Carpentry question - cut trench in post

[dazzler]

Hi

I want to put a rail between these two posts on each side of the deck (can't see the other posts in pic)



The rail is 90x45 so I need a trench cut into the side of the post about 50mm down and set so it sits out. So the trench or rebate will be about 50mm deep.

How would you do it so it's an interference fit and not sloppy?

I've got the following;

Routers, circular saw, levels, squares, string lines, laser levels. I also need to do the same across three posts to the right of the verandah post.

What ya reckon.


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[GGV8Cruza]

Set circular saw to 50mm deep. Mark the trench on the posts with a snug fit. Cut to the line on the top and the bottom, then cut as many cuts as you can between these two cuts. Break out all remaining timber and clean base with chisel. Fit rail and securely fix with correct length batten screws. If you have the time paint the inside of the trench before fitting rail for longer lasting posts

GG

[dazzler]

It's the getting the two outside cuts spot on. I suck at that bit

[Bird]

It's the getting the two outside cuts spot on. I suck at that bit

remove posts and send to GG... he will return cut and ready to go...

[GGV8Cruza]

It's the getting the two outside cuts spot on. I suck at that bit

Measure from the cut side of the blade (edge of tooth) of your saw to the edge of the baseplate. Clamp a piece of timber to the post the same distance away. Run your saw along the block and you should have a straight cut. Just be careful you measure the right side of the blade when setting it up and have the saw unplugged as you will need to slide the guard open.

GG

[Footy Shorts Shane]

Measure from saw blade edge to saw base edge. Clamp a piece of timber this distance under the bottom cut at correct angle. Run the saw through, move clamped timber up thickness of rail - width of saw blade and cut again. Gives you a guide to run the saw against.

(The Chippy's of the forum might have a much better way of doing it, but that's how a mechanic would do it  )

Edit, GG beat me to it. Likes like he's going to make a great mechanic some day 

[prodigyrf]

Yep what GG said and use your rail clamped to the posts as your guide but dont forget to cut the top of the rebate first and then shift the rail down to cut the bottom of the rebate bearing in mind you're using opposite sides of the blade with each setup/cut. You want the saw resting on top of the rail remember or you're holding it against gravity. Then with the rail still in place you can work up with several cuts toward your top cut and chizel them out or complete with saw. If you're not comfortable cutting near the top cut you could have moved the rail down a saw cut for a double cut initially and so on if you're really wonky. Bit tedious but you're not paying yourself chippy rates by the hour and there's always builders bog if you stuff it up.

[prodigyrf]

Oh and don't trust the angle guide but use a square to set the sole plate perpindicular to the saw blade 

[Rumpig]

if you mean just putting a horizontal rail between the 2 posts, then clamp a block to the post to run the saw across as has been mentioned already. Just mark it acurrately and err on the smaller side at the start, you can always recut it again if it's to tight. Just leave the block clamped in place as you try it (cut a short off cut of the timber you plan to put in there to check it's fit as you go), then tap it down a touch and recut if it's to tight.

[dazzler]

Would you trust a 'speed square' as the saw guide?  If so then I can mark 100mm up from the top cut as thats the distance from the blade to the edge of the baseplate.  Then mark down 42mm and go again which should give me 42mm + blade thickness = 45mm.?

[Moggy]

Didn't you pay attention to Joe the other day, dont be a tite arse & spend ya money & get someone to do it for you. The country's on the up

[Moggy]

Seriously though if those posts are structural i wouldn't be cutting a trench any deeper than 15mm. You'll substantially weaken the post otherwise

[GGV8Cruza]

Seriously though if those posts are structural i wouldn't be cutting a trench any deeper than 15mm. You'll substantially weaken the post otherwise

Probably too late, the bottom looks already to have been scarf jointed

GG

[Rumpig]

Seriously though if those posts are structural i wouldn't be cutting a trench any deeper than 15mm. You'll substantially weaken the post otherwise

X2 on this.... no need to go 50mm deep, 10mm - 15mm will be plenty to hold that handrail in position with a few bullet head nails skewed in through the bottom of it.

[prodigyrf]

Seriously though if those posts are structural i wouldn't be cutting a trench any deeper than 15mm. You'll substantially weaken the post otherwise

Tiled roof you might check the dead load specs but if it's a sheet roof no worries as the posts are largely holding the roof down, like holding down a large umbrella as the wind hitting the walls of the porch deflect upwards and want to lift the roof off.

