Threads Stripping in Plastic

[scott_davis]

Any tips for dealing with these problems?

Ive now had a few screw threads go on the plastic parts that are now becoming annoying as I have to tighten them up each race...

Main culprits:

Front Bulkhead
Rear Shock tower where it bolts to gearbox
Gearbox screws from bottom of chassis

Cheers

Scott

[Chrislong]

In threaded holes, try using metric screws as theyre slightly fatter.

I always used metric screws in front bulkhead (the ones hiden by the bumper), I never had trouble with the ones under the chassis, but the ones from above the gearbox were threaded on my B3 too and they stayed that way there as it was bolted firmly from underneath.

Chris

[scott_davis]

Where can I get metric screws from? :-[

The ones that screw into the gear box from rear tower keep working loose - am considering getting longer screws and using bolts to hold it all in place as a permanent cure...

Its nice that Im no longer breaking stuff each race but this thread stripping is doing my nut - even resorted to super glue this weekend that works for a while but messy!

[Chrislong]

Oh righty, I know the ones, there are four going from the rear shock tower - you mean the top two? You can replace that little bracket for £3 I think.

There used to be an alloy one which would cure it - but can't seem to get them now since B4 is out (I tried). Fastrax supplied it? I tinks?

Long screw and nut would be better in this instance, but when you can't get ur nut on it, use metric. Can get them from anywhere, they're what are used on any Schumacher/yokomo/kyosho/tamiya kits, whereas Losi and AE use imperial (being USA origin).

Try a hardware store, don't know the size but if they're same thread as your motor screw then that the one - make sure you get countersunk where needed though and the same length or slightly shorter. being fatter they'll grip best in the stripped thread.

Don't confuse metric for the self tapper type though. Take a motor with you to check the thread (if they don't go in with ease theyre wrong - don't strip ur thread in motor !!!)

[scott_davis]

Ta mate - its mainly the top two in the shock tower as you mention - I have managed to use screws and small bolts to sort that out...... have just also installed some slightly bigger screws into the gearbox casing from the bottom of chassis although the heads are a little bigger so suspect they will catch on the ground when bottoming out over jumps - will see.....

I will source some slightly bigger screws for the bulkhead *:)

Cheers

Scott

PS. Saving for the Factory Team B4 for when it comes out ;D

[Andrew_Carter]

u should be stripping threads in your tc3i haveno probs wot so eva! u only hav to pinch the screws up not tighten em as much as they will go or your going 2 strip em!

Andrew

[scott_davis]

u should be stripping threads in your tc3i haveno probs wot so eva! u only hav to pinch the screws up not tighten em as much as they will go or your going 2 strip em!

Andrew


TC3??? ???

Its not the fact Im over tightening them - more the fact that occasionally I have need to strip down some parts and the screws lose their ' tightness' so dont grip properly hence keep working loose....

[rc_jammer]

If their aluminium screws then replace them with new aluminium screws or steel ones as the aluminium tends to ware off and not grip as good (same in the TC3 for the gearbox casings). If they are still not gripping then get 3mm thread screws. These are slightly bigger and grip well. (standard assoc screws are 4-40)

[marcoski]

A drop of mild thread lock should sort it, but as with all plastic threads, they have a limited life. I also find that when installing the screw, if you go the wrong way, the screw will jump into the origonal thread, at this point go the right way - stops you cutting multiple new threads in the plastic and mashing it up. This is a must do procedure for the plastic used in projectors (day job), as the plastic is really brittle and crumbly.

[scott_davis]

Cheers Guys - have ordered some slightly bigger screws and will be doing some self repairing for the weekend to make sure everything is secure! :D

[super__dan]

On my B3 I used to run the same size screws that you use in the rear toe in block for the front bulkhead ones throught the ally plate, they site slightly pround as countersink isn't big enough but its nothing really, they never came undone.

Rear shock tower I used to use the gearbox screws (long ones) cut down and the ends filed nicely so that they are just long enough to use all of the available thread in the gearbox brace, much better than the std screws that only go half way through.

Gearbox screws, use the steel ones, as you know I'm not a big fan of ally screws in that many parts of the car, and thats one of them.

Dan

[scott_davis]

What you mention Dan is exactly what am planning on doing in next couple of days ;D

Cheers

Scott

[Tim Branigan]

I have got around this problem by using helicoils. I fthere is anybody that doesn't know what these are they are wire threads. They come with a tap which taps a larger thread into the hole and then you screw in a new wire thread. This will be stronger than the original. However it can still be stripped if overtightened or involved in a large crash. They are a bit of a special order in England due to the thread size and cost 40 pounds but will also save lots of money in the long run. PM if you need one.

[whoopass_racer]

However it can still be stripped if overtightened or involved in a large crash.

Useless for me then!! ;D

[MattWinyard]

get a 440 helicoil kit! ...

I have one... Dunno where I got it from, dad got it for me...

Anyway basically it places a spring inside the thread, so the screw uses that... Like a metal thread, only disadvantage you really need to tighten them down, as plastic has natural friction... Metal has less... and thus come loose...