Gas Struts

[rickst29]

I have not yet opened the TM to put push the bigger "through the floor" bolts up into the interior. It needs to be opened up to set the washers and nuts on bolt ends sticking out of the floor, and I'll need a friend with a wrench (underneath) to keep the bolt heads from turning when I tighten down the nuts from inside. I'm also still waiting for delivery on the big stainless washers for the lift arm strut mounting bolts. (The are each 2" wide, 1/8" thick.)

The 5/16 strut mount bolt goes through the arm sideways from "outside" into the TM. The the big washers let me add some smaller bolts and nuts through the washers at about 3/16 distance from the large bolt hole.

The additional holes and small bolts provide contact more area between bolts and the thin sheet metal of the two lift arm "wide" sides. That will help to prevent the strut post bolt from cutting and bending the sheet metal under load. (Al the bolts would have to start cutting together, in order for the washers to move at all.)
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If I were doing this again, I would cut the holes containing deck screws about 1/8" further from the inner bend of the the L bar. TM placed their own larger screws further inward from the floor edge than I did (one of those screws is present in photo 'Inside L Bar Corner Detail'.)

Photo #1 is curb-side, looking towards the front end (with TM hitch not visible at this angle). The angled and heavy "countertop support" is 12" long before a 90-degree bend, then 6" after.

In photos #2 and #3, the 12" long end of countertop support descends from the L bar at an angle, held at that angle by two bolts 1" which go through both bars. (I think that it's strong enough - but if one or both bolts were to shear off, I could re-cut the holes to larger diameter (bigger bolts). I could also add a 3rd bolt between these two.)

photo #2 is taken from the floor underneath the trailer. You see nearly all of my deck screws, they're all going up through curb-side edge of the floor, and into bottom of the wall. (They're not straight up, they're slightly angled from each other - the same way carpenters nail 2x4 and 2x6 framing pieces together.) Closer to the top of the photo, you see 1/4" holes pre-drilled for additional bolts into the floor, not the wall. These will come up into the front bench bench storage areas, bolted into interior nuts and washers on the floor. Coming down outside the assembly lift bar itself. Above that, also outside, you see the front shell's side edge and stapled-on bag seal going "up".

I drilled those 1/4" curb side holes at greater distances from the row of deck screw holes. I hope that the resulting "holes in the floor" will be slightly away from the curb-side seat support "bottom strip" lumber segment which is present along the corner between the wall and floor. TM is closed up, I don't remember how wide (from the wall) that piece of wood actually is, but it would save work if my bolt holes all come up inside of that seat supporting segment, by at least the 1/2 the width of my 1" washers..

On the street side, my "area of floor" is almost immediately disrupted by the water tank. I except to use either smaller washers or a thin strip of 1/8" aluminum, glued to the floor and replacing a very thin strip of molding which I see in Shane's photo (previous page). I hope to have maybe 1" of width before outside edge of the the water tank. My bolt holes are all cut to be barely 1/2" in from the inside wall vertical face.

[rickst29]

I think that the large number of deck screws is more than sufficient for the entire anticipated load, although I don't intend to actually test that.

All of my deck screws are going through TWO layers of 1-inch wood (not only one). The floor definitely contains more wood along the street side and curb side edges - that's 1 inch thick and possibly more than 1" one wide (horizontal).

Placement of the 4 OEM bolts, holding TM's shorter and thinner L" plates against the floor, seems to imply more than 1" of width in those floor edge boards. But those plates and torsion bar guide holes are probably not carrying significant weight, even in lifted/open configuration.
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All of my pilot holes were cutting into wood (not foam) all the way up. Just two screws easily hold the lower assembly in place, that's maybe 15 lbs all by itself.

I'm unsure of the actual force from these gas struts, the "ratings" may be referring to the weight being lifted. And the gas strut force will be offset from screws, creating torque with a moment arm of about 6" from the row of deck screws. But I think that they could handle all the force themselves; slightly bigger wood screws (#10 or #12) would have provided even more strength than the #9 deck screws.

I'm not going to test that. I will be using the additional 1/4" support bolt holes.

