Stim.Tech Articles

First Product Release: Billet Hydraulic Handbrake

March 13, 2017 Braking 0 Comments

Finally, with the launch of our website, we release our first production product and here we will deliver its release with excruciating amounts of detail. We wanted our first product to be something fun, something that could be utilized in any car, whether it be a drift car, a circuit car or a street car (not for street use). In our experience, we found many of the units available to do the job of locking the rear tires to be lacking. Lacking in appearance and lacking in function as well. You may wonder, what could be improved upon on such a simple unit? Well one of our main goals was to remove the play, the rattling, and simply improve the feel of the e-brake actuation. We all know the feeling of a solid smooth shift. With our e-brake we did all we could to mimic this.

The most critical part of our hydro e-brake is the lower handle assemble. Our 3-d machined billet aluminum lower body houses and all the bearings and bushings that make our e-brake so solid. As is common in the theme of our products, there is no expense spared on any aspect which is blatantly apparent in the machining of these units. Typically in mechanical design, machined bodies are altered or simplified to reduce the cost of production. Although this was considered, we did not let it lead the final design of this part. The finished unit speaks for itself as its appearance does not lack in any way.

The lower joint which mounts the handle assembly to the lower body is done through two sealed bearings. These bearings are pressed into the aluminum lower handle body. A stainless internal retaining ring finishes the mounting of the two bearings. The retaining rings will seldom see any load as the interference fit between the outer race of the bearing and the aluminum lower body keeps them in place. Pressed through the centre of the two bearings is the stainless main shaft. This shaft makes use of minor interference fit against the inner races of these bearings to hold its position. A stainless external retaining ring is located on either side of the bearings along this shaft to ensure location is never jeopardized.

Between the two bearings lies an aluminum take-up spacer. The purpose of this spacer is to ensure when the shaft is pressed through the inner journals of the bearings, no deformation or offsetting occurs. The spacer ensures with the shaft is pressed in, all compression forces are directed through the inner races only and no forces are put axially through the bearing itself. This may seem unnecessary, but any deformation in the bearing races could induce unintended play into this joint.

With the mounting of the handle assembly taken care of by the lower joint assembly, the master must be connected through the upper joint. The upper joint consists of hardened bushings, a stainless rod and a stainless upper shaft. Pressed into the aluminum lower handle are two hardened and honed steel bushings. These bushings are pressed in to depths that leave perfect clearance between them for the rod end to be inserted. The bushings and the rod end are pinned together via the stainless upper shaft. This shaft utilizes a slight sliding fit between its mating components. This allows quick assembly and disassembly, if necessary. Axial location of this shaft is retained via two stainless external retaining rings. Minimal axial loading, if any could ever occur at this joint, due to the design of the lower joint.

The main body of the hydro e-brake, which mates all the components together is the product of two stainless components. The main cage is a crisply laser cut and formed channel. The master cylinder mounting face is primarily laser cut. Steps are then milled into its edges to produce proper locating within the main cage. This notch also provides the perfect joint for final welding. Creating nicely finished weldments can be tricky as surface scratches and imperfections are easily induced when the cutting and forming processes take place. Each stainless piece is polished prior to welding. The seams of every weldment are hand Tig welded.

Motorsport, to us who live it, is as much an art form as it is a lifestyle. The elements used in our hydro e-brake encapsulate so many aspects of what motorsports is for us today; mechanical design, billet machining and beautiful fabrication.

Finishing is always extremely important in maintaining the appearance of a product. Our main billet aluminum components are finished with a clear surface anodizing. This treatment not only looks good, but it also aids in defending the components appearance during installation and use. The anodizing however, serves another purpose. The large pitch aluminum on aluminum thread that exists, mating the upper and lower handle components must be protected. As many will know, aluminum on aluminum threads can suffer dearly from something call galling, which, unaddressed in any situation can cause complete locking of the two threads. It is a common practice to lubricate these types of threads, but anodizing the components is the best solution available to avoid this.

Fastening is often overlooked by many, but with our products we make sure all areas are addressed. The threads (internal and external) on both our upper and lower handles are cut perfectly to ensure longevity and proper fitment. Also, being a standard 14mm metric thread, the handle assembly is modular, meaning that various handle lengths and knob set-ups can be easily created. If a longer or shorter set-up is desired down the road, you are not stuck with the original geometry.

Although we offer custom knob set-ups upon request, our standard options include a 32mm diameter straight knob and a 45mm diameter round option. These knobs are turned from white Acetal plastic. This material gives a clean look and a great feel.

Staying true to our tendency to obsess over every detail, we present the hardware used in the hydro e-brake. Above, centred, is the stainless rod end used to link the master cylinder rod to the lower lover assembly. This piece features a PTFE inner liner to ensure any misalignment rotation cause no wear between the ball and the body. The perfect length stainless stud to mate the master cylinder to the main body did not exist as an off the shelf fastener. In stead of compromising here, we have turned our own custom studs from stainless. Included with each hydro e-brake unit, is a set of stainless nut and bolt combinations which can be used in fastening the unit to the customers mounting solution.

Please see our product page here.

Moving forward with our coming products we will maintain the quality and design choices we have exercised here with our first product. We look forward to seeing these e-brakes in every vehicle they are chosen for.

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