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provider of comestables
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Ok Folks, I am fed up of loose wheels so what do you do I check tightness before each heat but I lost one last night. Should i try loctite or epoxy the wheel on?
 

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Loctite 242 low strength thread locker. Or try 290 which a medium/high thread locker. I use 290 but I let it wick into the axle/rim rather than the thread of the grub screw. That rim will not come off. I also use it to hold the spur gear on. Used to have the same problem in my 1/24th racing. Cost me second place in a series championship in the last race of the season.

cheers
rick1776
 

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Ditto to Dave's post on this, I also have a problem with my BWA rear wheels on my Cooper.
Anyone know what size grubscrew to use and which size hex head allen key? Probably would
benefit from new grub screws so if anyone knows where I could get some replacements that
would be very helpful.

Cheers
Eric
 

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as above low strengh thread lock and you could grind a small flat on each end of the axle ditto for the middle if you dont want the gear to move,you could grind the flats 120* apart but in all honesty it doesn,t really matter because the mass is so close to the centre you dont get unwanted vibration, john.
 

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Loctite isn't necessary (although it can be used as belt and braces if you really want to).

Some common causes of grub screws not being done up correctly are
Rounded off corners on the hex driver. Ordinary L shape allen keys are quite soft and wear out quite quickly in slot car use. A hardened hex driver is better, but even these will need a new tip after several years regular use.
Rounded off hex in the screw. Most commonly the screws are damaged by using a hex driver with rounded corners. The only solution is a replacement grub screw.
Debris in the bottom of the socket in the screw. The debris can be removed with a pin, thus allowing the hex driver to engage fully in the socket.

If you tighten the grub screw firmly with a hardened hex driver, having avoided the above list of problems, you'll have no trouble with wheels coming off.

QUOTE (stoner @ 23 Dec 2011, 10:26) <{POST_SNAPBACK}>as above low strengh thread lock and you could grind a small flat on each end of the axle ditto for the middle if you dont want the gear to move,you could grind the flats 120* apart but in all honesty it doesn,t really matter because the mass is so close to the centre you dont get unwanted vibration, john.
Unless you balance your wheels, that's not worth bothering about.
For high end racing it is normal practice to balance wheels, it does make a differance at the speed those cars are going. Lower down the performance spectrum hardly anybody balances wheels, it makes little differance at the much lower axle revs.
When balancing wheels, an allowance needs to be made for the grub screw being screwed further in on the flat.
 

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Julius Wilkko
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Ditch all the stuff with small 1.9mm grubscrews (mainly SlotIt) and start using SlotDevil rims with proper 3mm screws.

And while you're at it you can start using tubular tyres - that is tyres with no step inside.

SlotBox

I got fed up with small SlotIt screws three years ago and moved to SlotDevil and since then never looked back.

Cheers!

Julius
 

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Phil Kalbfell
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Larger screws will simply not fit some wheels like BWA! BWA use various size screws depending on the wheels shape. You will have to measure the OD of the grub screw. But being on a cooper I assume they are one of the narrow wheels designs so will use a 0.9 ( 35 thou) Allen key.
I replace all of my grub screws with stainless steel screws of the same size they are much better and do not round out in the hex like the softer screws.
I also grind a very small flat on the axle for the grub screw to seat onto.
 

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Julius Wilkko
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Below is a comparison with SlotIt type rim and SlotDevil tubular rim.

"Tube" rim has several advantages.

1. Bigger grub screw which will not wear and tear like SlotIt. Screw is 3mm, tool is 1.5mm
2. Screw hole does not take extra space allowing rim to fit wider variety of cars
3. No step is a benefit, you can have very low tyre profile
4. Easy to buy tyres, no step to consider, only outer diameter and width

Out of these #1 was the main reason for me to get rid of all the rims with small 2mm grub screws.

So far SlotDevils have had perfect fit for any car. And not a single loose rim at the competition !

Comparison picture stolen from SlotBox site



Cheers!

Julius
 

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Nobby Berkshire
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Nobody in their right mind - unless they have a fortune of cash to throw away - is going to replace all their wheels just to use a different screw.

2mm screws undo because the thread is stripped, or you've stripped your grubscrew or allen key. These are sdaly too easy to do if you overtighten in fear of losing a wheel. All you need to do is:

1. Pop a tiny bit of threadlock or evostick glue into the thread. End of problem.

2. Cut down your allen key to a fresh hex-face.

3. Stop over-tightening your screws.
 

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QUOTE (jonnynobber @ 25 Dec 2011, 10:36) <{POST_SNAPBACK}>I must be lucky, I,ve never had one come loose.

