Thread: Delicate engineering problem

If you want to try the glue route, Click Bond CB200 is the way to go; 5-10 minute cure and insanely strong. Might have some out of date sachets at work that are still perfectly functional but we can't use them because aerospace.

Rather than gluing the tool in place, it's probably easier to glue a nut on the end to get a socket on.

The CB200 looks like a very good candidate for this task.

To take the bonding process one step further if it has merit, I was thinking that the hex tool could be bonded to a dilled collar or nut, with a small length of the hex sticking out the bottom. What this would achieve is a belt and braces approach to the bond. The hex will bond inside the screw and the collar will bond to the flat top part of the screw. Therefore increasing surface area and strength.

If this method is to be used it would be very easy to do a quick bit of testing. Take a round bar and glue it in a stainless hex screw head. Bond a nut on the other end of the rod. Once cured take a torque wrench and see how much force it requires to brake the bond. If the head shears off you know you will get as good as possible.

I had a read of the SDS. It would appear that nitrile gloves are recommended for handling. Therefore a nitrile glove/sheet with a small hole can be placed around the screw head to form a protective barrier between glue and human.

This glue does not appear to generate heat when curing. This can be verified during the testing phase. I think for some of us we still ting of adhesives from 20 years ago. There are products that replace welds and CB200 appears to be one of them.

Good luck and I hope you get a solution soon.

Steve

Reidy and Elan I like the sound of the glue, if it works (and I hope it does) it certainly would be the quickest and easiest route.
If no joy there then my offer is still open

Originally Posted by Reidy41

This glue does not appear to generate heat when curing. This can be verified during the testing phase. I think for some of us we still ting of adhesives from 20 years ago. There are products that replace welds and CB200 appears to be one of them.

I can confirm both of those things. We've used it to butt join 1.2mm steel plate and it's genuinely weld-worthy; stronger than glue has any right to be. 2 part glues will generally give off some small amount of heat when curing but it's negligible.

Originally Posted by snapatap

I think the best option might be to try to dremel it out. would it be possible to fixture the exposed bush to a bench or similar to dampen the vibrations going into your leg?

Maybe. I would possibly have to stand on one leg, in an awkward position.....dunno...... Would need some thought.

Originally Posted by shedhappens

Steve there is a chamfer there between the disc and the bit it is attatched to, that might be enough to engage a matching vee formed into a split cylinder that would be threaded at the other end for a bolt that would push a splined bit, similar to a torx tool, into the damaged head of the bolt.
The bolt would then be removed and socket inserted to turn the bit to undo the bolt.
If you would like to try this I could make it if you like but i would need some measurements.
These pics might give you an idea of what i am thinking??

Sorry Shed. Not sure exactly what you mean. You saying to press a Torx shaped tool into the mangleg cap screw hole?

Might work. Would need to fab a small hydraulic puller, I think?
Am I on the right track??

[QUOTE=Reidy41;1977318]I am guessing all ideas are a starting point, so here is one. If i understand correctly the hex is rounded out and the bolt is over torqued. [/QUOTE

yes. I 'assume' it was over torqued by trying to undo it the incorrect direction.

Originally Posted by Reidy41

In the aeronautical industry there are some really strong metal bonding "glues". Can you "bond" the hex tool in place. Once cured the screw may undo.

Steve

They did try that, using a Loctite product. Don't know what it was. Blue in colour.

Originally Posted by elanjacobs

If you want to try the glue route, Click Bond CB200 is the way to go; 5-10 minute cure and insanely strong. Might have some out of date sachets at work that are still perfectly functional but we can't use them because aerospace.

Rather than gluing the tool in place, it's probably easier to glue a nut on the end to get a socket on.

Sounds like 'Magic'!....lol
That might be worth a try. I've not heard of that stuff.

I will mention it to the Techs and see what they say. thanks.

Originally Posted by elanjacobs

I can confirm both of those things. We've used it to butt join 1.2mm steel plate and it's genuinely weld-worthy; stronger than glue has any right to be. 2 part glues will generally give off some small amount of heat when curing but it's negligible.

A little bit of heat would be ok. We could douse the shaft with water as a precaution anyway. ( heat will kill the bone so very bad!....)

Good thought about using ex AND a collar of some desprition....good stuff.
Thanks Gents.


You guys post too quick for me to keep up....lol

Steve

Originally Posted by snapatap

How do you plan for this to work? the bolt is attached to his leg, so a edm will cover him in nasty oil, and electrocute him.

I think the best option might be to try to dremel it out. would it be possible to fixture the exposed bush to a bench or similar to dampen the vibrations going into your leg?

Edm's can work with d ionized water. If the ground could be close enough there would no problem. Just tossing out an idea, never know where it will end up, good or bad.

Originally Posted by mcostello

Edm's can work with d ionized water. If the ground could be close enough there would no problem. Just tossing out an idea, never know where it will end up, good or bad.

EDM requires the part to held perfectly stationary and totally submerged. Neither of those are practical with something that's physically attached to a living human and the non-zero risk of electric shock means that this is categorically a bad idea. Sorry, but there's no way of it being workable.

[QUOTE=Sterob;1977389]

Originally Posted by Reidy41

They did try that, using a Loctite product. Don't know what it was. Blue in colour.

I think the blue stuff is just a thread locking compound, the real adhesive is red Loctite 680.

Originally Posted by Sterob

A little bit of heat would be ok. We could douse the shaft with water as a precaution anyway. ( heat will kill the bone so very bad!....)

When I say a little bit, I mean you can barely even feel it, especially with the tiny quantity of glue involved here. I doubt it would even raise the area to body temperature.

Originally Posted by Sterob

Maybe. I would possibly have to stand on one leg, in an awkward position.....dunno...... Would need some thought.

Able to lie down and hold in vice from the side?

A picture of the stuck piece in situ would make it much easier to suggest best removal.

Originally Posted by Sterob

Maybe. I would possibly have to stand on one leg, in an awkward position.....dunno...... Would need some thought.

https://www.gettoolsdirect.com.au/st...CABEgKtavD_BwE

I'm thinking lie on your back on a table and use a swivel vice like the link above, so it can be put in a comfortable position for your leg. I think the glue the driver to the screw idea is the best on here so far, so i would try that first.

Originally Posted by mcostello

Edm's can work with d ionized water. If the ground could be close enough there would no problem. Just tossing out an idea, never know where it will end up, good or bad.

Deioinised water only works on Wire EDM where the cutting energy is low and flushing is good. On a sinker EDM the cutting energy is much higher and tends to turn the water to steam and cause problems. Also having been booted through my had a few times by a EDM i wouldn't like to know how it feels through a implant straight into a bone. Good thought but not really practical for this application.