Need to remove the horizontal control knob on my 576 so I can remove the board to get at the display selector board. One of the grubscrews undoes easily enough, but the other appears to have its hex slot stripped. A 1/16th allen key just rotates in the slot.

Any tips on how this could be removed? I don't have a screw extractor small enough (I presume the grubscrew is 1/8th ?).

I'm sure you'll get a lot of great suggestions. Until then, here are my bodges. One is to use a sacrificial metric wrench that fits tightly, perhaps with a little tapping to encourage insertion. A Dremel comes in handy to fashion one to fit.

Another method is to dip the wrench in a little valve grinding compound to take up the extra space and give the tool a little more bite.

Those usually work for me. In very desperate cases I've used a tiny drill bit to mill out a groove to convert into a slot head. Then a standard screwdriver might get the job done.

Good luck!

Tom

Sent from an iThing, so please forgive the typos and brevity

On Feb 1, 2021, at 11:33, keith@peardrop.co.uk wrote:

Need to remove the horizontal control knob on my 576 so I can

remove the board to get at the display selector board. One of the grubscrews undoes easily enough, but the other appears to have its hex slot stripped. A 1/16th allen key just rotates in the slot.

Any tips on how this could be removed? I don't have a screw

extractor small enough (I presume the grubscrew is 1/8th ?).

Hi
When I find in that situation I use a torx drive, the size that best fits, it has always worked for me

-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de snapdiode via groups.io
Enviado el: lunes, 1 de febrero de 2021 20:47
Para: TekScopes@groups.io
Asunto: Re: [TekScopes] Extracting a knob grubscrew

They are typically 1/20" or 0.050" keys. Sometimes it's Bristol drive but if someone forced a hex key in there it's probably not a Bristol drive anymore.

Unfortunately I have found no way to extract a stuck set screw of that size. You might try a 1.3mm key, sometimes they really are 1.3 and not 1.27 so you get a bit more grip. I don't know, seems random.







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I have had success using a torx driver and angling it to wedge it in, applying a high down force along with the angling force, and turning very slowly so that it doesn't slip and further turn out the hex opening, or the bit on the torx driver. I had thought that I was ruining the torx driver, but it seems to have survived the ordeal relatively well. Still, it's best to use a sacrificial tool for this process.

-- Jeff Dutky

They are typically 1/20" or 0.050" keys. Sometimes it's Bristol drive but if someone forced a hex key in there it's probably not a Bristol drive anymore.
Unfortunately I have found no way to extract a stuck set screw of that size. You might try a 1.3mm key, sometimes they really are 1.3 and not 1.27 so you get a bit more grip. I don't know, seems random.

On Feb 1, 2021, at 16:36, Paul Amaranth <paul@auroragrp.com> wrote:

These things rarely get seized; they are just really tight.

If you can heat the screw with a very small soldering iron and let it cool
(or shoot it with freeze spray), it might loosen up enough to get out.

Paul

On Mon, Feb 01, 2021 at 01:32:47PM -0800, Jeff Dutky wrote:
I have had success using a torx driver and angling it to wedge it in, applying a high down force along with the angling force, and turning very slowly so that it doesn't slip and further turn out the hex opening, or the bit on the torx driver. I had thought that I was ruining the torx driver, but it seems to have survived the ordeal relatively well. Still, it's best to use a sacrificial tool for this process.

-- Jeff Dutky

--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows

I have sometimes had to drill out the set screw. The damaged hex recess
provides a guide for the drill bit.

I use a left-hand drill in my vertical mill where I can easily reverse
the rotation direction. Left-hand drills are available in a full range
of sizes, down to #80. I often find that in drilling the hardened set
screw that the drill will catch in the screw enough to actually loosen
the setscrew.

Even if that does not happen, you can increase the size of the drill bit
and eventually remove so much set screw material that is is too weak to
retain itself. Just don't use a drill larger than the minor diameter of
the internal thread in the knob.

This approach with left-hand drills works in many kinds of stuck
fasteners. One of my local machine tool dealers has a cabinet full of
left-hand drills; I went through it and picked out a bunch of sizes to
keep on-hand.

I have hex keys in Imperial Inch and metric, and Bristol with different
numbers of flutes depending on size. There is no Torx that small that I
am aware of. I often work on microscopes and some cameras that need this
approach.

Regarding larger size screw heads, remember that both Tek and HP used
PoziDrive screw head fasteners. These are NOT Phillips even though they
look quite similar. The distinct advantage of PoziDriv is that the
driver does not cam out of the head as it does in a Phillips head.

But, if a Japanese product has what looks like a Phillips, remember that
it is more likely a JIS head. So, you need to have Phillips, PoziDriv
and JIS screw drivers in your tool kit. You really need the correct tool
for the job!

Larry


On 2/1/2021 11:46 AM, snapdiode via groups.io wrote:

They are typically 1/20" or 0.050" keys. Sometimes it's Bristol drive

but if someone forced a hex key in there it's probably not a Bristol drive
anymore.

Unfortunately I have found no way to extract a stuck set screw of that

size. You might try a 1.3mm key, sometimes they really are 1.3 and not 1.27
so you get a bit more grip. I don't know, seems random.
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

Need to remove the horizontal control knob on my 576 so I can remove the
board to get at the display selector board. One of the grubscrews undoes
easily enough, but the other appears to have its hex slot stripped. A
1/16th allen key just rotates in the slot.

Any tips on how this could be removed? I don't have a screw extractor
small enough (I presume the grubscrew is 1/8th ?).

Need to remove the horizontal control knob on my 576 so I can remove the
board to get at the display selector board. One of the grubscrews undoes
easily enough, but the other appears to have its hex slot stripped. A
1/16th allen key just rotates in the slot.

Any tips on how this could be removed? I don't have a screw extractor
small enough (I presume the grubscrew is 1/8th ?).