Inner wall template cutting

[kokomoto]

I am attempting to follow the sandwich method in Steve Fredrick's manual. The sandwich frames are completed (for the most part). I have already gang cut 4 sheets of 1/4" plywood to the teardrop shape using the template. I am now looking at cutting the inner walls down to allow for the ledge that the ceiling and spars will sit on. As I read the instructions, my understanding is that I need to mark a concentric line on the inner wall that is approximately 1 5/8" short of the outside wall edge. Then gang cut the two inner wall plywood sheets to to that smaller, concentric shape. These sheets will the be used as a template to cut the wall sandwich frame down, creating the remaining part of the ledge.

The part that is hard for me to visualize is when it comes to the galley portion of the wall. It obviously doesn't need a ledge with no spars in that area. So, can I assume that the ledge cut out of the inner wall plywood would end at the rear portion of the doubled up spar for the galley hinge with sandwich wall aft of that left alone and matching the original template profile? There seem to be a variety of ways to skin this cat. I have seen a few examples of builders cutting a square notch through the entire wall to sit the galley hing spar into, or that is the way it appears. That looks like a method I'd like to use. I just want to make sure I am understanding this clearly before cutting the sandwich frame, and possibly ruining several hours of labor.

[tony.latham]

So, can I assume that the ledge cut out of the inner wall plywood would end at the rear portion of the doubled up spar for the galley hinge with sandwich wall aft of that left alone and matching the original template profile?

Kokomoto:

Yeah, you want the ledge cutout to end at your hatch spar. I'm trying to think where Steve has that 1 5/8" measurement? Is that going to be your roof depth?

Here's some pics that may help:



I think the next phase, after this photo, is to remove the hatch ends.


This one is from a different teardrop. And as you can almost see at the bottom of the page, the inner wall hasn't been cut to the same level as the skeleton. The next step would be to cut it off with a trim bit that follows the skeleton edge.




Tony

[kokomoto]

In the 2nd photo, the wall has the inside facing down, if I am looking at it correctly. Are you rough cutting the hatch recess with a jigsaw, then trimming it level with a template and router? If so, the next step would be to glue the 1/8" & 1/2" ply sheets to the galley wall insides?

You're method looks like it follows Steve's with a few minor changes. Was it one of your posts that described gang cutting the 2 inner wall plywood pieces, then using them as templates to cut the skeleton down for the spar ledge instead of Steve's method of using the roto zip bit in the router? I thought I had bookmarked it, but can't find that post.

Thanks Tony! The right picture clears up a lot of confusion.

[kokomoto]

Yeah, you want the ledge cutout to end at your hatch spar. I'm trying to think where Steve has that 1 5/8" measurement? Is that going to be your roof depth?

I think it's around page 56. That's 1 1/2" for the 1x2 and 1/8" for the ceiling ply. I guess that's what I'll use. Would 12" spacing be sufficient for spars that are doubled up 1x2s? Use poplar boards or yellow pine?

You're using the skeleton as a template with a guide bit to trim the interior ply for the ledge. For some reason, I thought you did it the other way around on your builds.

[tony.latham]

In the 2nd photo, the wall has the inside facing down, if I am looking at it correctly. Are you rough cutting the hatch recess with a jigsaw, then trimming it level with a template and router? If so, the next step would be to glue the 1/8" & 1/2" ply sheets to the galley wall insides?

You're right, that's the outside. I just cut the hatch ends with the jigsaw and call it good. I think if you finished it up with a pattern and trim bit you'd lose too much material.

You're method looks like it follows Steve's with a few minor changes. Was it one of your posts that described gang cutting the 2 inner wall plywood pieces, then using them as templates to cut the skeleton down for the spar ledge instead of Steve's method of using the roto zip bit in the router? I thought I had bookmarked it, but can't find that post.

I don't think that was my post. I do gang-cut all 4 of the exteriors/interiors. I think it's time-saving to mark the roof-lip on the skeleton and cut it out with a jigsaw––and save it. And that way you've got the blocking pieces that you'll glue between the spars. When I set the blocking pieces they sit 1/8" proud because the are now sitting on the ceiling. A long trim bit with the bearing on top will fix that issue.

Tony

[kokomoto]

Got it. I think.

image.jpeg (132.23 KiB) Viewed 1117 times

Which leads me to another question. On the photo of your wall above, is the distance between hatch spar square cut-out and the cut-out for the hatch critical for any reason? Looks like something less than an inch in the photo. I plan on using the "better than hurricane hinge" if Grant still sells them.

