Hatch, butt joint or dovetail ?

[Sven]

I'm a romantic masochist ... I've convinced Nancy we should stay with teak framed hatches rather than replace them with aluminum Lewmars or the like. I really like some teak even if it is more work.

The "glass" will be 1/2" smoked gray transparent acrylic from Tap Plastics (pre-cut, beveled and finished

When I replaced La Petite's hatch I used dovetail joints just for the look http://picasaweb.google.com/lh/photo/K48ajP9L6SV3j73KtZavNA?feat=directlink (and the experience too). The hatches on the E39-B are much simpler than the one on the E23-II; they are just simple (if large) straight-sided boxes. I'm tempted to also make the joints simpler; butt joints rather than dovetail.

My question is what the relative strengths of the two types joints are ?

Thanks,


-Sven

 

[treilley]

I am partial to box joints for non mechanical joints. I think they look very nice although the dovetail joints that Martin used on his hatch frames are very beautiful. Box joints are also easier to make as a simple table saw jig can be fabricated quickly. Dovetails will require either a jig/router combo or some very intricate and exact cutting with hand saws(more of an artform). I think Dove tails are mechanically stronger but not necessary in your application.

If you decide on butt joints, use biscuits to make strong joints.

BTW, the Morris 36 daysailor uses butt joints on it's hatch frames.

 

[chaco]

Go Stainless !

Personally...I prefer Stainless. Much rather spend my time Sailing :nerd:

 

[Sven]

I am partial to box joints for non mechanical joints. I think they look very nice although the dovetail joints that Martin used on his hatch frames are very beautiful.

I know. The bar has been raised. If you look at Martin's architecture pictures you realize that he is working on a different plane of aesthetics for others to enjoy viscerally - more power to him.

Our hatches will be going off-shore so strength is a real concern, but not to the exclusion of beauty. I asked Simon (GOODONYA) about his hatches and he indicated that he was very happy with them with just simple weather stripping to keep them from leaking.



-Sven

 

[Sven]

Personally...I prefer Stainless. Much rather spend my time Sailing

Very interesting.

Who did the fabrication and do you have more pictures from other angles ? Is the SS wrapped around a wood core ?

Of course, how much did it cost and has it been stainless or stain less ?

As I said, very interesting !


-Sven

 

[Mark F]

Hi Sven,

I'm sure you have searched the archives but if you missed the "Wanted E29 hatch" thread there is some info there on different joints for hatches. I rabbeted the corners on the lower frame then biscuited the top boards to the frame. The photo shows the top boards overlaying the frame.

 

[chaco]

Stainless Replacement Hatches

The original Ericson 1"x 2" Mohogony Box Frame Hatches where replaced with matching 1"x 1 1/2" welded stainless steel tube frames. 1/2" smoked grey acrylic lens screwed to frame with DOW Sealant. 1"x 2" angle cover frames screwed to sides. 1"x 1/2" neofoam gasket. Used exiting hinges in-place.
This way you can use the old style raised cabin hatch frames and have custom ss repleacement hatches. The (2) E35II hatch frames & covers where $600 at a local weld shop. The acrylic lenses $300. Used traditional hatch lift arm hardware fastened to lens with ss plate washers and neoprene washer. This hatch cover does not leak a drop and is ready for ANY Gale !

 

[Howard Keiper]

My E-35 II has the original box frame hatches and, over the years, I've sanded the wood away to such an extent that there was a very unsightly lip where the plexiglas overlaps the frame.
So, I thought that it would do nicely to add teak rather than take it away. I bought 1/16th" teak vaneer, had it sawed into 2" strips, trued up the frame (box) and glued the new 'facia' over the old. It looks just like original and Sea Quest looks much happier.
Howard Keiper
Berkeley

 

[Martin King]

I'm a romantic masochist ... I've convinced Nancy we should stay with teak framed hatches rather than replace them with aluminum Lewmars or the like. I really like some teak even if it is more work.

That's the first step, convincing the admiral.

The "glass" will be 1/2" smoked gray transparent acrylic from Tap Plastics (pre-cut, beveled and finished

I would much rather have the real deal. Lexan, polycarbonate and the
like scratch easily.

I'm tempted to also make the joints simpler; butt joints rather than dovetail.

Why? You've already made dovetails on your last hatch. It only gets
easier with practice. If you don't want to hand cut them, I can show
you how to build a jig out of scrap to use on the band saw.

Here's a video of Rob Cosman hand cutting dovetails in record time.
http://www.youtube.com/watch?v=xxIgNel0H_I

And for further inspiration, here's a deck shot of Hetairos, designed
by my dad. Check out the 10 sided skylight!.

Martin

 

[Sven]

Hi Martin,

I would much rather have the real deal. Lexan, polycarbonate and the
like scratch easily.

Do you mean real glass ? where do you get it and is it the same shatterproof glass used in skyscrapers ? Can it be drilled or does it have to be set in a frame ?

You are right about the dovetail joints. That is probably what I'll do and I have the router jig for it so it is pretty easy with proper setup. My old router was getting ... old, so it was slowing down too much and chipping the teak no matter how careful I was so I ended up getting a new Porter Cable and now I don't have any excuse.


-Sven

 

[Martin King]

Yes, real glass. I used laminated safety glass in my hatches. Same
stuff in Hetairos, above and yes it needs a frame rabbeted to accept
it.

I don't like router jigs for dovetailing. First, the tails look machine
made and second, tearout, particularly in teak is a problem.
Unless you are doing production, you don't need to do them with
a router. Hand cut, and it really ain't that hard.

 

[Sven]

Hi Martin,

Yes, real glass. I used laminated safety glass in my hatches. Same
stuff in Hetairos, above and yes it needs a frame rabbeted to accept
it.

I don't like router jigs for dovetailing. First, the tails look machine
made and second, tearout, particularly in teak is a problem.
Unless you are doing production, you don't need to do them with
a router. Hand cut, and it really ain't that hard.

I admire your dedication to perfection. I'm just glad I don't have to compete with you

Edit: The video of the 3+ minute dovetail is amazing.


-Sven

 

[tenders]

That is an awesome video. He seems to eyeball all of the cuts he makes with the Japan saw. How he manages to do that and keep the patter going at the same time...if that were me I'd end up with 4 fingers left and the "dove" screaming for mercy.

 

[Martin King]

Yep, Rob is a fantastic craftsman/teacher.

 

[Sven]

Glue ?

Compromise, the worst of all choices.

I can't equal Martin's hand cut joints or bedded glass, but I'll do the best I can in the spirit of aesthetics.

So what epoxy do we use to glue the routed dovetail joints ?

Or some other glue altogether ? (we have quite a selection



-Sven

 

[Martin King]

West Epoxy.

 

[Sven]

Boy that was fast !

West Epoxy.

Even before I had time to reload the page

Martin, have a great weekend and thanks for the posts.



-Sven

 

[jthistle]

box joint for hatch

I was inspired by this post and started on the remake of the forward hatch of a 35-II. Here are the snaps. Simple. Sawblade width box joint. These are the rough cuts...fingers are a bit proud. I think they will sand smooth and a pinch of sawdust will make all well.

cheers
jason

 

[Sven]

I finally ripped and routed the teak we had set aside for the replacement hatches. The rough work is now done.

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