RC10Talk - The Net's Largest Vintage R/C Community

It seems I'm always needing thinner 12mm drive hexes than what I've got! Do hexes exist that are less than 4mm thick, use crosspins, and 4mm axle holes on the outside, and I believe 5mm holes on the inside?

I have some Kyosho hexes that are barely 3mm but they are press-fit style and require a tapered axle, and don't use crosspins.

Even 1mm less than the standard 4mm hexes out there would be fine. I just can't seem to find hexes that will work for my needs. Any help or ideas would be appreciated.

anything thinner is probably going to cause problems with the cross pin starting to fold the hex in half as you tighten up against it. that's more than likely the reason you don't see anything thinner.

Can I ask why that 2mm is so critical? It seems it really wouldn't change much unless you are shooting for roar maximum widths and you are already too close.

the original traxxas bullet had steel hex drives, they might have been just under 4mm, with a 5mm axle. I can check when I get home. I only have one that isn't damaged.

jwscab wrote:Can I ask why that 2mm is so critical? It seems it really wouldn't change much unless you are shooting for roar maximum widths and you are already too close.

It's because the Kyosho's swing shafts & CVDs I'm using have shorter axles (the outer threaded part), at least for the wheels I'm using...I can't get a standard 4mm lock-nut fully threaded onto the axles. A lower-profile lock-nut just barely threads on fully, and that's after downsizing the wheel's center washer from a 1.5mm-thick one to the 1mm-thick ones you custom-made for me. I'd ideally like to be able to thread on a lock-nut far enough that there are some extra threads poking through. I guess I'm a perfectionist...

sounds like you need to narrow the section width of the wheel at the hex/axle, is there enough material to do that? Does the wheel have a fat middle where the axle goes through? Is this a plastic wheel?

Maybe you can grind a groove in the wheel and make it pin drive rather than hex if it's thick enough? OR, grind a plastic hex flatter and glue it into the wheel to make a pin drive.

it's always something isn't it?

I have a few things contributing to my problem. I needed to add a few spacers inside the front & rear hubs/carriers to get the bones to fit at least halfway inside the outdrives, which also all but eliminates any side-to-side play in the wheels once installed.

The wheels I'm using for Barney aren't your typical 2.2" dish-style buggy wheels like you see on everything else. The set I chose are beadlock crawler wheels which evidently are a bit thicker at the wheel-centers than other wheels, further pushing the wheels outboard on the axles.

The end result is that a low-profile 4mm lock-nut just barely threads completely onto the axle threads, practically flush with no extra threads sticking out. Normal lock-nuts don't thread on enough.

One thing that I can suggest to anyone customizing a vintage buggy: equip yourself with a boatload of spacers in various inside/outside diameters and thicknesses. I can't count how many times I've had to use spacers to remove play or make something fit properly!

I managed to source some very thin hexes. I've seen thinner ones--Kyosho makes some that are only 3mm or so thick, but those use a tapered-hole, friction-fit. Pretty much all the hexes I'd seen that use cross-pins, and have a 5mm inside hole/4mm outside hole, are at least 5mm thick or more....until I discovered these:

http://www.ebay.ca/itm/250910875379?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
These hexes are only 4mm thick, and the raised central portion to offset from the bearings is lower than all the others I have, only being 0.3mm high...so the total hex width is only 4.3mm. It may seem like a minute difference but 1mm of threads is a good extra turn or two for an M4 nut to bite onto.

Golden Horizons makes thin 12mm hexes for the 1/16 E-Revo, but those required modding to fit normal 2mm cross-pins, as the recesses for cross-pins are too narrow & short. I had to widen & lengthen the recesses and file the length down of some 2mm cross-pins to get those GH hexes to work. With these hexes, no modding is required, they work fine with standard cross-pins and are at least 1mm thinner than any other hexes that use cross-pins. And bonus: they're available in several colors!

So, if you're in search of thin hexes because your wheels barely thread on enough or you need to narrow your track width a bit, try these out.