opening Keithley 2015, how to remove rusted screw?

[neslekkim]

My 2015 have two screws under, so I can remove the cover, one screw is ok, but the other one is rusted, and I cannot get it to move, and are afraid of destroying it.

How should I do this?, if I drill it out i guess It's too easy to rip the threads from the chassi?, and i don't want to have metal shavings inside my meter
I have inquired about calibration of this meter, if the price is ok, would it be better to let them handle it, or will they return it because it's in this state? (or will they destroy it? )

If I know the threading and size, I guess I can get an new screw, if I only can remove this without destroying the meter in the process..

[tjb1]

Not sure what they are called or where to get them in your part of the world but over here they are called Screw Out or something along those lines

[Wytnucls]

If the meter works, don't screw with it. There is no need to peak inside, unless you have a fault that needs fixing or you want to do a teardown like Dave's.
Calibration is going to be expensive, so check first against a good voltage reference, to see if it is really required. More than likely, the meter accuracy will still be within specs.
Calibration is performed closed-case and any required adjustments are done through software. So, the rusty screw doesn't matter.

[justanothercanuck]

How about a little WD40?

[G7PSK]

I find that if you put a screw driver into the screw head and apply a little bit of torque in the correct direction and at the same time gently tap the end of the screw driver with a hammer the screw come loose, don't hit hard very lightly and fast is best more of a vibration than a blow.

[SeanB]

Buy the appropriate size left hand drill, which when drilling will tend to undo the screw as it removes the head. Use a shop vacuum cleaner nozzle close by to remove swarf as it is made, and you will have the screw out or at least without a head, so you can then open the case and remove the remaining stub easily.

[neslekkim]

good tips!

Not sure what they are called or where to get them in your part of the world but over here they are called Screw Out or something along those lines

Pig-cock they was called, changed name recently, but that small ones?
https://no.wikipedia.org/wiki/Grisepikk

If the meter works, don't screw with it. There is no need to peak inside, unless you have a fault that needs fixing or you want to do a teardown like Dave's.
Calibration is going to be expensive, so check first against a good voltage reference, to see if it is really required. More than likely, the meter accuracy will still be within specs.
Calibration is performed closed-case and any required adjustments are done through software. So, the rusty screw doesn't matter.

Yeah, I was thinking about checking so there is not loads of dust etc in it, but since calibration labels are taped over the  the cover and back, I thought they needed to go inside it?

Tapping is know, but I didn't want to do that on an bench meter, but let some wd40 do its magic, and then, maybe it would work.

[Macbeth]

When I encounter rusted and rounded off screws that can't be turned with a screwdriver, I use a pair of old side cutters to pinch vertically into the sides of the screwhead and twist it off that way.

[KJDS]

Unfortunately, these are countersunk, so the easiest way is a little percussive engineering and a left handed drill bit.

[neslekkim]

Unfortunately, these are countersunk, so the easiest way is a little percussive engineering and a left handed drill bit.

Does it exist small ones that would fit these screws?

[KJDS]

Unfortunately, these are countersunk, so the easiest way is a little percussive engineering and a left handed drill bit.

Does it exist small ones that would fit these screws?

Down to 1mm

http://www.phantomdrills.co.uk/shop/product/left_hand_drill_bits

[neslekkim]

Does it exist small ones that would fit these screws?

Down to 1mm

http://www.phantomdrills.co.uk/shop/product/left_hand_drill_bits

Thanks!, I thought it only was those "screw out"thingys, but they are bigger often, these looks like they would do the job.

[Stray Electron]

Buy the appropriate size left hand drill, which when drilling will tend to undo the screw as it removes the head. Use a shop vacuum cleaner nozzle close by to remove swarf as it is made, and you will have the screw out or at least without a head, so you can then open the case and remove the remaining stub easily.

   This!  You'll be amazed at what a difference it makes if you use a LH drill bit! Usually the drill will start to cut in and then the screw will unstick and back right out. If you use a normal RH drill bit it will only drive the screw in tighter.

   LH drill bits are hard to find so I treat them like they are made of gold!

[KJDS]

   LH drill bits are hard to find so I treat them like they are made of gold!

I too treat them as if made of gold, but mostly because trying to remove a broken screw when it has a broken drill bit in it is more difficult than getting a straight answer from a politician.