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pete beadle

Hacker B40 motor and Maxxon g/box damage

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pete beadle

Hi all

After unintentionally thumping my Circle Dancer 3000 hard into some soft ground at our flat field this weekend, I stripped everything out of the fuselage to check for any damage, and found that, while removing the retaining screws in the front of the Maxxon gearbox, I'd managed to shear off one of them at its base, just as it entered the gearbox casing leaving a stub 1.5 - 2.0 mm still proud,  (literally) screwed into the face plate. I tried to undo the bolt with pliers but simply didn't have enough of the stub to get a grip of.........any ideas how I could  get this TINY bit of the bolt shaft out of the face plate please?

Are there any engineers out there who've done something like this themselves perhaps? Could this be something that only Hacker could deal with? or are their any repair specialists out there who might be able to help do you think? Any helpful suggestions would be appreciated

Regards

Pete

BARCS1702                                                      

Hacker B40 and gbox damage 002.JPG

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Kyri

Hi Pete

A couple of options.

1. Dremel the protruding part to give it a flat screwdriver receptacle, if that makes sense. The bolt steel might be too soft for this to work but its worth a try. Then see if you can unscrew it. You may have to clean up the outside of the bolt with the dremel, as it exits the g/b as the bending of the head off may have left a small bend in the end of the screw which is why it is tight and won't unscrew. 

2. Drill out the screw but you might need someone with  a drill press to do this properly. Then tap the hole to M3 (existing hole is M2 or 2.5 I think)

 

Once sorted, replace all the screws with high tensile allen bolts and also put a support under the back of the motor, as then it is less likely to dislodge screw heads or firewalls in future (don't ask me how I know this!)

 

Hope that helps, and maybe there will be other suggestions and options as the above is only what I have had to do in the past. 

 

regards

Kyri

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PeteMitchell

I have used a pair of top cutters to grip the screw stub.

Needs care not to just nip the screw stub off, but with gentle pressure I have been able to get enough of a grip to start the screw to turn. 

If you can get a soldering iron on to the screw to heat it before you try to turn it, that most likely will help.

Good luck

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pete beadle

Thank you gentlemen!

Two things I've gleaned from these two replies - first, a bend in the screw shaft is probably causing the "jam" and I'd forgotten the old "heating locally with a soldering iron" to help freeing it off

Thank you, I will try again with that knowledge......

I'm not really happy with the idea of drilling out the bolt and re-tapping it though, I'll put that on the "last resort" shelf for the moment

Thanks again, anyone else have any ideas to add before I try again?

Regards

Pete

BARCS1702

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EssexBOF

You could try filing a couple of flats opposite each other then grip these with a flat nose pair of pliers or in my case I would use a small toolmakers clamp, which could be tightened up on the flats to hold the screw firmly.

The only other way IMHO is to make a template to fit over the holes then screw into place. Then use a piece of brass tube 2.5 dia, with a 1-1.5 dia I D, to drill down the centre of the screw, then use a small cross blade screw driver to engage in the hole to remove. I still have small broaches from my tool making days that I use for this type of thing.

As an after thought, there may be enough projecting out, to use a Dremel thin disc, to grind a slot in the projection, to use a screwdriver to remove.

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pete beadle

Hi Brian

Thanks for this, both suggestions sound good to me

Unfortunately, as you know, I am very one-handed these days and my biggest problem is attempting to get round this disability.

Until recently I was able to obtain the services of a good mate, who is also a model flyer, but worked as a dental engineer, and he had the right sort of tools for very small jobs. Since he moved to Las Vegas in the US of A I've missed his well-equipped tool-room as well as his friendship, ah well!

Thank you for all this help chaps, I really appreciate it

Regards

Pete

BARCS1702 

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Peter

Pete, give it to Ken Goddard. I find him invaluable as my chief engineer and he will have it out in no time. He is not on the forum so won't know of your problem but he will be at the Hockliffe flat field on Sunday and, failing that, you know his number and where he lives

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pete beadle

Hi Peter

Thanks for suggesting KenG, I'm sure I've got  him on my committee list as flat field contact

I'll ring him and tell him what the problem is, and let him know of the suggestions I've received too

Thanks again

Pete

BARCS1702

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