Sunday, June 9, 2019

Cargo Door Latch

Decided to tackle the problem of how to latch the cargo door. In my research, I've come across many ways to accomplish this task from very simple to very complex. I've chosen to keep it relatively simple and use a cabinet lock. This is a simple keyed lock for cabinets.

So, the advantages are:

It's simple to install
It's lockable
It's relatively light
It's secure
It has a pretty low profile

The disadvantages are:

It requires a key to operate
It's heavier than some other options
It requires some other parts to be installed

First thing I had to do was make a stiffener for the rear of the door. This actually accomplished two things, to stiffen the door so it won't flex in the vertical axis and provide a little more material thickness for the lock to attach to. A primary concern with stiffeners in general is how to attach them to the door? I really was wanting to avoid using any rivets and thus preferred using Hysol. The stiffeners are not a structural component so Hysol alone will be sufficient.

At first, I was thinking of using L bracket material for this but decided against it because of the added weight. It absolutely would be great for stiffening the door but would add too much weight. Instead, I decided to use .020 aluminum sheet and bend up my own L bracket. This would provide plenty of stiffness while keeping the weight to a minimum. I measured and cut a piece to test it out. Seemed to work perfect so I proceeded to Hysol it in place after deburring, sanding and cleaning the areas to be Hysol'd.

After it cured, I measured and marked where to drill a starter hole for the lock. The lock requires a 3/4" hole so I used a step drill to slowly work my way up to the correct sized hole. Once drilled, I installed the lock to check fit. Worked as it should however, the steel lockbar was operating against a soft aluminum tube. This would require installing some sort of protector striker material.

Initially I thought of a piece of steel or sacrificial aluminum plate, and also considered anti-chafe tape but wanted something a bit more robust. Then I came across some leftover delrin seat track material. This would provide a nice slick, quiet, durable, replaceable striker surface but it is a little thick. Maybe the same material in 1/16"? Maybe I can sand down the delrin I have to the correct thickness? I'll have to try this.

Next, I started looking at how I would mount the delrin. Hysol came to mind but it wouldn't allow easy replacement. Then I looked at rivets. This is when it occurred to me that the fabric wraps around and covers the area where the lockbar will go. This will requre a slot for the lockbar to operate. I can't just cut a slit in the fabric for the lockbar. I would need an actual slot which means I would need a fabric plate to be installed to give the fabric a place to attach around the slot for the lockbar. So, I fabbed up a fabric plate with a slot for the door opening and Hysol'd it into place. This plate will allow the fabric to attach around the slot so I can cut the slot out for the lockbar in a nice neat fashion.