Indispensable tool issue - i'm flummoxed!

[Greenman]

Re: Indispensable tool issue - i'm flummoxed!

i get what you are saying, i'm just trying to think how to practically build the tool to suit this.

would you just position the main arm of the tool inline with the centre of the brick, and have the angle iron or whatever it is that supports it on top of the arm?

If it helps here are a couple of pics of my IT. Worked fine for me. I did lose the clamp part very quickly as it was not required. If you want to make it further adjustable it is only a matter of cutting the threaded rod and putting a threaded tube in.

[alexi82]

Re: Indispensable tool issue - i'm flummoxed!

Alex,
The center of the IT should hit at half the thickness of the brick or the angle of the tilt on the dome is off center it becomes cumulative on each course. Currently your IT center is hitting the top of the brick. IMHO

i get what you are saying, i'm just trying to think how to practically build the tool to suit this.

would you just position the main arm of the tool inline with the centre of the brick, and have the angle iron or whatever it is that supports it on top of the arm?

[UtahBeehiver]

Re: Indispensable tool issue - i'm flummoxed!

Alex,
The center of the IT should hit at half the thickness of the brick or the angle of the tilt on the dome is off center it becomes cumulative on each course. Currently your IT center is hitting the top of the brick. IMHO

[alexi82]

Re: Indispensable tool issue - i'm flummoxed!

*pick that up rather! Thanks heaps. Again

[alexi82]

Re: Indispensable tool issue - i'm flummoxed!

I can't believe I didn't puck that up! Sheesh!

[cobblerdave]

Re: Indispensable tool issue - i'm flummoxed!

G'day
You Have compensated for the thickness of the base board, BUT this makes it only true when in the vertical position, any other position it will be to short.
The IT needs to be adjustable to complete the dome accurately.
To set it for every row of bricks, a simple guide is to cut A 1/2 shape of your dome. Then fit it every row and adjust the IT for the next.
Another thing you will find that if you work off the IT it will tend to dislodge the brick you just laid. Design it to take a spacer say a piece of ply with you can slip out and then move the IT cause its now clear of the brick.
There are other ways of doing this but this is the simplest one I know.
Regards dave

[alexi82]

I know it's a fairly simple tool...but i haev an issue and i can't figure it out. hoping i can explain it on here.

So...i created a board that is round, 42 inches diameter. I have created my tool with a hinge attached to the board.

i have taken into account the thickness of the board

I have taken into account the slight gap between the base of the timber and the hinge

I get an exact 21 inches to where the base of the brick should sit.

Yet I have a gap between the tool and the first course of bricks as seen here.



The board is exact in size, no issue there.

If i was to continue using this tool, the size of the first mortar joint would be huge, as seen below.



I even measured the height as it would be at the top of the dome using this tool and yep, its exactly 21 inches. see below.



So if its 21 inches at the top, why am almost an inch short at the base...and that is the same gap all the way around the base....
it's definitely centred.

i'm flummoxed graham...

EDIT - i should also note, the hinge isn't secured to the floor at the end of it, it is pretty well right under the timber...prob a mm off centre but that has been accounted for.