Pin Guides

[GPGarages]

There are times that a car model has a small, short, nose, and there may be no way to hide a traditional guide shoe. Myself, I would rather not build a car that looks like it's sole purpose is to push a big fat guide shoe around the track. There is an alternative..........
On my current 1/32nd midget project (see the thread in the Oval Track forum here), this is the only way I could see to solve this problem.
First a bit of history.....when slotcar racing began, there were no guide shoes available, and cars were built using a "pin" guide. When you see photos of very early slotcars, like those built and raced by the Kalamazoo and Chicago groups around 1960-61, this is all you would see. The molded plastic "shoes" came along later.
The pin guide is very simple, comprising a block of a non-conductive material with a rigid vertical pin protruding from the block down into the track slot. The pickup brushes are arranged pretty much as we see them today, with the exception of being shorter and not trailing the pin location by much, if any. The brushes are attached to the block, and the block to the chassis. The reason for the brushes not trailing by a half inch or more can be seen if you picture the car at a 45 degree drift angle to the track slot. With the brushes fixed, they will lose contact with the appropriate contact strip and/or short out across the contacts. By making them contact the track on either side of the pin, with little or no trail, this problem is minimized.
Let's talk about advantages and disadvantages. The negatives are:
a) the guide will have to be scratchbuilt,
b) the car will be able to spin out and will lose contact at a certain point,
and c) the pin guided car may be a bit harder to turn marshall, at least until the marshalls get the idea.
On the plus side are:
a) appearance.....if this is no concern to you, you can save time and not read further........but I'll argue that with the appearances of the cars you guys have presented on this and other sites, you're still with me......
b) in my opinion, there is no performance loss, having loaned a pin guide car to a racemate in Denver and having him beat all of us convincingly for my trouble...I would venture to say that if I placed one of my pin guide cars on a track and had you drive some laps, unless you seriously overcooked it and saw that the car would do a 180, you would never know.
c) there are tracks where a pin guide will not work, if the slot is routed poorly, or on some plastic track joints. That said, we have run pin guides through digital crossovers with little or no problem.
On to building a pin guide:
A shopping list:
*a suitable block of a non-conductive material, like acrylic plastic, delrin, bakelite, hardwood, resin, plywood, etc. You will need to be able to cut, grind, carve, drill and thread this material. Think fat sugar cube size....
*a short piece of .047 piano or spring steel wire
*a section of the red Teflon tube supplied with many contact cleaners and WD-40
*some flexible contact braid material
*appropriate machine or wood screws. (I use 1-72 and 2-56 sizes a lot, found at better model train shops, or online)
*tools...to include drills 3/64" and whichever is needed to drill and tap for the screws you wish to use. better R/C shops will offer these drills and taps in the sizes needed, as well as the screws in many cases. Those in less enlightened countries can make do with the French system and fall back on 1.5 or 2mm machine screws, or if in the UK, there is always glue...lol

Along with the chassis of choice, compare the chassis and body to determine the shape of the block needed, and make the block so. Width needs to be a bit more than your contact braid overall width, depth from 1/4" to more if you body shape allows, and length maybe 1/2 to 5/8" , not much more than a sugar cube.You will need a way to mount the block to the chassis, which can be wood screws for wood, or machine screws for any of the plastics. The chassis should end just behind the block where it would be attached, usually with screws through the chassis into the block. Allow enough space forward of the pin location for the braid to be attached and trail a bit, say 1/4" or so, a bit more if you have room.
I usually locate and screw the block to the chassis, shape it to fit under the bodywork, then locate the centerline and location for the pin itself. A drill press is handy here, in order to get the pin in a vertical position. Drill 3/64, or if you want to impress your neighbors, first drill undersize with a #57, then ream to size with the 3/634", which is .047". A better fit ensues. Use a cut-off wheel (NOT sidecutter pliers) and slice off a suitable length of piano wire, and slide the wire up into the hole you just made in the block. If it's tight enough, trim off to suit your slot depth less maybe 1/16", so you do not snag joints in the track. If needed, use superglue to lock the wire in place, or if too loose, you can also drill and tap for a setscrew to lock the wire in from one side. This would also allow adjustments in pin depth if you wish. Slip a short section of the red Teflon tubing over the guide pin, contact cement if needed to retain. This tube will wear out, and can be replaced as needed.
Next, drill and tap for screws to fix the braids from the front of the block, again allowing for body clearance. I can tell you on a 1/32nd midget there is no extra room.
Tin one end of the braid, and punch a hole through for your screw. Solder a motor lead with to the tinned end of the braid, and screw the braid on to the front of your block.
Adjust the braid to lie flat against the bottom of the block, with a slight amount of spring away, then trim off the braid to no more than 1/8" aft of the guide pin. In some cases, the braid may only be 1/4" long below the front edge of the block. Rounding the front edge of the block where the braid folds under may help get the alignment you need.
As with all things, some adjustments may (will) be needed.
And there you have it....no more purple jet flags being pushed laboriously around your track by a poor little midget or F1 car. Better looks, less cost, what could be better. Amaze your buddies........
Dan
ps, there will be questions, and we'll try to answer them here...................

