Woodworking joints and machines

[Tim Watts]

I was bored the other day (= putting off awkward job!) and was musing on
my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two cuts (the
steep angle short cut).

But I've never seen such a saw that can cut much more than a 45 degree
cut by tilting the cutting head - in fact if it could the piece would
probably foul the head and the depth of cut would be too great.

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

All I can think is good jigsaw or handsaw (latter obviously the way it
used to be done).

It might be something one could make a guide plate for the jigsaw shoe
thus getting quick and repeatable cuts.

Or is there a clever way?


[1] and just to complicate things, I'm rather taken by having a gambrel
roof - it would look different to the average workshop...

 

[Chris J Dixon]

I'm rather taken by having a gambrel
roof - it would look different to the average workshop...

Well that is something new I have learned. I hadn't realised that
a true mansard is hipped.

Chris

 

[Tim Watts]

Well that is something new I have learned. I hadn't realised that
a true mansard is hipped.

Chris

That's what I thought until I googled for mansard (because I couldn't
remember if it was Mansard, Mansell or something else).

I *could* make the shed from Amytiville ;->

It does have the advantage of looking less boxy, having a lower roofline
(shed, so this is important for PP reasons) whilst still having good
headroom.

I notice in some construction plans I found that it does use seem to use
nearly twice the structural timber of a normal pitch roof due to all the
extra braces though.

 

[Chris J Dixon]

That's what I thought until I googled for mansard (because I couldn't
remember if it was Mansard, Mansell or something else).

I think Mansell has a rather different approach to corners.

Chris

 

[Andy Dingley]

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

Handsaw usually, particularly softwood. Handheld circular in 12" oak.

If you want accuracy, Japanese ryoba saw

 

[dent]

I was bored the other day (= putting off awkward job!) and was musing on
my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two cuts (the
steep angle short cut).

But I've never seen such a saw that can cut much more than a 45 degree
cut by tilting the cutting head - in fact if it could the piece would
probably foul the head and the depth of cut would be too great.

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

I've just done 10 of these for my extension. I used the mitre facility
of an SCMS to cut as far through as I could from each side, bringing
the blade as close as I could to the inner corner of the birds-mouth
without overcutting. In the corner the cut depth will obviously not be
full thickness, but it's an easy job to just finish off with a panel
saw which will be guided by the rest of the cut.

dan.

 

[Tim Watts]

Handsaw usually, particularly softwood. Handheld circular in 12" oak.

If you want accuracy, Japanese ryoba saw

<googles>

http://www.axminster.co.uk/product.asp?pf_id=364249&src=froogle

I see- that does look a most interesting device.

Thanks Andy - font of all knowledge as usual - I've learnt something

So knowing a handsaw is a common approach, the best thing (for me) might
be to make up a cutting jig from two bits of ply screwed to a 2" spacing
batten with slots to guide the saw. That would ensure quick setup and
repeatability.

 

[Tim Watts]

I've just done 10 of these for my extension. I used the mitre facility
of an SCMS to cut as far through as I could from each side, bringing
the blade as close as I could to the inner corner of the birds-mouth
without overcutting. In the corner the cut depth will obviously not be
full thickness, but it's an easy job to just finish off with a panel
saw which will be guided by the rest of the cut.

dan.

Yes, I see. Presumably, your SCMS goes to > 45 degrees on the mitre?
Sadly, mine doesn't.

Or do you make a wedge for the fence?

 

[Tim Watts]

I was bored the other day (= putting off awkward job!)

<Long rant>

Now I know why I was putting it off...

Last of the remedial work on the flooring joists...

Stacked 4x2 on top of 4x2 ceiling joists. Needed to pack one up (New
flooring joist in effect) and the other existing one was badly twisted
and split to buggery at one end - bad fit for the flooring on top.

Anyway, bought some PAR 4x2, finished depth 94mm or so. This happened to
be a perfect fit for the new "extra" joist I wanted. Glued and screwed
on top of the old ceiling joist and it is a perfect level with the
adjacent joists.

OK - so now to the buggered one. Can't remove it entirely - too many
nails, goes under the dormer beam, likely to smash the ceiling doing so.

