Nuovo record front derailleur - limit screw snapped

[Ian Raleigh]

Using something hand held could lead to damage if it slips.

All depends on the user of the Dremel Ned

Having used little power hand tools you get the knack of not slipping with them.

I've been making model aircraft/cars for years and regularly use small electrical power tools so know my limit.

Using a milling machine or vertical drill on such a small thing would be a joke :!:

 

[Midlife]

I use the equivalent of a very expensive Dremmel every day.....either air driven, electric driven or torque compensating...and have done for the last 30 years.

Not something I would tackle by hand as the screw is harder than the surrounding substrate.

By comparison we do not drill out by hand hard metal posts (in teeth) from surrounding softer dentine unless very desperate LOL

Shaun

 

[nammonk]

Just stop that right now, Shaun! If I wanted talk like that, I'd go to retroteeth. Sending shivers down my spine.
Nick

 

[wriggles]

LOL I did think of dentistry when looking at it for some reason.

Ian's dremel suggestion I think is the closest so far..... I guess the screws are stuck because of forming some sort of corrosive bond with the alloy and I'd still like to explore some way of breaking that before I attempt removal.

 

[Old Ned]

Using something hand held could lead to damage if it slips.

All depends on the user of the Dremel Ned

Having used little power hand tools you get the knack of not slipping with them.

I've been making model aircraft/cars for years and regularly use small electrical power tools so know my limit.

Using a milling machine or vertical drill on such a small thing would be a joke :!:

Me too on model railways - but I still wouldn't want to try it. Wouldn't take much to snap a drill considering the depth it's going down to. With a small end mill to flatten the top end, a small centre drill to 'pop' the now flattened top and working up to a 3mm drill there's no reason why a small milling machine/vertical drill couldn't be used. I'd do it on the lathe (Cowells) but not so easy to hold the piece of tube in the cross slide on it - and I sold my vertical drill some time ago. Silly me :roll:

 

[Ian Raleigh]

I don't know what this would be like but a mate has suggested getting a hot air paint stripper gun,
putting the alloy part in the deep freezer for a few days then take it out of the freezer
hold the part with pliers then blast the alloy with the hot air gun on the highest setting,
the alloy will expand faster than the steel and i should break the corrosion bond !

Allow to cool then to cut slots in the lower section of the screws and see if they move :idea:

 

[wriggles]

Thanks Ian - think I threw out my knackered dremel years ago, but this is a good excuse to get another and give it a go

 

[Old Ned]

A very common problem with these mechs. I have 2 or 3 bodies like this including a very rare early one. I was going to mount them on a section of seat tubing in the jaws of a milling machine vice and drill them out - very carefully! I know this can be done as an acquiantance has had it done by an engineer friend of his but I haven't been able to ask who it was! However, I have several friends in the model engineering hobby with the correct equipment who may be able to do it. I just need to get on with it!

A couple of weeks ago I gave 2 mechs and a section of seat tube to a friend who has an amazing collection of precision machine tools and he has done exactly what I said above with complete success. Not got them back yet but I have no doubt that they will be OK.