[dreinecke]

Hmm...very good tutorial Dan! Lots of things to now think about as I get ready to build my midget from your body.

I think some pictures would be great as well...I'm kinda slow...just ask Bibbster...

[Derby City Speedway]

I can dig it Dan, I've built a few pin guided cars, and as you say they can be driven hard and fast enough. But for me the main reason is I can't stand a car with a guide flag leading the way...that's just not right, right up there with saying it's finally finished, but no inserts.

[padirtfan]

that's a really cool idea. I'm going to have to try this.

[gascarnut]

Pin guides are cool as long as the car has enough traction. When there's good traction you don't have to worry as much about 180-degree spins or loss of contact.

One disadvantage not noted so far is that on de-slotting a pin guide drops into an adjacent lane much more easiy than a flag, so you get more "riders" with pin guide cars.

The other option sometimes is a trailing guide, but those are difficult to find these days.

[GPGarages]

Hi, Dennis!
True enough about the "riders" problem, but perhaps not as common on a two or three lane home track. And trailing guides....how the heck can you wire one up to last....I had a bunch of Sakatsu guides that I got from Patto, neat idea, if you could go wireless....lol
Have you ever tried a combination, where the flag itself is in the slot, attached to a pin at track level and above? Pickups as per pin guide. The only advantage I can see is that it may slide past rough spots in the track better. I have one like this in a Morgan trike project in 1/32, which will have steering linked to the "buried" flag, and no visible guide unless you look down in the slot. I'll paint it "slot" color to blend in..........

dan

[oz10k]

I built an Eldon Camaro with a Parma womp chassis. To keep everything under the body I decided to use a guide pin.

I started with an old 1/43 chassis (you can get them cheap on ebay) and cut-off the pin portion:



With some cutting and filing you can get them to fit nicely:





You can use the pin as-is, or you can beef-it-up:



Here are a few other pics of the Camaro. Has EJ rubber tires and an adjustable magnet. It’s a fun car to drive.







Ron

[Retro Racer 44]

Dan;

Great post on pin guides. :text-goodpost: When I was racing in the Toronto area in the 60s, pin guides were all I used. Both 1/32 and 1/24 scales. We could buy 1/8" nylon rod that was perfect for the pin, and I built my front end out of 1/2" plexiglas. The front axle holder was in a brass tube through the block, and the plexi block screwed into the brass chassis pan. Even after a lot of the guys started using only guide flags, I kept using pins until I quit in 68 (I was off to teach in an Inuit village in the Arctic). I wish I had kept those cars. :cry:

You're right about marshals. They kept telling me my flag had fallen off. Before each race, I made a habit of showing my car to each marshal, and then it really saved time.

I currently have a Ferrari D50 short nose that had a pin guide made from a piece of Carbon fibre rod. (I'm thinking 1/8 cord for a gas weed eater might work in such a short length). I was planning to re-build it with a flag, but it would have to be set between or behind the front wheels. I think I will just put it back together with the pin and block.

:flags-canada: