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SCChris 08-20-2009 11:17 AM

New brick cutting tool - Old tool?
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.


pacoast 08-20-2009 12:06 PM

Re: New brick cutting tool - Old tool?
I can imagine the tool you want being fabed with a decent metal lathe. Ball heads with "thumb head" set screw would position each axis as you want and pantograph the required angle. But to me it seems more work to design & make the tool than just do the cuts for one oven conventionally.

Perhaps someone with a metal lathe or better imagination than me will be more helpful. For my oven, I circumvented 99% of the cutting by casting the dome. Anyway, I wish you luck & will look with interest to see if you are successful in fabricating the tool you want.


SCChris 08-20-2009 12:14 PM

Re: New brick cutting tool - Old tool?
2 Attachment(s)
I think I can do it all with a cutoff saw, table saw, and drill press. I don't think it needs to be too elegant, but it might be nice to have it more like a tool and less like sticks and nails.

2 Side rails - L metal 1X1X24"
Front and rear platforms 3/4 plywood or nylon cutting board. 2 at 9 by 10. These for resting on the platform base and attaching to the angle iron. One forward of the cutting area also for connecting to the angle iron and providing a anchor point for the spoke.
12 screws, or so, to attach the plywood to the angle iron.
1 spoke - 3/16 by 1.25" bar 36", or so, long.

3 1.25" gate hinges one for the front and back of the cradle one for the angle setting bar.
1 L metal 1X1 by 1.25 inches in length, for the front of the brick
1 L metal 1X1 by 2.5 inches in length, for the back of the brick
1 3/16 by 1.25" bar 6" long for the underside of the brick a hinge in front attached to the spoke a hinge attached to the back to provide for the lift.
2 3/16 by 1.25" bars 8" long one hinge attached to the opposite side of the rear cradle hinge, one hinge attached to the last hinge and the other side of this hinge attached to the last 8" bar.

By lifting the cradle and clamping the tail 8" bar to the tail of the spoke the slope angle can be set.
Spoke distance can be determined by drilling a new hole(s) and connecting it to the forward platform with a through bolt.

The attached pictures show the rear platform, the easy part of the whole thing.



SCChris 08-23-2009 06:57 PM

Re: New brick cutting tool - Old tool?
2 Attachment(s)
I got a bit done on the tool, all I've got left is the swing arm and brick cradle. I'd hoped to get more done but the arch is my next big hurdle. What the pictures show is a drop on bed for the HF10. Thi bed sits nice and tight and has the ability to slide left or right to center the blade with the line of holes to recieve the pivot point of the swing arm. These holes are 2" apart on an axis with the blade. The other photo shows a 1" square channel and a 3/4" square bar. The bar fits nicely within the channel, I'll use the bar and the channel to build the arm, cradle and lift for the back end of the cradle.


RTflorida 08-23-2009 09:52 PM

Re: New brick cutting tool - Old tool?
Hey Chris, I have a question...are you planning to go into the business of building and selling ovens? Seems like alot of time in engineering/building a tool for one oven. Not to be negative (I'm into tools and gadgets more than most - having worked for a power tool manufacturer for the past 10 yrs selling tools). BUT, it sure seems as if you have redirected the frustrating lost time spent on free had cutting to a new project of re-engineering a tile saw to cut the perfect brick. Dude, you could have been done with your free hand cuts by now and be moving rapidly up the dome. I utilized the cut to fit manta to have nearly mortarless side joints on all my dome bricks my only gaps wer 3/16" on the outside wear the nxt course motars to the course below. The entire dome build only took about 6 days (2 days spent doing nothingbut cutting bricks.
I realy appreciate you tool and gadget passion, I would love to have a neighbor with similar "jaded" ideas that I have.......but I've got to say this - GET BACK ON THAT OVEN, it may seem to be all about the process........but it isn't. it all about the great food that soon should be coming out of your oven. Good luck with the project within a project,I am very curious how well it works for you.


SCChris 08-24-2009 08:04 AM

Re: New brick cutting tool - Old tool?
Youre right RT, Im obsessing a bit. Im sure that if I just cut a wood jig to set the angle of the course and swaged the radius, Id get close enough for any inspection. If this exercise helps others, then its been all for good.
As for the oven, the arch is moving along. Ill be fighting the calcs for the forward, entry area. Given that its really a partial cone, growing from about 23 to 25 in about 8 of depth.

Thanks Again RT..


SCChris 09-01-2009 02:42 PM

Re: New brick cutting tool - Old tool?
4 Attachment(s)
Done!! Now to give it a whirl. Due to the angle of the bricks in the cradle, mimicking the row below, and the 3.5" max cut of a 10" saw, I'm going to have a bit of the brick not fully cut.


Les 09-01-2009 02:55 PM

Re: New brick cutting tool - Old tool?
Chris - it looks like the back end of the brick is raised more then needed. I recall lifting mine .4 to .5 inches. That would put it at 3 inches high and a 10 inch blade should pass through it. Just my thoughts. BTW, very cool work on the jig.


SCChris 09-01-2009 03:08 PM

Re: New brick cutting tool - Old tool?
I’m up about 23 degrees at this point, 1.75 inches of lift. My initial hope was that I could get a few rows before it got to be too much trouble to use the jig. I’ll have to weigh these things out this weekend. Before someone asks the question, why?, This whole project is about the fun of it, and this is just one more facet.


Les 09-01-2009 03:22 PM

Re: New brick cutting tool - Old tool?

Originally Posted by SCChris (Post 63310)
1.75 inches of lift.

Are you sure about that number - its seems huge.

I found this project to be fun after I was done. ie. Back and legs were no longer hurting. ;)

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