Designing For Laser Cutting

[28ten]

Guv',
Timber rafters,4"x2" and ceiling joists,4"x2", normaly fixed at 16" centres, youv'e shown a collar truss, 5"x 2," and these would be bolted to the rafters, the ridge board would probably be 7"x 1 1/4"

Col

Im thinking it would be easier to cut the lot in one go which is why the truss is integral, I could cut individual pieces and make a jig or am I going round the bend?I wasnt going to bother with ceiling joists it is only a parcels office.
A thin brass roof with the corrugated stuck to it should allow it to be lifted off whilst retaining some strength.
I have yet to make my mind up about the floor but im leaning towards concrete

 

[28ten]

If it's a corrugated roof then the beams would be lengthwise so the corrugations are at 90 degees to them, and this is where I could be very wrong but the gap between the beams are 1/2 the length of the sheet. In effect there is a beam at each end of the sheet for the overlap, and one in the middle. Having recently helped knock an old building down which had asbestos roof sheets about 6 foot long, there were 3 sheets to the fall and 7 cross beams. Having looked at the (leaking) roof in my garage today, they are set out the same.
Hope this helps.
Alan

Yes I see what you are saying they might be best left off so that it will be a bit less visually crowded when the roof comes off. I shall need to think about it.

 

[28ten]

Shouldnt look too bad

 

[Steve Cook]

I know I said I wasnt going to do any interior ..... this is my best guess at the rafters, based on Jaggard and the fact that it was a wartime build with a corrugated roof. Im guessing that 18" centers would be about right.

Getting carried away again? Excellent
Engine shed design is superb btw

 

[Dog Star]

I have yet to make my mind up about the floor but im leaning towards concrete

Oh no, please re-consider. You and your laser ought to be able to do a smashing job of a planked pine floor.... just think of the fun you can have in replicating splits, knots and cut-nails..... and then the weathering.

If you do add roof trusses or rafters then we shall all expect to see the light bulb and shade!

Appreciate the work going into this model, regards, Graham

 

[Rob Pulham]

Shouldnt look too bad

Now that has to be a major understatement - it looks fantastic.

I agree with Graham a plank floor would look the business.

 

[Ressaldar]

I have yet to make my mind up about the floor but im leaning towards concrete

granite setts would be a suitable alternative - or put another way - cobblers to concrete

Seriously though - all looking the dogs doo dahs.

cheers

Mike

 

[Eastsidepilot]

Yes I see what you are saying they might be best left off so that it will be a bit less visually crowded when the roof comes off. I shall need to think about it.

Guv'
Alan's correct, I missed the point of it being built at the out set with corrugated sheeting, they would of coarse be tranverse timbers. The timbers would have been housed into the brickwork at the gable ends.
If you do produce a conventional roof with rafters and tiles at any time then there would be a 4x2 timber plate on top of the walls with the rafters birds mouthed over them.
You mention cutting the rafters and collar being cut in one, the collar would be fixed along side of the rafter in reality so you'd have to cut them seperatly.
Great project Guv'

Col

 

[Eastsidepilot]

I have yet to make my mind up about the floor but im leaning towards concrete

And of coarse if you have a timber floor then we'll need air bricks just below the damp coarse

Col.

 

[28ten]

A quick test
One jig



One pile of bits


Bits in jig with a bit of Rocket. The jig needs to be a bit tighter but I hadn't allowed for the kerf of the laser cut


Allow 20 seconds and remove jig you probably cant see them but there anr some indentations for the nail heads


Do a second one and add some battens. More jigs needed here, these are done by eye



And in place



I will need wall plates which can be notched to help the alignment.

 

[Eastsidepilot]

Guv'
Excellent, proper job mate, I've shown how the rafters would be cut to fit the plate, I take it you'll laser these?

Col.

 

[Dog Star]

....but there are some indentations for the nail heads

I think that the brace to the rafters would have been fixed with bolts and nuts rather than nails. Never the less, good to see the quality of the design and construction.

 

[28ten]

Guv'
Excellent, proper job mate, I've shown how the rafters would be cut to fit the plate, I take it you'll laser these?

Col.

Yes. I need to find a way of keeping the whole lot square for assembly as it is a bit fragile. would there be a rafter flush with the end wall as in my shot?

 

[Dog Star]

... would there be a rafter flush with the end wall as in my shot?

There are two answers (probably) to that question and which answer is appropriate depends upon how the bargeboards are attached.

[1] the purlins extend beyond the brick wall and the bargeboard is nailed to the exposed end of the purlins.

[2] a rafter is positioned on the outside face of the brickwork and the bargeboard is nailed to the rafter. The outermost rafter is attached to the rafter closest to the inner face of the wall by wood spacers, looking rather like a ladder.

 

[28ten]

Looking at my diagrams I have a feeling it is the latter although I cant find anything suitable in Jaggard
the tie should be a dovetail, you are probably right about it being bolted.

 

[Eastsidepilot]

Looking at my diagrams I have a feeling it is the latter although I cant find anything suitable in Jaggard
the tie should be a dovetail, you are probably right about it being bolted.

The tie or collar across the rafters would be bolted with coach bolts and not always dovetailed in my experience.

Col.

 

[28ten]

The tie or collar across the rafters would be bolted with coach bolts and not always dovetailed in my experience.

Col.

I doubt they would have bothered with dovetails for a building such as this, anyway off to look at scale hardware for some bolts....

 

[28ten]

One for Colin..... the door is rather wide 4' 6" would this be plausible bearing in mind it is a wartime build? I havent got a decent photo of the original

 

[Eastsidepilot]

Guv',

There's no reason why they would not have made a door of that size and hung on heavy duty strap hinges, but it may well have been put on a track as a sliding door also (this is a parcels office, yes?) So it would have to be wide enough for the sack barrow at least.
You mention that you don't have a decent photo but do you have a photo even a poor one ?, as we might be able to ascertain what was actualy fitted.
I have attached a scan from another book of mine showing door detail, again if it's 4'-6" wide then they would not have hung it on butt hinges, a pair of doors, yes and they would be rebated at the meeting stiles.

Col

 

[28ten]

I know it was a hinged door and it looks as if it is a single, my first thought was a double because it is so wide.