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Juhunio

TB-02R not TB? One kit, two builds

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On 2/14/2021 at 6:39 AM, Juhunio said:

Interesting that there's no full gearbox cover on the TB-02 (compared to a TT-02). This must leave it quite exposed to grit and stones getting in there??

@Juhunio - On my TT-02R Audi R8 LMS I raced at the 2018 TCS Finals in SoCal, I had a very small pebble/rock lodge itself in between the spur and pinion gear. This was WITH the spur/gear cover installed on the TT-02R.  This little pebble took out the 29T pinion gear and made all sorts of a racket running. I imagined it nestled itself in there with my learning curve to try and stay on the racing line — I was off line too many times, ugh. I immediately stopped and had to replace it, this was right in the middle of qualifying sessions to boot! Tamiya USA didn't have a spare 54229 set there at the track and to continue racing I had to drive 45 min one-way out to the desert in Chino, CA to TQ Racing, they had a spare 54229 set (28, 29T) which enabled me to continue to race. If it's a shelfer, no problem, but if you run it, I'd suggest on the cleanest surface possible (indoors carpet?) and carry lots of pinion and spur replacements or keep the rear cover on.

This is my only hesitation going forward with the rear CF brace.

But, on the other hand, all the TRF chassis racing there that day are totally open spur/pinion gear sets and maybe because there isn't any cover(s) lessens the chance to have this happen?
I seemed to be the only TT-02R racer this happened to this weekend, as far as I could hear — it definitely made a racket! Maybe it was just a fluke, don't know.

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@studioRS sounds like you got VERY unlucky there, and the gear cover caused the problem it should have prevented to actually become worse :(

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Yes, quite the sullen feeling at the race course with a munched pinion gear causing me to stop and no factory Tamiya parts on hand. I could have run a 28T, but in GT Spec, the 29T was the only pinion to run for top speed.

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I got around to installing the Stabilisers last night. The mounts were installed at the same time as the front and rear arms, so it was a pretty straight-forward case of choosing a strength (yellow / medium, like the springs) and adding the rod connectors

Well, almost...

The instructions say that if you're using Yellow or Blue rods, you have to cut a groove into the N4 / A7 parts that secure the rod to the front / rear gearboxes

I did a quick test install first without cutting the groove, and the fit was too tight; the arms would move up (ie compress), but wouldn't then return to rest

So I cut the grooves...

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...and the arms move freely while the rod itself stays in position

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Then attached the dampers front...

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...and rear

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And couldn't resist a little test fit of the wheels too ;)

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@Juhunio - I've got to get button head screws and bolts to replace ALL the TB-02 kit Phillips versions. Time to make a list, unless of course there is an already made kit?

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24 minutes ago, studioRS said:

Time to make a list, unless of course there is an already made kit?

Not that I could find, I just have a stock of them that I've picked up along the way, some YR, some Square RC, some from an online fixings site here in the UK

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Last couple of steps now :(

First up today was attaching the bumper and body posts 

I didn't have any 18mm hex head tapping screws in the box to replace the kit JIS screws, but did have 18mm hex machine screws

So I put the drill tap to work creating a thread in the lower bumper...

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... which meant I could keep it hex heads throughout :)

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So I'm down to the last few finishing touches

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Here's a full view of the underside with the SSG Carbon Centre Plate installed. Mmmmmmmmm, hex heads screws B)

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Noticed something curious with the front dogbones. Why does the right front get 2 urethane bushings (MB24 red and MB23 white), while the left calls for MB23 white only? Is this a mistake in the manual? The diff outputs seem to be symmetrical. What am I missing here? 

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18 hours ago, Room335 said:

Noticed something curious with the front dogbones. Why does the right front get 2 urethane bushings (MB24 red and MB23 white), while the left calls for MB23 white only? Is this a mistake in the manual? The diff outputs seem to be symmetrical. What am I missing here? 

I didn't have to do that as they don't feature in the EvoIII diff build, but looking at the manual I would assume it's because the RHS diff joint has a much deeper offset than the LHS...the RHS is the longer of the two diff joints, the LHS shorter. So although they look symmetrical once the gearbox is closed up, there's actually more potential travel for the RHS dogbone, hence the extra bushing to limit that travel. 

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Indeed. One side of the diff has the hex bolt head taking up some of the space in the diff joint, so doesn't need as much bushing thickness as the side with no bolt head.

