beaming oak with heart on face

[Chalky]

Ive just stated milling my oak frame for my new house and the framers have asked for certain spec with no heart on face. Does anyone know the best way to achieve this without wasting loads off good timber. I was thinking of starting with a larger diameter log,squaring it off then taking certain sizes off like 200x125 working towards a 200x200 box hart to finish. Any tips would be greatly appreciated

 

Thanks

 

Chalky

[agg221]

Most beams from commercial suppliers seem to be cut from trees pretty close to the size of the biggest possible section achievable throughout the length. The curved offcuts are mainly sapwood and bark and the wastage is pretty minimal.

 

When milling your own (as I did) you don't have so much choice over your timber. I did as you are suggesting, but cut the beam out first. Where possible, I then cut timbers with the bigger dimension radially from the tree. So, say I had a 2' top end diameter butt and wanted to get an 8" square beam out, this would mean I had a further 8" either side. Slabbing this off, then rotating it by 90deg and cutting into widths I would get either an 8" x 3", 2off 5" x 3" and 2off 4" x 3" or a 6" square and 2off 4" x 3". The deeper sections would be near quartersawn so more stable.

 

You can see from above that the key thing is to get a full cutting list first (in my case I had to push my architect and engineer to complete this before they had even completed the detail drawings). I then copied out the sizes I needed (depth x width x length and number of each size) and wrote them out in a numbered list, in decreasing order of size. For each piece of timber I measured it and scanned down the list to the biggest section I could get out of it, cut it out and inspected it. When I found a defect which meant that it failed visual grading, I reassessed it to the biggest I could still get. I then numbered it on both ends, ticking it off of the list. This kept waste to an absolute minimum.

 

I hung on to all the really outer sections too, even the ones which would have cupped badly. My design needed a lot of batten so I just batched up all these offcuts and ripped them down to size with a circular saw against the fence. So much better quality than the softwood cheese you get from the builders' merchants (although you do then need to use stainless nails).

 

Hope these thoughts help.

 

Alec

[Chalky]

Thanks Alex, very helpful. One thing I'm always trying to get is keeping the heart in the centre which can be tricky with some logs which means you can only get thin boards off to get beam good quality. Its a bit of a head scratcher to get you head round but sure it will come good with practice. I have a cutting list as long as your arm for my oak frame.

[Copford sawmill sussex]

Heart on one face isn't usually a problem as the other 3 sides should be clean. If you know what your doing you can usually always hide one face if need be, no point ruining timber just cos of a face. Also if it's for your build and your happy with how your own timber looks the buikders hopefully shouldn't mind

[Chalky]

That is what i was thinking, seems a real hassle and big waste of timber as you say. Its for my own house so if i'm happy then the framers should be.

[Aunt Maud]

That's interesting, why don't they want heart on the face ?

[Copford sawmill sussex]

Technically it can be classed as a crack which is frowned upon when grading.

[Aunt Maud]

It's the most durable part of the tree, apart from the pith of course, and traditionally the heart is placed to the outside on a timber framed building as its the face less likely to split and doesn't have any sapwood on the edges. If you box the heart you'll get splits on each face when it dries, but you know that already.

 

Funny lot modern framers.

[SteveA]

Not sure if this is right but I've been told that splits in oak will naturally occur from a knot to the next knot.... so it's good to have knots so long as they are in the right place, ie not where a mortice & tenon needs to be.

 

Is that right?

cheers, steve

[Aunt Maud]

Cutting a tennon where a knot is is tricky, as the grain flows around the knot and you may have to cut the tennon with a saw to keep the shape. When using a chisel it will want to run off and follow the grain and may weaken the tennon.

 

Mortices are not really a problem if you are using a chain morticer. Plus the face the mortice is in will be covered with the infill panel or enclosed in the cladding if you're building a barn.

 

As for the splits running from knot to knot, I've never experienced that, as they usually seem to run up the face and I frame the heart to the outside, as I work on historic frames and not new builds. All of the timber I cut for external walls is halved, as I can keep any sapwood on the inside of the building.

Edited December 12, 2015 by Aunt Maud