Here we go again with some curves

[ScottyT]

Well, apparently my next job was casements, and that just went out the window (pun intended of course) when a chap wanted a building/arbour type folly ASAP, and I was the only one available at the time.
It would seem just lately I’ve turned into a carpenter who prepares his own timber as opposed to a bench joiner.

I’ll do this in two or three hits as and when I can.

Here’s the drawing I have to go off of, unfortunately the sizes changed so it was reference only really, the overall width changed which in turn rendered all the radius’s and widths shown useless, never mind though I enjoy making rods anyway.

Essential to any joiner worth his salt. A fantastic pair of eclipse trammels. Made in England of course.
The go to tool for starting any curved work. I am working on the keystone and arches here to fit inside the middle of the arbour, it’s a 4 sided building so x4 of these to get out.

A drawn out one to one of the arches, from this rod I can now get my template out and make all necessary marks for machining.

Rout the template out

Stick it on the rod, here I have used 3 squares to mark the flat edge that’ll butt to the inside of my posts, if you get this accurate you can let the spindle take out the straight edge so it’s done in one. As a side note I would usually put a tenon on here instead of a butt joint but the way in which it’ll be assembled would make this very tricky indeed.

The edge has been put on the template and follows the rod lovely

Job done. Moving on

I started with the roof plate as I was waiting on lumber and that’s all I could get on with, we were that low I had to use 3 pieces to make up one side. A shame but what can you do, can’t have it all

Mitred corners ready to roll

The lumber arrived so i dogged into some posts. 12 required but settled for 6 at a time, titebond was flying on here as it goes off pretty quick in 35 degree heat they are loose tongued 120 square about 3 metres long atm rough cut. I’ll set them aside for a later date. They have some type of plinth/skirting on the bottom of them as shown here, it machined quite nicely considering I was using some really knarley iroko.

I had all the lumber I needed now to make my ring beam, roof plate and rafters. I started with the boss, a quick sketch on some mdf to give me a size and positions of my Mortices. I went for a 7/8 chisel just for that little bit more meat on a 44 rafter.

 

[ScottyT]

A very simple boss, around 200 square so two pieces of 4” laminated does the trick here

Here’s the boss laminated, planed, 45ed, and ready for some mortices

Morticing done, 7/8 chisel 8 moritces to revive 4 commons and 4 hips.
To anyone who is interested, this a Wilson morticer that we have adapted to be pneumatically assisted via the two rams fixed to the main casting and then onto the chisel slide. A wonderful wonderful machine. I have been hammering this machine for the last 15 years as has many many other people and it has never ever missed a stroke.

I machined a top cap now (usually something i would probably leave until the end) to get better accuracy of the finished height, far better than speculating
Now the boss is done. The plate is mitred and there is wood aplenty it’s time to have a look at these rafters. I’m no carpenter but I do enjoy these cut roof type affairs.
The main ring beam is a necessity here to ensure absolute squareness, it is square to within 0.5mm, spend time here and save a heap of trouble down the road. Square is paramount.

Roof plate attatched to my main ring beam, on dummy posts.

Here is a better shot of the dummy posts (identical to the full length posts that will be used ‘on the day’) showing the ring beam, which is 7/8 Morticed and tenoned into the posts.
My trusty string line is used to go from corner to corner to find dead centre, I can then get my plum bob off the boss to easily find it’s resting place.
I use a ‘squaring rod’ which is no more than a long stick to get spot on square, only then will I clamp down and proceed. I treat this job and any other job I do as if I were making a standard 4 panel door. Think square.
The curved rafters are now ready to look at.
Lovely

 

[foxbat]

Brilliant! My head hurts just looking at the photographs

 

[Stuart Moffat]

Superb. I look forward to seeing the end result!

 

[Blister]

Ruddy Nora , Wow , blimey , Am I impressed , You bet I am.

 

[Fred48]

I'm really enjoying your posting. Thanks for sharing

 

[ScottyT]

Thanks for the kind words. It’s time to get a little more in depth with these rafters. I have 4 commons and 4 hips to get. It starts the same way as any curve work I do. Working from a set height and width that I rod out on MDF and my good friends the Trammels.
This is double curved, so I need a radius for above and below, it’s trial and error until the sweet spots are found.
It is possible to rout the templates for a double curve in the same manner I have shown above for the arch curves, all that is different is I leave a small portion where the two lines intersect in the middle and finish that up with a spoke shave to get a really good blend between the two curves.
The alternative is to just simply bandsaw out as accurately as the hand and eye allows and spoke shave the finish. It is important to have a smooth edge on your templates as any bumps, wobbles, digs or rises and falls will be put directly from the template on to your workpiece via the ring fence (or router cutter etc etc)
One the template is out and I am happy with where I am going it’s out to the timber rack in search of lumber. The rafters are finished at 44 thick x 150 deep. So that’s a rough sawn board 2” thick by whatever is wide enough. Just simply stick the template on we’re making inroads.
A little video I hope will explain things a little clearer

That’s the MDF template on the right hand side with the holes in it (for Morticing at a later date I’ll go through that when i am at that stage)

It’s just the rite side of being safely manageable for just me to work on all of this, we do have a new chap who fancied a change of career (he was a basket maker) who has been on and off with me as and when I’ve needed two more hands and he’s been an excellent help.

