Cambo SC (II) Refurb stripped screw advice

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A great condition Cambo SC arrived today from the Real Cam Co Liverpool. Everything is in great condition except some of the nuts and screws which I plan to replace (it pushing 40 years old). The dutch using lovely metric screws mean replacement parts will be easy.
On dissassembly I stripped the small retaining screws that grip the mono rail. They look to be super rusted and are very short . The good news is the threads seem to be fine. I think my options are

1. Tiny metal drill bit through the middle to remove - prepare with some kind of thread releaser ( wd-40)
2. Reverse thread drill bit to try and grip the screw and pull it out
3. Find a local machinist to remove and rethread the hole. Looks like to could even go a bit bigger since all it does is hold the monorail in place

p.s praise be iPhone auto macro mode
 

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Re option 1
I have not used PlusGas but if as @tijuana taxi says it is good at freeing rusted parts then great.
But when you pilot drill it, try to find a suitable size (those grub screws are small!) "screw/bolt extractor". (teaching you how to suck eggs ;) ) that are reverse threaded and tapered to bit into the broken screw and the more force the tighter they are supposed to latch on to the broken section.

PS the smallest I could see from a cursory search was here https://uk.rs-online.com/web/p/screw-extractors/4609516 with a size No.1 in the set of 5 pieces but note they say you get a tap wrench and as I recall they are double ended so you will need space to use it/them?

EDIT ~ if you zoom in on the product image the case it says that the Size one 1.75mm ands the Size 2 2.20mm
So subject to getting the right(?) size(s) I hope with pre-treatment you will succeed if extracting it :D

PPS they have others https://uk.rs-online.com/web/c/hand-tools/screwdrivers-hex-torx-keys/screw-extractors/
 
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I used to rebuild/refurb mountain bikes and always used PlusGas to free up the rusted in components.
Leave overnight if possible for it to penetrate, does stink a bit so in a garage or shed might be best
 
Looking at the part(s), it LOOKS like the body is an Aluminium alloy of some sort with mild steel screws so there's some heat expansion differential. An overnight soak of a penetrating oil followed by a dunking in just boiled water might be enough to break the corrosion weld. Be careful trying to drill into the screws - you'll need to get the drill well centred to avoid the drill drifting off into the softer alloy.

If all else fails, is there room to drill and tap new holes for any needed grub screws?
 
Nod said:
Looking at the part(s), it LOOKS like the body is an Aluminium alloy of some sort with mild steel screws so there's some heat expansion differential. An overnight soak of a penetrating oil followed by a dunking in just boiled water might be enough to break the corrosion weld. Be careful trying to drill into the screws - you'll need to get the drill well centred to avoid the drill drifting off into the softer alloy.

If all else fails, is there room to drill and tap new holes for any needed grub screws?
Click to expand...
Precision and care is IMO indeed needed.

If it were possible to dismantle the tripod and get that part onto a bed of a pillar drill, that would/should aid drilling 'accuracy'. With such a relatively small working area i would have reservations trying to drill it with a handheld drill.
 
The fridge magnet indeed shows its alu. Yeah it breaks down even further so I should be able to get a good line on the centre of the screw
Box Brownie said:
Precision and care is IMO indeed needed.

If it were possible to dismantle the tripod and get that part onto a bed of a pillar drill, that would/should aid drilling 'accuracy'. With such a relatively small working area i would have reservations trying to drill it with a handheld drill.
Click to expand...
 
Nod said:
Looking at the part(s), it LOOKS like the body is an Aluminium alloy of some sort with mild steel screws so there's some heat expansion differential. An overnight soak of a penetrating oil followed by a dunking in just boiled water might be enough to break the corrosion weld. Be careful trying to drill into the screws - you'll need to get the drill well centred to avoid the drill drifting off into the softer alloy.

If all else fails, is there room to drill and tap new holes for any needed grub screws?
Click to expand...
Yeah if it goes tits up lots of space for new tapped holes.
 
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