Tucson tortoise: Edit for photos

[noseoil]

Thanks for the picture Frank, will see how things go when I get there. Not going to be too soon at the pace I'm working. So you didn't use any plywood for an underlayment for the skin, just the aluminum?

Back at it again this morning. Started locating things a bit more, worked on the bumpers, latch mechanism & strut attachments. Here's the latch block, 3/4" plywood with "T" nuts to hold the 1/4" bolts. I counter-bore the back side with a speed-bore bit to set the inserts flat to the block & flush so the 1/8" goes on without any lumps when it's time to do the plywood skin.


After things are located, I mix up some 5 minute epoxy to pot the inserts & make sure they stay put once things go back together again. Screw it all together & let it sit, all set in no time in the heat! Have to work fast and have everything mapped out or the epoxy kicks off too fast and I run out of time.


Same thing for the strut braces. All of this will be glued in place with titebond for the final assembly, but as I said, it's all just a dry fit for now to check things & locate all of it first. The last thing I need now is to get out of sequence on something at this point. It's enough work without the mistakes.




Here's the hatch now with a few more things in place. The bumpers are located, but I still need to pot the inserts once the hatch is out of its opening. For now just a few drywall screws are holding them in place in the pilot holes. The latch handle is located, but I will still need to drill for the rods & cut them to length so they extend into the sides when they lock. With this latch type, the rods travel about an inch with a 1/4 turn of the handle, so I'll have about 5/8" engagement on both sides, which should be plenty for what I have. I may leave the rods out about 1/8" if the hatch doesn't have any twist when it's done, so there might be more like 3/4" of grab into the sides.


What's left still in the hatch framing department? Need to do the blocking for the back-up lights. They will be above the bumpers and routed into blocks. Need to make a jig for the cuts as I'm using a reverse flush cut bit & the plunge router. Stereo speakers will need enclosures which hang down from the inside the hatch and miss the cabinets, struts, etc. Galley light blocking, license plate blocking & paper towel holder all need to be located. Wire runs & grounds will need to be located as well, so I'm not there quite yet. All in all it was a good weekend of work.

[KCStudly]

Great progress!

You may have already given this some thought, but now is the time to set the length on those hatch latch bolts. Once you have them set, bag and label clearly so that it is easy to keep track of them; you wouldn't want to put too long of a bolt in there once the outer skin goes on. Where I had the leeway, like on my hidden floor to trailer threaded inserts, I actually sank the inserts a little deeper than flush in order to be sure I get full thread engagement while still leavening a good margin between the tip of the bolt threads and the skin. Sometimes you can set the t-nut depth to suit a stock length bolt (with whatever stack up of grip is needed for the clamped item and washers, if used), but other times you will have to trim the bolt length and chamfer to suit.

[Sheddie]

Thanks for the picture Frank, will see how things go when I get there. Not going to be too soon at the pace I'm working. So you didn't use any plywood for an underlayment for the skin, just the aluminum?

It is skinned with 4mm ACL, which is made up with about 3mm of plastic composite core and around 0.5mm of aluminium bonded each side. All the exterior is clad with ACL and it is pre-painted. The sides are glued on to the ply walls and the front and top, are like the hatch, and glued directly to the spars.

I really like the grab handles you are using on the back

[felixx]

Looking good

[noseoil]

Thanks guys. KC, I'll get some shorter fasteners or cut off the long ones and use a zip-lock baggie to store them (clearly labelled) until I'm ready for the assembly. A bolt sticking out 1/2" would be handy for hanging something later on, but might not look too good in general sticking out of the back of the hatch.

