Oak pergola (finished, with a twist)

[Mike G]

This is going to be image-heavy.

In the scheme of things, building a pergola isn't very high on my list, but I have the wood (bought last year when I did the garage), and I haven't got any seasoned oak yet so can't do what I really want to be doing. This is going to be a bit detailed, to show hand-tool working on larger pieces of wood. Before the woodwork, though, there's always a drawing:



It's about 4 metres long and 2.4 metres wide. I have hidden a design detail which I am going to save as a surprise for right at the end.

This timber is small enough (around 3" square) that I can plane it up through my thicknesser, rather than doing it laboriously with a plane and belt sander. That's a luxury you don't normally get with oak framing.

My workshop has a hatch in the end for this very purpose:



This wood is OK, but not straight. It is varying thicknesses, too, and I made no attempt to square it up or straighten it. It just went through the thicknesser until the faces were clear of saw marks:



After selecting which piece went where, I cut them all to length:



As always, I worked on the setting-out plates first. All the pieces, as you'll see in the drawing, have a fancy end on them. This is the 3rd or 4th iteration, and a trial on some scrap:









When I say these pieces aren't straight, take a look at the winding sticks here:



I have decided to just work everything square from the bottom face, making no allowance for any twists etc. I'll be able to pull these thinner bits of timber into the proper alignment as I erect the construction.

After roughing out the end shape with my frame saw, I used any and every tool I thought might help to bring it to the final shape:



There are lots and lots or mortices in this structure. Here's how I do mine (in green oak framing):







Note I leave the ends to last. Everything is cleaned out and neat before I tackle the ends, so that levering waste up doesn't destroy my lines.

Sneaking up on the lines, using Mike's Rule of Halves:







Rinse and repeat for all 6 posts. Then, on to the tenons:



Again, Mike's Rule of Halves comes into play. Cut the shoulders, then chisel away half the waste:



Then half again:



........and half again



.....and again:



Before the final clean-up using the scribed lines:



Two minutes work.

A huge deal with repetitious work like this is to always know where you are and what you are making, so all joints are carefully labelled. It's really easy to get confused and work from the wrong end or the wrong face, when all the bits of wood are the same:



First time fit, as it was for all 6:



Here's why you start only at half way:



The grain here is running into the joint, so that calls for a lot of cross grain chiselling, rather than chopping in from the end.

On the top of one of the long plates was this nasty knot:



That would be a real weakness if left, so I did a Dutchman:





That latter photo shows the drill marking out the correct size circle for me. On to the bandsaw and then belt sander:





The secret is in the taper:



Then smear it with glue and bash it in as hard as you can:



The following day clean it up quickly with chisel and plane:



It's only at that point that I remembered I've got a lathe, and I could have turned the plug.

That should keep the rain out for a few years.

That's all the mortices and tenons done:



The top cross-pieces are half lapped (well, quarter lapped) into place. Each piece of wood is a differing thickness, so each joint was bespoke. Here's the kit:



And here's the result:



The dial gauge is used only as a useful caliper. I don't read the measurements, but just set it to the width of the wood, then the opposite jaws, which face out, are used to mark out the locations of the saw cuts for the half-laps. With pieces of wood this size there is no possibility of offering them up into place to do your marking.

There's 10 of those, so twenty of these to cut. The ones facing up are only 10mm deep, and the ones on the cross-pieces facing down are 25mm deep, meaning that the bottom face of the cross-piece should be about halfway down the face of the plate.



Next time I get into the workshop it'll be to tackle the braces, and I've still got the fancy ends to cut on the cross-members.

 

[Malc2098]

Nice.

 

[AJB Temple]

Good sequence. I use similar methods. Usually thicker wood. Brilliant that you do photo sequences like this. Never occurs to me until I have a coffee break.

Not fond of spade bits though in corded drills. They catch too easily.

 

[Cabinetman]

The rule of halves, they used to use that in gambling in the long-distance past but that was for silly beggers it’s also used of course when splitting slates or shingles as I found out when I tried to make my own shingles, I thought how difficult can this be just split it off, no doesn’t work, much much better splitting a log in half and half again well you know the rest. I don’t blame you not trying to make everything square Mike, it’s horses for courses it’s a pergola not a fine piece of furniture. You’re working at a cracking pace as always.

 

[johnward]

Very interesting Mike. The photos are excellent. A pergola is on my very long list so probably won't get done!

John

 

[Mike G]

........Not fond of spade bits though in corded drills. They catch too easily.

I love them......but you really do have to be aware of their potential to break your wrist.

