399 replies to this topic

[Mach9]

   I figured Steve would bust me on the pi thing. LOL. I went back and redid my calculations. As a little test, I did the calculations for a 2" radius cone with a 45 deg. angle, drew it up on AutoCad, printed it out and cut it out with a pair of scissors. I glued the two ends together matching the lines up and out came a perfect 45 deg. cone that was within a few thou. of 4" at the large end. The math works!

   The great thing about a CAD drawing  is, you don't have to worry about scale while you're drawing. When I draw a track, I just mark the centers of where each corner will be, draw circles that are the outside and inside diameters of each turn, and then just connect the turns with straight lines. Go back and trim away the parts of the circles you don't need and you have an outline of the track. Then, you can use the dimension functions to get all of the angles/sizes of each piece. The program does the math. Thanks again for all of your help.

[LolaGT]

Thank you Mr. Ogilvie for showing us how to build our own tracks, so now I'm thinking about fourlane routed track plans all day.

 

I'm having problems visualizing how your circle cutter works for some reason. I see the two holes at right for making the track width, and the plate at left the router sits on. I take it the gap in the center is for making different sized curves by moving the router's plate in this space toward or away from the pivot points.

 

So, how do you keep the router's plate locked at the place it needs to be at for a certain size of curve? Are the aluminum C sections drilled every 1/4" or so all the way lengthwise down the section and bolts run into the router's plate through them? Or is the aluminum just threaded for setscrews?

 

Thank you,

Ken

[Steve Ogilvie]

I first started with a small sliding tube clamp. But I found it bent too easily so I just drilled holes for screws as needed .After a while , I had all the holes I needed and I could just take the screws in and out .Use a 1/8" drill bit for drilling the holes and #8 wood screws to hold the router plate in place. Using 4 screws prevents the router from twisting, but I only found this was needed as the jig got older. Thanks for the question, there is stuff that I forgot to mention so it is great when people ask about it .  Steve 

[LolaGT]

Mr. Ogilvie,

I'm working on making one for the track I'm hoping to make this summer, so I wanted to get all the details down. Now I can see where I was wrong.

Thank you, ken

[woodman]

Steve, I have built a few tracks since the 80s , but I find using a flexible fence really intriguing.....For my latest D Oval I wanted to increase the radius as the as the cars exit a turn. Where the radius of the Exit of the turn is larger than the Entry of the turn. Therefore the Entry is usually much slower than the Exit, allowing you to accelerate harder on Exit.
This enables the car to accelerate in a forward moving yet sideways controlled slide .....

Steve Crawford....

Attached Images

• 

[Steve Ogilvie]

So will this be a flat or a banked track? You can do the same thing by varying your radius when you cut your corners. But I like the flexibility of the guide fence idea, would be a way to set the skid apron up any way you want. I would not use a fence myself just because it would slow me down time wise.

[woodman]

I built it flat, the lane spacing varies, it has a squeeze at one end......

Video's. https://youtu.be/aDbTjqz9NCA


http://s147.photobuc...l?sort=3&page=1

http://s147.photobuc...l?sort=3&page=1

[Steve Ogilvie]

Love the videos. Did you have a go pro on a car ?

[woodman]

Steve I used just a $20. Mini cam...

[woodman]

In the 80s I made this router jig for cutting the braid recesses...just a pin on either side if the bit...

[Steve Ogilvie]

I used to use a similar system when I first started building tracks. The drawback is as you go around a corner, the relief is wider on one side than the other. The other disadvantage is that you can't spin the router as you go down the track without picking it up and turning it around. A pin in the centre of the bit is easy to make and works great. There is a how-to on page 1.

[Steve Ogilvie]

I have not added to this thread for a while. But I have decided to make an effort to get more information on here. Probably not something that is going to happen every day but I thought I would start by adding track plans. So today I drew up a king track. This design does not incorporate a pinch and it came out about 6" too long but if I were to build it I would still build it to this length. King tracks sometimes need an adjustment to the main straight to make sure the bank stays smooth so the extra 6" might disappear during construction. You can make a lot of other kings if you draw this one first and then change things- kick the donut over to get more marshal space, pinch it change degrees of turns etc. I don't have any of my old drawings so all of these are drawn from scratch. I did not put cutting radius lengths on because everyone will have their own ideas about banking.

Attached Images

• 

[MattD]

thanks Steve, enjoy all your track info.

[Chris Dadds]

 Steve I'd think that extra 6" may be taken up by the elliptical effect of cutting the slots off the previous slot. By the time you've cut four, the compound effect, multiplied by a thousand or so degrees of arc, could total up to a significant length at the centerline.  Could you ever take the time to plan a King and then actually measure to get the average of blue and orange after it was built?  
  Only recently since the market has gone to smaller tracks with tighter turns set closer to each other have I ever tried cutting slots guided by the previous slot.  When I started building in the 90s mini-boom I cut all slots off a frame guided by the outer edge of the surface, so I just haven't had much experience with that way of doing it.

[Chris Dadds]

HA!  After 8 years on this board, I've actually achieved "full member" status! :-)

[Steve Ogilvie]

I was kind of surprised by how close the calculated measurements for inside and outside lengths were. And thats all the calculated lengths were ever based on (outside and inside calculated circumference). But on king tracks that I built and put an actual measuring wheel and ran it around a track I used to see almost a foot difference between red and black lanes. Maybe because they were more radical designs I don't know. As far as losing 6" with the eliptical routing process I don't think so. On some corners you end up cutting a smaller radius and others you end up with a bigger radius so it ends up a wash I think. Thanks for posting Chris good to hear from you. 

