CNC Build: The Bed and Breakfast at 4 years and 40,000 miles

[KCStudly]

Any reason for making the notch between the 'C' part and the rib part so deep, and the 'C' section there so thin? Why not leave this "meat" in for added strength?

Watching your progress is pretty cool.

[capnTelescope]

Any reason for making the notch between the 'C' part and the rib part so deep, and the 'C' section there so thin? Why not leave this "meat" in for added strength?

Just cuz it was easier to draw a vertical line. Good idea.

Watching your progress is pretty cool.

Thanks! I'm enjoying the process. It wouldn't be near as much fun if nobody ever said anything.

[mezmo]

Not trying to be a killjoy here, but have you thought about using:
Car trunk lid hinges?

https://www.google.com/search?q=car+tru ... 9#imgdii=_
Shop for them on Google:
https://www.google.com/#q=car+trunk+lid ... 1013719859
An example:
http://www.ebay.com/itm/like/280935028045?lpid=82

Other than wanting to do it out of wood - as a design preference - something
like the above may be cheaper and stronger.

Just throwing it out there for consideration.

Cheers,
Norm/mezmo

[capnTelescope]

Hi, Mezmo. Thanks for joining the discussion.

,,,have you thought about using:
Car trunk lid hinges?

Funny you should mention that. I've been contemplating a trip to a pick-your-part to do some research and/or part finding.

Just throwing it out there for consideration.

Consider it to be considered, considerably.

It might be good to get away from the drawing board for a while.

[capnTelescope]

I've been contemplating a trip to a pick-your-part to do some research and/or part finding.

So Mezmo motivated me out of my chair and I went. Hey, where else can you have this much fun for $2?

Here's what I learned: They had lots of cars with no trunk lid, but with the hinges still attached. I wonder if that means anything? There are basically two types of trunk hinge. There's the capnTelescope(cT) version, and there's the 4-bar linkage type:

Four bar linkages require a deeper wider drainage ditch for mounting, which is undesirable for this application. But they are a bit cool.

The cT version is far more common, at least in this sample of junkyard cars. Are cars more prone to end up in the junkyard with the cT hinge? Gas cylinders or torsion springs are used for lift assist. There's a third variation on old VW Beetles that has a guide rod thru a coil spring which is actually quite compact.



All of the cT examples have the pivot point up high. How high? I'm not sure, as none were accessible. I'm speculating that to get to the top half of the hinge, you have to get in under the back window. I did not see any means of removing any hinge from inside the trunk. This might by why so many empty hinges were still attached. Plus, they probably charge extra. Bottom line, I went home empty handed.

something like the above may be cheaper and stronger.

Cheaper? maybe not so much. Stronger? Without a doubt. Now I'm pondering what a small weldment would look like. With the wooden cT hinge 3.0, the pivot point is 1-1/4" radius from the spar bottom and 2-1/4" from the bulkhead. Even only 3/4" higher and farther forward would be a good thing.

[capnTelescope]

Hatch 4.0 is now up on the dry assembly. Based on Hatch 3.0 and inspired by my trip to the junkyard and Mezmo getting me thinking in metal (stronger), Hatch 4.0 is an improvement in geometry over previous designs. It uses a real metal hinge for higher, more forward placement of the pivot point.It offers a clean, non-interference opening/closing with a reasonable gap between hatch and roof. Finally, it should be more economical of plywood, as the fat end isn't as big as before. Unfortunately, at this early stage of the design, it is more difficult to accurately locate the parts for optimum fit to the hatch opening.

Ladies and gentlemen, I proudly present Hatch Hinge 4.0! (Cue "Putting on the Ritz.")

The perspective gives an incorrect impression that the plywood "skin" is low. it's just fine

This is the best full up yet. On Hinge 3.0, the end of the skin piece was just below eye level. Now it's up over my eyebrows.


Top view. The gap between hatch and roof can be even smaller than shown, but this is pretty much what I want all the way around.


The left end is low by the amount of light colored wood you see behind my finger. This is the worst first try, so far. The cause is probably some obvious mistake in layout.


