Author Topic: Any carpenters here? Building an Octagonal "Glassebo" (Read 4615 times)

SLOweather · « **on:** March 28, 2013, 03:36:10 PM »

We've build a few sheds over the years, all 8 x 10 feet. The first one was a simple tool house from 84 Lumber plans. The next was a cabin made of 3x laminated logs, with a stamped concrete floor and masonry fireplace (my avatar photo), and the third a machine shed with a porch roof homage to John Deere's shop in Grand Detour IL.

Now I'm looking at the stuff I've accumulated over the years, including 7 tempered glass panels 46" x 76", and the aluminum frame from a 12' satellite dish.

I'm thinking about a post and beam octagonal glass gazebo/greenhouse, and using the dish frame for the roof. Posts and beams would be 6x6es.

Frost is not an issue here, (central California Coast) and I might put raised beds in it for garden veggies, so I'd probably put it on post footings rather than a slab, and maybe floor it with open pavers ballasted with float rock for drainage.

I can install a vent of some sort in the roof, or raise the roof above the wall tops and install vents. And the door could be a Dutch style 2 piece door.

Last weekend I temporarily assembled the dish on the driveway. I think It will make a pretty interesting roof frame.

And I brought a 10' PT 6x6 home from the lumberyard for practice laying out the cuts.

After a LOT of thought and sketches, I think I have my 3 way base and top beams and post joint figured out.

The beams will be cut to 135 or 45 degrees (depending on how you look at it) and rabbeted accordingly for half-lap joints. Then I'll temporarily joint them with bolts or clamps and cut a square mortise all the way through the center of the joint.

On the post, I'll cut a matching tenon on the ends, and then rip the face of the post to match the 135 degree outside angle of the joint.

Gravity and the mortise and tenon joints will hold the frame together, and the entire joint should require very little in additional hardware.

And, (keeping this weather related) I can do something else I've always wanted to to. The pipe sticking up out of the center of the top of the dish used to be inside the dish to hold the LNA assembly at the focal point of the parabola. I can fab up a weather vane of some sort for the top of the pipe, and then extend its shaft down into the gazebo, and put an indicator on it at the top of the ceiling so we can watch the wind direction from inside.

BTW, the Internet has wonderful sites to help with dimensions of things like this. I found some octagon calculators that I used to easily refine some of the dimensions.

SLOweather · « **Reply #1 on:** April 08, 2013, 11:04:11 AM »

Well, I got the itch this weekend to make a practice joint, rather than do yet another drawing.

It took me a while to overcome some misapprehensions and figure out how to do everything. For instance, a 7.25" circular won't cut half way through a 5.5" 6x6.

So I brought the radial arm saw out on to the driveway.

Here are 2 6x6 plate beams half-lap jointed on the radial arm saw, and then laid up for fitting:

Then I reset the saw and cut a practice tenon on a stub of 6x6. The first layout of the mortise was off 22.5 degrees:

Cut a mortise in the top beam.

And trial-fit them:

I ran out of time before I could do the bottom mortise. That's for next weekend.

BTW, here's the satellite dish frame for the roof temporarily assembled on the driveway:

W3DRM · « **Reply #2 on:** April 08, 2013, 12:55:04 PM »

Nice idea Chris!

In your second post, you mention "Here are 2 6x6 plate beams half-lap jointed on the radial arm saw, and then laid up for fitting:". Perhaps it's my tired old eyes, but that plate beam looks more like a 4x6 than a 6x6...

Be sure to keep feeding us your photos as you go along. Just to be safe, you also may think about putting a pin of some kind in the tenon rather than relying just on gravity to hold things together. You do live in earthquake country and earth movements can be both horizontal and vertical.

SLOweather · « **Reply #3 on:** April 08, 2013, 01:54:28 PM »

Thanks Don!. That's a trick of perspective on the photo. All the timber is indeed nominal 6x6 (5.5" x 5.5"). The bottom plate beams are pressure treated, and the posts and top plate beams will be Doug fir.

I hope the mortises start going faster. That one took over an hour and I have 31 more to do. The laps and the tenons go pretty quick, doing repetitive cross cuts on the radial arm saw and then cleaning out the waste with a chisel.

I do plan on pinning or bolting the joints during final assembly, either with dowels or through-bolts. Just one through the bottom lap will probably be enough.

moehoward4 · « **Reply #4 on:** April 08, 2013, 03:25:10 PM »

SLOweather If you had or could borrow a dado blade set (stacked or wobble), that would make the lap joints faster and easier. Some radial arm saws can use dados, just make sure to use "stops" for the stock. AND, depending on the size of the mortises, you could use an auger bit to drill out most of the stock and then clean up with the chisel.

SLOweather · « **Reply #5 on:** April 08, 2013, 04:14:46 PM »

Thanks for the suggestions, Jack. I have both kinds of dado sets. I'll have to see if the saw will take either one. Boy, that'll make a lot of sawdust in a hurry.

I also might need to move the saw to an outlet closer to the panel. The motor was bogging down on some cuts, not as bad when I changed outlets out where I was working.

I might have a 2" Forstner bit, too. If I do, I'll see about using that in a drill press to start the mortise holes. Or maybe a hole saw.

moehoward4 · « **Reply #6 on:** April 08, 2013, 06:55:42 PM »

DON'T use the hole saw, the forstner bit is the better option...just be sure to use some kind of secondary handle on the drill so it doesn't 'get away' from you. And if you can switch from 120v to 240v on the radial saw, DO IT.

stevebrtx · « **Reply #7 on:** April 09, 2013, 03:46:33 PM »

Down here there are tons of old huge FTA sat dishes, I've still got one 11' on my casita that needs to go, they flip them over, put them on posts (or a center post) and place palm thatching on them for wonderful palapas - although I suppose palm thatching is probably a bit hard to come by for some of you folks up north - huh?

Bushman · « **Reply #8 on:** April 09, 2013, 04:03:17 PM »

I am sure you aren't going to like this suggstion - now. I would have pinned the posts rather than a mortise/tenon. You merely drill a hole in the bottom of the post and a receiving hole in the timbers. A few inches of round dowel and you are done. Glue/screw the post to the base and done. M/T is fine for cabinetry, but not the right choice here IMHO.

SLOweather · « **Reply #9 on:** April 09, 2013, 06:01:58 PM »

I'd actually already thought of that, and I've only done one mortise "for keeps". I have a bunch of clothes pole left over from when we remodeled our closets that would work fine.

OTOH, my grandfathers were great woodworkers, and classic post and beam construction would be a testament to them.

But, doweling it sure would go faster...

SLOweather · « **Reply #10 on:** August 03, 2015, 01:54:05 PM »

Geez, I started this project over 2 years ago. I had to put it on the back burner for a while, due to circumstances beyond my control, as they say.

But, since I got laid off a couple of months ago, off and am now even more more partially retired, I've resurrected it.

The delay wasn't necessarily a bad thing. I did a lot of research designing the cypress bridge mentioned in another thread, that I can put into this project. I've been thinking, sketching and measuring and stuff for a few days, and I think it's going to be a much better finished project. Things like wedged tenons for the joints, a louvered cupola on top for ventilation and making templates for all of the joints. And, since the roof frame is a satellite dish, I can make the ceiling out of Masonite or door skins, and have a cool domed ceiling.

Yesterday, I finished up the demo lap/mortise and tenon joint. I assembled the 6x6s on the driveway and used the mortise in the top one as a template to mark the bottom one, and a guide to start a 2" hole saw. Once the hole was cut, I used a battery reciprocating saw (like a Sawzall) to square it up

SLOweather · « **Reply #11 on:** August 03, 2015, 02:59:34 PM »

Does anyone have experience with Google Sketchup? I checked it out 2 years ago, and again just now. It seems like they might have added some libraries since the last time.

There are a bunch of gazebos I can start with ...

SLOweather · « **Reply #12 on:** September 07, 2015, 02:01:04 PM »

I finally figured out what has been bugging my subconscious about this project. One major aspect of it is the satellite dish as the roof support. While qualitatively, I think it will be strong enough, I don't want to spend money and time building everything else only to have the roof fail.

I don't remember enough from my mechanical engineering classes in college to do an analysis of it.

So, I'm going to use the brute force and awkwardness approach. I've been assembling the entire dish on the driveway. I got all new hardware from McMaster-Carr, and found all but 2 of the rib spreaders (which I know I used for something else a while back.

Once it's all together and all the hardware tightened. I'm going to climb up and stand on the hub of the inverted dish. If it will hold up my 230 lbs, it'll be strong enough for some sheathing, felt, shingles, and a cupola.

SLOweather · « **Reply #13 on:** September 08, 2015, 01:53:03 AM »

OK, here's the fully assembled dish, being load tested.

It didn't bend, shift, wiggle, squeak etc. It's really solid. I bought a 6" piece of 1 x 1/8 aluminum bar at Ace and fabbed up the 2 small spreaders I used a few years ago. There's 80 1/4" bolts, washers, and nuts holding the spreaders to the ribs, and 32 5/16 bolts, washers, and nuts holding the ribs to the hub plates, all new from McMaster-Carr.

I think it's going to be fine for a roof frame. One way this is better than when I started 2 years ago is I decided to use all of those spreaders. It makes the dish frame way more solid.

W3DRM · « **Reply #14 on:** September 08, 2015, 12:39:02 PM »

Very nice Chris, well done!

SLOweather · « **Reply #15 on:** September 24, 2015, 02:54:02 PM »

Well, cr@p.....

I bought a sheet of 3/8 OSB to start figuring out the roof panels. I screwed 2x2 cleats to the sides of the 1x1 Al ribs to screw the OSB to. I can just get 2 pie slices from one sheet, with a little opening left over at the top.

To add strength, I need to add a 2x2 support under the seams/cuts in the OSB are, where the bend in the rib is. Because of the octagonal, dished shape, those are compound miters.

I just got the radial arm saw set up and made a couple of test cuts when the motor burned out.

It's not a big loss, in that the saw was free 15 years ago or so. It's a Craftsman made by Emerson, and therein hangs a tale of why there are no new replacement motors available.