 

[AJB Temple]

:lol: Exactly. When I made the first twin bay oak building here, used a 110v very good Makita drill I got from an oak framing guy Ben from the other place (he gave up and I bought his gear). Was cutting some one inch peg holes in 10" oak and the spade bit caught and whipped the drill round faster than I could ever react. Got lucky as it yanked the cord out of the transformer as it wound up.

Usually use Auger bits now. They guide better when running deep.

 

[Mike G]

The problem with auger bits in a power drill is that they are hard to stop at a set depth. They pull themselves in so fast that you'd need a proper mechanical depth stop to prevent them drilling all the way through the wood. I have 70ish mm wood here. 55 depth of mortice, and above, a 10mm deep half-lap. That leaves 5mm spare. The spade bit can be stopped at precisely the right depth just with some tape on the shaft as a depth indicator.

 

[Alf]

Mike, your w'shop's too tidy and you work far too fast, but other than that :eusa-clap:

 

[Dr.Al]

The problem with auger bits in a power drill is that they are hard to stop at a set depth. They pull themselves in so fast that you'd need a proper mechanical depth stop to prevent them drilling all the way through the wood. I have 70ish mm wood here. 55 depth of mortice, and above, a 10mm deep half-lap. That leaves 5mm spare. The spade bit can be stopped at precisely the right depth just with some tape on the shaft as a depth indicator.

I seem to remember in one of the Tally Ho episodes, Leo ground the screw part on the end of his auger bits into a simple unthreaded cone for exactly that reason: so he could control it more easily in an electric drill.

 

[MY63]

Thanks for taking the time to show how you make your joints, At school we were taught to use a saw to cut the cheeks of the tenons. I see the advantage of your method. I need to find time to practise my joints.

 

[TrimTheKing]

Following with interest. Now we're staying at this house a pergola over a new seating area is on my list for this spring/summer so looking forward to seeing this pan out, and there's a strong chance I'll just copy it!

 

[AJB Temple]

It's why I use an 18V powerful battery drill Mike these days. I can set it to run at very low speed. But fully understand given the dimensions you have there. For shallow stuff, especially repetitive such as setting in lots of rafters into mortice sockets (probably the wrong terms), I often use a router as it is neat, precise and cuts down on chiselling. I have a WIP to post on my most recent oak build showing this, but it will wait until the forum is updated for drag and drop.

 

[Mike G]

Thanks for taking the time to show how you make your joints, At school we were taught to use a saw to cut the cheeks of the tenons. I see the advantage of your method. I need to find time to practise my joints.

If there is a horrible knot through the tenon, then occasionally I'm forced to pick up a saw. It's just such incredibly hard work, and so slow in comparison. Of course, you do whatever you can to avoid knots in tenons in the first place.

 

[Mike G]

The problem with auger bits in a power drill is that they are hard to stop at a set depth. They pull themselves in so fast that you'd need a proper mechanical depth stop to prevent them drilling all the way through the wood. I have 70ish mm wood here. 55 depth of mortice, and above, a 10mm deep half-lap. That leaves 5mm spare. The spade bit can be stopped at precisely the right depth just with some tape on the shaft as a depth indicator.

I seem to remember in one of the Tally Ho episodes, Leo ground the screw part on the end of his auger bits into a simple unthreaded cone for exactly that reason: so he could control it more easily in an electric drill.

Did he? I missed that bit. I have some wonderful new augers which I'm reluctant to tamper with, and some wonderful old ones for which that would be sacrilege. What I would need would be some grotty new ones, damaged...but I don't have any.

 

[Mike G]

.....Mike, your w'shop's too tidy and you work far too fast, but other than that :eusa-clap:

You're too kind, Alf.

 

[Dr.Al]

The problem with auger bits in a power drill is that they are hard to stop at a set depth. They pull themselves in so fast that you'd need a proper mechanical depth stop to prevent them drilling all the way through the wood. I have 70ish mm wood here. 55 depth of mortice, and above, a 10mm deep half-lap. That leaves 5mm spare. The spade bit can be stopped at precisely the right depth just with some tape on the shaft as a depth indicator.

I seem to remember in one of the Tally Ho episodes, Leo ground the screw part on the end of his auger bits into a simple unthreaded cone for exactly that reason: so he could control it more easily in an electric drill.

Did he? I missed that bit.

I'm sure he covered it in a bit more detail in a later video, but it's mentioned in passing here:

https://youtu.be/Q02EG5y4bBk?t=962

 

[AndyT]

Brilliant, watching with interest.

Mike, one of these might be the perfect compromise between power tool and hand tool for this sort of work - it's what they were made for after all.

 

[Mike G]

Yes, it would Andy. That'd be perfect. Unfortunately, I don't have one.