This design holds the most promise so far, If I can conquer the layout problem.

Thanks for stopping by!

[KCStudly]

That's a little different.

What will keep the rain water from rolling down the roof and hatch into the top of the galley? I realize that you plan to create a gutter around the inner edge of the opening, but will that be enough for run off water?

[capnTelescope]

What will keep the rain water from rolling down the roof and hatch into the top of the galley?

Good question. There will be weatherstrip across the top (and bottom, as well) for when it's closed, but I'll have to have enough sense to close the hatch if rain threatens. I'm unlikely to be cooking in a downpour. I suppose a rain gutter across the top edge of the opening wouldn't hurt either.

Yet another advantage of the Hurricane Hinge.

BTW, in this design, did I address your concern when you wrote

Why not leave this "meat" in for added strength?

about hinge 3.0?

[KCStudly]

Yes, but I wasn't anticipating the change to what looks like a gate hinge and perpendicular plywood mounting plate. I assume this was an attempt to move the hinge center further forward.

Are you planning on using a harder wood for the hinge spar in the beta test?

Regarding the rain; I guess I'm looking at it a little bit differently. What say it is a modest rain in warm weather with on-and-off sprinkles among periods of dampness. Do you huddle inside the camper, or try to make the best of it under the ez-up that's pitched behind, (slightly overlapping) the raised galley lid? (Some people put a party tent up over their whole TD!!!)

Sure, if it's pouring buckets and splashing all over, but what if there is a steady light rain for a day or more? Mans gotta eat.

I'm playing the devil's advocate because I want this to work for you.

I struggled with choosing a piano hinge with rubber strip outer cover instead of a hurricane hinge because I don't want the rain gutters sticking out and interrupting the wall to roof radius (aesthetics), so I get the concept. However, utility (i.e. keeping the rain out and not whacking your head on the edge of the open hatch) needs to come first.

I wish I was at this stage in my build! (Soon enough, I suppose. )

[capnTelescope]

... what looks like a gate hinge

It is a gate hinge. It's a gate hinge because that's the hinge I had. I'll get good heavy door hinges if this design goes to build.

...and perpendicular plywood mounting plate.

Yeah. I'm not happy with that part, yet. Actually, it would be the top end piece of the hatch frame. I mentioned earlier about layout. This piece as-is doesn't positively locate the hatch ribs, which is very 'portant for good fit. Needs more drawing board work. There will be a hatch hinge 4.1.

Are you planning on using a harder wood for the hinge spar in the beta test?

I'm thinking maybe a nice hunk of 4/4 quartersawn white oak for the final build. That spar is a major important piece. I will continue to prototype in poplar and HD sheathing grade ply.

Regarding the rain...

I guess I'm not that used to rain. Central Texas has been in a drought since I got here, and in SoCal, well, the song says it pretty well.

... what if there is a steady light rain for a day or more?

I've had occasional rain when I camped, never steady for a day or 2. Always checked the wx report before I took off. Never had a teardrop to worry about getting wet, either. This is all so new to me. OTOH, a nice rain shower is all part of the camping entertainment. Like watching your camping buddy get soaked trying to find a tarp in the back of his truck so he can cover up his sunroof hole, because he can't close the sunroof, because he can't find his car keys, which are hanging from his driver's door lock, right there in front of me, and I can't understand why he's going to all this trouble.

... because I don't want the rain gutters sticking out

I don't either. That looks like something to rip your clothes or skin on. The great outdoors is already fraught with enough danger and discomfort without bringing it with you.

Besides, it's a camping trailer. After a while, it should look happily camped in.

I wish I was at this stage in my build!

Hang in there. You too will get finished one day. Well, OK, campable. You'll get campable one day. Poet Creek is calling you! I wish I was where it looks like I am. I so wanted to keep going when I did the loose assembly. Once I get this hatch settled, I think things will move pretty fast.

[GuyllFyre]

Paraphrasing the quote, "no one has ever complained that they should have built heavier."