[dales133]

I wouldn't piss about either beg borrow steal or hire a router.
Sounds like you have a bit of knowledge but a mortise and tennon style joint if that's what your proposing is a whole joiners aprentiship  worth of tools and techniques.
Rout out a slot made with a jig

[Rumpig]

I wouldn't piss about either beg borrow steal or hire a router.
Sounds like you have a bit of knowledge but a mortise and tennon style joint if that's what your proposing is a whole joiners aprentiship  worth of tools and techniques.
Rout out a slot made with a jig

if all he is doing is housing the rail into the post, it's as simple as a few saw cuts and clean up with a chisel, no need for fancy joints. A sharp saw blade and sharp chisel is a must though, a blunt saw blade will splinter the timber

[dales133]

Exactly. A cheap router and 5 mins to cut a template is cheaper than a good chisel and a good saw.not to mention the fact they are easier to use

[dazzler]

Thanks all. Not structural. I actually do fine furniture but that's in the shop where.  you can set things up on the bench and use the TS and SCMS.
Different to this sort of stuff of course




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[kylarama]

I wouldn't piss about either beg borrow steal or hire a router.
Sounds like you have a bit of knowledge but a mortise and tennon style joint if that's what your proposing is a whole joiners aprentiship  worth of tools and techniques.
Rout out a slot made with a jig

If we're talking a simple housing joint like this that others have mentioned.




Then a circ saw and sharp chisel wins hands down.

[Barry G]

I have found a router far more precise for doing this sort of replication work than a circular saw.

With a parallel router bit and a template (6mm ply is ideal) sized to allow you to run the router base against the top and bottom edges, you can replicate the correct cut width as many times as you need to, quickly and easily.

Just need to take a bit of time getting the template precisely right first.

Here is an example of how to determine the width of the opening in the template:
Diameter of base; 200mm (radius 100mm)
Diameter of bit 30mm
Distance between edge of base and edge of bit  100-15=85mm
Width of timber rail 45mm
Distance between top and bottom edges of template:
85 + 45 + 85 = 215mm

[kylarama]

Yes a router jig is better for repetition work, but we're only talking about 4 posts in Dazzler's case.  This is a very basic joint than can be done in a matter of minutes by any competent carpenter or joiner with nothing more than a jack saw and chisel.  Anyone with half reasonable wood skills would be finished and sucking stubbies admiring their chisel/saw handy work quicker than making a jig.

As for precision. A tool be it hand or power, will only ever be as precise as the operator.

Would you trust a 'speed square' as the saw guide?  If so then I can mark 100mm up from the top cut as thats the distance from the blade to the edge of the baseplate.  Then mark down 42mm and go again which should give me 42mm + blade thickness = 45mm.?

So long as the square is long enough to comfortably run the saw along the edge and you can clamp it. 

If you make furniture then this should be a doodle for you.  Worst case, it's a painted surface so you can neaten it up with a tube or 2 of 'No More Skills'  AKA No More Gaps...

[Barry G]

Dazzler already has a router and a bit 'into' woodwork, so why not make an adjustable template that could be used for other housing joints?  I find that making a template I know I will use again can be 'half the fun'.

Granted, ultimately accuracy always relies on the skill and care of the operator. However, whatever the skill level, a router with straight bit and template will always be able to be adjusted to a greater degree of accuracy than can a circular saw. For starters, there is inevitably a degree of movement in a circular saw blade that is not present in a router bit.

[Rumpig]

Yes a router jig is better for repetition work, but we're only talking about 4 posts in Dazzler's case.  This is a very basic joint than can be done in a matter of minutes by any competent carpenter or joiner with nothing more than a jack saw and chisel.  Anyone with half reasonable wood skills would be finished and sucking stubbies admiring their chisel/saw handy work quicker than making a jig.

As for precision. A tool be it hand or power, will only ever be as precise as the operator.

That is all i'd do at work, and have done for over 20 years now as the timber is usually a different size, even though it's supposed to all be machined the same size. Making a jig and adjusting the depth of the router all the time takes time to do, just set the saw at one depth and do multiple cuts close together, then lever the cuts side ways and break most of the timber out, then clean up the base of housing and job done.

So long as the square is long enough to comfortably run the saw along the edge and you can clamp it. 

If you make furniture then this should be a doodle for you.  Worst case, it's a painted surface so you can neaten it up with a tube or 2 of 'No More Skills'  AKA No More Gaps...

If he uses a sharp 7 1/4 power saw then one of these squares in this link
https://www.tradetools.com/product-range/hand-tools/general-hand-tools/johnson-structo-angle-square is all he should need, just need to make sure you don't move it whilst cutting (i usually freehand my cuts though, and once again i'll say a sharp saw makes the differance in being able to do this neatly or not). It's ok for me to say this i guess as i use a power saw daily, so for a novice i'd suggest clamping (or even tack nailing or screwing..but you'll have to patch the holes later) something like a bit of timber or even a square in place  to run the saw along. If you don't want to damage the paint then put a block of timber on both sides of the post, as you could damage the paint where the clamp hits the post on the other side when it does up.

[Footy Shorts Shane]

Just hurry up and do it, before this thread ends up in the electrical section.