[rickst29]

The lift arms are about 3/4" thick, and I need about 1/4" of bolt shank sticking out the opposite side of the lift bar (next the the side of the shell) to use ALL the Threads of the terminating nut. Even if I squeeze the lift arm sides together a bit a tiny bit, there is "room" for only 1 or 2 extremely thin washers.

This "straight up bolt" style of 10mm ball mount post is not available with a shank longer than 1" (with 5/16-18 threading on the shank), or 25mm (M8-1.25 threading), which is nearly identical length.

The total length which I need, WITH my pair of really wide and thick washers (1/8 thick each), is about 1-1/2" inches. Wasting a bit more time and money, I bought some M8 - 1.25 12mm-wide round couplers off Amazon. At 20mm, the coupler length fits the lift bar thickness almost exactly.

I also bough some short M8 bolts, and cut down the shank on each of them (two bolts) so that the portion into the coupler, with the washer tight, is a bit less than 7 threads long. I put those in (with locktite).

From the outside, the lift bar ball mount post has about about 8 threads going into the coupler using the big washer alone. (I may add a lock washer between the body of the ball mount an d the big washer, in addition to some medium "locktite" in the coupler threads) This can be tightened to the limits of the 8MM SS bolts and coupler, although I will not push them anywhere near that far.

After attaching to the lift arms, I will add 5 or 6 thinner SS bolts and nuts (1/4" x 1-1/2" long, 20 TPI), arranged in a circle, close to the rim of each big washer. The bolts go wil go all the way through, using tight pilot holes through the lift bar "inside" and "outside" sheet metal plates. There is no "interior reinforcement" to prevent these bolts and nuts from collapsing lift bar from outside in, so I will be leaving the torque low on these "helpers".

[rickst29]

My previous "into the sidewall" deck screws felt WOOD all the way up, for both the pilot holes and the too-short deck screws themselves. As it turns out, this was entirely through the floor alone, the short screws never reached the sidewall at all.

I think that my proposed "through the floor, inside from the wall" bolts are unnecessary, the "up into the wall bolts" can handle it all if they are much longer. I am able to buy AWG-10, 4" deck screws in a 10 minute drive to a local big-box store, upgrading from the currently used AWG-9 2-1/2" versions.

I will guess that think my large number of those screws will be sufficient, with no added interior "helper" bolts at all. And, if they they strip out, I can still upgrade these bolt paths into the framing wood by drilling out my L-bar holes, so that they can accept AWG-12 deck screws (an unusual EBAY order with delays) or 1/4" lag screws.

My "100 lb" struts are probably too powerful, but I'm going to try them anyway.

[rickst29]

Here's the more important problem: My "wild *** guess" for the height of the lower strut bar end was not good, it required too much range-of motion from the 20" strut.
My two options are (1) to carefully reduce the angle of the countertop support "L", coming down from fixed "l" bar which is TM attached. Or (2) Switch to longer struts with larger rang of motion ,also cutting new holes to attach those higher along the lift bars.

With either of those choices, My current holes lift bar holes, diameter 7/16 and 1/4, will have to be be abandoned and sealed up. They are only correct for "full open" position with the current countertop support angle and the current lift bar length. The 20" struts became fully compressed before I was able to push the shell all the way down.
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I could have also tried to to reduce the angle of drop in the "countertop support" bars (raising the lower ball end upwards, closer to the TM floor), but the changes would be complex to guess or "measure", and such a change would probably required two new hole cuts in through THICK THICK steel (5/8") on each side.

I have chosen the "longer struts" alternative, buying this pair instead: https://www.amazon.com/gp/product/B0BBMCRZX5/. This pair is described as "30.9 inch, 90 lbs". Arana also has a 29" model at 85 lbs and a 28" model at 80 lbs, but the 28" version had a much later delivery date.slower delivery.

I successfully removed the lift bar assemblies shortly after the test. The not yet-cured "weaker" anti-vibration locktite which I used was not yet cured, and it gave way before well before I would have created any from excess torque on the the ball mount shank.

[rickst29]

Originally Posted by Shane826

Rick- How’s that scheme coming along?

Rain+Snow, and some yard work, has delayed pulling the TM out of the garage to drill new lift arm holes for the longer struts on the front shell. I still anticipate excellent results when I find some time, probably within the next 2 weeks.