Wooden tongue and construction

[Arne]

I'm giving some thought to bulding no. 3, a standee... It would be based around the idea of the wooden house with rounded front and back ends.

I'm thinking of building a V shaped wooden tongue. Probably a 2wx3h" box. Ply 1/2" sides with solid wood top and bottom, similar to beams used in houses. Seems like it would be quite strong. It would be the simple V shaped tongue back to the torsion axle stubs.

In the front it would be solid wood for the hitch. Where the frame meets the tear, it would also be filled/solid wood for attachment, and also at the back next to the torsion stubs.

I have not figured out the weight yet, but I know that even one section of the h/f frame is noticeably heavy.... this is all about shaving off weight.

Once I figure out the weight, I'll post it....

AND, if anyone has a h/f frame unassembled, I'd like to know the weight of one piece of frame, I think it is 4' long....

Any comments are welcome.

[afreegreek]

there's a lot of boats out there that have their motor mounts bolted to two wood beams. I've seen a few with the beams built out of several layers of plywood too. these are real motors too.. 300 horse power cummins diesels and the like..

[Lou Park]

I'll back up anyone who wants to build a frame from wood and help anyway I can, but I wouldn't recommend a wooden tongue. It is definetly the one part of your build needs to never even crack. A hairline crack in a frame will still be supported by the box of the camper, but the A frame has no other support. It may last quite a while but sooner or later you will hit enough pot holes and RR tracks to break something up.
Lou

[afreegreek]

here's something that might interest you.. this bench is made up out of 6 sections each of 5 pieces of 1/2" x 4-1/2" epoxied together to make 2-1/2" x 4-1/2" beam.. this is a very strong method and under stress it won't break all the way through like a single piece of wood will..

[High Desert]

here's something that might interest you.. this bench is made up out of 6 sections each of 5 pieces of 1/2" x 4-1/2" epoxied together to make 2-1/2" x 4-1/2" beam.. this is a very strong method and under stress it won't break all the way through like a single piece of wood will..

Glulam construction is a tried and true method for many types of building. At first thought I'm sceptical of a wood tongue but it makes a person think.

[afreegreek]

nothing says you can't sandwich in a strip of 1/2 inch (or whatever) aluminum or steel either.

[aggie79]

nothing says you can't sandwich in a strip of 1/2 inch (or whatever) aluminum or steel either.

I think that is called a flitch beam.

[eamarquardt]

A friend of mine has a steamshovel (actually he has two!) and he's in the process of rebuilding the boom. It has a central wooden beam surrounded by steel reinforcement.

I agree that the tongue should be bulletproof. A couple pieces of 1/8 steel or even aluminum on the outside of the beam would add considerable strenght.

Good luck.

Cheers,

Gus

[dwgriff1]

The wood tongue on my woodie is laminated oak. I have punished that tongue on horrible roads for 4 years now and it shows no sign of failure.

Wood will show signs of stress before it fails and I religiously watch for any of those signs.

The triangulated tongue that I think Arne is talking about should work well. I gave great thought to the same thing, but got lazy.

The original tears were usually wood framed, but often used braces from the tongue to the corners of the box. Making that whole assembly into a box beam would provide great strength.

Also, tongue length will affect this. The old woodies had quite short tongues. There will be a lot more leverage on a 4 foot tongue as compared to a 22 inch one.

In this case shorter is better.

dave

[gregp136]

I like the idea. For me it is the definition of this forum. Try new things and let others know how it goes.

Greg (and Laurie)

[angib]

To my mind, trying to build a steel frame out of plywood is all a bit bass-ackwards. Steel is a very heavy, very strong material so you make a little of it do a lot of work - so a frame made only 2" deep is possible.

But plywood is a fairly light, fairly weak material so you want to use lots of it to get the same strength (and you can do that with less weight). So a wood tongue should be a very large (but thin) structure by comparison with a steel frame. That's how I ended up with this design for an all-wood Ultralight:



The tongue rapidly expands to a box at least 12" square and then simply blends into the front of the body.

Incidentally, plywood is in many ways not the ideal material for a frame as most of the stress is running one way - that's why glue-lam beams are made from plain wood, not from plywood. In normal plywood, about half the layers are running at right angles to the direction of load, so they don't contribute much strength. There are exceptions - these leeboards on a dinghy I built are made from very special plywood blanks intended for racing dinghy centreboards, which also are mostly stressed in one direction - so they have something like 17 or 19 plies (in just 3/4" ply so this is ultra quality plywood) but only 3 of the plies run across the board and all the rest run along it. So it's a bit like a glue-lam panel.



Andrew

[Ageless]

Andrew; in tooling we built seal and gasket dies using a high density ply; 3/4", 12 plies. I actually took a piece out and shot it with a .32 mag. The bullet did not go thru. This was obtained from a marine supply company.