A Lesson In Symmetry
Article and Photos by Will Ramsey – Faith Forgotten Choppers – faithforgotten.com
Originally Published In The January 2015 Issue of Cycle Source Magazine.
I’ve received quite a few questions over the last year about the handlebars that I built for Tight & Shallow. So many questions in fact that I have done a couple of small production runs and currently sell these handle bars on my website in both a complete form and in a builder’s kit. These handlebars feature short solid risers that are welded to the bars. This creates a very clean look and an extremely solid mounting system that will never “slip”. However, there is no adjustability in this set up, since the risers are welded to the bars. Therefore some builders prefer the builder’s kit, which allows them to weld the bars to the risers at the specific angle for their particular build. Since the handle bars on a motorcycle sit right on top of everything and literally connect the rider to the bike, maintaining symmetry during the fabrication process is very important. No one wants to roll down the road feeling crooked, so the handlebars must be bent properly. This tech article features a Mittler Brother Rotary Draw hydraulic bender. I have used and owned many different rotary draw benders over the years and they all have their pros and cons. I will caution everyone to stay away from cheap pipe benders that simply press a die into the tubing which causes the walls of the tubing to deform and can seriously reduce the strength of the finished product. The rotary draw benders pull the tubing around the die and use a follow block to help maintain the geometry of the tubing as it is bent. Bending tubing can be somewhat of a “black art.” Different types and sizes of tubing behave differently when bent and there is really no substitute for experience. So if this is a skill that interests you then grab some tubing and start bending, but be patient and think critically because it can be frustrating.
The whole process begins by cutting stock. For these bars we use American made 1 inch DOM steel with a wall thickness of .095 inches. This wall thickness is selected because it allows for an easy fit to most internal throttles.
After cutting the DOM stock to length, the ends of the tubing are faced and deburred in the lathe with a file.
A small carbide tool is used to deburr the inside of the tubing. This simply improves the presentation on the final product and avoids leaving any sharp edges to deal with.
The tubing is cleaned using a piece of scotch-brite. I do this in the lathe but it can simply be done by hand as well. If you are using a lathe be very aware of your hand placement. It only takes a second for your hand to get pulled under the spinning part. And please DO NOT WEAR GLOVES.
The tubing is marked in 5 places with a fine tipped sharpie. Two bend marks are marked equally from each end of the tube and the center is also marked. When bending handlebars I always bend from the center out (instead of from end to end). I find that this helps limit compounding error and maintains better symmetry in the final product.
For this set of bars I use a 3” radius die for all 4 bends. The marks on the tubing are carefully aligned to the die. I always check this multiple times as tubing in my shop has a terrible habit of moving off the mark…
Like I said earlier, all benders have their pros and cons. The digital readout on this Mittler Brothers bender is incredible for obtaining accurate repeatability in bends.
Now this is where the fun begins. The rotation of the tubing between bends is very critical. There are multiple ways of measuring this and I use different techniques for different products. Often a degree finder or digital level fixed to the tubing behind the die works well. However, in this case I find that a long digital level works best. This is where experience and time under fire comes into play. If your rotation is off from one side to the next, your bars are going to be goofy.
Some people may choose to make individual bends and then slug and weld all the pieces together to get a symmetrical part. I would strongly encourage anyone to push themselves and their craft and just learn to do it right.
After the final bend is made the part can be checked on a flat surface. It’s up to each person to determine how much deviation is acceptable, but ultimately you should strive for perfect symmetry. This set lays dead flat on a surface plate.
For the risers, we start at the notcher with a 1” piece of cold roll steel. The cope is cut into the center of the stock to allow a tight fit against the bars. This can also be done by hand with a drum sander.
The sharp edges of the cope are sanded back on a belt sander to allow sufficient material thickness for a good strong weld.
The risers are sized to length in the lathe. This is a critical point: we took great care to bend a symmetrical set of bars so we must make certain that our risers are of equal length.
The risers are then drilled and tapped for a ½”x13 thread.
A drum sander is used to quickly clean up any burrs on the coped surface of the risers.
The center line that was marked before the tubing was bent can now be aligned in the jig to center the bars. Again we are striving for precision and symmetry. There’s no harm in critically thinking your way through each set of your design work. This fixture is very simple but very accurate and easy to use.
Finally after thorough cleaning with scotch-brite and acetone, the risers are welded to the bars using the TIG method with purified argon.
The final product is ready to go out the door to be plated or powder coated and bolted to someone’s chopper. If you have any comments or questions please feel free to reach out to me. Also please feel free to let me know what fabrication tech articles you would be interested in seeing in the future. Thank You. firstname.lastname@example.org
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