Dental Light Brackets
Slowly, but surely, making progress on the dental light brackets (you know, to hang these on the wall--actually to hang them on the Reconfigurable Tool Rack)...
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Definition: TEDIOUS. adjective : tiresome because of length or dullness : boring : fitting and preparing multiple, small parts for riveting.
Actually, that is not quite true. While the process is painstaking, it is, oddly enough, anything but tedious for me. I have enjoyed the process and continued to learn more about design for rivets. I have a job which is quite literally life-and-death and often feels like drinking water from a fire hose for up to 12 hours at a time. Coming home to spend as much time as needed to make something exactly the way I want it is quite refreshing.
Here is a little sample of what has been taking part of my last 6 hours out in the studio What you see here are corner brackets, which will be attached with rivets, to fasten parts made of 1/4" (6.5mm) aluminum plate. What you see is the process of figuring out where the center rivet needs to go. Once you figure out where each end rivet goes, you use what is called a 'rivet fan' to space your rivets equally between the end rivets. There are a lot of ratios you need to know to sort out generally how far apart they should be, but I won't bore you with that...
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Let's suffice it to say that there was a lot of measuring to do (until I spent an hour-and-a-half building two marking templates for the end holes.) The first template was made of sheet metal and worked well for one end of the corner brackets, but not for both ends. The second was made of the same aluminum angle you see in the pics above, was MUCH simpler to make, and marks the spots I wanted it to mark perfectly...just too bad I was wrong in my estimation of where those spots should be.
It is long story, which I will summarize with: Lessons were learned. The hard way. Most people will never spot the problem. The second bracket, and everything else I design from this point on, will be better for the lesson learned.
This is where 'building from scratch' is COMPLETELY different than 'repair work,' because THERE IS NO MANUAL FOR WHAT I AM DOING...if it has be be decided, I get to (have to) make the decision.
Here is the result of a LOT of trial and error. This first bracket is probably going to look fabulous to pretty much everyone. I will know the problem areas and remember it every time I see it (but I am an unusually-detail-oriented fellow. When I install screws in something, I make sure all the slots of the screws are lined up. If you remove the backs of each remote control in my house, you would find all of the batteries lined up 'just so.' It is a sickness, I know, but it is part of who I am and part of the way I build things.)
This is early enough in the project that it doesn't really look like much, but what you see there represents about 6 hours of work, again, because this isn't a kit I am assembling, I have to figure out every aspect of the design and build process as I go. I expect things will go much more quickly from this point.
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The process for fitting these corner brackets goes something like this [those of you who are bored to death by detail should skip this part...I wrote it out so that those few could see just how much is involved in fitting each piece of this project]:
- square up one end of the aluminum angle on the disk sander.
- test fit the aluminum angle to the piece it will support.
- cut the piece of angle slightly longer than needed and test fit again.
- slowly remove material from the other end of the angle, with the disk sander, checking the fit frequently.
That works for the first 2 pieces on each side. For the remaining two pieces on each side, they must also be cut out to fit the pieces of angle which are already fit to the piece:
- Mark where to make the rough cuts and cut out a majority of the material on the band saw, check the fit for how much to remove.
- Use a double cut file to remove a majority of the material, checking fit after every few strokes of the file.
- Once the fit is good on one side, adjust the fit on the other side with a file.
- Clean up the edges with a single-cut file and check the final fit.
Wherever the piece is going to go, it now needs to be measured and drilled for rivet placement:
- Use the template to mark the location of the rivet holes on the end of each piece.
- Mark these holes with a ***** punch and then a center punch.
- Drill these two end holes with a #40 drill bit (size of hole used for the smallest common solid rivet--which also the size of the holes in the rivet fan).
- Attach the rivet fan to the piece with two clecos (specialized sheet metal clamps) and mark the holes for the center rivets.
- Mark these new holes with a ***** punch and a center punch.
- Drill ALL of the holes with the correct size of drill for the rivet you are going to use (in this case, a #20 drill bit).
- deburr all of the holes and the edges of the corner bracket.
Then, you get the fun of lining all these things up, making sure the holes all match, and temporarily fitting everything up with clecos, until they are permanently attached with solid rivets.
There is definitely a specific build order. For this project, that ended up being "start building around the piece which cannot easily be adjusted to fit other pieces." It also includes a lot of "build this in the order which allows you to use the pneumatic rivet squeezer on as many of these rivets as possible, so you don't have to hand buck all these rivets."
Needless to say, I am getting very good using a hand file to finish up fabrication. I am also learning more and more about designing for rivets. All the while, my new welding rig is sitting in the corner, begging me to 'come out and play.'
Kev
It is fun to go back and see where it all started.