Negligible chance anybody can be that lucky all the time.
You must be doing something right.
Maybe you are tighten them up properly?
(It really isn't as difficult as some contributors seem to think!)

QUOTE (Screwneck @ 25 Dec 2011, 05:39) <{POST_SNAPBACK}>2mm screws undo because the thread is stripped, or you've stripped your grubscrew or allen key. These are sdaly too easy to do if you overtighten in fear of losing a wheel. All you need to do is:
Cannot say I've ever stripped a 2mm thread myself, but they are fairly delicate (particularly in ally).
If you do strip one, it's easy enough to repair by tapping out the hole to the next convenient thread size.
A convenient size for a lot of racers is 4/40 (that is the international standard size for grub screws in high performance slot cars - even in countries that otherwise use metric - so lots of racers already carry the hex wrench and a few spare grub screws that size).
M3 is slightly larger than 4/40.
 

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phil. stainless is softer than steel, what you need is a hard grub screw from a good manufacture like UNBRAKO to name one . you can tell because there a bitch to shorten, the hacksaw screams when you cut them, same goe,s for l shaped keys, a good one [unbrako for eg] will bend and almost snap before you round out the grub screw. and the flats only have to be tiny 2mm across at most. this is a minute piece to grind from the axle. you want cup point screws and i garantee? you,ll never have a wheel come off again. slightly off subject the flat hub wheels i use, but i drill holes round the centre of the out side dia and use tyres with the widest internal step then glue the edges of the tyres to the rims using a 20-30 sec c/a glue which gives you plenty of time to get the tyres on straight voilla! air tyres that work really well. john. thi is a quick edit ive just remembered, using a steel grub srew in an ally wheel immediately puts it out of balance grinding the small 2mm wide flat on the axle near as dammit puts them back in balance, and if you strip a 2mm grub screw the hole left is the perfect size to tap them 2.5 mm. a cheap chinese tap is good enough if youre carefull 1 turn in 1/2 turn out till the hole is tapped and use lubricant.
 

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Tel
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Stainless may be softer than steel, but from my experience it is better quality than the ones that normally come with cars.(especially ninco's
)
If I buy alloy's I normally go for ones with a NSR size grub screw (M2.5 ?) but for supplied ones using the M2, I use the NSR wrench and M2 tip.
Any that get start to get rounded off get replaced with these from ebay, under £2 for 20 and decent quality IMO:Click for Ebay linky
They also do longer ones for the front axle height adjustments


I must say I have never had a grub screwed wheel depart in a race, but I have had the independant front ones fly off due to using unsuitable glue for the hollow axle end cap

Tyre's flying off, however, are a whole different kettle of fish .... I am hoping thats a thing of the past since getting advice on which glue to use, we will find out this year !


Sorry I digress ... but back O.T. I have found the above Ebay seller very good
 

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Having been racing for over 45 years I've never had a problem with alloy wheels coming loose - plenty of problems with plastic wheels, as my clubmates will testify! I've always used the better quality Unbrako screws and HSS wrench tips, or if I've managed to break one, an Unbako allen key.
In the early days with silver steel axles a dog point screw held well but meant it was next to impossible to remove the wheel due to the damage caused by the grub screw. The answer was to grind the end of the screw flat to give the max surface to grip with minimum damage.
Even today I still grind the ends of the screw flat to give max grip on drill blank axles and don't use anything other than drill blanks and don't grind any flats on the axles. Another advantage of grinding a flat on the screw is that the effective length of thread engagement is increased by one to one & a half threads, a great help when there's only four or five threads in the alloy hubs. I've tried stainless grub screws but found the hex drive socket does wear quickly.
As for balancing the wheels I've always thought it unnecessary for plastic car racing but maybe for BSCRA racing where the wheel speeds are much higher.

Regards,
Mike T
 

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Phil Kalbfell
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Stoner stainless is not always softer than steel! I did not mention hardness. Many of the grub screws use in slot car wheels are cheap mild steel screws, softer than stainless. Unbrako are very good high carbon grub screws, made to a high standard.
I use the stainless because they are about the same quality and can easily be identified from any of the poor quality screws.
 

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your right phil an after market stainless grub srew is harder than oem ones, in fact ive used a fair few and never had any problems, but a good quality allen key is a MUST have. john.
 
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