This is why we test...

[electric]

Well, I am two weeks away from racing my Backlash Hydro in an unlimited class(gas, nitro, electric) and I just recently replaced all the electronics and took it out to test yesterday. I punch it and immediately something goes wrong with the drive shaft and I just have enough momentum to hit the rudder and get the boat back to shore. As you can see I cracked the drive dog in half. Never done that before. I then figure out it's the collet slipping that caused this.

I have not had this type of failure in a long time, but it makes sense in this case. I usually use Neu motors so you have to grind a flat spot. Well, when you do that you have a flat spot for the rotation, but you also end up with an edge that prevents the collet from sliding towards the motor using the set screw. As you can see, the Castle comes with a flat spot already set for the entire length of the shaft, great for cars, not so great for 10s boats.

I was using the MBP collet before with a clamp style attachment to the motor shaft and this worked perfectly(no slippage). I now have that collet in the unlimited mono I am going to race as well. I checked to see if the collet is back in stock(still no luck). So, pondering my next step. I suppose I could try grinding a spot on the opposite side of the Castle 2028 so I can get the set screw to stop the forward slide of the collet? Might be an issue given half the shaft is already ground down.

Thrust bearings are really not the way I want to go at this time. Any other ideas before I break out the dremal?

[oscarel]

Ouch that sucks! You may have to use some red locktite to get through this race... BTW, it's next weekend!!!

[electric]

Ouch that sucks! You may have to use some red locktite to get through this race... BTW, it's next weekend!!!

Ha Ha, I am still counting this week, which is rapidly disappearing. By the way, Oscar is quite happy as he will also be racing me in in the Unlimited Hydro class with another Backlash!! Don't worry, I will have it fixed in time...chuckle.

[runzwithsizorz]

" I was using the MBP collet before with a clamp style attachment to the motor shaft and this worked perfectly(no slippage). " / " I checked to see if the collet is back in stock(still no luck). "
Rocket City Racing *indicates* 1 in stock. http://rocketcityracing.com/cart.php...&category_id=1

[flraptor07]

Figure out exactly where the set screw makes contact with the shaft then put the shaft in your drill press vise and make a little drill spot in the shaft for the set screw to lock into. It won't take much of a spot at all, this should cure your problem the collet will not be able to turn or walk up or down the shaft.

[electric]

" I was using the MBP collet before with a clamp style attachment to the motor shaft and this worked perfectly(no slippage). " / " I checked to see if the collet is back in stock(still no luck). "
Rocket City Racing *indicates* 1 in stock. http://rocketcityracing.com/cart.php...&category_id=1

Sorry, I need a 8mm - 6.3mm (1/4" drive shaft)

[electric]

Figure out exactly where the set screw makes contact with the shaft then put the shaft in your drill press vise and make a little drill spot in the shaft for the set screw to lock into. This should cure your problem, the collet will not be able to turn or walk up or down the shaft.

Nice solution, without the grinding. Thanks.

[flraptor07]

Nice solution, without the grinding. Thanks.

No problem, glad I could help.

[dasboata]

I would say your set screw backed off and caused this problem ,The shafts are very hard best to use a sharpie and mark the set screw hole ,dremel reinforced cut off wheels work the best,, you just need a tiny flat spot don't over do it you will weaken the shaft good luck Chris

[Fluid]

Jim, I may have a spare MBP, send me an e-mail to remind me to look and I can bring it Saturday.


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[electric]

Jim, I may have a spare MBP, send me an e-mail to remind me to look and I can bring it Saturday.


.

I might take you up on that Jay if you have one. Are you planning on running this weekend? I was thinking about it today at lunch and the MBP may no longer be an option. The reason is I have moved from 4s batteries by the drive shaft area to 6s batteries and this is reducing the space between the battery and the collet. I am not certain if the MBP will fit anymore due to the greater diameter of that collet. It is already is pretty tight, look at the pictures above. I might really be forced to make the collet I have work. I will take another look at it tonight and let you know. Thanks again for the offer.

[oscarel]

Ha Ha, I am still counting this week, which is rapidly disappearing. By the way, Oscar is quite happy as he will also be racing me in in the Unlimited Hydro class with another Backlash!! Don't worry, I will have it fixed in time...chuckle.

You better have it fixed!! Mine's sitting on the shelf waiting, can't wait!!