 

[Mike G]

I grabbed an hour or so in the workshop this evening, and started on the arched braces. I found some spare 3mm ply, and set out the pattern from my drawings:



If using this method to create a curve, it's important to flip the bow over and see if it is uniform. It wasn't:



So, I picked the lower curve on both sides of the centreline, and cut to that. I then flipped the off-cut over, and noted where it touched, and adjusted with a spokeshave:



The lines designating the ends of the shoulders of the tenon are the most critical on the entire piece, so I cut these with a fine tenon saw. The rest wsa done on the bandsaw and cleaned up with a spokeshave:





There are two slightly different braces because the cross members at the end are raised in relation to the longitudinal plate, so I made the second pattern in the same manner as the first. The critical geometry is the right angle bewteen the shoulders, so particular care is taken there:





I have quite a lot of 9x2 oak to cut these braces from. Braces are very wasteful of timber when cut from straight boards, but these days, unless you mill your own wood yourself, you're never going to find anything else.

 

[kirkpoore1]

Great project as usual, MIke. For the end cleanup on your top rails, I think a spokeshave would have helped a lot, especially one with a rounded bottom to get into the concave parts. I built one just for that, and it works very well. For drilling mortises, you can also consider a forstner bit for more control at the cost of speed.

On your cross-piece half laps, are you considering varying the depth to counteract for twist?

Kirk

 

[Phil]

Nice work Mike

As said somewhere before "your speed of work" - I would have a heart attack

 

[Mike G]

Great project as usual, MIke.

Thanks Kirk.

For the end cleanup on your top rails, I think a spokeshave would have helped a lot, especially one with a rounded bottom to get into the concave parts.

I used one. I've got a nice rounded one. The problem is the wood is 3 inches wide, and that's really a bit much for a spokeshave.

On your cross-piece half laps, are you considering varying the depth to counteract for twist?

No, I'm going to wrestle the twisted timbers into compliance. They are long enough and skinny enough that I'm just going to rely on 7 pegged M&Ts to get them into place and hold them there. The half laps will also help hold them twisted-out-of-twist.

 

[AndyP]

Great to watch you work as always.
Kinda wishing that I had saved up and built mine from oak rather than pine.


Edit: I wonder if I can convince the missus that what I built 3 years ago was just a prototype.

 

[AJB Temple]

Forget that Andy. We have an old pine Pergola here. Must be 15 or 20 years old and still survives. Not built by me and hence is basically screwed together rather than made properly, but I reckon you have at least 10 years life left in your. However, I won't let on to Valerie :lol:

(My plan is demolition and put a new workshop there. However, this is top secret.)

 

[Mike G]

Apologies for the snail's pace here, but I really have had no decent runs at this, just the odd hour here and there. I think we'd got as far as templates for the knees. So the next job was to toddle off to the woodpile and cut out the blanks, armed with a pencil, the templates, and a circular saw:



After thicknessing, the template shapes were transfered to the blanks using a pencil for most of it, but a knife for the ends of the shoulder line, which is the only critical part of the piece:



The basic cutting out was then done on the bandsaw:



It's a very wasteful way of making braces, cutting them from straight:



One pair of shoulders was carefully marked by hand (with a straight edge and knife) on one face on each knee:



There's 12 of everything:



This wood is still green, but I've had it for 7 or 8 months so it isn't as green as normal. Forgive the upside-down image:



And here a knife mark raises water from the surface:



Absolutely standard stuff when working with green timber.

I'd now got 48 cheeks to remove. I had the benefit of a mortise gauge for the first time in my life:



I don't know what this is called. I can't believe Saint Paul's "knife wall" is the correct term. Anyhow, I'd lots of them to do:



Followed by a saw cut defining the shoulder. This saw has a particularly coarse cut for a tenon saw, and is longer than normal, so ideal for this sort of cut in green timber:





Because I hate chiselling in a vice (all that bashing doesn't do them any good), I tried wherever possible to chisel horiontally, rather than aiming downwards towards the vice. Mike's Universal Rule of Halves applies, of course:





I'm entirely self-taught, and my teacher was, frankly, hopeless. I've got to my age without knowing this trick, picked up from Andy's thread a week or two back. I varied it by using a screw rather than a nail, which allows really fine adjustment:



I didn't plane much, to be honest. It's just quicker and easier to pare:





Note the colour of the newly exposed wood. A quick chamfer all round, then on to spokeshaving:





I love that wooden spokeshave, but I just couldn't get it to stay open enough for this wet wood. I ended up making it screw-adjustable:



Not all tenon cheeks are doable with a chisel:





Mabel was taking a keen interest in my technique:



It took about 45 minutes to an hour to do each brace. Here's the general scene of my bench during that time:



Lots of fire-wood was produced:



And lots of mess on the floor:



But at least I ended up with 12 braces:



I also ended up with some wood to be dated and put away to dry for a couple of years:



Now, onto the mortises into which those braces will fit. Remember, I will be wrestling the posts and plate into the place they should be if they were straight, rather than adjusting each junction to fit the wonky timber. So, I set out a right angle, and laid a brace on it carefully so as to take off the position of the mortises onto a story stick:



That stick was then laid on the post, using the shoulder as a reference, and the tops and bottoms of the mortice were marked:



Then chopped out in the usual way:





It fits!