Here’s one after bandsawing, epic amount of waste in this type of work but it keeps me warm in the winter months. And some of it is still big enough to be repurposed for other jobs.

Here’s the 4 commons that have been band sawed, surfaced over the planer (the one pictured) and thicknessed finished size. When bandsawing a curve out in preparation for the spindle There are a few things to consider, taking into account direction of grain, long and short grain, splits and shakes that could be avoided by placing the template in a different position and how much material to leave on the edges to be machined off. All of this comes down to experience and doing it time and time again. On a large piece like this 2-3mm on either side is no problems for the spindle and afford me a little richness in the casting during the band saw process.

A basic overview of the spindle set for profiling (or ring fencing) my curves, or any other curve for that matter. I’ve made cradles in the past that allow mouldings to be put on the faces of curves too, it’s a fantastic machine the spindle, possibility’s are very very broad on what they can do.
I’m running a 50mm rebate block under the brass ring in which my template will hit and follow.
My square is showing that the ring and block are in line with each other, meaning if my template is 150 wide and it follows the fence at its closest point to the block the work piece will also finish 150 wide. If the ring is set too far back it’ll cut into the workpiece more and finish narrower, and oppositely if it’s too far forward the work will be too fat.

Template tacked on we’re ready to roll.

And here I am this pretty much shows the long and short of it on the machining side of things.

The edges profiled up, I also machine the end grain, vitally important to the process that I’ll explain that when it’s more relevant later on.
We are now getting to the stage of hitting the tenoning machine to fix into the boss I made near the start.
Hope I am being fairly clear on the processes here!

 

[ScottyT]

Oh, the template is quite clearly on the left hand side

 

[ScottyT]

Onto tenoning the rafters now, the commons are first up. 40mm tenons going into the boss, and I have to cut a notch out of the roof plate to allow the seat cut to travel down the main beam.
There is a few ways i could of done this but decided the most accurate was a 1:1 rod taking about 10 minutes.
Overall width and overall height, divide the width by two, draw half the boss in off the centre line at the correct height and offer the rafter up. Strike all the lines and set the tenon machine.

I mentioned the importance of matching the end grain off of the template during the spindle stage, and here’s why. All my rafters are machined off of the same template, so are all as near as identical to each other as is possible using these machines.
This allows me to set up one rafter to exactly how I want it to be, cramp blocks on the tenon bed and set the depth stop. With those things in place all I need to do is offer the next rafter up and if all is well they’ll be the same.

Here’s the notch I needed to take out of the plate on each side, this will allow the birds mouth to sit snug to both faces.

The tenons were machined to a nice fit, not tight and not sloppy, this greatly helps in assembly. Too tight a tenon is a real no no, it’s promotes twist, can knock things out of square if you need to beat it in and puts strain and tension in all the wrong areas (including the joiner and surrounding crew ) I always go for a ‘relaxed fit’ as it’s easy times all round.

So with all 4 commons tenoned, i can loosely assemble the rafters and make an offering up on the plate, to get a feel for how it’s sitting and see what the state of play is with the shoulders on my tenons.
It all looks sweet as it stands here, so i can mark the plumb and seat cut for them and sink it into place.

It’s the hips next, they hate longer of course as they are running to the corners, but need to run in the same plane as the commons. It’s fairly simple to get the template for it, it involved a sheet of mdf and a level.
By offering the sheet up to the boss and running over to the roof plate at 90 you have got a span and height that can be marked. The in between bits are taken from the common rafter and holding a level on top of it ‘level’ and ticking where the edge of said level hits the mdf. Mark it every 6 inches until you reach the bottom and connect the dots. Bingo I have my hip template.

Hips machined in exactly the same way as the commons, all the angles were different but the theory remains the same.

Decent shoulders on the joints, we’re within a nats whisker top to bottom on the boss so that’s good enough for me.

Slightly trickier in the corners to cut the plate as it lands on the shoulders of the posts, a bit of hand tool work here to create a 45 face 90mm down. This saw was my great grandads, he was a pattern maker and I was fortunate enough to inherit some really good quality hand tools that have been handed down through the generations. It stays sharp for ages even whilst using iroko, I have sharpened it 2x in 4 years of heavy use. (Saw sharpening should be taught at college in my opinion)
Great stuff.

The rafter is marked out here ready for cutting. Once i am happy this hip fits nicely I shall use it to cut the other 3 as my template.

 

[baldkev]

Looking great you also did the one a while back with the circular ring on top?

 

[ScottyT]

Looking great you also did the one a while back with the circular ring on top?

Yeah that’s rite that one had 4 rafters to a round boss, and two elliptical hoops to go over the top. Way more work that was, it took an age but jobs like that often do with me

 

[ScottyT]

The hips are all cut in now and it all runs through just the ticket. The last photo of the 90 degree on the end of the hip rafter I put in alongside the photo below just to show how many tools it takes to make that 90!!

