Baby, Don't Fear the Router

[Fast Co.]

Baby, Don't Fear the Router

Here are some lessons I learned routing a few mdf tracks. These tips might help you avoid some of the mistakes I made:

1. Use a new router bit. On my second track I used an upward spiral bit because the guy who used it to rout his track before me preferred it over a straight, double-fluted bit, which is what most guys generally use. The upward spiral bit removes material from the slot as you rout. That's all well and good, problem was the bit had already routed through 240 linear feet of mdf prior to my using it. It took some effort to push the router through the mdf and the slots were a bit ragged. It was easily fixed with a little sanding but when I changed the bit for a brand new double-fluted straight bit the router cut clean and without effort. Why make yourself and the router work harder? A new bit will cut through mdf like a hot knife through butter. Whether upward spiral or double-fluted straight, use a new bit. It seems that a router bit is good for about 240 linear feet or one 4-lane, 60' circuit.

2. If using a lexan strip such as the ones Luf sells online- http://www.oldslotracer.com -be sure to use straight nails to hammer it in place. Nails that have even a slight bend in them will tug the lexan strip in one direction or another resulting in slots that are wavy.

3. A plunging router will eliminate slight nicks in your slots at the point where you begin routing. If you do not have a plunging router balance the router on the bit so that it is plumb and level and against your guide fence and give the switch a little blip to drill a hole as straight and plumb as possible at the correct distance from the guide fence.

4. Rout across the seams of adjoining sheets of mdf. This will ensure that your slots line up perfectly at the seams. You will find that you have to do this anyway as your guide fence will extend past the point where you begin and end routing.

5. Always rout with the guide fence to the LEFT of the router as you PUSH the router. (If you are pulling the router towards you then the fence will be to your right). The router will wander away from the fence if you push it in the wrong direction.

6. Rout banked turns flat and then bend into shape after routed. Remember the degree of arc will increase as you form the bank so that a 180° turn may end up being 185° or more depending on the angle of the bank. After banking, check the slot width. Depending on the degree you have banked it, the slot width may decrease slightly. Hand sanding the slot with medium grit sandpaper is usually all it takes to bring the slot width back to where you need it. And it's always a good idea to give the slots a light sanding after routing anyway.

7. When using a pin jig to rout equidistant parallel slots make sure that the slot the pins travel through is clear of dust and debris. You don't want the router to unexpectedly stall because the pins hit an obstruction in the already routed slot. The torque of the router will kick the router slightly causing small nicks at each point where the router is stalled.

8. An alternative to using a pin jig is to use a Sintra strip in the already routed slot to act as a guide fence. This will work only if the radius of your router base is equal to the lane width you desire. If I were to rout another track I would use the Sintra strip versus a pin jig. The jig I used was a home-built version made of wood and attached to two steel rods that directly attached to the router with set screws. I realized as I attempted to close the loops on my slots that the wood portion of the jig was slipping ever so slightly along the steel rods resulting in slight lane width variations so that the starting and ending points of my slots did not flush up.

9. To calculate necessary track width multiply the desired lane spacing by 1 less than the number of lanes, add another 1/8" for each slot and another 8" for borders (In turns you'll want a minimum of 5" for an outside border and a minimum of about 3" on the inside - you may be able to get away with less than this depending upon the turn, but this is a good general starting point for a 1/32 scale track). For a 4-lane track with 3.5" lane spacing this will be a 19" track width [(3 X 3.5") + (4 X 1/8") + 3" +5"]. The more room you have for track width the greater the flexibility you will have in your routing. A track width of 16 or 17" in the turns is restrictive for a 4-lane circuit with 3.5" lane spacing.

10. Bondo is great for fixing routing errors. Be sure to apply enough so that it sits above the level of the track since Bondo shrinks as it cures. If you scrape the Bondo so that it is flush with the track surface while it is still wet you will end up with a depression where the slot is and you will have to apply a second coat. So apply a little more than necessary and sand down to track level once dry. You will know you have sanded to the track surface when the line of Bondo looks to be the same width as the slot it is filling. It's good to scrape away excess Bondo from the track surface away from the slot to minimize sanding later. To avoid a thin, unsupported strip of filler at the edge of a slot you may want to over-rout the area to be filled and then rout one or two fingers perpendicular to the error to serve as anchors. Once filled, sanded and painted the repair will be invisible but it will be much stronger than a thin sliver of filler clinging to nothing but the edge of the slot. Another anchoring method is to over-rout the error and then to drill 1/8" holes to the bottom of the mdf and filling the holes with Bondo.

11. Durham's Rock Hard Putty works great for filling small nail holes and screw holes. It is water soluble, easy to work with, and gives off no harmful fumes. It doesn't work as well as Bondo for fixing routing errors because it's quite brittle and therefore there is some risk that it will chip when you rout it or later when the track is in use.

12. Luf's tape laying tool is a great time-saver but I found that the tape would sometimes try to cut inside corners. To prevent this, I applied a couple of self-stick felt pads to the base of Luf's tool. This burnished the tape as I was laying it and prevented it from wandering inside the corners. Afterwards, I burnished the tape again with the curved edge of a Bic lighter.

