Another body mounting method

[mattb]

I've seen lots of body mounting methods. No one way is best, they all have their place and it's good to have a lot of options. This is how we mounted hard bodies when we were racing them at the local track, generally on an H&R chassis. I'll try to keep it short and clear. Have your body bare and ready for mounting.Have your chassis setup with tires and wheels.

Use a mounting bracket similar to this. This view is chassis side up. The space in the center is for lead wires if this is attached to a flat chassis.

I made a piece from balsa and used it to make a resin mold. Some guys cut them from 1/8-1/4 inch plastic sheet. Balsa wood is fine, too. It can even just be a single piece for each side. It doesn't have to be a solid piece like this. Sand the edges so it will fit in the body at the approximately the right place. Once fitted, center it on the chassis and mount with one screw. I like to use flush mounted screws tapered at the head. The screw will center itself in the hole when it's tight. You now have the frame with the mount screwed to it and the tires and wheels on it.

I use a paper towel cardboard insert to make tire covers as shown in the picture. Just cut about 1/2 wide and wrap around the tire and hold with some kind of clamp. Then put the chassis in place in the body.

You have the chassis where you want it with about 1/32 tire clearance. Use cya to glue mounts in place. Remove the one screw and pull the chassis off the mounts. Epoxy the mounts for a permanent attachment. Put the chassis back on and tighten your one screw. Center and drill the other 3 holes now. Basically done at this point. You can double wrap the cardboard for more clearance. You can also cut shims if your body is too low. I like flush mounted screws and if you want more body movement you can drill the chassis holes a bit bigger. It always helps to use a Dremel to round off the threads right at the bottom of the head.

Some of the guys were pretty rough and known to break glue joints, so I always tried to remember to sand the insides of the body to give the epoxy some tooth to hold onto.
This always worked for us to be an easy way to mount a body and not have interference between tires and body. Just another option.

[HomeRacingWorld]

Dang nice option too. More than one way to skin a chassis!

[mattb]

I always had trouble with body too low or a tire rubbing. This method made me 100% successful and was quick and easy.

[Brad_T]

More great info, thanks Matt

[Broman62]

Outstanding MB!!!!!

[HO RacePro]

I wonder how corrugated cardboard would perform if substituted for the balsa wood. Since corrugate is mostly air it could be lighter than even balsa wood. It is also stiff in one direction but a bit more flexible in the other.

You wouldn't be able to use screws to fasten it to the chassis. Double-sided tape should work. You could bend the sides of the cardboard up to make fastening to the body easier.

Just playing with ideas here...

[HomeRacingWorld]

Since corrugate is mostly air it could be lighter than even balsa wood

The almost immeasurable weight difference makes it a non-issue really. Just passing it along.

[HO RacePro]

It is hard to beat corrugate for both lightness and stiffness -- which is why it is universally used for packaging. But you want those advantages high on a car, not near ground level.

So really, where corrugate would be most useful is in the body itself. Problem is, body geometry is typically too curved to be practical in cardboard. And body stiffness is not critical, since slotcar bodies usually have no structural role.

The only place I'd think corrugate might be useful would be the wings on sprint cars. But the aerodynamic loads on slotcar sprint wings are so low that there's no gain to be expected from cardboard over thin plastic sheet.

Yup, here we are nearly 70 years into slotcar evolution with no use of corrugate. Or at least none I've ever heard of. Not likely to change.

[HomeRacingWorld]

Like many other aspects of this hobby, we just look for that balance...or "sweet spot".

A combination of weight efficiency AND strength/durability.

In these races we hold, there will be accidents. Sometimes they can be quite brutal. We need a mount system that can hold up to the conditions we put them in, and still try to minimize weight.

The other advantage to wood (balsa, old yardsticks cut in half, popsicle sticks) is it absorbs vibration very well. The pressure of the wood helps prevent screws from backing out due to vibration. Some models have the chassis removed quite often, and with just plastic you can wear the holes out to the point of the screws working their way out during operation.

Velso is a nice option, but its hard to accurately account for the thickness of both sides when trying to get the desired ride height. And then again, velcro needs a sturdy mounting point.

And then body float. Simple screws can allow us to create just enough float.

But there is no perfect, one size fits all answer. I simply pass along techniques/methods we have tested for may years onto those just staring out.

If someone comes along with a better approach, I would certainly give a try.

[Brad_T]

Don't forget the punishment the packages receive from postal services and courier companies when they are shipped for proxy events, not just accidents during the race event. The chassis fabricated from brass are much heavier than their plastic counterparts and often held in place only by a few screws, not tight chassis to body distance.