Hatch design help

[Mike Angeles]

Hey Folks,
Take a look at the picture below if you don’t mind. I’m not too certain how Ill Make the hatch, 5 spars? Ill use 2" spars on the ends and middle, cut from 3/4 Plywood and glued up? My concern would be that their only a 1 1/2" wide?
But wait there’s more, how do I make the Hatch seal against my framing, Any suggestions or pictures would be greatly welcome. I’ve scoured all the Hatch threads for idea or pictures. Help I’m Stuck!





Mike

[Leon]

If it were me, I wouldn't use plywood cut to 1 1/2" to make the ribs. I don't think you will have as much strength as solid lumber. Others may have a different opinion but that's my take on things. I cut mine from a hardwood and finger jointed the smaller pieces into long er ribs and it is very rigid and has no springback.

[Miriam C.]

I cut mine from 2 sheets of 1/2 Baltic birch I laminated together and cut the same as the sides.

Looking at your sides you have a 1 1/2" space between the outside and the inside. I see that as an obstacle to design around. If you make you hatch with vertical ribs I would put a thick rib on the outsides to match your framing and let it sit on that wall just like your roof spars. Make it less the thickness of your hatch skin so it will be level on top.
I think you will have to cut in your sides too. Make the cut the depth of the seal you are using.

Next I would make some thicker ( 1" x 1 1/2" at least) ribs to do the rest. If you are going to finish the hatch inside you need to decide if this is a pain to skin. Leave a slight over-lapp on each side.

I can't tell how thick your sides are but you might even build them up so that edge will hold a seal. (the edge of the outside where it is taller)

Picture would be better.

MHO- hope it gives you a start

[mikeschn]

Mike,

Have you checked out the hatch directions in the Generic Benroy Plans, up there in the menu? It tells how to notch the sides, build the hatch out of baltic birch ribs, and cover it so there is no springback. It even tells how to seal it...

Mike...

Hey Folks,
Take a look at the picture below if you don’t mind. I’m not too certain how Ill Make the hatch, 5 spars? Ill use 2" spars on the ends and middle, cut from 3/4 Plywood and glued up? My concern would be that their only a 1 1/2" wide?
But wait there’s more, how do I make the Hatch seal against my framing, Any suggestions or pictures would be greatly welcome. I’ve scoured all the Hatch threads for idea or pictures. Help I’m Stuck!

[Mike Angeles]

Leon, Im afraid finger Joints are not my Forte' as cool as that would be.

Miriam, Ill shoot some close ups and repost, I DO plan on using Vertical spars that are about 1 1/2" thick. (3/4 Ply doubled). I would agree on enlarging the surface aera of the top of the profile to accept a seal.

Mike, your kidding right? I sure did, along with almost every post pertaining to the hatch. I really would like to stay away from cutting the ribs from the Side so the Hatch can lay in place of the piece that was removed, My main concern would be the Profile and how it would look wrapped in ALU. Id perefer to have a clean profile, with the Hatch going in between the sides,

Ill post some close up with demensions shortly, Thanks for looking!

Mike

[Miriam C.]

Leon, Im afraid finger Joints are not my Forte' as cool as that would be.

Miriam, Ill shoot some close ups and repost, I DO plan on using Vertical spars that are about 1 1/2" thick. (3/4 Ply doubled). I would agree on enlarging the surface aera of the top of the profile to accept a seal.

Mike, your kidding right? I sure did, along with almost every post pertaining to the hatch. I really would like to stay away from cutting the ribs from the Side so the Hatch can lay in place of the piece that was removed, My main concern would be the Profile and how it would look wrapped in ALU. Id perefer to have a clean profile, with the Hatch going in between the sides,

Ill post some close up with demensions shortly, Thanks for looking!

Mike

Mike, if you don't notch the sides the hatch will sit higher than the roof and your hinge will be off set. Of course you can always add a layer to your roof. It isn't required, just be aware. The side edge does need to be wide enough to accept a seal of some kind. It can even be a thin one.

You can also hang the outside hatch rib over the edge.

[Miriam C.]

I looked back through some of my favorite builds and Steve Fredricks is the closest to what you have.

He didn't put the inside wall in the galley and that is what makes your different. Not bad but different. I think you can still make your hatch the same way. Check it out. The Lil Diner has the best pictures.
http://www.steve-frederick.com/diner3a.html

Somewhere in this forum I asked for hatch detail pictures because I really didn't want to notch. It was so much easier to just cut it.

[Mike Angeles]

Hey Thanks for doing that Miriam. I found this one, Author Unknown. Anyone?




This is what I was thinking, Have the roof over lap and seal at the top. I can to add 1/2 to the Outer wall so they'll be more surface area a seal, probably end up notching out for the compressed seal? All the spars will be 1-1/2" plywood, I have a couple sheets of 1/8 Luan ready to go then eventually skin with Aluminum. Plan to order the Grant Hinge this week, 6 WHOLE feet of it.

Anyone else?

[Gerdo]

I have 2 bows that I lap jointed, epoxy glued and screwed together out of 1x8 Maple. I then traced my patern, that I made earler, and then cut them out.


I only used 2 bows that are 1x4s. I also used maple 1x2s as ribs (8, the top one and the bottom ones are also doubled up, glued and screwed)

The second picture shows the frame of the hatch after I glued and screwed everything together, before it dryed. I strapped and clamped it exactly where I wanted it be including shims for gapps on the sides. This allowed everything to glue and dry in place insuring that it fit. Even if the opening is alittle out of square it will fit. I also had ZERO spring back. I belive it was the combination of the Maple and going 1x4s on the bows.

I did notch the sides to allow for my weatherstrip, about 1/4".

[Keith B]

Hey all.. I'm also working on my hatch and could use a little help. My roof is 1/4" plywood. I was going to continue the 1/4" ply on the hatch to keep everything the same height and flat- it's a pretty gentle curve... or is it better to use two sheets of 1/8" to prevent spring-back? My hatch spars are doubled 3/4" plywood w/ 3/4" poplar...about 1.25"x2" deep, spaced every 14". I saw the Benroy plans above only call for one 1/8"...but I already went 1/4" everywhere.