13. You reap what you rout.

Steve

[HomeRacingWorld]

Very well done sir. Thanks for taking the time to share this. Excellent points made.

[Fast Co.]

Thanks guys! I'm all for making it a sticky! Ooh, mailman just arrived with a couple of packages. ;)

[HomeRacingWorld]

We might as well do that now :)

[oldslots]

Use this tip to make your track building experience more pleasant - make it a two man job. One to handle the router and the other the shop vac to pull all that evil dust away!

[dreinecke]

Or, get a router with a vacuum port - I had almost no dust!

[bobbyraz49]

[Johnnyfly41]

I want to commend BobbyRaz for taking the time to write down such a succinct summation on track routing.

It's always great to learn from other's experiences (we wouldnt call them mistakes)

For instance, I used the Lexan strip with great success. Then, I decided I was suddenly smarter than Luf, The Great One,,,, Silly Luf, he put way too many holes in this lexan strip, I will just use every other hole to nail the strip down for routing.....

And that friends, is how I gained the experience of filling a errant slot with Bondo !!! The strip WILL deflect if you dont put a solid straight new nail in every single hole !

On the dust, I just couldnt see myself managing a dust collector tube and router and doing fine work. So, being a old woodworker, whats a little more dust, right. Well, I made a clear plexi base for my router. Very easy, take the black plastic one it came with off, and transfer the mounting holes, drill and countersink for the mounting screws. My base had a stepped edge, I think I used 3.5",,, 3.75" and 4" from edge of bit center. This is important if you intend to rout parallel slots using a perspex strip in the previously routed slot as a guide. It's way faster than nailing down the lexan strip again. Anyway, to drill the center hole in my new router base, I had the 1/8" carbide bit chucked up, and turned on the router and lowered it through the new plexi base. For the most part, this meant zero clearance around the cutter bit, and when routing, the dust remained packed into the slot. Dust really was not a issue for me. I would rout, then, clean out the slot after. Maybe it will work for you too, or, maybe I am just too conditioned to dust.

When doing the flexible strip/perspex strip routing technique, If you have made the stepped edge router base, you can avoid having nail holes close to one of your slots. If you route say your middle lane first, then use the perspex for routing lanes on either side, if you use the 3.75" router edge for all, one of those lanes is going to have nail holes very close to the slot. So, rout your first lane by say nailing the strip 3.5" or 4" from where you want to put the first slot, then, when doing lane relative subsequent slots using the perspex strip in the first slot, your nail holes should be .25" from the slot and not right next to it. I learned that the hard way too, but, you know, it makes no difference.

Never bothered to do the calculations Bobbyraz did, another kudos to you Sir. I used 3.75" as a compromise, to let me run the occasional 1/24th car. Then, I used a Monogram Chappy D coupe slot car as my measuring stick for curbing size. There were places where even a 1/32nd car could find the fence with it's tail, but, thats part of the fun.

For me, building my track was the most rewarding experience, and thanks to the smooth flow possible with flexible strip routing and the smoothness of wood in general, it delivered to me the driving experience of my youth racing my Cox Chaparral on a American Orange commercial track. For me, I just couldn't achieve that with plastic.

My track is gone, a house fire and the ten or fifteen thousand gallons of water brought to the party didn't do the MDF much good. It was a 3 lane 85' track occuping about 8' by 23 feet of space. The good news is, I get to do it again, using what I have learned !!!

The wheels are turning, and, I am back to lurking and learning and scheming.... One day there will be a notebook of layout sketches.... then, some full size layouts on paper to see if it looks like what I want,,, then the incredible gravitational pull of that router will have me in it's clutches, helpless to defend.....

j.

[HomeRacingWorld]

If you need to make your own strip, see your local auto glass shop. Luf's kit is worth it, but if you manage to break it, there is the alternative.

[slothead]

I'm considering making my 3rd routed track, a 4'x8' oval as a portable track to use on the deck. For my first oval (4'x14') I mounted the router on a 1/4" piece of Luan plywood and put a screw through the corner's center point to maintain a constant radius. This worked great for a 2 lane track with consistent 3 1/2" lane spacing, but it doesn't have lanes that follow realistic racing grooves. I'm going to use one of Luf's flexible strips, or equivalent, for the new oval to create sweeping entrances into and out of the corners, which should make for much smoother transitions.

It's great to have so much experience, and passion, here on HRW to tap into, so here's another thought. How to plan ahead for an indoor/outdoor track that could inadvertently be exposed to moisture? It doesn't have to be made from MDF, or if sealing MDF on all sides might not be good enough, what about covering it with vinyl sheeting (flooring) and routing through that? Anyone routed a vinyl or plastic surface? Any thoughts about a waterproof or water resistant material that is route-able and that copper tape would adhere too?

Slothead

[dw5555]

. Rout banked turns flat and then bend into shape after routed.

I always wondered why this is. Why can't you bank your curve 1st and then rout it? Then you wouldn't have to worry about lining up your next sheet. :think:

Dave

?????

[bobbyraz49]

[dw5555]

[HomeRacingWorld]

[Fast Co.]