Stubborn screws: Milling out screw heads, recommendations for milling cutters

[forest bagger]

As you suggested some weeks ago I bought this plier.
But when the remainig stump is only 0,25 mm above the surface of the metal the screw is in nothing and nobody can help.

 

[Andreas Thaler]

As you suggested some weeks ago I bought this plier.
But when the remainig stump is only 0,25 mm above the surface of the metal the screw is in nothing and nobody can help.

But it works from 0.26 mm

 

[forest bagger]

Yes - if the screw with an unspoiled head would have been removable.
In the cases of cemented bayonet screws there is no hope...

 

[eli griggs]

Yes - if the screw with an unspoiled head would have been removable.
In the cases of cemented bayonet screws there is no hope...

Pinpoint application of heat, breaking the adhesive seal, in a metal to metal arrangement, should assist the removal of screw heads, IMO.

A heating tool can be made with ⅜" to ½" square bar or inexpensive metal striking die, such as a "A,B,C and Numerical lettering set" and a copper stem that'll allow the heat to transfer from the red hot, heatsink bar section, through the copper stem, directly through and in to the screw head, breaking a hard adhesive, or leaving it soft enough to twist out the screw.

A third or fourth limb, soldering or welder's hand, a real help with holding the heated probe, in direct contact

 

[forest bagger]

Yes, I tried that, too.
But there is a problem with the tansmission of the heat from the screw to its surrounding.
The screws of a bayonet mounting are less than 2 mm thick and only 4 mm long.
The surrounding metal (brass and alu) is about 15 mm thick and about 40 mm in diameter - and should not get too hot...

 

[Alex Varas]

Recently I got Moody’s screw extractors and with the smallest size I got screws out without damaging the surroundings, it’s a manual tool after all.

Micro-Tools Europe Tools | Home page | Miniature Tools for Camera and Watch Repair

Tools and Miniature Tools for Camera Repair, Watch and Optical Repairs. Spare Parts and Supplies.

www.micro-tools.de

 

[Andreas Thaler]

Recently I got Moody’s screw extractors and with the smallest size I got screws out without damaging the surroundings, it’s a manual tool after all.

Micro-Tools Europe Tools | Home page | Miniature Tools for Camera and Watch Repair

Tools and Miniature Tools for Camera Repair, Watch and Optical Repairs. Spare Parts and Supplies.

www.micro-tools.de

I have those too, but they didn't help with screws secured with adhesive.

 

[Andreas Thaler]

At the moment I am using this method in combination with cobalt metal drills and a cordless screwdriver:

Loosen stubborn screws: Boa Micro Grabit Extractors

Screws that cannot be loosened and whose screw head is damaged by attempts to unscrew it, so that nothing works anymore: every craftsman's nightmare. When dismantling cameras and lenses, it often happens that a screw does not want to come out. Be it rust or a thread being fixed with glue - the...

www.photrio.com

This will destroy the screw head too, but there will be no collateral damage.

 

[4season]

I've had some success using watch screw extractors. They can be had in sizes as small as 0.6 mm, but 1 mm is more typical for me. Hand tools only: The metal used is much too hard and brittle for use with motorized tools.

 

[Alex Varas]

I have those too, but they didn't help with screws secured with adhesive.

Against adhesive, heat, of course before the head is out

 

[Andreas Thaler]

Against adhesive, heat, of course before the head is out

Unfortunately, this combination was also unsuccessful (bayonet screws in Nikkor 15/2.5 Ai).