So, Craigslist, here I come. I have a line on a couple of saws here in town, from $40-$150. A new one is about $850...

W3DRM · « **Reply #16 on:** September 24, 2015, 04:44:14 PM »

Looking good but, I think that roof is going to require a crane to lift it into position!

SLOweather · « **Reply #17 on:** September 25, 2015, 12:29:47 AM »

Quote from: W3DRM on September 24, 2015, 04:44:14 PM

Looking good but, I think that roof is going to require a crane to lift it into position!

I agree, Don... except...

If there's a theme to this project, it's "Knowing the things I don't know." or maybe "Figuring out the things I don't know."...

If I work on how to build how to build the roof on the ground, where it's accessible and easy to work on, I can figger out all of these little details before it goes up on top. I can always take the roof panels off and slide the dish up nekkid and lighter, and then add them after that. But it's way easier to do these cuts, compound miters. and trial assembly on the driveway first, and then take it apart and do it "in the air" later.

Still, I wonder how I will get the cleated dish up there. I have a tractor, and some scaffolding, and the familial Dunbar/Arndt "brute force and awkwardness" genes in me, so I have faith that I'll get it up.

I can always host an Amish style, um, "dish raising" and ply the neighbors with food and drink...

vreihen · « **Reply #18 on:** September 25, 2015, 05:33:34 AM »

Quote from: SLOweather on September 25, 2015, 12:29:47 AM

I can always host an Amish style, um, "dish raising" and ply the neighbors with food and drink...

For some reason, I don't think that the Amish would be lining up to help install a satellite dish.....

SLOweather · « **Reply #19 on:** September 28, 2015, 02:18:26 PM »

After looking at a couple of Craigslist radial arm saws, I bought one. Hint... if it's listed at $40 without a picture, it's REALLY a $40 saw. I wouldn't have gone and looked at the first oue if I'd seen a picture. It was a bit rough.

I got one for $150 that is just a little older than but substantially the same as mine. The seller was only a half mile away, and helped me load it and unload it. I spend a couple of hours Saturday going through it, cleaning it up, and doing all of the adjustments. Some of my parts were better than his, so I swapped them. The carriage rollers were loose, so it must have been a chore to make decent cuts with. Now, it cuts beautifully...

Friday, I took the old saw apart. There is an on-going safety recall for all Craftsman/Emerson RASes from 1959 to 1992. Hence the reason there are no new motors available. If it fits your model, you can get a free blade guard upgrade. If not, or if you don't want to get it, they will send you a box and shipping label, you remove and send the motor back, and they send you a check for $100.

So, I applied and they are sending me a box to return the dead motor.

FWIW, there are used motors available on Ebay. Someone has figured all this out and buys cheap working garage sale saws, and takes the motors off to sell for $150.

After I got the old one disassembled, I added some 2xs to the top and made a roll-around work bench....

And, yeah, I have considered buying the $40 saw, doing the recall on the motor to net $60, and turning its stand into another bench.

Now I'm on to learning about compound miters....

SLOweather · « **Reply #20 on:** October 05, 2015, 03:17:02 PM »

OK, last week I got the radial arm saw fired up and completes some test framing for the roof:

I can get 2 pie slices of sheathing from one sheet of OSB...

SLOweather · « **Reply #21 on:** October 05, 2015, 03:24:48 PM »

OK, in typical family fashion, I'm building this from the middle up and down.

I was originally going to make the cupola out of 1' wide redwood window shutters, but they were too expensive.

So I found 12" square painted steel gable vents at Home Depot.

The I realized that I needed to know the footprint of the cupola, to put the support 2x2s in the right place under the roof.

So, I started on the cupola.

I measured and cut 2x4s to 45 degree angles on the miter saw and then bevel ripped the underside to the angle of the roof, and assembled them into an octagon.

It's shown upside down to show the beveled underside.

That's a cargo strap for a clamp, and I used Gorilla Glue and screws.

SLOweather · « **Reply #22 on:** October 06, 2015, 05:16:34 PM »

Here's the cupola framed for the vents, and a roof mockup started to see how it looks. I ran the posts tall for later trimming.

It took a session out in the Think Tank and a glass of wine to figure out the roof support hub.

That's a 2x8 cut to a regular octagon, and then beveled on all 8 sides on the table saw. THAT was exciting to cut...

SLOweather · « **Reply #23 on:** October 14, 2015, 02:46:33 PM »

A few days ago I finished the basic framing of the cupola. (All so I'd know where to put the supports under the main roof...)

Here's a shot straight down on the center hub.

SLOweather · « **Reply #24 on:** October 29, 2015, 03:38:49 PM »

Here it is today. I finished up all of the 2x2 dish frameout so I'll have something to screw the roof sheathing and cupola to.

One idea I hope to realize in this project is a "through-the-roof" weather vane, with shaft extending through the roof and a win direction indicator arrow beneath the ceiling. The white PVC is a mock for sizing purposes.

I can't find such a thing for sale, or plans for one, so, like the rest of this project, it's gonna be home-brewed. I think I'll make it out of copper water pipe.

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Author Topic: Any carpenters here? Building an Octagonal "Glassebo" (Read 4615 times)