Frank, I'm hoping the combination of blocking, 1/8" plywood on both sides & the ribs will be enough to hold things in place. I may still add a couple of "doublers" or "cripples" to the inner framing, to stiffen up the outside edges if it seems a bit soft or wants to flex too much. Just gluing some extra sticks may help a bit. The main stress in this design will be at the point in the curve closest to the strut attachment, roughly the center-line of the hatch as it opens & closes. Most of these forces will be transferred through the hatch when it's opening & closing, with the hatch trying to fold up at the strut attachment. We'll just have to wait & see how it does later on. The "grab handles" are just 12" Moen bathroom assist bars, made out of stainless steel. They actually look OK the way they're being used, but I may move the blocks outboard a bit more. They look too close together now for my taste. Maybe another 2" or so perhaps for each one? Since it's a dry fit, I can still move them as much as I want.

felixx, thanks for the kind comment. Means a lot to me coming from people who have done their own builds or are a bit further down the road than I am at this point. Still amazes me to see how much time, thought & energy something simple like a hatch can consume, to say nothing about the amount of effort & hours spent on this thing. So far I have 258 hours of actual build time. No way of telling how many hours of research, planning & thinking I have now. Fortunately, that's not something I'm tracking!

[KCStudly]

The handles look okay where you have them, but I tend to agree with you that they would look a little better just a little further out. I think you want the space between them and the outside edge of the hatch skin to be about the same as the space between them and the tips of the T-handle on the latch, or there about.

Might have to nip the corners of your corner gussets a tad to move the blocking, or just replace the gussets with a slightly larger block that performs both functions.

It is amazing how much time the details take!

[noseoil]

OK KC, I did just that & trimmed the bolts so they won't poke out through the skin when it's glued in place. I think it looks better with the bumpers farther apart now.

Here's the setup for the router to mortise the back-up lights into the blocking which will hold them. Used a reverse flush cut bit to cut the blocking for the trim rings. This is how I do a jig setup for routing out a hole that isn't round. Band saw the two halves which have the curves, cut a few sticks on the table saw & then glue & nail the parts together. It takes a bit of time to make the jig, but it's really easy if there are multiple cuts that are all the same size & it isn't any trouble to make. It's still faster than making two holes by hand & trying to make them fit well & be the same.


The parts before assembly.


The parts as a jig prior to glue & the end blocks being set in place.


Router setup for the passes. Just a series of steps to cut the 3/4" plywood. Used drywall screws to hold the jig to the plywood so it's indexed properly. Nothing fancy, just something which works.


Here's a shot of the corner with the bumper moved outboard & a back-up light in place in the hole.


Worked on the latch rods for the latch setup. Cut them to length, bored the holes, then lined it all up & put the rods in place. I made a simple jig with a center-line marked & giving the correct depth from the back edge, just a hole from the drill press & another block attached to keep it aligned & in the right place. That kept the holes aligned & I cheated a bit on the inner holes, wobbled them just a tad up & down so there isn't any binding when the latch turns & the rods move vertically a little closest to the handle.

I'll wait to drill the rods into the body until the hatch is swung on the hinge, gaskets are in place & everything is glued together as a final assembly. No need to hurry on this part of the build. I want the hatch to give a solid "click" or maybe a "thunk" when the handle turns that 1/4 turn & the rods engage into the sides. I may use some 5/16" I.D. tubing to line the holes in the sides as inserts, so the wood doesn't wear over time.

]

The hatch now with things located & ready for final assembly. I'm thinking tomorrow I'll begin the actual assembly with glue to put it together permanently, then it's ready for the 1/8" outer skin to go on. I made a cardboard pattern for the speaker boxes this morning with the hatch in place, just a couple lines traced with a pencil to get the contour. They'll be next to the struts & hang down from the inside when the hatch is closed. When open, they point aft & down a bit. Still thinking about how they'll be made, fastened in place & installed. The boxes are located in front of the upper cabinets somewhere when the hatch is closed. Paper towel holder & galley light is between the speaker boxes.

[dales133]

Hey mate where did you get the internal lock mechinisim for yout T handle galley latch?
Im struggling to find one.
Ive installed stacks of handles on garage doors but the mechinisim they use is unsuitable.
Any help apreciated

[noseoil]

I got this one at Vintage Technologies. It's a good latch, stout, positive mechanism & well made. The rods are about 8mm steel, so it should work well enough. The list is about $40 USD, so it would be a bit "spendy" to get it shipped over to you. That price includes the latch body, locking handle & 2 rods about 3' long each.

[dales133]

Thanks mate.
Going to the special order desk at my supplier now to see what they can get

[KCStudly]

The bumper arrangement does look better now. You'll be glad that you took the time to get that the way you wanted it now, rather than be unhappy with it.