 

[rogxwhit]

It's a pleasure to see all this unfolding of logic when someone else is doing all the work!

 

[pe2dave]

For me, this is woodwork that I'd love to do.
Oh that I was offered an apprenticeship at 16!

 

[ScottyT]

For me, this is woodwork that I'd love to do.
Oh that I was offered an apprenticeship at 16!

Did you turn down the opportunity for a career in the trade or was it never even on the radar?
I started my joinery apprenticeship when I was 18, did the 3 years advanced NVQ etc and have been doing it ever since. After 14 years I still have a lot to learn and that’s what makes it.

 

[pe2dave]

Did you turn down the opportunity for a career in the trade or was it never even on the radar?
I started my joinery apprenticeship when I was 18, did the 3 years advanced NVQ etc and have been doing it ever since. After 14 years I still have a lot to learn and that’s what makes it.

No, never had useful career advice and hadn't a clue at that age. From my reading, when asked what I wanted to do by the youth employment, I asked about whaling (in mid Yorks) which received a blank look. Oddly they guy had literature about trawler training, so my first job was 18 hours a day, 7 days a week on deep sea trawlers. No job has ever seemed 'hard' after that!
20 years ago I helped renovate an 'old' watermill (unpaid). The joy of working on big timber. I'd have paid the guy for that

 

[ScottyT]

onto the 4 arches now that I rodded out at the start, variation on the same theme here really.

The arches have to sit in a very specific place within the posts (dead centre) but the keystone is being used to attach the arches to the ring beam above so it took another little 1:1 drawing to work out where it all lands.

Here’s my template, I used the rod to get my dimensions and went up the top of our yard to where the 4” is kept.
Rough cut 5 bits with the chainsaw (1 spare/set up piece) and it’s ready to mark around, bandsaw and plane and thickness to finished size.

I would usually spindle these on the ring fence but it was in use so I had to use a router with a top and a bottom guide. I’m not a fan of this method but needs must

Once I have the keys machined all round It can be offered up to the rod, marked and then morticed using an 1” chisel

All that’s left to do on these now is to remove a large section of the top of this key, to leave a 5/8 thick ‘wing’ that’ll go behind the ring beam and up under the plate. This will be used as a fixing point for the top of the arch!
I marked the shoulder line, cut to a set depth leaving about an eighth on the bottom, bandsawed the waste off leaving the same amount.
I then went below my workshop where we have an Overhear Router, and I made a simple jig to ‘mill’ off the excess down to exactly 5/8. Worked a treat and it is very accurate and fast. This machine is a superb piece of kit, insanely accurate and versatile.

I couldn’t allow the fluted cutter to go dead up against the shoulder here as I would have been asking for trouble, so I was left with a little 90 degree ridge to finish up by hand, it’s not often I get my 2” Marples out, but when it does it always makes lite work of it. Rare to find them in this size now, I think the hand forged ones are 20-30 years out of print. Never to happen again.

That the keys done with for now, drilling and sanding to go but I won’t do that until the curves are machined to them. Time to get some curves fitted into them now

 

[ScottyT]

Back up the top in and around the 4” to get 8 curves for arches with the template I got out at the very start.

Template on, draw round etc etc your getting the drift here……

All 8 plus a spare ready to roll down to the bottom of the yard into the machine shop

Band them, plane them and thickness them to finish size ready for the spindle

Time to spindle them now, as with any machining care must be taken, but in these instances extra care is to be implemented as we have 85mm of iroko (it’s a very hard timber with pretty grim grain in places) to face up using a 4” rebate block.
I machined them in two passes to keep a nice finish with no lumps and bumps.
All end grain was spindled too so they are all the same, that makes tenoning a doddle.

This is the amount of material I leave on from the band saw to allow me to machine the faces up.

Ready for facing

First pass

Faced up fully

Done.

Tenoning machine please

 

[ScottyT]

It’s now a simple task of marking, checking, setting, machining, checking again on we go……

This curve is scrap so i am not bothered about is not being pretty, it’s just to give me my settings for the 8 proper jobs.

Not a million miles away for the first offer up. We shall see how it goes on the other side

 

[ScottyT]

The arches are now finished (pretty much) so here’s a quick run down on the finished article. I did a few short videos to better explain the fundamentals, much easier than explaining it

Taking my original template for cracking the curves out, I drew the detail on so I could get accurate repetition on all 8 by just placing the template to the shoulder every time.
Mark round it, cut with a portable band saw as I can get that well into the tight spots leaving a mil or so on for routing off. They are 80 thick or close to it so I used top and bottom bearing guides on the router to finish it

Rough cut with the band saw first

First hit with the top mount bearing guide

Full hit done, a rasp, a file, and some sand paper will finish this up a treat.
The curves are stop chamfered, I just came in 2” from all shoulders and cracked them off.

Chamfers on and the detail on, these just need sanding all around and two half inch counterbores on the bottom (taken from the rod, it’s all marked on there) and then we’re nearing the final stage.
The keystones have to have little slots cut at the top of them to allow them to avoid the common rafters.
I made a simple jig to do this as they have to be accurate, it takes longer but it’s clean and easy.