OK, methinks, I'll cut the top 4x2 about halfway along (where it isn't
twisted) and scarf joint in a new piece. Won't be much worse than the
old one as that was just more or less acting as packing anyway as it was
so knackered. And I'll bolt though an 8" long tapered scarf joint with 3
6" screws and glue the lot, glue and screw it to the ceiling joist, then
plate it with ply for good measure. Should be nearly as good as an 8x2
then... (we like to raise bodging to an art form here).

Cut out old piece (1.9m), removed fairly easily (2 nails), some amount
of buggering about with a jigsaw, electric plane and hand plane and
managed to form one half of one of these quite well into the top 4x2
(note ceiling rafter underneath is fully intact, nothing is falling down):

http://photos.oes.org/albums/userpics/10002/normal_scarf_joint.jpg

(Mine has a 1:8 angle).

Come to mark up a piece of 4x2 PAR to cut the matching joint and what!??
The top would be 1/4" under the level of the adjacent joists???

Feck knows what's going on. Same 4x2 PAR as I used for the other joist.

Nothing for it - abort job, run down Alsfords tomorrow and see if they
will plane me something that's correct while I wait...

Yeah, I could use what I have and shim it for flooring, but I think I
have quite enough bodges without adding another!

Bllrrp

 

[Tim Watts]

I was bored the other day (= putting off awkward job!) and was musing on
my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two cuts (the
steep angle short cut).

But I've never seen such a saw that can cut much more than a 45 degree
cut by tilting the cutting head - in fact if it could the piece would
probably foul the head and the depth of cut would be too great.

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

The traditional way it to start with a pattern rafter - then use that to
mark all subsequent ones.

Ah - that seems like a good approach.

Decent jigsaw was the way I went. With an aggressive blade and some
pendulum action you can chop lumps out of 4x2 (or whatever) at a pretty
high rate.

I might use this as an excuse to buy a decent jigsaw with a stable foot
plate.

Ta

Tim

 

[Tim Lamb]

I was bored the other day (= putting off awkward job!) and was musing
on my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two cuts
(the steep angle short cut).

But I've never seen such a saw that can cut much more than a 45 degree
cut by tilting the cutting head - in fact if it could the piece would
probably foul the head and the depth of cut would be too great.

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

Umm... not tried it but how about clamping a set of rafters together,
tacking on a softwood guide and using a hand held circular saw?

regards

 

[Tim Watts]

I was bored the other day (= putting off awkward job!) and was musing
on my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two cuts
(the steep angle short cut).

But I've never seen such a saw that can cut much more than a 45 degree
cut by tilting the cutting head - in fact if it could the piece would
probably foul the head and the depth of cut would be too great.

OK - so how do people do cuts like that, especially when you need lots
all the same fairly accurately?

Umm... not tried it but how about clamping a set of rafters together,
tacking on a softwood guide and using a hand held circular saw?

regards

Ah, the quick way - mass production

 

[dent]

Yes, I see. Presumably, your SCMS goes to > 45 degrees on the mitre?
Sadly, mine doesn't.

Ah yes. 57 deg so just about okay for a 38 deg roof!

Or do you make a wedge for the fence?

I do that sometimes. I've got a selection of wedges of different
angles.

A recip saw might be another option. Same idea as a jigsaw but better
able to tackle the thicker timber (although a better jigsaw than mine
may be able to cope with 50mmm timber).

dan.

 

[Tim Watts]

;-) you won't regret it. The difference between a jigsaw and what most
people think of as a jigsaw is astounding.

Something like:

http://www.lawson-his.co.uk/scripts/details.php?cat=Jigsaws Makita&product=63320


With a 3 stage pendulum, it cuts fast, and the solid cast base plug
decent mechanics mean its a smooth and precise as a sewing machine.

That looks the business - Think I shall get one Thanks for the tip.

 

[Tim Watts]

A way to get a joist out of the way without wreaking the ceiling:

Sounds extreme but, chainsaw it into 1 to 2 foot lengths, then twist
each lump sidewards - that either pulls the screws or nails out of the
wood - or pulls the heads through the plasterboard. Leaves the ceiling
below generally undamaged (as long as you don't hit a nail with the saw!).

I had to do this with one ceiling joist on my loft conversion, and was
surprised just how clean and easy it was.

Interesting.