Oops!! In the words of Mark Knopfler, one of them must be wrong:



Unfortunately, working by braille on the power-cut day meant I stupidly used the storey stick upside down. Only one thing for it:





That'll be where the rot sets in in a decade or three.

Each mortice was checked with a brace and straight-edge to see that everything lined up properly:



And this is where we are, with all the mortices cut. The middle posts have a through mortice, because they have a brace on each side. The "X" is my face mark:



Next, when I get the time, will be the mortices in the underside of the plates.

 

[AndyT]

That all looks very satisfying, especially when you can zip off a big slice in one go like that



I must get back to my bed soon!

(And it's nice to see Joyce's little depth gauge making an appearance.)

 

[AJB Temple]

I'm glad you're not infallible Mike :lol: I too have made exactly the same error cutting a mortice slot for braces. I may even have showed you the evidence Easily done when you are doing dozens of the things.

One annoying feature of green oak anyway is that these things start off as fitting perfectly and two years later a slight gap has appeared, despite pegs and an initial tight fit.

Very nice job on the braces. Last time I did this I used the band saw to get rid of most of the waste but your approach looks lovely.

Currently in a hospital bed, so plenty of time to surf the web

 

[Mike G]

....(And it's nice to see Joyce's little depth gauge making an appearance.)

I thought you were going to admonish me for defacing a spokeshave.

 

[Mike G]

.....Currently in a hospital bed, so plenty of time to surf the web

I hope it goes well/ went well (delete the inapplicable). Get well soon.

 

[AJB Temple]

Thanks. I've been sliced up and stitched up and a now resting up.

Surgeons approach to sharp tools I hear you ask. They just bin them and get a new one out.

 

[Mike G]

That's what they tell you. What they actually do is just give them a quick wipe on their sleeve, and get on with the next operation.

 

[Cabinetman]

Yeah, bit of spit as well, don’t spend too long in that hospital bed Adrian we want you back at it soon. Best of luck.
As usual Mike you are racing ahead and cracking on wonderfully. But it’s a shame you got your story back to front, a big dollop of paint on one end would help but then if you’re like me they don’t last long enough and it’s usually a fresh one for each job, — I use white wooden venetian blind slats, just happen to have a pile of them, 3 x 25 mm x 2 m and straight – perfect, first job tomorrow mark all one ends of them so thanks. Ian

 

[Alf]

....(And it's nice to see Joyce's little depth gauge making an appearance.)

I thought you were going to admonish me for defacing a spokeshave.

I tutted a bit over the use of anachronistic crossheads instead of slotted, if that helps. There's a fine tradition of sticking screws in wooden shaves to get the things to do what you want, so That's Allowed.

Anyway, looking good, Mike. Don't think much of these pathetic claims of untidy bench and floor though. You can still see them, can't you?!

Hope your recovery goes well, Adrian. And that the surgeon didn't get his story stick the wrong way round.

 

[Mike G]

....I tutted a bit over the use of anachronistic crossheads instead of slotted, if that helps......

I searched high and low for a small enough pair of slot headed screws, but they all seemed to either be too long, or the head too large. They will be swapped, I promise you, when I find something suitable to take their place.

 

[Phil]

Mike, looking good.

Nice write up and pics

 

[Alf]

....I tutted a bit over the use of anachronistic crossheads instead of slotted, if that helps......

I searched high and low for a small enough pair of slot headed screws, but they all seemed to either be too long, or the head too large. They will be swapped, I promise you, when I find something suitable to take their place.

Well I can sleep easier knowing that, Mike, that's for sure.

 

[AndyP]

Was Mabel taking pictures too? Nice to see a craftsman at work.

 

[Mike G]

I spent the morning chopping out mortises in the beam on one side. This is a dry fit:



The overlapping tenons where the pair of braces meet the middle post I dealt with like this:





And it all went together with a few good whacks of a rubber mallet:



That's going to be about it for a while, as I've got a silly week coming up in which I have to work all day every day. So, remember where I got up to.....

edit: I've titled this "dry fit", but of course, the whole thing will only ever be a dry fit. I guess I mean a non-pegged fit rather than dry fit.

 

[Craig Salisbury]

Nice work indeed Mike!