Then let me be the first.
My 4x8 was too light.
It towed better with a few hundred more # added when I put the ice and beer into it.
My 5x8 will be heavy enough this time.

[capnTelescope]

Welcome to my thread, GuyllFyre.

KCStudly wrote:Paraphrasing the quote, "no one has ever complained that they should have built heavier."

Then let me be the first.

Oooo. That can't be good. I stand corrected. (KC was quoting me from my design thread.)

And then there was the lady foamie builder, her name escapes me, whose tear blew over on its side in a strong gust. While she was quite upset about the whole thing, she didn't make that particular complaint.

Thanks for stopping by, and better luck with the 5x8.

[GuyllFyre]

When I saw "CNC" I had to get into the thread.
I so wish I had a CNC. Maybe in a few years. Would make it easier to manufacture perfect side profiles.

[capnTelescope]

Would make it easier to manufacture perfect side profiles.

and hatch spars, cabinetry, ... It's a really versatile tool, for general woodworking as well as for teardrop building. In the meantime, learn CAD, if you haven't already. CAD skills and your imagination are the only real limits with CNC. It's a blast. Get one!

[GuyllFyre]

I think the CNC started acting up after I replaced the original computer that died. It just finally became a really big PITA problem. I couldn't really pin down what the cause might be. Could it be that stepper I dropped once, the motor wire that got caught in the gears, weak stepper driver, the breakout board (a real black box for me), bad connection, the PC? How can it be a computer and be an intermittent problem? It was like staring into the abyss of a huge time and money pit. What if it needs another new computer? Do I go to the same store for another cheap used one? What if that one doesn't work either? Do I upgrade to a new desktop and put the one I'm using now to run the CNC? What if it doesn't work? What if I don't want a new desktop? What if Mach doesn't run under Win 7 or 8? What if none of this works? Aarrrrrrrghhhh!!! ( I want my mommy!) While I'm in the middle of this meltdown, the Ethernet SmoothStepper came to my attention. The size of the bet was a little bigger than another used computer, but I was disillusioned with the parallel port thing. Fortunately, the SmoothStepper appears to be working very well. (Knock on wood. ) I did have to install a second network card so I won't have to run SneakerNet for drawings, g-code, etc.

I know that this is quite a way away from the end of the thread but I wish you lived closer because one can build a "purpose built" computer/controller for extremely cheaply. If Mach3 only supports Windows, then there's other tweaks you do to the computer and the version of Windows it supports.

There's a few factors at work and it has to do with the fact that Windows is supposedly a multitasking operating system, which does not make it a "real time" operating system.
Ethernet connection to an old Windows box is a BAD idea. In order to make a Windows computer fast enough to support realtime, you should never connect it to the network. Also remember that there are going to be no more patches or security updates for XP in April. The Internet/network is a bad place for an old XP box.
If Windows XP, go into system properties and set the advanced properties to "best performance." Then go to your desktop/video settings and select Windows Classic. Also go into your video settings and select the lowest useful color bit settings, like 16-bit instead of 32.
You run no antivirus, you disable the firewall, you disable any security notifications, you strip out every option you do not need, you run the fastest CPU you can find and have 4GB of RAM, you use a decent video card to offload any video to the separate GPU (onboard takes away CPU cycles and RAM), you disable Windows Updates services, Windows Firewall services, BITS services, and network server services. If possible, go into BIOS and disable audio, com ports that aren't needed, IDE/SATA ports that aren't needed, and anything related to network. If you can pinpoint and disable any USB ports you won't be using, disable those as well.
Any hardware you can disable so that it doesn't have to be kept track of gives the computer more time to focus on what it should be keeping track of.
It is also best to use a new SSD (Solid State Drive) instead of a conventional hard drive. The speed increase is stunning
Once this is done, you can also set the Mach3 software to run at the highest level of priority available. Windows won't always let you set it to realtime but at least you can set it to a higher priority.

Yes, this results in having to sneakernet stuff to the computer on a flash drive but it also sets things to be more "Controller" than "Computer."