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Ah the hex head bolt! Makes perfect sense now. Thanks guys. One of the things I love about this hobby are the engineering details in these cars. 

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On 2/18/2021 at 8:16 AM, Juhunio said:

18mm hex head tapping screws

@Juhunio - On all the other JIS kit screws, did you fit 8, 10, 12mm etc. button (or flat head) tapping screws?

Or will regular machine screws work fine to replace the kit supplied JIS self tapping? I've never done a screw bolt conversion before. While I love my Tamiya black handled screw drivers, my set of Hudy socket drivers is far superior and would prefer to use these.

Here's the list I compiled from both TB-02 / TB-02R. The only screw that is not listed in the combined machine screw list is the servo horn 2.6x10mm.

TB-02 / TB-02R
Button head conversion screws, bolts
A Parts
MA1 3x12mm tapping screw x6
MA2 3x10mm tapping screw, flat head x12
MA3 3x8mm tapping screw x8

B Parts
MB1 3x10mm tapping screw x12
MB2 3x12mm tapping screw flat head x2  - TB-02
MB2 3x8mm machine screw x2  - TB-02R
MB3 3x8mm machine screw x4  - TB-02
MB3 3x6mm machine screw x6  - TB-02R
MB4 3x12mm tapping screw, flat head, x2
MA2 3x10mm tapping screw, flat head, x8
MB5 3x10 machine screw, flat head, x2
MB6 3x8mm machine screw, flat head, x12

C Parts
MC1 3x18mm tapping screw x2
MB1 3x10mm tapping screw x12
MB2 3x12mm tapping screw flat head x3  - TB-02
MA3 3x8mm tapping screw x12  - TB-02R
MC2 3x10mm machine screw x1  - TB-02
MC3 3x10mm machine screw x10  - TB-02R
MC2 2.6x10mm tapping screw x1
MB2 3x8mm machine screw x1  - TB-02
MB3 3x8mm machine screw x1  - TB-02R
MB4 3x12mm tapping screw flat head, x3  - TB-02R

 

Combined and converted to all machine screw list
Button Head Socket machine screws
Size (mm), QTY
3x6mm, x6
3x8mm, x27
3x10mm, x25
3x12mm, x6
3x18mm, x2

Flat Head Socket machine screws
3x8mm, x12
3x10mm, x22
3x12mm, x10

 

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On 2/19/2021 at 5:35 PM, studioRS said:

@Juhunio - On all the other JIS kit screws, did you fit 8, 10, 12mm etc. button (or flat head) tapping screws?

Or will regular machine screws work fine to replace the kit supplied JIS self tapping? I've never done a screw bolt conversion before. While I love my Tamiya black handled screw drivers, my set of Hudy socket drivers is far superior and would prefer to use these.

I have a few pots of 6, 8, 10 and 12mm hex head machine screws both button head and countersunk, which cover most bases. I also have a few tapping screws in the same formats

For this I used a mix of tapping and machine screws...the tappers were primarily used to attach the CF damper mounts, gearbox covers, SSG Centre Plate and body posts, the rest were machine screws

Quite a few folks here drive machine screws straight into the plastic, maybe using a bit of grease on the screw tip to help it on its way

I prefer to use the threaded tap tool, it just makes the whole process much easier. In theory it should mean that you can use machine screws throughout, as the tool creates the thread so you don't need the self-tappers. I just happened to have some hex head tapping screws in the right lengths, so I used them :)

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On 2/18/2021 at 8:19 AM, Juhunio said:

Here's a full view of the underside with the SSG Carbon Centre Plate installed. Mmmmmmmmm, hex heads screws 

@Juhunio - Forgot to ask you, what size are the SSG carbon centre plate chassis hex flat head screws?

My guess is either M3 x 8mm or M3 x 10mm? Certainly there is depth for longer in the tub.

Decided to forge ahead and run my TB-02R with an open rear gear set, **** the pebbles! Full CF and I’m drafting the TB EVO.III upper deck, rear brace and having a set cut in carbon fibre. Interested in an EVO.III replica upper deck?

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17 hours ago, studioRS said:

My guess is either M3 x 8mm or M3 x 10mm? Certainly there is depth for longer in the tub.

Solid guess!

