TOPIC:

This should be out of beta by now, think its ready for production.

Not until I get an answer to - "what fits the smaller top of J12 & BM4"
& - "Tapped M3 through or both ends?"

Tolerance needs adding to top of BM1 too ("dia 6 -0.02 -0.05") or you'll get 6.00 & won't be able to fit the bearings (Unless the end user owns a press)

Otherwise, smashing!

eddrick wrote:

does the top of J12 also have to fit into something, (Is it actually 6.00 diameter x 5.00 tall or does it need tolerancing?)

Same question for BM4 - I take it the smaller diameter has to fit through a damper eye, so would the 4.2 diameter be ok at 4.20 or does it need to be (eg) 4.15-4.18?

do the M3 tappings have to be continuous all the way through BM6, BM6 & J12, or can they be tapped from both ends?
ie, do they have long screws that pass all the way through, or do they have short screws in both ends?

Top of J12 goes into plastic so it will need some tolerance :



Second question is a Hi-Cap one for wb...

Tapping from both sides would be fine for all the parts.



Edit - I'll measure the hole in the front gearbox too...
Double edit - and the original J12.

Thanks Edou.
A plastic socket isn't too bad as it'll have some "give" - I'd guess at 5.90-6.00 for J12 & it would fit ok, but yes please check the original J12 cos I'm only assuming the plastic gearbox socket will be 6.00 (It might be J12 is 6.00 & the socket is 6.10, ie the tolerance is the other way around)

Plastic J12 is 6mm exactly at the top. Hole in the gearbox is 6.08mm, after J12 was pressed in.

I measured 3 sets of mount parts and Tamiya made them dead on .00, I think we are fine if you can stay within a tolerance of 0.05

only part were its visibly off the mark is the 6.05 on the BM1. (checked again is the only one that gives a clear .05)
you are right on the dia 5 of BM1 that has to fit the bearing it would need as you suggested -0.02 -0.05
(measured 4 bm1's they are all very close to 5mm more like 4.98 not going near 4.95, no wonder Tamiya cars are so expensive)

the fit for the J12 is quite slopy, measured three gearboxes gets close to 6.15 so dia 6.0 will do

the BM4 fits a rubber ring so dia 4.40 is fine.



M3 both ends will do on BM5, BM6 and J12 (15mm or so)
on BM1 it has to go through it has to fit a 25mm screw that comes from the bottom.
BM2 needs approx 5mm and SP1 10 or 15mm

BM4 just has a 3mm hole btw.

Could there possibly a slightly better design than the Avante pipe nut?
After all, that was not specifically made for this purpose...



Plastic J12

Height of the smaller top is 4.95mm, as is the depth of the hole in the gearbox.
It then goes to a diameter of 6.95mm. This widening kinda serves a purpose to support the gearbox.
Although in practice an alloy part is already a much more solid construction than this plastic bit...
Hex (is it, really?) size at the bottom is 7.20mm. But somewhat deformed so that might not be very accurate.
And not that relevant - more a zone for free interpretation (would be nice if a metric size tool fits).

now that we almost got the dimesions sorted out, do we want to start a discusion on the finish of the surface roughness?

bling!

Cheers kids.

Any preference to the shape of J12? As Waterbok's drawing, or with a hex base?
Hex makes more sense as it gives you something to get hold of when the screw seizes in, but all the mounts share this problem, so it might be better if J12 looks the same as the rest of the standy-uppy bits - thoughts please?
(I'd say as WB's pic, to look the same as the rest. We could always do a cheaper easier "all hex" upgrade kit as well, for those not interested in curvy-looking stuff)

Now realising I'm a few steps behind with wb's input!
Curvy would be great if you ask me.