She's coming right along. Keep up the good work!

[noseoil]

Thanks KC, I think it looks better also, just a small thing, but better in general. Again, I'm glad I'm still not in a hurry on the build or some of this stuff would be driving me nuts at this point.

Took an easy day today (Sunday) and nothing much to show by way of a picture. I took the hatch completely apart & glued it all back together with Titebond II & 2" drywall screws. It's shimmed back in place again with the 1/2" spacers & is now baking under the tarps in the afternoon sun. It's only 97 today, but with the sun shining on the tarps & the hatch sitting under them, the glue should be nice & cured by next weekend's work.

I've started looking at the hinge setup & realized that somehow I got the gap at the top off just a bit. It looks like I'll have to shim the top edge of the hatch with a small strip of oak to take up some of the slop & tighten things up for the fit. Not entirely sure how I managed it, but I'll just rip a piece of 4/4 red oak which is 5' long & tapers from about 1/8" down to a 1/6" at the other end. This will be glued to the hatch prior to skinning with the 1/8" BB on the outside, so when the edge is cleaned up with a router, it will finish out OK & give me the gap I'll need so the hinge closes correctly.

I'm beginning to realize that the hatch is perhaps the most complicated part of this entire build and consumes the most time in the overall scheme of things. Ah well, not going anywhere next weekend and it may be cooling of a little, down into the 90's for a change. Might need to break out a sweater soon....

[KCStudly]

No biggie on the hatch adjustment. Sounds like you'll be able to work it out

IIRC my walls are about 1/16 inch different in length and about 1/32 shifted from side to side. But worse, my cabin side hatch spar is about 1/8 inch further forward on the cabin side. With my surface mount piano style hinge, my only concern is seal compression, not hinge or hatch alignment. But then again, I have yet to do my final seal gaping, so not worried yet.

[OP827]

Noseoil, I have a suggestion if I may. I looked at the strut attachment and thought, would that be a good idea to glue a reinforcing vertical piece of hardwood to the plywood hatch side rib to reduce the stress on the rib from the strut pushing it outwards, especially in closed hatch/transport mode? Just some food for thought.. I saw someone on this forum did such reinfocement, but could not find that picture or thread.

You have a nice build, well planned and executed.

[noseoil]

Yes, I think it's a good idea to put an extra block at that point on the sides. Just a stick glued against the back of the plywood block & against the side frame would help stiffen things up a bit more and make it more solid in general. When the hatch is held in the open position by the struts, there will be a fair amount of weight hanging on the lower edge (lights, bumpers, latch assembly, blocking, etc.) & trying to fold the hatch at the strut attachment point. When the hatch is in the closed position, I want it to keep its contour on the curve to maintain a good seal, so a few more blocks with nails & glue can't hurt. It's not that much more weight and should help tie it together a little bit better. Also need to add two corner blocks at the top edge (where the hinge attachment is), as they aren't in place there yet and will help hold the top corners in place.

I'm thinking I will add some blocking along the outermost two ribs, from bottom to top, to stiffen them up a bit more. Right now they "feel" strong enough, but with the added weight from the skins, aluminum and the other odds & ends fastened in place, a bit more strength & stiffness can't hurt things. I'm also thinking I may add a couple more small braces in the center section as well, just some more sticks added to stiffen the ribs and spread out the forces into thicker members which would have less give to them.

What it would really need would be some "X" bracing to really make it solid and add more depth to the structure, but that's the job for the inner & outer skins when they're in place. Once the sandwich is made, it will be rock-solid and shouldn't change it's shape at all. I just want to get the curve as stable as possible before I do the skins. Frank's hatch (Sheddie's build) set up very well when he added the inner composite skin & that's what I'm thinking will really help with mine as well when it's time.

Once I've added the extra sticks & fixed the gap-atosis issue at the top where the hinge is attached, it's time to put the outer skin in place & work on the hinge attachment at the spar. Thinking I'll do wire runs prior to skinning, as it's easier to drill holes without having the outer skin in place.

Thanks for looking & for the input & feedback, it's greatly appreciated.