Lower Folding Struts Delivered

All pieces of the Lower Folding Struts are now delivered, they look fantastic!

Great job from the guys at Machining Solutions.

The thickness was machined down to 34mm along the entire length as per the optional method provided in the plans to reduce weight.

The final weights came in at 5.2kg for the side rails and 1.736kg for the webbing pieces

(Back in this blog post, I estimated 6.5kg for the side rails after machining, so the difference x8 figures out to be 10.4kg less weight to haul around!)

Lower Folding Strut Side Rails

Mark sent over a picture of one of the completed Lower Folding Struts with some machine bolts temporarily holding everything together. He said the SS bolts I sent over are out of tolerance and need to be cleaned up with a die before installing.

Ian demands really tight tolerances on the Lower Folding Struts and Mark was concerned with the parts twisting during machining. Fortunately, that didn't happen. They even spent the extra time to bolt the side rail pairs together before reaming out the outer end holes to ensure a perfect fit. All the parts were put together and checked with a 1.125" rod before being marked with the proper assembly location.
(The press fit igus bushings will reduce the reamed size from 1.125" down to 1.0")

The parts should be delivered next week sometime.

More pics and final weights when they come in.

Lower Folding Strut Center Web

I just received these photo's of the Lower Folding Strut Center Web pieces (2 of 8) from Mark over at Machining Solutions.

They look REALLY nice!

He mentioned that they should have some time to start on the struts later this week.

In other news, one of my Tenants just called to report a burned out Central AC unit.
So there goes another $1500 and a days worth of crawling around in a crawlspace.
On the bright side, this will make 5 of 6 units replaced in the last five years - so with any luck I may be problem free for a few years...?

Lower Folding Strut Bolts

The plans call for  75mmx12.5mm 316SS Button Head bolts to assemble the Lower Folding Struts. Generally speaking, bolts are easy to come by, but this particular configuration was a bit difficult to source. The usual suspects (McMaster & Grainger) didn't have the proper grade of SS or didn't have bolt sizes that large. I finally located the Mutual Screw company over in New Jersey. They had what I needed, but didn't have it in a shoulder bolt configuration as I would have preferred.
(You'll notice the bolts I needed were the largest items in that category on the page.)

I also found some G10 washers to isolate the bolt head from the aluminum frame. Those were a bit easier to locate at MSC Industrial Supply.

Next project is to get all the pieces over to the machine shop for processing. I'm guessing that might be an expensive job, so I've asked for a quote before moving on.

Upper Folding Struts

Upper Folding Struts were also delivered today.
Big weight loss for these parts as well.

Blank weight was 7.3kg each.
Finished weight is much better at 6.1kg each.

All of the aluminum parts will eventually be anodized, but that won't be for quite some time yet.

More aluminum purchased

This latest shipment of Aluminum bar, sheet and angle should cover the material required to produce the various brackets and plates for the build.

Lower Folding Strut Blank Material Received

Trying to keep things crawling along here with the purchase of items that don't have expiration dates or special storage considerations. With that in mind I received the aluminum blanks for the Lower Folding Struts.

Aluminum 6061-T6511H

Lower Folding Struts (Four struts - 2 bars per strut)

Eight Pieces: 1.5" x 2.5" x 54" 

(38mm x 64mm x 1372mm)

Lower Folding Strut Spacers

Two Pieces: 1" x 6" x 50"
(25.4mm x 152mm x 1270mm)

Beam Compression Pads

One Piece: 1.5" x 2.5" x 54"
(38mm x 64mm x 1372mm)

All the pieces neatly packaged for transport
Each blank weighs in at 9.9kg (I'm curious how much they will weigh after machining)

Nitronic 50 Stainless Steel

Received three rods of Nitronic 50 Stainless Steel today.
They will be used as "hinge pins" for the folding mechanism.
It's a bit more material than required, but the price difference between a cut rod and a whole rod was negligible.

Super packaging and quick shipping from HPAlloy!

These bars are 1" (25.4mm) OD and 60" (1524mm) in length.

And fit perfectly into the Lower Folding Strut molds.

Upper Folding Strut Blank Material

I spent some time doing research on the 6061 aluminum alloy specified in the plans.
Ian specifies a "-T6" temper (solutionized and artificially aged) but then some additional work can be done to the metal to improve it's characteristics before leaving the factory. The -T6511 aluminum is solutionized and artificially aged, then internal stresses are removed by stretching slightly and finally, some minor straightening takes place. If you look around you can find the "H" identifier (6061-T6511H) which is an Alcoa Special Temper. This temper indicates improved machinability and higher minimum mechanical properties than standard -T6 or -T6511. Minimum properties of 42 ksi tensile, 38 ksi yield and 10.0% elongation are guaranteed.

Anyway, I scoured the Internet and local shops for some aluminum to make the Upper Folding Struts (UFS)

The prices for these four pieces were all within the 300-500 dollar range, which I thought was pretty high. I finally found a supplier that provided a much better price, so I placed the order.

They were really quick on the email replies and answered all my questions satisfactorily.
UPS delivered these yesterday:

Aluminum 6061-T6511H
(1.25" x 2.5" x 50" or 31.75mm x 63.5mm x 1270mm)

The pieces weigh in at 7.3kg each. I'm guessing they might weigh closer to 6.5kg after machining?

igus bushings

Today I received all the igus bushings (plus a few spares) that are required for the boat build.
Expensive little things, but I did get better pricing by contacting a company representative instead of ordering directly from the web page.

Another thing to mark off the checklist - next comes the Upper Folding Struts?

Beam Outer End Bolts

Massive 316 Stainless Steel bolts 1" x 6.5" (25mm x 165mm) for the Beam Ends arrived today.
I ordered them a little longer than the plans showed because I wanted the thicker Mil-Spec nuts to be fully engaged. I also ordered some additional nuts and washers for the other inner beam bolts (plus a spare set for whenever it inevitably falls into the water).

I still have to get the eight (the Materials List call for four, but the plans seem to show eight) 3" (75mm) partially threaded bolts for the inner beam lock down.

McMaster didn't have those, so I'll have to order from another source at a later time.