NOTE: These brackets require that the Hondaline luggage rack and backrest be installed.
I started working on another set of luggage brackets a few weeks ago for the late model Nighthawk 750. These brackets will be made for use with Storm IM2200 boxes which I choose because of their durability.
Here is a video I found on YouTube which will help explain how good the Hardigg Storm Cases are. The Pelican Cases are also good but I have found the Storm Cases to be less expensive.
For this project I'm once again using 6061 T-6 Aluminum. I’m partial to this alloy because it's very tough and it machines well. I came up with a few quicker and better processes just for this project and so far they have worked out nice.
The last time I made a set of brackets like this I drilled the main clamping holes with a drill press. The finished hole in each part was 7/8" diameter and they came out very rough and were not very good quality (but they worked). This time I decided to try drilling the 7/8" holes using my milling machine. Using the milling machine allowed me better control of speeds and feeds for this operation. I slowed the speed way down and used the manual rotary feed dial and got very good results. The only other option I had was to bore the holes using my lathe but that would have been very time consuming so I’m glad I didn’t have to go that route.
I'm not sure that I could have gotten a better finish than this even if I would have had to bore this hole. The quality was good and it was much faster than a boring operation would have been. When drilling large diameter holes in Aluminum it tends to tear the metal instead of cutting it. If you have ever tried drilling aluminum then you know what I’m talking about, that’s why I was so pleased with this hole's finish.
After drilling the two clamping holes I separated the two brackets using my band saw to just over 3" in length. Aluminum also tends to gum up my saw blades so I use an old candle to help keep the aluminum from sticking to the blade by letting the blade teeth cut into the wax. Normally Bees Wax would be used for this but candle wax will work too and is much cheaper.
Once the two parts were separated I needed to use the milling machine again to square up the saw cut ends and bring them to finished length. I used a fly cutter for this operation but first I needed to sharpen a piece of high-speed steel to insert into the fly cutter.
This is where I had another idea I wanted to try. Instead of using the fly cutter in a collet attachment I just inserted it into a drill chuck to help save some time. This also worked out very well for this machining operation (this is something I would most likely NOT do if I were removing large quantities of metal but, for a finishing operation it seems to work well).
After finishing both parts to length I moved over to the drill press where I did a three step drilling operation on each bracket. The first step is the minimum thread diameter drill that will yield a 75% 1/4-20 thread later. The second step is a clearance hole for the 1/4-20 threaded hardware to fit into. The third step is a counter drill relief hole for the head of a 1/4-20 socket head cap screw (stainless steel of course).
I did the above drilling operation in three steps as another attempt to save some time rather than doing each of the drilling operations separately later. Doing it this way will ensure that once the clamping halves have been separated they will line up perfectly on reassembly.
The second step (1/4" relief hole) will also serve as a thread guide to ensure proper alignment during the thread tapping operation.
This is what the brackets look like with the stainless steal hardware installed. All that remains to be done on the clamping end of the brackets is to separate the clamping surfaces once again using the band saw. I will also need to machine a set of Ultra-High Molecular Weight Polyethylene bushings that insert into the 7/8" drilled holes to protect the 5/8" diameter clamping surface they will be attached too.
The mounting surface for these brackets have a slight angle so I adjusted the milling machine head for a 7 degree angle.
I used the same fly cutting setup that was used earlier since it was quick and easy.
I used a sharp pencil and a set of dial calipers to make layout lines 1/2 inch from each edge of the new surface just made. Since everything is now on a 7 degree angle I thought it best to drill and tap the two holes in each part while the milling head was still setup.
After drilling two 13/64" holes 1.250" deep in each part, I placed a 1/4 - 20 tap in the drill chuck to start the threaded holes. By doing it this way I could be sure the tap was started strait for a good quality thread.
I finished each threaded hole by hand with a tap wrench. Due to some clearance issues I had to changes vices for the drill and tap operation.
At this point I would have been almost done with this part as far as machining goes. However I thought it would look better with 45 degree chamfers cut along each side. So, I set my mill head to 45 degrees and cut a 1/4" wide chamfer on all four edges of each part using a high-speed steel end mill. I used the Mighty Mag in this photo as an edge stop to save time and use of my dial indicators.
Now I needed to cut the spacer blocks for this project so I loaded up some 1" x 2" bar stock into the band saw and cut two pieces 1.5" long.
I had the mill setup for cutting 45 degree chamfers from the last parts so I went ahead and cut the chamfers on the spacer blocks.
I then reset the mill head and squared up the ends to cut each part to length (1.5"). The spacers on my Nighthawk are 2" but I think 1.5" will work much better.
After laying out the locations of the clearance holes I setup the drill press to complete the drilling operation on each part.
This completes the machine operations for this part.
This project requires four aluminum mounting plates ( 6" x 7.5" x 1/8" ) which I had sheared last week at a shop in KC, MO. The Storm IM2200 box will be positioned between two of these plates on each side of the motorcycle for optimum stability.
I stacked all four plates on top of each other and measured out the hole locations needed. Then I drilled all the holes using my drill press. Stacking the plates and drilling all four pieces at once is the fastest way to perform this operation and it makes all four plates interchangeable.
Its now time to cut the vertical stabilizers. I cut two pieces of 1/8" x 1" aluminum 6.5" long.
I drilled the lower mounting holes on one end of each part and machined a 5/16" slot on the other end. The stabilizers I made for my bike had only holes and no slots. I decided that slots would work out much better since it will allow each part to be adjusted for proper fit once on the Nighthawk.
A belt sander works great for making the 45 degree angles at the bottom of each stabilizer to finish up these parts.
Next, I loaded the main clamping blocks one at a time into the band saw for separation.
Then, machined the rough surfaces of each piece using the milling machine to finish these parts up.
The machining of these brackets is mostly done except for some plastic bushings that I will make later. Time now to assemble each bracket and see if everything bolts up correctly.
I was going to clean the brackets up and leave them alone at this point but decided to powder coat them black instead. This means that each part of the brackets will need to be disassembled and cleaned with detergent, rinsed with clean water, and glass beaded in my sand blaster.
Here are a couple of the parts loaded into my sand blaster.
Time to fire up the oven for pre-heating to 400 degrees. Powder coating is new to me and this is the most complex job I have done so far.
After switching on the power and connecting the ground wire I sprayed each part with black weather resistant polyester powder. The ground wire creates a negative charge in the part and the powder in the gun is positively charged. The powder sticks electrically to the part which will then be baked on using the pre-heated oven. Each part is baked at 400 degrees for 20 minutes.
The whole powder coating operation was very time consuming but makes a big difference in how the brackets looks. Here are the completed brackets after all parts had been powder coated and re-assembled.
All I had to do now was cut a couple of pieces of UHMW plastic to machine a set of clamp bushings out of. After placing each piece into my lathe chuck I drilled the center out with a 5/8" drill.
Then I finished machining the outside of each part so that it would fit into the aluminum clamp I made earlier.
I then sawed each of the plastic pieces in half. I added a few drops of glue to each halve before inserting them into the clamping part of each bracket.
This is the finished bracket set ready to be installed on the motorcycle.
Here is what the Hardigg Storm iM2200 Cases look like installed on the Nighthawk 750.