Octura Collet 5mm x .078

[Tyneside]

does anyone know the allen key size used to fasten this collet to the motor shaft,

[properchopper]

Good question ! I tried every possible allen key I have. The ONLY one that fits (the one in the collet with blue tape on it) isn't size-marked. I got it years ago from Ray Fuller during a race in Arizona.

Jeff Wohlt [ rcraceboat.com] should be able to help ; I tried

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[martin]

The correct size Allen key is 5/64", a 2mm will also fit. Both these size keys give no slop so they wont slip & round out the hex.

[martin]

You also need to purchase good quality allen keys, cheapo Chinese in my experience often are undersized & are not a nice fit in the hex.

[Tyneside]

I tried 2mm and 5/64 both are to big 1.5 mm and 1/16 are too small its almost like I need a 1.75mm but I have no idea were to find one

[properchopper]

The correct size Allen key is 5/64", a 2mm will also fit. Both these size keys give no slop so they wont slip & round out the hex.

The 2mm and the 5/64 didn't fit at all. Only my "mystery wrench" fits my smaller Octura collets. The .187 collets use the bigger size (2mm or 5/64)

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[martin]

Yes Tony mine are 5mm x .187", I wrongly assumed they would be the same size screws.

[martin]

Tony on the 5mm x .150" couplings that I have it has smaller screws so are probably the same screws. I have several 1/16" keys that are probably Chinese & slip in the hex (new keys & new coupling) they measure .0585", I had to buy a good quality 1/16" for this specific purpose which is .0625" so only 4 thou larger but is a perfect fit with no slip.

[properchopper]

Good info Martin I'll go get a good 1/16 to be a backup for my current one. I've lived in fear of losing it (hence the blue tape). I do run several Ltd. motors with the .150 collets that take the smaller size.

[martin]

Tony I always take a vernier or micrometer with me when im looking for a specific size key as in the case of coupling screws which tend to be very tight indeed. Ive bought to many just on size alone & most have been under sized by a few thou rendering them useless for couplings etc, a lot of the cheap keys also don't have nice sharp tips at the on the hex. I also find grinding the end of the key back giving it a nice square shoulder at the tip also helps giving the key a better fit in the hex as some keys arnt square at the tip where during manufacture the hex bar is just chopped to length before bending. this messes the end of the hex up, & with these very small screws can tribute to the key slipping easier.

[Tyneside]

I think il take the screw to the hardware store and see if I can find a 1/16 to fit, thanks for the info

[properchopper]

Yup, I'll grind the tips on my face grinder when they start to round off

Tony I always take a vernier or micrometer with me when im looking for a specific size key as in the case of coupling screws which tend to be very tight indeed. Ive bought to many just on size alone & most have been under sized by a few thou rendering them useless for couplings etc, a lot of the cheap keys also don't have nice sharp tips at the on the hex. I also find grinding the end of the key back giving it a nice square shoulder at the tip also helps giving the key a better fit in the hex as some keys arnt square at the tip where during manufacture the hex bar is just chopped to length before bending. this messes the end of the hex up, & with these very small screws can tribute to the key slipping easier.

[properchopper]

I think il take the screw to the hardware store and see if I can find a 1/16 to fit, thanks for the info

Pkg of 10 for $1.83

http://www.grainger.com/Grainger/EKLIND-Hex-Key-4RE11?gclid=CO3vndfUirkCFWfhQgodbiQAug&cm_mmc=PPC:GooglePLA-_-Hand%20Tools-_-Wrenches-_-4RE11&ci_src=17588969&ci_sku=4RE11&ef_id=UT-FhAAAAGZmzu9o:20130819232806:s

[martin]

If your favourite & only key starts to show some wear through use just grind the key back a bit say 3/32" & hey presto you have a brand new key.

[martin]

Id be wary on the quality of those keys at $1.83 for 10, I payed that for 1 good quality key in the UK. They also say country of origin USA but in brackets country subject to change.