[MSwiss]

Steve,
On the almost 1 ft. difference, Do you recall if Black was the longest lane?

When I built my King, I was into the World Record mumbo jumbo, so it was measured very carefully, numerous times.

I used 3 identical lengths (10 ft.?) of 14 gauge wire, that fit in the slot, perfectly.

I alternated them, always having 2 pieces in the slot, while I laid a 3rd.

Orange is 155'4", while Red is 154'11", and Black, 156',1.5", so 14.5" difference, across all 8 lanes.

Not really knowing what I was doing, I purposely made the finger 180 degrees, and dialed in the length on Orange, the qualifying lane, by trimming the straights entering and exiting it, to the appropriate length.

[Steve Ogilvie]

You are correct Mike on the tracks I measured black lane was the longest. I think on the design above the overcut (normally a 90* turn) on the turn leading in to the donut might have evened the lane lengths up a bit. The donut/lead on area was drawn using standard drafting triangles just to make it easier because I was just going by memory. But if you use a 36' main straight, 14' bank, 10' donut and 90, 9' finger, deadman and lead on turns it is fairly easy to get it close to 155'. I always tried to design my tracks to get orange lane as close to 155 as possible but very few of them were perfect. The lengths of the other lanes I wasn't too concerned about.

[Chris Dadds]

Just because I have always cut all the turns slots from the outside of the turn, I assumed everyone did. So I missed your observation of the right and left turns closely canceling out the lane length difference imparted by the practice of cutting each lane off the previously cut lane.    But understanding why there is a lane length difference between red and black on a King or any other track with a big bank can be most easily done by visualizing the track from directly overhead and noticing that in the bank the surface width and the lane spacing, relative to true horizontal measurement, is narrower or foreshortened.  

[MSwiss]

I get that the track takes up a smaller "footprint width" where it is banked, but I don't see how that has any bearing on the lap length, Red to Black.

Having equal lap lengths is a non-existent problem in slot racing, where every race I know of is contested on all the lanes.

I've never understood why it has ever been brought up, in this modern age of slot racing.

[Steve Ogilvie]

There are very few tracks that will have exact lane lengths and yes in modern slot car racing it really does not matter. With a king track it is just the nature of the beast that the lanes are not going to be exactly the same length.But even if they were exactly the same no one is going to jet on the gutters to win a big race from behind.(probably some one has but pretty rare in the modern era). I only made a handful of tracks that were designed and built to set qualifying and lap total records. It is a fine balance between wider radius turns and maximizing straightaway lengths to keep a car up to max speed without a ton of glue. And it goes with out saying that you need a ton of banking that causes all the short straights to have huge twists in them. That makes it difficult to stop those straights from dishing which will result in a tires contact patch getting smaller. Most of those tracks set records first time out but I was always glad when customers wanted a flatter more general use track. It is a lot easier to make a track look nice when it isn't banked to the max all the way round.

[Steve Ogilvie]

I hope to be more diligent in the near future to add to this thread more often than the once a year patern that has developed. My oldest son and I spent all last summer building a large addition to his house. I am planning to put a 4 lane track in the new basement. So I am going to draw up a few designs and post them here. I think I mentioned somewhere in this thread that I do not have any of my original drawings. So I am going to redraw them as best as I can and maybe improve on them a bit, just posting the easiest versions to build of a handful of designs. I also need to draw up an all inclusive wiring diagram, incorporating a high/low power circuit. My wife and I are both retired and we travel a lot so I have to pick my spots to have time to do things like this. And I recently added a 2 post car lift to my garage and that makes it hard to stay out of there working on my hobby cars. 

[Rob Voska]

After a layout is thought up.  What other factors do you look for?  Number marshals?  Racer visibility with marshals in the way?  Wider skirts so a car off does not impede the outside lane?  Others?

 

Have you even built an oval with an outer drop-off / real gutter so the car does not come back & take others out?

[Steve Ogilvie]

Sorry I did not notice this post and questions. I have been on vacation and busy helping my oldest son build an addition to his house over the last year.

  The simple answer is I always built what the customer wanted.If they asked for extra skid apron we did that. But being that most of our tracks were for commercial use, most customers did not want to pay for things like gutters to catch cars.

  We built a lot of tracks that were designed for a minimum of marshals. On a lot of our hillclimbs, I tried to design it so that the donut end could be handled by one person. Make the kickout turn before the donut wide radius and banked so most cars would not fall off under the leadon. Make the leadon and the exit to the donut reachable by the marshal inside near the kickout. Make the turn under the big bank easy so you do away with a marshal there when you are short of racers. All of this tends to diminish the skill level required to drive the track though, everything is a compromise.

   On King tracks we tried to place the driver panel where everyone could see better and a lot of tracks the order was reversed as well. Cutting a bit of an inside wall to increase visibility was done as needed too. But that weakens the track strength so I kept that to a minimum.

   A few members here have PM'd with there questions about track building and I do not mind that at all. I try to check new content every day but some weeks I am just not on the computer much so I will miss posts from time to time. 

[Steve Ogilvie]

 

 

I was playing around with drawing up a small 4 lane king track and it needs a lot of work to get it right. As the drawing says it is too big at 36 feet by 16'. Most people do not have basements big enough for that including me. But I thought I would post it anyway.