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Discussion Starter · #1 ·
Looks like an easy question that must have been answered many times but I can't find any threads!!!

How wide does a slot need to be?
Graham says 3.2mm and he should know but I have no R1 radius curves so reckon I could do less......

Help!!!!!

Andi
 

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[quote name='MrFlippant' date='10 Jun 2011, 07:38' post='625691']
Mathematically that's 3.2mm (or 3.175 if we were in Germany) but looking here it seems there's 3.2 or 3.5mm equivalents??

Sorry for this ignorant question but I assume you're talking about a drill bit - do you just push a a it round the line of the track sideways rather than drilling vertically?
 

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Depends on the cars you want to use ?

if slot it/NSR/scaley etc then 3mm is fine but if JK Parma etc then it would be better with 4mm as they use a larger guide and it will catch in a 3mm slot and even break with some tight and fast corners.

T
 

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QUOTE (chris99 @ 10 Jun 2011, 07:28) <{POST_SNAPBACK}>Mathematically that's 3.2mm (or 3.175 if we were in Germany) but looking here it seems there's 3.2 or 3.5mm equivalents??
1/8 inch = 3.175mm - that's the exact answer whatever country you are in.
A router won't cut a slot width to that sort of precision, but small variations in slot width are unimportant.
Cutting a slot 3.2mm or 3.5mm wide will work just as well, as will 4mm.
 

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QUOTE Mathematically that's 3.2mm (or 3.175 if we were in Germany) but looking here it seems there's 3.2 or 3.5mm equivalents??

QUOTE (300SLR @ 10 Jun 2011, 16:21) <{POST_SNAPBACK}>1/8 inch = 3.175mm - that's the exact answer whatever country you are in.

Sorry, just an intercultural reference/joke
 

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Yapp! 3mm wide and 8mm deep should work well. If using braid, bed for braid should be 0.2mm less then thickness of braid (mentioned by some gurus
). Regards Jens
 

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... the exception proves the rule then Jens.


Slightly off topic but I guess you guys use MDF board. This is new to me & the translation into French gives the equivalent of chipboard which is different I think. Anyways, this external comment worried me a little:
QUOTE MDF can be dangerous to use if the correct safety precautions are not taken. MDF contains a substance called urea formaldehyde, which may be released from the material through cutting and sanding. Urea formaldehyde may cause irritation to the eyes and lungs. Proper ventilation is required when using it and facemasks are needed when sanding or cutting MDF with machinery. The dust produced when machining MDF is very dangerous. Masks and goggles should always be worn at all times. Due to the fact that MDF contains a great deal of glue the cutting edges of your tools will blunt very quickly.
Source: http://www.design-technology.org/mdf.htm

Is this well-known?
 

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QUOTE (Kellerkind @ 10 Jun 2011, 17:07) <{POST_SNAPBACK}>Yapp! 3mm wide and 8mm deep should work well. If using braid, bed for braid should be 0.2mm less then thickness of braid (mentioned by some gurus
). Regards Jens
Did you mean to say the bed for braid should be 0.2mm more then thickness of braid?
It is normal practice to recess the top of the braid slightly below the track surface. Having it above the track surface means the braid is more exposed to damage by the cars and frays much faster than if recessed.
 

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QUOTE (chris99 @ 10 Jun 2011, 16:22) <{POST_SNAPBACK}>Slightly off topic but I guess you guys use MDF board. This is new to me & the translation into French gives the equivalent of chipboard which is different I think. Anyways, this external comment worried me a little:

Is this well-known?
The normal track surface material these days is Medium Density Fibreboard (MDF). This superseded chipboard as the preferred material for tracks. Apparently the material called chipboard in the UK and Australia is known as particle board in the US and Canada.

There are all sorts of potential hazards associated with building tracks with power tools.
The safety measures needed are simple enough to follow.
If you understand what you are doing, and take the proper safety measures this is absolutely nothing to worry about.
 

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And if it were in Indian it would be 3mm with the head bobble *grin*

not sure if this question was ever answered: "Sorry for this ignorant question but I assume you're talking about a drill bit - do you just push a a it round the line of the track sideways rather than drilling vertically?"

The short answer is that there are various families of side-cutting bits...(a drill is only for vertical use, as you observed). In this case milling bits (side-cutting drills) or spiral bits apply in particular...milling for greater precision of the slot, spiral for quicker cutting.

I personally went with 5/32" (4mm)and have been very pleased with it's universality for both guide thicknesses and it's "generousity" in helping cars negotiate exceptionally tight radius turns (tighter than Scalex hairpin).

as for chris99...MDF is essentially very fine powdered wood particles held together in a glue matrix. This glue off-gasses the aforementioned formaldehyde during machining and even thereafter from any surface not sealed (with paint etc). The issue is not just with MDF though...the same glues apply to plywood, chipboard, particleboard and virtually every other man-made construction material these days. So...it's definitely an issue, but a universal one unfortunately. Have good ventilation when cutting, seal all surfaces afterwards...and be sure to wear a "mold-rated" breathing filter as the particles are particularly nasty for your lungs. Again, this is true of all woodworking to somewhat lesser extent. It's the tiniest particles (1 micron or so) that cause the biggest problem...over and above any allergic reaction to the wood or glue.

John
 
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