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I’m a bit frustrated at the time it takes to cut the bricks to the accuracy that I want. I know that some simply split bricks, used an ample amount of mortar, and in the end have fine, working ovens. I found JCG31’s bevel and angle calculations and other treads and info on cutting bricks for our ovens, but still find that I’m doing too much freehand cutting and I’m wasting time and bricks. I know mortar is my friend but, bricks are stronger than mortar and I want a tidy tight oven.. I’m not normally a neat freak, I’m just a simple guy and I want a simple tool to help me cut bricks and minimize the joint sizes. If I can make the tool then the dome part of the build will go much faster and the product, I hope, will be more acceptable. Moreover, I’ll get my pizza sooner.
I put this idea out to all of you to use your collective brains, to refine or all together dismiss this exercise as folly.
Here is where this all has taken me. The simple truths as I see them are:
• All vertical brick joints are on a radial plane with the vertical axis of the oven hemisphere.
• The inside faces of the oven bricks face the center point of the hemisphere.
• As we move up the courses the diameter of these courses gets smaller until we have the keystone.
• The course radius along with the slope defines the side bevels.
• A tool that allows me to set the course distance, the radius, and also set the course slope, should allow me to make near perfect cuts on each course ring of bricks.
I’ll try to describe the tool I’m building as best I can.
• The tool needs to firmly cradle the brick being cut setting the slope of the last course measured at the oven
• The tool also needs to set the distance of the brick, for the course being cut, to the oven’s center axis, the course radius.
• The width of the finished “cut” brick will be variable so the spoke, setting the distance, needs to swing the brick cradle along the radius to allow for this difference in desired brick width.
I have a HF10”, I wish it was 14” as this additional blade size would allow something greater than the 3.5” maximum cut depth. Wish as I might this isn’t going to change and I know when I get high up in the courses I’ll have to deal with it. I’m already dealing with it in the brick bevels and the entry arch.
The Jig base sets on the rolling cutting platform of my HF 10” but necessarily extends out on both ends. The jig extends out in the front beyond the cutting platform to allow the maximum course radius to be set. Since I’m building a 43” oven and the outside diameter is +9 of this, 52”, the maximum radius out from the radial axis of the oven is 26”. The depth of the cutting platform is about 10” so the distance out from the front of the platform needs to be greater than 16”. No real weight is out this far and the jig is clamped to the platform so vertical stability doesn’t need to be much of an issue. Lateral stability is a greater issue out here, outward pressure of cutting bricks and the incidental bumping need to be designed for, angle iron will handle these. Imagine a triangular platform that extends out in front of the saw.
Other needs include the ability to bring the swing arm that holds the brick, closer to the cut point of the saw as the radius of the courses decline while maintaining the axis point of the arm in line with the saw blade. A slot, in line with the saw blade, or simpler yet holes drilled in this forward platform would suffice. The swing arm, spoke, needs to decrease in length as I step up the oven courses. I’d like to do this without disassembling the tool. This is to maintain the distance from the radial axis to the bricks being cut. If the tool works as imagined I will be able to call out the width of the brick I need and have cut it by a helper. I can imagine that the mortaring of the bricks might take longer than the actual cutting.
The cradle has a few features that I hope to include.
Stability is important. If I build the spoke from 3/16” by 1 1/4 “ bar stock, I should be ok for compression forces but I want to make sure that the cradle and brick don’t twist this bar while cutting. Maybe I need to include a wide, rear, cross piece. Also this part of the tool should allow me to move the angle without disassembling things. I figure this out when I get there.
Additionally I want to immobilize the brick in the cradle, a set screw? a bungee? Another thing to figure out.
I hope to have some part of tool built and in use this weekend so I’ll send pictures when I have them.
Chris
I put this idea out to all of you to use your collective brains, to refine or all together dismiss this exercise as folly.
Here is where this all has taken me. The simple truths as I see them are:
• All vertical brick joints are on a radial plane with the vertical axis of the oven hemisphere.
• The inside faces of the oven bricks face the center point of the hemisphere.
• As we move up the courses the diameter of these courses gets smaller until we have the keystone.
• The course radius along with the slope defines the side bevels.
• A tool that allows me to set the course distance, the radius, and also set the course slope, should allow me to make near perfect cuts on each course ring of bricks.
I’ll try to describe the tool I’m building as best I can.
• The tool needs to firmly cradle the brick being cut setting the slope of the last course measured at the oven
• The tool also needs to set the distance of the brick, for the course being cut, to the oven’s center axis, the course radius.
• The width of the finished “cut” brick will be variable so the spoke, setting the distance, needs to swing the brick cradle along the radius to allow for this difference in desired brick width.
I have a HF10”, I wish it was 14” as this additional blade size would allow something greater than the 3.5” maximum cut depth. Wish as I might this isn’t going to change and I know when I get high up in the courses I’ll have to deal with it. I’m already dealing with it in the brick bevels and the entry arch.
The Jig base sets on the rolling cutting platform of my HF 10” but necessarily extends out on both ends. The jig extends out in the front beyond the cutting platform to allow the maximum course radius to be set. Since I’m building a 43” oven and the outside diameter is +9 of this, 52”, the maximum radius out from the radial axis of the oven is 26”. The depth of the cutting platform is about 10” so the distance out from the front of the platform needs to be greater than 16”. No real weight is out this far and the jig is clamped to the platform so vertical stability doesn’t need to be much of an issue. Lateral stability is a greater issue out here, outward pressure of cutting bricks and the incidental bumping need to be designed for, angle iron will handle these. Imagine a triangular platform that extends out in front of the saw.
Other needs include the ability to bring the swing arm that holds the brick, closer to the cut point of the saw as the radius of the courses decline while maintaining the axis point of the arm in line with the saw blade. A slot, in line with the saw blade, or simpler yet holes drilled in this forward platform would suffice. The swing arm, spoke, needs to decrease in length as I step up the oven courses. I’d like to do this without disassembling the tool. This is to maintain the distance from the radial axis to the bricks being cut. If the tool works as imagined I will be able to call out the width of the brick I need and have cut it by a helper. I can imagine that the mortaring of the bricks might take longer than the actual cutting.
The cradle has a few features that I hope to include.
Stability is important. If I build the spoke from 3/16” by 1 1/4 “ bar stock, I should be ok for compression forces but I want to make sure that the cradle and brick don’t twist this bar while cutting. Maybe I need to include a wide, rear, cross piece. Also this part of the tool should allow me to move the angle without disassembling things. I figure this out when I get there.
Additionally I want to immobilize the brick in the cradle, a set screw? a bungee? Another thing to figure out.
I hope to have some part of tool built and in use this weekend so I’ll send pictures when I have them.
Chris
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