I used M3x10mm countersunk tapping screws APART from the screw that goes through the SSG plate into the inner servo mount

If you're using the kit plastic mounts, then you need a 12mm countersunk tapping screw for that one

If you're using aluminium servo mounts like I did, then substitute the tapper for a machine screw

17 hours ago, studioRS said:

Interested in an EVO.III replica upper deck?

Thanks for the offer...there's a company called Fibre Lyte here in the UK who offer a full set of CF plates for the TB-02, and I'm seriously considering their upper deck :D

 

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Last little finishing touch on the main build is the battery plate and the 3 Racing blue mount posts. 

The battery was a very tight fit with the cable exiting at the rear as per the manual, and when I swapped ends around to have the battery cable at the front it interfered with the steering link

So I ended up taking the top off the mount post and remounting it on a 16mm screw rather than the 10mm it came on. This meant I could add a couple of spacers beneath the mount which enables the battery cable to exit left and over the battery plate, staying out of the way of the steering

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Just one spacer on the rear post is enough to level it out enough while keeping the extra clearance at the front

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5 hours ago, Juhunio said:

seriously considering their upper deck

@Juhunio - I read your initial posting inquiry on that. Yes, l looked into Fibre Lyte UK, but a mate of mine has full CNC carbon fibre machining available and we design and develop RC racing boat parts here on the west coast.

One question you had in the beginning of your beautiful build thread was, what issue(s) the TB-02 was blessed with. The non floating propeller shaft is the biggest problem, any shunt on the front strips the front diff gears. Several solutions, 1. Reinforce the tub chassis rigidity with all CF TB-02R parts and the TB EVO.III upper brace and lower tub CF brace (and shim the spur as you did - very clever!)  2. Fit EVO.III diffs, and some other ring gear, think it’s in my notes on the other thread. 3. This is much less factory Tamiya, is to make a floating prop shaft. I’m sure I could figure out how to keep it mostly Tamiya parts, but why when you can dip into the TB EVO.III bin and make a TB-02R EVO :P


Tamiya always refines models through evolution of design. The TB-03 has all new gear boxes, floating propshaft, and many other design changes that some get carried over to newer models. My next build, I picked up a TB-03 for a proper R tribute. ;)

Cheers, Thompson

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On 2/21/2021 at 5:06 PM, ThunderDragonCy said:

That looks fantastic! Top job. I can really see thr lineage with my TB03R there. 

Cheers! One day I would love a quiet day on a track like you have access to, and the chance to run this and the other TCs to get a proper feel for them and their differences 

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On 2/21/2021 at 6:07 PM, studioRS said:

One question you had in the beginning of your beautiful build thread was, what issue(s) the TB-02 was blessed with. The non floating propeller shaft is the biggest problem, any shunt on the front strips the front diff gears. Several solutions, 1. Reinforce the tub chassis rigidity with all CF TB-02R parts and the TB EVO.III upper brace and lower tub CF brace (and shim the spur as you did - very clever!)  2. Fit EVO.III diffs, and some other ring gear, think it’s in my notes on the other thread. 3. This is much less factory Tamiya, is to make a floating prop shaft. I’m sure I could figure out how to keep it mostly Tamiya parts, but why when you can dip into the TB EVO.III bin and make a TB-02R EVO :P

That's interesting, thank you. It compelled me to look at the TB03 (and then TT02) to understand the difference between 'floating' prop shaft and 'direct'. I completely get it now, and can totally see why the direct/TB-02 set up could cause problems. Hopefully my shimming will help, the shaft itself was a very tight fit into the prop gear so that should also help I guess?

I managed to find an original EvoIII top deck today, so I'll look to add that when it arrives :) Thanks for all your positivity and advice, much appreciated 

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Took advantage of the bit of sunshine yesterday to brave an hour or so in the garage and cut out the body shell

It's not going to get painted for a couple of months yet so this was just to test fit and finish the final steps of the manual, attaching the mirrors and rear wing

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Pretty happy with the fit, looks nice and straight

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I will do a bit more tidying up with the Dremel before painting, but it's not far off ready

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The only slightly weird thing is the way the rear body posts are moulded, they have a large nib on the rear edge which means you can't get the shell down low enough over the rear wheels :huh:. This is as low as it will go, and it's a bit high for me...

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If I'm feeling brave at some point I might try and trim some of the nib off to get the shell to sit a bit lower. Maybe. Possibly. Dunno. Not sure. 

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