My indispensible tool (a variation on a FB theme)

[cuda]

Re: My indispensible tool (a variation on a FB theme)

The jig I built is essentially just a turnbuckle and 3/8'"-18 threaded rod. I welded a bolt onto one yoke end and it goes into a T-nut, which is in turn recessed into the center of the plywood. It is infinitely adjustable from 18-24", allowing me to build from 36-48" ovens in the future.

The fine range of adjustability (each turn is 1/18") also allows for making a lower, flatter, elliptical dome (as long as the floor diameter is greater than 36") and eliminates the increase in dome height due to starting above the actual floor brick.

I had toyed with this idea a couple of years ago, but was only going to use it to locate the bricks before mortaring them. The cradle and clamp idea to actually hold the bricks in place seems so simple that I don't know why I didn't think of it at that time.

This could be made with no welds if the floor end used an end yoke and a clevis-type eyebolt. This was about $15 in materials.

[geisen]

Re: My indispensible tool (a variation on a FB theme)

Jim
I finished with the tool and as promised, passed it with all your accesories to a another WFO Builder here in SD. (Eric Prante - eprante). Also passed him my plywood floor template and both arch supports so he got the complete do it yourself kit. Your tool worked great through out and made for a perfect dome. Thanks again.

[Likeithot]

Re: My indispensible tool (a variation on a FB theme)

Looks great. Love how the joints in your dome look. I am sure they look spectacular from the inside too. I build these for a living and prefer the sand mold method. It requires a bit of shoveling (of sand) but its fool proof and allows multiple layers to be built at the one time. Use styrofoam boxs as infilling with the sand over the top. Great gadget tho!

[jcg31]

Re: My indispensible tool (a variation on a FB theme)

Jim
I finished with the tool and as promised, passed it with all your accesories to a another WFO Builder here in SD. (Eric Prante - eprante). Also passed him my plywood floor template and both arch supports so he got the complete do it yourself kit. Your tool worked great through out and made for a perfect dome. Thanks again.

Ahh you are a man of your word and thanks for all the kind words throughout the process. Your oven looks great, what are you doing for a top enclosure?

Jim

[fxpose]

Re: My indispensible tool (a variation on a FB theme)

The fine range of adjustability (each turn is 1/18") also allows for making a lower, flatter, elliptical dome and eliminates the increase in dome height due to starting above the actual floor brick.

I can see that, and this might be insignificant, but I think the angle of the brick holder itself needs to be varied each and every time the rod is shortened for each course of bricks. Otherwise, on the courses where adjustments have been made, those courses will come out staggered.

[fxpose]

ceiling height

Afer posting my above response (post #50) regarding ceiling height I came up with an idea on another variation of this ingenious indispensible tool. I drew up a couple of crude pencil sketches which perhaps better illustrates this idea. Perhaps someone has already done this or have come up with this idea, I don't know.
Obviously, by looking at the sketch, the ceiling will start to level off once you approach the last couple of courses by following this geometry.

[dmun]

Re: My indispensible tool (a variation on a FB theme)

You would get two intersecting arcs, and if carried to it's conclusion it would dimple down in the center, not that there's anything wrong with that. A builder recently did a rounded rectangle oven that had a flat on top. I was sceptical, but it seemed to work. Brick ovens are very forgiving of geometry.

A true eliptical indispensable tool would have two pulleys mounted on the lazy susan, and a sprung arm pivoted in the center with a pulley near the top, the three pulleys would be connected by a loop of cord or line. I think just having a thumb screw length adjustable slide on the arm would do the same thing with less work. After all, you only need to adjust it once for each ring.

[Gromit]

Re: My indispensible tool (a variation on a FB theme)

fxpose,

Indeed, another builder has used that variation just recently:

http://www.fornobravo.com/forum/f8/c...oven-7630.html

[fxpose]

Re: My indispensible tool (a variation on a FB theme)

fxpose,

Indeed, another builder has used that variation just recently:

http://www.fornobravo.com/forum/f8/c...oven-7630.html

That's fantastic! That's the jig I'll use.

[cuda]

Re: My indispensible tool (a variation on a FB theme)

fxpose,
You are correct in that for a flatter roof, the angle does change slightly with each course. If a hemispherical dome is built, there's no need to change it - the right angle holder is correct. But, in doing an ellipse, I just measured and shimmed for the correct angle and let the holder support the brick in the vertical plane, instead of clamping it tight to the inside of the bracket.

[3G_]

Re: My indispensible tool (a variation on a FB theme)

Nice work, these jigs look awsesome. i just bought a castor wheel and a quick clamp to build my jig with. I had a thought, which has probably been covered already, but if i bring the clamp end in 1/8th of an inch for each course this should bring the top of the dome in flatter. I will probably stick to a true half sphere but just an idea.

[cecilB]

Re: My indispensible tool (a variation on a FB theme)

You know, I'm getting so nervous every time I read about someone inventing a tool to put the perfectly cut bricks at exactly the right angles.
How many of you successful oven builders used these tools?
What if I don't?

Anyway, I haven't even started on the dome yet - I need to get out of my kitchen and quit cooking and baking so I can work on the oven!

Cecelia

[fxpose]

Re: My indispensible tool (a variation on a FB theme)

This is such a simple guiding tool, how can it not work? I most certainly intend to use it on my build.

[cecilB]

Re: My indispensible tool (a variation on a FB theme)

It's not that I think it can't work - I am wondering what happens when you don't use it? Will my oven collapse? I will admit it's because once I start thinking about angles and such, I get nervous - I was a lousy geometry student!
Eyeballing is probably what I was thinking about doing - also making a form.

hmmmm.

Cecelia

[fxpose]

Re: My indispensible tool (a variation on a FB theme)

Eyeballing is probably what I was thinking about doing - also making a form.

Hi,

There's absolutely nothing wrong with eyeballing, but the tool, like using a form, will help place each brick more accurately than simply eyeballing.