CNC routed track questions

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CNC routed track questions

Postby lancelotalove » Sat Apr 01, 2017 11:45 am

I can get access to a CNC router to make a slot car table and I have many questions. I routed a test track following a Top Gear track and found out that many of my turns were too sharp in radius meaning the guide gets stuck or the car just doesn’t make that sharp of turn. The test track is 8ftX4ft.
I am looking at making a 15ft long X 4ft wide, 2lane track with an elevated bridge to get more straightaway. It will be made of ½ inch MDF.
I got a couple of tracks drawn up but when I check the radius on some turns they are about 4 or 5inch and too sharp. I almost have to have the machine draw the carving out on a board to see the radius of the turn. How do you know if the turn is too sharp?
How do you set up Ess turns to be equal lefts and rights and how many 2,3,4,5?
How deep is the slot? .3 is just over ¼ inch.
Any suggestions on tracks or track flow?
I am using Inkscape to draw (Inkscape seems limited) and then converting it to Vcarve 8.5 (coding software I have to use)
Is there any suggestions from people with experience on CNC?
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Re: CNC routed track questions

Postby Nor Cal Mike » Sat Apr 01, 2017 5:40 pm

It depends on the guides you use. If you have gone are running Carrera cars with stock guides or some of the aftermarket wood guides, they will hang up a lot easier than most other stock slot cars due to the length and thickness. First I will define my terminology as it is often used in different terms in discussions among slot car folks on the boards I read. Mathematically, radius refers to the distance to the center of a circle or 1/2 of the diameter. I believe your CNC program will read radius as that.

I have an inside slot on my track that is 3.5" radius (7" inch diameter) but that is very tight and will cause hangups for large guides, especially Carrera as they are thick as well as long. To drive it you have to kind of toss the car in and let the rear end swing around to point the car out the exit. It is definitely not a curve for newbies. If you use this type of curve, it is best to use them in opposite pairs so that the disadvantage of a slow tight inside lane is apportioned to both border lanes equally.

I personally like this pair of sharp hairpins but they do take some getting use to and definitely trimming and grinding of stock Carrera guides. For general purpose, I would recommend nothing less than 5"radius (10"diameter) on the inside slot if you have newbies racing or you don't want to fuss with guide modifications. A minimum of 6" radius (12"dia.) would probably be best for most people's taste.
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Re: CNC routed track questions

Postby chappyman66 » Sat Apr 01, 2017 6:22 pm

^^^^^ what he said.
I have a hairpin on my large track that is about a 5" radius and it's really tight and slow. And the Carrera guides do hang up. A 6-8" radius works pretty well. There are lots of options for 4 x15 ft. Should be a great track, I am looking forward to seeing it come to life!
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Re: CNC routed track questions

Postby RichD » Wed Apr 05, 2017 6:40 am

Carrera cars come with extra guide flags, the red ones are shorter, but they are also not as deep. If it was me and I wanted a track with a very tight turn I would shorten up one of the spare black guide flags. I really don't see any advantage to running a very long guide flag unless perhaps you were going to run the car on a regular commercial 1/24th track.
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Re: CNC routed track questions

Postby lancelotalove » Thu Apr 06, 2017 12:53 pm

Does anyone with CNC experience use inkscape and is there a better software to just cut a slot in wood?
i still have to use Vcarve to code the drawing.
The slot is a standard 1/8 bit and i can adjust the depth.
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