Help me find the best way to do an inverted T shape cut in 2.4m oak sleeper

[JohnMi]

Yes I want the support of the concrete post which goes 80 cm deep in the ground bellow and i want a vertical oak post to cover the concrete as i want to turn this space into an outdoor kitchen with all natural materials. Thank you so much for the suggestions. I think i will cut the sides of the concrete post and then it is a much easier job as it eliminates the need to cut “ears” out . I will do several cuts in the oak and the chisel the material out. I got these green oak sleepers at a very good price And i think that in time they will dry out beautifully and will shrink nicely on top of the concrete making a strong “bond” . I want the concrete to provide the stability and carry the load. Have you ever worked with green oak? I am an amateur in woodworking but i really enjoy the process of working with wood especially sanding and oiling. I find it very satisfying. I am thinking to allow 3mm for shrinking as i do not want the oak to crack too much when it shrinks on the concrete “core”

 

[JohnMi]

I got a makita 5903R circular saw with a 235 mm cutting blade and guide rails . The saw can make 80mm deep cuts (which is the exact depth i need) at a 90 degrees angle. The saw is quite heavy and hard to handle but i think it has the capacity to do the cuts. I will cut and chisel out a 55x80mm “canal” in the heart of the sleeper and attach it to the concrete and then sand and oil the sleepers and in time I will will have a beautiful heavy oak beam low cost outdoor kitchen. I want it to have a more rough and natural look. There are 5 concrete posts. I want to cover them all with a sleeper each and then put a few sleepers on top vertically to frame it and build an yellow brick wall in the gaps. Concrete posts being there as this is not structural oak and also no underground rotting for the oak.

 

[Adam W.]

I've got a Festool AP85 1800w saw and it struggles with that much cutting in green oak and I trench with a modified chainsaw.. A 1500w saw would struggle even more, but that's not saying you shouldn't give it a go if you wish, don't forget the post has steel reinforcement in it too.

I've done a lot of green oak carpentry, with much larger sections than the stuff you're planning to use and I still can't see how you plan to cut the T shaped trench.

The oak will also likely split a lot more than you think it will and a 3mm tolerance is too tight as it shrinks a fair bit.

 

[accipiter]

@JohnMi The green oak will expand as well as shrink - even when treated with whatever you are intending to treat it with. Wood continues to move, more so when used outside and I would think the 3mm (1/8th inch) you say you are allowing for "further" shrinkage is really an unknown - same with expansion when the weather changes throughout the year from dry to wet.
With now knowing what you are using these green oak sleepers for *I* would be inclined to suggest cutting down the concrete posts to remove them. Then drill holes down in to the remaining concrete base to fit/epoxy stainless steel bar in. Then drill corresponding holes in the oak sleepers and drop the sleepers down on the bar. That way you don't have to be concerned about trying to wrap a *relatively* none moving (expanding/shrinking) concrete post with timber that will be subject to the vagaries of the weather. If doing the cutting as you are considering and the wood expands in wet weather around the concrete posts the wood will be very likely to split and may then reveal the concrete post/s.

 

[Myfordman]

so many ways to do this with out the near miracle difficulties the OP is favouring.

 

[JohnMi]

I really do not want to cut the concrete posts down…maybe if I allow 5 mm for shrinking and expanding and use long bolts to keep them together it would work ?

 

[HOJ]

I am an amateur in woodworking but i really enjoy the process of working with wood especially sanding and oiling

Your not filling me with confidence!

5 concrete posts. I want to cover them all with a sleeper each and then put a few sleepers on top vertically to frame it and build an yellow brick wall in the gaps

Do you mean horizontally?, presume you'll then need to dig some footings for the yellow bricks as well?

 

[toolsntat]

Personally I think the way you are thinking of cutting the oak out is fraught with disaster as you are leaving the face too thin.
For me option A would be favourable but it depends on how tight for space you are?
If you are capable and want to "pinch an inch" option B would be about the limit of removing oak I'd be happy with.
Both A and B make use of stout long grain "buttons" to hold it onto the post.
Remember, these sleepers when drying/deforming, have the ability to snap these concrete posts.
Hope this helps.
Cheers, Andy
Ps, forgive me the drawing errors but you should get the "picture"....

