Boxing in columns

[PhilC]

Hi some of you may have seen my previous posts re wanting to box in some steel columns and how a I may go about it. The columns are approx. 80mm square but 2 meters long. I want to cover them in 32mm oak to give the impression of an oak post on 3 sides. Originally I was going to attempt to do long 45 degree bevel cuts and then a spline at 90 degrees to the bevel to hold everything together all on a table saw. However it's been suggested that this may be hard to do and possibly dangerous. So I'm looking into the possibility of doing much the same but on a router table with a mitre lock cutter from here http://www.wealdentool.com/acatalog/Online_Catalogue_Mitre_Lock_Jointer_143.html
The one I would need would be the 89mm diameter version and was wondering what your thoughts are. The router I would be using is a CMT1E 1850 Watt variable speed. I know the setting up of the cutter and getting the oak into and out of the table would be critical but are there any other issues or problems that I should consider or any other methods of achieving the same?

Thanks in advance.

 

[Racers]

I am having trouble understand why you need such a strong joint for some cladding, I did suggest a mitre and biscuits which would be strong enough, the mitre would be about 45mm so plenty of area to glue and some biscuits for alignment, job done.

Pete

 

[Jacob]

I 'd just plain butt joint them. Two opposing boards clamped to sandwich the other two boards, with plenty of glue. No need for any special technique or kit but some short clamps would be handy and perhaps a few pins on the inside for the boards to align up against. Or some thin battens pinned on to make a bit of a rebate to locate the narrower boards.

 

[PhilC]

I am having trouble understand why you need such a strong joint for some cladding, I did suggest a mitre and biscuits which would be strong enough, the mitre would be about 45mm so plenty of area to glue and some biscuits for alignment, job done.

Pete

Hi Pete, maybe as a newbie I'm over engineering but as the cladding is in a conservatory there will be big differences in temperature and over time I wouldn't want the box corners to open. Also On the 4th (open) side there will be my double gazed units pushed and sandwiched against the oak. I will also need to use the same technique to cover some steel beams in and around the ceiling and as the mitre cutter goes from 20mm to 36mm it sounds ideal?
Basically I'm try to achieve the end result as easily as possible and the mitre cutter would seem to fit the bill in terms of the 45 degree bevel and alignment in one go but I was wondering if there was more I should be considering.

 

[PhilC]

I 'd just plain butt joint them. Two opposing boards clamped to sandwich the other two boards, with plenty of glue. No need for any special technique or kit but some short clamps would be handy and perhaps a few pins on the inside for the boards to align up against. Or some thin battens pinned on to make a bit of a rebate to locate the narrower boards.

I would prefer to have the join on the corner as If I just butt joint them there would be no mistaking that the post wasn't solid.

 

[Racers]

Well if its going to open up it will no mater what you do, the thicker the wood the more problems you will have.
Its going to look like a cap no mater what you do, you should make a feature like butt joints and a 3mm deep reveal to make a feature, or hollow a joist to fit!

I would go for 18mm oak a mitre and biscuits.

Pete

 

[RogerP]

The Wealdon cutters will do the job BUT ...

NB: T5596½ and T5598½ are large cutters. Please ensure they are suitable for your machine. These large cutters should only be used in a fixed machine and at 10,000 rpm maximum.

... they are massive and will need a heavyweight router and a strong router table plus good effective guarding. The boards will need to be perfectly flat and of an even thickness. Initial setting up is crucial.

 

[PhilC]

The Wealdon cutters will do the job BUT ...

NB: T5596½ and T5598½ are large cutters. Please ensure they are suitable for your machine. These large cutters should only be used in a fixed machine and at 10,000 rpm maximum.

... they are massive and will need a heavyweight router and a strong router table plus good effective guarding. The boards will need to be perfectly flat and of an even thickness. Initial setting up is crucial.

Yup I read that too, what would you consider to be a heavyweight router to be?

 

[Billy Flitch]

Phil if you are going to use the mitre lock get ready for a very sharp learning curve, I would recommend that you run many test pieces before you try it on a 2 meter piece.
The benefit of the mitre lock is the increased gluing area in the joint itself and the setting out of the machine no simple matter. You should be looking for a feather edge finish to both sides of the joint. The problem with this is the piece that you have standing tall against the fence, once it has past the bit its reference face is almost gone and you lose the super sharp edge that you are aiming for as you press down on this very edge.

A way out of this is to cut your stock a little longer than you need it and fasten a wooden straightedge to the piece so that you are Bering down on the straightedge and keeping the sharp edge of the stock.

Jacobs way would work but as you say you don't want the but joint on the corner.
I was taught that if you cant hide something you should exaggerate it and Pete has a good idea with putting a revel on the corner but maybe you could router a ogee on the corner and incorporate the revel in the joint so it looks pleasing on the eye . I made a quick sketch so you can see what I'm talking about .

 

[PhilC]

Thanks again, I have used the hide in plain sight approach before but this time I don't think it will fit in with the "ye olde" look I was hoping for. Might opt for the mitre cutter and see how some test pieces go (thanks for the tip re the straight edge).

 

[RobinBHM]

I use a lock mitre cutter to machine dummy post covers for orangeries, its something we do all the time in 25mm thick iroko. We do it with spindle moulder tooling and it is probably the most difficult set up we do, I wouldnt attempt it with a router, especially not in oak.

The mitre lock joint does look very good, ive done it occasionally in oak and you cant tell it isn't a square solid beam.

Ive seen some conservatory makers make corner post covers which are butt jointed. They disguise the joint by machining a chamfer down each mating face and edge, so when assembled it forms a V. Then a V cutter is used to machine a V groove down the long edges of the full width post cover, at a distance in (to centre of V) from the edge by the thickness of the timber. Assembled the post cover has a V joint, set in by the timber thickness on all corners.

Alternatively, rebate the post covers and then put stopped or through chamfers which leave a slight flat before the joint

 

[n0legs]

I've got a lock mitre cutter for 3/4' and it's a pain to set up.
It's a good joint on mdf but i wouldn't be so sure on natural timber. As Roger said your boards will need to very well prepared.