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isomer1

these 3.78mm step screws are driving me mad, please advise

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I'm trying to upgrade the attachment points for my GF-01 and as far as I can tell the 3x14mm step screws are unique to Tamiya. I did manage to find the side-grade component (OP-1409 Tamiya 54409 3x14mm Low Friction Step Screw). In a move that is fairly baffling, they have molded the 3.78mm in to the chassis components - requiring a bushing/bearing/flange/eyelet/adapter (call it what you will) to keep a standard M3 screw held firmly. The more common 4mm (id 3mm, od 4mm) are too big for the molded holes.

I know these components must exist: I see them in some of the member builds and I see them in GPM and other manufacturer ads on ebay and aliexpress. But I can't seem to find them anywhere. My goto location (McMaster) doesn't carry that non-standard size.

Does anyone know a good source for the 3.78mm adapters needed for mount 3mm through rods (or screws) in place of the existing 3x14mm step screws? Flanged/flangeless it not particularly important to me.

Any info is appreciated, pictures attached of the screws, usage example, and screenshot of mystical flanged bearings in the wild.

Screen Shot 2019-04-17 at 8.13.07 AM.png

Screen Shot 2019-04-17 at 8.20.28 AM.png

Screen Shot 2019-04-17 at 8.29.54 AM.png

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Can you not use and screw and put a small piece of brass tube on it to give you the step section? Or fit a brass tube in the hole to mount a bolt through?

Would a shock eye bush fit?

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Those are good suggestions but I haven't been able to make them work. The brass/copper tubes are generally 4mm outer diameter and won't squeeze in to the 3.78mm hole on the chassis. Same with the shock eye bushings (at least the ones I have), they're at 4mm as well.

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I got some of these when I got fed up of the upper links working their way loose on GF01, WR02, TL01 etc. They are long enough that you can put a nut on the other end. I added a dab of blue threadlock too, never had one escape again.

http://www.rcmart.com/3racing-step-screw-heavy-duty-tt01-tt0110hd-p-22708.html?cPath=595_744_708

Not sure if that's any help to you?

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It's a Tamiya design failure from way back. They're in love with those stupid little step screws, and I have no idea why. Usually if you assemble them once and leave them alone, they'll be fine (but sloppy) for the life of the car. But after you take the screws out a couple of times, they start backing out on you...

The best way to fix it is to just use the 4mm brass tubes that they use for shock ends. If the holes aren't worn wobbly enough for them to fit yet, then just ream them out with a 4mm drill bit (you're only taking off a tiny sliver). Then use 3mm machine screws and lock nuts, and you can tighten the nuts up just enough to take out the slack. You'll never have one fail again.

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I am not 100% sure on the number but you can use Tamiya - 50579 stepscrews and a ballnut.

use that in several chassis to replace plastic upper arms for turnbuckles and ball ends.

-SI-0aHLJs7caBcZqdVhUIHTd0OTzcJnEZQ728fxyZtHQ101_Z12ogjZ8bvBRY7BlPg58flviqr-oANOGh8Hrt5vFWRCRDZAO5Ar7BHOQGQoNWG8mFzjJKkU-reuj9_TZ6-9FCidoijDwFh56U-wZBuCxx76sZNWa5Ko_ONVDuo9fzcOfnMWD8jy6uMNVfC9KskjvyvMAkZE-2vmef9hN8N-reRsqhwsg9SlGdL_KX-S5lynTo7iz4y7FOceFeZSEdwZUufKK0hln6UZ7Je8T8P70C-Yw0bPghFIioxf8KhB-kHawVkBVKZ-57R2a17rclt4GVHou0iDgFFMsPVagY-L2uglpWkjeAGh1vhGYEaiSf6mG-Ara9TMIb_fpvhW_5z2kS6SeQx4j8jy-q6SWcSzN0nX1gr8zyWGoxY97HdtEPyBJ56CstWsWNAwRl5dl7J8l9NIX38z3fn3PWX9MBBPICRWyItwDiMSAFPHfPw1SQXIrmi3xlDDFEeO0cbzqmVQfOJysn695l2QWJWJti46BNMIhkXus9BLnOgydWEvJAQ7Cqu5KzCXaN9AQ50aqQuSr6ICL7HPRA94W2ZezjzGXDIgHIuxIjYx-vFDI_XSZg6nFTieom92ZPWhVXJ2RD0p-8njtoq-n0gXPBD_flUJHm0KfBgx=w1415-h1212-no

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@isomer1, I don't care much for step screws either; take a look at my in-progress build for some ideas on how to upgrade away from them.

 

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On my frequent runners I change stepscrews out for a Flange Tube and a 3mm machine thread screw of appropriate length.

I think this is the part...

b_50593.jpg

They're bright golden colour when new, will dull with use.

Not sure of exact part# as I've never had to buy them too often, a few come with every pack of CVA or TRF shocks so there's a decent supply. They've been out since the Brat I believe, 

Don't confuse with other flange tubes (of several different size/lengths!!) that T has used for TA05/TRF style suspension c-hub. These are usually chrome or gunmetal though, and a lot harder to find/buy. They might be chubbier than 4mm too, perhaps... I don't think they fit where a stepscrew was. Dunno... got all these hardware spares tossed together in same jar in pitbox, it's still not hard to pick out which fits where. 

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Btw when using flange tube, put the flange side against the plastic part.

have in the past have tried making temporary replacements from K&S tubing, but without the flange they'll start eating into the plastic. Put a 3mm washer perhaps but it gets fiddly trackside. 

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Thank you for the fantastic suggestions. Most of the people that responded are the same people whose posts & builds I've been perusing for the past month or so, so that was pretty cool.  I put in an order for the M3x18mm step screws @nowinaminute, I had never come across them in my searches, so thanks for pointing them out.  I agree on the 50593 Flanged Tube @WillyChang, I can't tell if it's exactly right, but it's worth trying. Ordered a bag, and I'll post measurements when it comes in.

On a related note, the aluminum hub carriers arrived in the mail today (Tamiya 54661) for this same build:

IMG_20190418_202207.jpg.8d01e6afe39acca57c174484d1441621.jpg

And sure enough they have the exact flanged tube needed:

407270850_ScreenShot2019-04-18at8_44_00PM.png.b5c0957cfe18890ca8da52c59c3a1dae.png

Here's a closeup in the front upper suspension mount:

326193053_ScreenShot2019-04-18at8_36_49PM.png.a5081a06b91615e58a3e8a8703466d10.png

So they're definitely out there. Here are the measurements from this part:

Inner Diameter: 3.07mm,

Outer Diameter: 3.77mm,

Total Length: 6.10mm,

Flange Thickness: 0.47mm,

Flange Diameter: 5.52mm

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