The ceiling isn't fixed to this one though. This is the one on top of
the ceiling one - unfortunately it goes tight under (and is nailed) to
the dormer end wall base beam and then goes another 2 foot into a small
void under my electrikery onto the external wall plate where access is
difficult and wielding any sort of saw is almost (probably) impossible.

That's why I defaulted to replacing half of it, though not ideal. It'll
be OK - scarf joint, plating and extra noggins will leave it stronger
than before

 

[The Medway Handyman]

On 21/05/2010 12:03, Tim Watts wrote:


I was bored the other day (= putting off awkward job!) and was
musing on my shed I might build next year from scratch.

I was considering some of the joints, in particular, the birdsmouth
joint at the base of the roof rafters[1] to wall timber.

Now, my sliding compound mitre saw would manage one of the two
cuts (the steep angle short cut).

But I've never seen such a saw that can cut much more than a 45
degree cut by tilting the cutting head - in fact if it could the
piece would probably foul the head and the depth of cut would be
too great. OK - so how do people do cuts like that, especially when you
need
lots all the same fairly accurately?

The traditional way it to start with a pattern rafter - then use
that to mark all subsequent ones.

Ah - that seems like a good approach.

All I can think is good jigsaw or handsaw (latter obviously the
way it used to be done).

Decent jigsaw was the way I went. With an aggressive blade and some
pendulum action you can chop lumps out of 4x2 (or whatever) at a
pretty high rate.

I might use this as an excuse to buy a decent jigsaw with a stable
foot plate.

;-) you won't regret it. The difference between a jigsaw and what most
people think of as a jigsaw is astounding.

Something like:

http://www.lawson-his.co.uk/scripts/details.php?cat=Jigsaws Makita&product=63320

With a 3 stage pendulum, it cuts fast, and the solid cast base plug
decent mechanics mean its a smooth and precise as a sewing machine.

Alleulah. Praise the Lord. Its a jigsaw Jim - but not as we know it.

 

[The Medway Handyman]

That looks the business - Think I shall get one Thanks for the tip.

Mr Rumm made bullied me into buying one a while ago - its the dogs bollox

 

[Tim Watts]

When I did my first workshop, I planned for a 30 degree roof. But when
building it, it looked "wrong" (probably because you could see it next
to the neighbours one), so ended up reducing it to 20.

The plan:

http://www.internode.co.uk/workshop/plans.htm

The adaptation:

http://www.internode.co.uk/workshop/images/outside.jpg

Very nice 20 degrees looks good. I'd probably use that sort of angle
for the top section of a gambrel, or maybe 15.

I had a look at some shed plans online (free ones) and there are a lot
that don't bother with the diagonal bracing which seems surprising.

I like the idea of leaving a gap between internal lining and insulation
for wiring.

 

[D.M.Chapman]

http://www.lawson-his.co.uk/scripts/details.php?cat=Jigsaws Makita&product=63320

Mr Rumm made bullied me into buying one a while ago - its the dogs bollox

Heh, it's next on my buy list as well. You bullied me into buying the
impact driver last year for deck building (again, mutts nuts) - decent
jigsaw this year


Darren

 

[Tim Watts]

Here's what all the fuss was about

The new half-joist glued and screwed:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0004.jpg.html

Screwed with 6" Paslode screws (they're GOOD):
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0010.jpg.html

Surprisingly, my little Bosch screwdriver could handle them, almost with
drill to finish:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0011.jpg.html

(I did drill pilots, especially near the ends of the timber but they
will go in softwood without)

Joint detail after cleaning off excess PU glue:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0013.jpg.html

Other end, before cleaning:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0001.jpg.html

Oooh - notice the large knot in this (yes it goes right through):
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0014.jpg.html
Not sure how string that was... And the bit of 4x2 above that had split,
large lumps missing, hacked to buggery - and it's in front of the door
so it gets all the foot traffic)

Here's that other one, the "new packup" I did last week - for this
regular PAR worked for size:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0022.jpg.html

Here's some of that plating I've been doing:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0008.jpg.html
and a finished (both sides) also supporting a notch infill:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0015.jpg.html

And why I'm plating:
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0017.jpg.html
(The one at the back - with the big notch - others like that one have
5x2" notches!)

And just to show the whole place isn't falling down, here are some they
did properly to start with!!!
http://photos.dionic.net/v/public/bungalow/2010-05-22-img_0021.jpg.html
(4 full span 8x2's in perfect condition)