Fabricating the Custom Banked Turns
Okay, we’re ready for round 2 on building up the banked turns on Woodrum Ridge Raceway. We left off (as you can see in Part 1) with drilling the pilot holes for each table mounting point of the bank curve supports. We’ll start with one of the supports that make up the majority of the height and shape of the new banking.
I went ahead and ran the screws up through the table to get an idea of how far they would penetrate the bank supports. As seen in this picture, the screw to the left (Higher side of the support) does not reach up into the wood too far. So we’ll use a slightly longer screw to securely lock the support in place. The shorter side of the support on the right will get 1” wood screws, the ones on the left will be 1-5/8” long.
You want to leave enough wood between the tip of the screw and the top of the support bracket. This way you won’t have the screw effecting the way the track will lay against the support’s top surface. Here we have left the screw about 1/2” below the top surface.
Here we have one of the shorter transition supports that start the banking process. As you can see in the picture, the screw on the left is too tall and will be above the top surface of the support. We will use the 1” wood screws for both sides of the smaller supports (see below).
No worries about the screw interfering with the track’s position now.
Now it’s time to start actually getting the track into place. Let’s take a look at the details of how we will accomplish forming the flat turns into banked versions. The screws that anchor the track down and form the curvature of the banking are an important part of this process. You want a flat-head style screw with enough area to secure the track under the pressure that it will be placed under. We used #4 and #6 screws each 3/4” long with Phillips heads (See below).
Here’s a quick comparison of the different head sizes, #4 on the left, #6 on the right. We will use the #4 size as default and use the #6 in areas in need of more support or if the countersink of the #4 screw pulls through the track surface by accident.
You want to make the pilot holes for the track screws as small as possible, but large enough so when you drive the screw into place it does not distort the track’s racing surface. In this case, our weapon of choice will be the 5/64” drill bit. It is just slightly larger than the auger portion of the #4 screws.
Make sure to measure and mark the locations of the pilot holes on the track. As you can see in the picture on the left we are centering the marks to the width of the bank supports. This is a great example of “measure twice – drill once”. If you happen to not locate the pilot holes in the correct position, it could require you to start over with a new section of track or even a new bank support. Remember, these screws not only anchor the track in place, but will be forcing the new contours of the banking itself. So proper and secure location of the track screws are paramount.
You should have something like this once you have your track measured and marked. I use the short leg of the “T” shape to register where I place the drill bit. Notice that we are securing the track at its edges and not the center section. This will assist in getting the track to conform to the new banked shape we are wanting to achieve. We’ll address how to make those surface areas smooth and bump free later in Part 3. Now let’s get out the power tools!
Here we can see the 5/64” drill’s fine work and our first pilot hole is in place. Work one section of track at a time. Do not start drilling all of the pilot holes at once. As the track is formed into the banked shape, the location of the pilot holes may change. If you drill all the holes at once, as the track forms its final shape, you may find pilot holes that no longer line up with the center of your support brackets. So work one section at a time and on one support bracket at a time.
Although it’s a bit difficult to see in this photo, I have drilled a counter sink depression into the pilot hole area. This will allow the flat-head screws to sit flush with the track surface. Take your time on this step. You want the countersink to be low enough for the head of the screw to sit flush, but the deeper you make the countersink depression, the less track material is left for the screw to anchor the track in place. Because we are also using these anchor points to force the track into a new shape it is very important to retain the integrity of the joining surface the screw is holding in place. If you happen to go too deep or if the #4 screw should pull through the track surface, use the #6 screw as a replacement. The slightly larger head should take care of any holding issues, although you may need to take some additional finishing steps to make the larger screw flush with the track surface. We will address that later in this article and in Part 3.
We can now start securing the track to the banking supports. Starting from the first transitional support and working from the inside towards the outside edge we will install the #4 screws by hand. Avoid the power drill here, even with the torque settings. A little too much “oomph” and you can drive the screw head right through the track surface. You want the screw to sit tight and flush with the track surface and the track to be tight against the bank support. Always make sure the top surface of the bank supports are clean and debris free. The smallest thing between the track and the support could offset your racing surface or cause problems later down the road.
Here’s a nice flush fit. The screw head is just below the track surface. The track is nice and tight against the bank support. We will address covering these up and making the racing surface nice and smooth later in this article and in Part 3. Repeat this process, working from one track section at a time, moving from the inside of the turns towards the outside of the turns. Make sure to keep the track sections aligned and the turns properly nested against each other as you progress through (1) Drilling pilot holes, (2) Drilling countersinks, (3) Installing the screws.
As you can see in this picture, we are working from the inside of the turns, towards the outside. Only do one section and one support at a time.
Now we are getting to the meat and potatoes part of the program. We are starting to form the actual banking of the track sections. The inside track section (15” radius sections) will be formed first. Note that we anchored the first edge of the inside lane before working up the remaining outside sections. That ensures the track joints transitioning from the curves to the straights remain aligned. You can see where the track is beginning to conform to the new shape, starting in the middle of the inside turn.
We have now worked our way around one full 90 degree turn. As you can see, we have a nice 14 degree bank that is smoothly contoured and has no high/low spots in transition. Also note that we have left a 1” area on the inside and outside of the support brackets to add a skid apron around the turns. It took about 3 hours to measure, drill and secure 8 sections of track, about 1/3 of this end of WRR’s oval. After I complete the rest of these steps this week, we will start on the next phase of the process, the skid aprons, retaining walls and smoothing the racing surface and removing any traces of screws and countersinks.
We stopped here on August 1, 2012. More to come!