 

[Fergie 307]

Have to say I think the whole idea is flawed. These concrete posts are not that strong, and an awkward shape to boot. Entirely possible that movement of the wood could break the post, and they also have a habit of snapping at ground level. They are fence posts, and should only be used as such. I would use a suitably sized steel i beam as the basis, then clad it. Use treated softwood batters in the sides of the beam to bring it up slightly proud of the sides. You can use an I beam smaller than your concrete post as it's much stronger. This will leave you with a thicker section of oak which will be less likely to split. Then just cut a straight slot in your oak beam, big table saw multiple cuts to the required depth and remove the waste with a chisel. Slide your oak over and I would maybe secure it to the softwood infill pieces using dowels. Treat the steel with something like Synthaprufe, and ideally don't have the oak actually in contact with it. You could cut thin treated softwood battens, maybe 5mm thick to go on to the flat face of the I beam to separate it from the oak. This is important as otherwise the oak will react badly with the steel.

 

[Jonm]

Personally I would not cut concrete off the posts, the steel is essential to its strength, reduced cover can result in the steel corroding. It would also be a horrible dusty job.

I have a fence with concrete posts which I wanted to cover with timber so I could attach wires for training plants and to improve the look. I did not want to drill holes in the posts as it would have compromised the cover to the steel. The whole reason for using concrete posts with concrete gravel boards was for long term durability and ease of maintenance. I used cut down angle brackets as shown below. This is not a solution for you but you could just box in the posts and if you have problems it would be easy to remove and replace.

As others have said, some more information about what you are trying to achieve would help. For example, why can’t you use just the oak posts. My previous house was oak framed and that was still standing after 450 years.

 

[dickm]

Ps, forgive me the drawing errors but you should get the "picture"....

Andy, you can't do this to us! A partial view of an interesting old catalogue(?) with just enough to whet the appetite, but all the essential details obscured!

 

[pip1954]

You say you are armature carpenter but what about bricklaying , if and it's a big if you do do it don't try to build up under your sleepers on top do the brick work the put timbers on top after.
I think you would find it easier to do it like toolsntat said as this was a amended way of what I suggested .
Is there more to this idea are you trying to make some sort of enclosure ie a room with maybe a roof structure on it .
There is only ever one way to do a job and that is the right way.

 

[toolsntat]

Andy, you can't do this to us! A partial view of an interesting old catalogue(?) with just enough to whet the appetite, but all the essential details obscured!

I'm sure I don't know what you mean Dick....
https://www.abebooks.co.uk/Farrow-J...hoGqvnpZL-J-BXBmipxhl7tDkgz4XltoaAvFKEALw_wcBNice and cheap as well.
Cheers, Andy

 

[okeydokey]

I would think boxed in would be a good resolution to the problem, if you want the oak effect use oak gravel boards or suchlike, instead of brass screwing together you could drill and peg to hold the vertical sides together, make some pegs easy enough you have the oak

 

[Jonm]

Is there more to this idea are you trying to make some sort of enclosure ie a room with maybe a roof structure on it .

JohnMi is not telling us so it is difficult for us to give good advice.

 

[dickm]

I'm sure I don't know what you mean Dick....
https://www.abebooks.co.uk/Farrow-J...hoGqvnpZL-J-BXBmipxhl7tDkgz4XltoaAvFKEALw_wcBNice and cheap as well.
Cheers, Andy

Fascinating combination, selling wines and spirits together with engineering. Hope noone did too much of the latter while patronising the former!

 

[JohnMi]

There is nothing special that I want really. No room or roof structure. Just a wall. The posts are there as existing posts and I want to cover them just so they are not visible. I like the look of the oak and I love it when it just looks solid. This is in my own garden. I am also doing this as it is a fun little project for me. I am a computer engineer I work from home and sit in a chair all day and this is a way to be more physically active.

 

[JohnMi]

I “trimmed” the posts today. It should be a much easier job now. Thanks for your help and ideas.

 

[JohnMi]

This is how i imagine it to be. It is all for decoration purposes really.

 

[hugov]

Looks like you did a good job on cutting the concrete posts, nice one! As for cutting the (now) trench (rather than T-slot) in the sleeper, I would say your best bet is to cut a number of kerfs to the desired depth, each a few mm from the next, and break out the thin strips remaining with a chisel. You'll probably have to take multiple passes down each kerf to get to the desired depth without overloading the saw. Make sure you monitor how hot the motor is getting and give it some tea breaks