[tony.latham]

Got it. I think.

image.jpeg

Which leads me to another question. On the photo of your wall above, is the distance between hatch spar square cut-out and the cut-out for the hatch critical for any reason? Looks like something less than an inch in the photo. I plan on using the "better than hurricane hinge" if Grant still sells them.

Damn good question. Yeah, that's the 3/8" gap for your hinge. That's for Grant's hinge.

Tony

[kokomoto]

That should give me enough Intel to proceed with the walls. Question thrice, measure twice, cut once.

I'm not sure that I wouldn't still be drawing this thing out on grid paper if it weren't for Steve's manual and your guidance. It sure it fun building this thing though.

[tony.latham]

That should give me enough Intel to proceed with the walls. Question thrice, measure twice, cut once.

I'm not sure that I wouldn't still be drawing this thing out on grid paper if it weren't for Steve's manual and your guidance. It sure it fun building this thing though.

It's even funner camping.



Tony

[kokomoto]

It's even funner camping.
Tony

Now there's some motivation.

Walt

[noseoil]

This is the side panel, different but the same. Hatch is a different style than Tony's.



Rabbet joint for spars using an edge guide for the router.

[kokomoto]

Yeah, you want the ledge cutout to end at your hatch spar. I'm trying to think where Steve has that 1 5/8" measurement? Is that going to be your roof depth?

Here's some pics that may help:



I think the next phase, after this photo, is to remove the hatch ends.


This one is from a different teardrop. And as you can almost see at the bottom of the page, the inner wall hasn't been cut to the same level as the skeleton. The next step would be to cut it off with a trim bit that follows the skeleton edge.




Tony

BTW, what are the dimensions of your hatch spars? Looks like they are a bit thicker than the rest based on the square you have cut.

[Esteban]

My understanding is that the 1-5/8" ceiling rabbit is to provide just enough room for 1/8" ceiling plywood plus (actual sized) 1-1/2" high spars glued on top of the ceiling plywood.

The plywood for the roof then can be glued/attached to the top of the (higher) outside edge of the rabbit and the installed roof spars.

If you use another (height) size spars and/or ceiling plywood your rabbit would need to be calculated to fit them both.

[kokomoto]

My understanding is that the 1-5/8" ceiling rabbit is to provide just enough room for 1/8" ceiling plywood plus (actual sized) 1-1/2" high spars glued on top of the ceiling plywood.

The plywood for the roof then can be glued/attached to the top of the (higher) outside edge of the rabbit and the installed roof spars.

If you use another (height) size spars and/or ceiling plywood your rabbit would need to be calculated to fit them both.

That's the method I intend to use from Steve"s manual for the standard roof spars. However, in the picture that Tony included in his post, the square cut-out for the galley spar is cut deeper than 1 5/8". The top or first picture in his latest post illustrates it more clearly. I guess the question is, should the galley spar be larger than the other roof spars to provide a stronger structure for the galley hatch attachment (besides doubling them up ?

[Esteban]

My understanding is that the 1-5/8" ceiling rabbit is to provide just enough room for 1/8" ceiling plywood plus (actual sized) 1-1/2" high spars glued on top of the ceiling plywood.

The plywood for the roof then can be glued/attached to the top of the (higher) outside edge of the rabbit and the installed roof spars.

If you use another (height) size spars and/or ceiling plywood your rabbit would need to be calculated to fit them both.

That's the method I intend to use from Steve"s manual for the standard roof spars. However, in the picture that Tony included in his post, the square cut-out for the galley spar is cut deeper than 1 5/8". The top or first picture in his latest post illustrates it more clearly. I guess the question is, should the galley spar be larger than the other roof spars to provide a stronger structure for the galley hatch attachment (besides doubling them up ?

My teardrop construction is long delayed.

The hatch bulkhead area spars I'll use will be (widened) doubled 3/4" x 1-1/2" popular and/or a hardwood so the hidden hinge has plenty of "meat" to screw into. If one side of the spars is exposed to the eye in my galley I'll use ash or oak on that side for appearances sake. They will be built directly on top of the galley wall/bulkhead; or just a few inches further back into the galley. I foresee no need to make them taller in order to make them stronger. Doing that would slightly reduce the upper cabinet space which I don't want to do.
Although I have thought about making the last one of them just a little deeper, maybe about 2", with a small lower lip that would conceal the base of a LED light strip in the upper galley ceiling area. Decisions, decisions?!