read your post and understood better what you are doing (must pay attention); effectively hanging 4x2 joists in between 11x7" beams. Would agree then that joist hangers would be easier and quicker unless (as I suspect) they are exposed, in which case a router starts to make sense. A template guide would work if your joists are all identical. I think I'd still do the bulk of the waste with saw and chisel though.

 

[ColeyS1]

Forstener bit out the guts of the waste (starting at the edge so the chips clear) then use your router and jig to trim out the remaining bits

 

[twothumbs]

John Bodddys in Boroughbridge (just off the A1) do large beams but possibly only in Oak. They may be too far away for you but they do deliver. Best wishes.

 

[zb1]

I get most of my structural softwood and hardwood from Somerscales. They are very good. They will deliver too.

 

[hanser]

Sorry, I should have said the beam and joists are exposed.

Initial thinking was finding a reclaim beam but there are the inevitable mortices, bolt holes, scuffs etc and that's assuming I can find the sizing I need. I did have a chat with Somerscales who are very helpful. They can cut green D Fir to size. How much movement/shrinkage should I expect as it dries out?

Thanks

 

[zb1]

Less than 0.1% over the length. 4-7% across the face and 8-10% tangentially. So your 275x175x3000 will probably end up somewhere around the 256x163x2997.
Shrinkage is not you biggest worry with a floor beam. You need to watch out for sloping or spiral grain as this will potentially cause the beam to fail as it dries. You'll want to have boxed heart for the floor beam and tangentially sawn joists.