Security screws

[dankilb]

Still think (carefully) adhering another fastener on top might bring them out.

Then either bin the old fasteners and replace or use heat to break the adhesive and clean them up to re-use.

Is the case just plastic??

 

[ianat182]

Looking at the chart there the polydrive looked the best fit to your scewhead without knowing dimensions and depending how much assault to the original has been done.

ianat182

 

[Dellquay13]

Looks a bit like this but don't know about sizing:-

Cemobile Gamebit Screwdriver 4.5mm 3.8mm, Double-End Bit Security Gamebit Screwdriver Kit for Opening NES, SNES, N64, Gameboy, Gamecube, Virtual Boy, Sega, Nintendo Consoles, Game Cartridges : Amazon.co.uk: DIY & Tools

This does like it might be close enough, and is double ended for two sizes.
If i could find a teenager; A, they would have all the answers because they already know absolutely Everything, and B, they would have a games console to compare the screws.
It's at the price point I guessed at too...

 

[Dipper]

Some are recessed about 18mm down narrow access tubes, i did think about drilling them on a pillar drill then using stud extractors, but its tiny work, i don't have the above tools, and my past experience is a litany of disasters, compared to hopefully just identifying and buying a £7 bit from an online supplier

I have an Autohelm 1000 and can confirm that the original screws do look like the one that you have. As you say, two of the screws are deeply recessed so it's impossible to cut slots or dab epoxy on them. If you can't get a security bit to fit then as far as I can see the only option as already suggested is to try a left handed drill bit followed if necessary by a stud extractor but the screws are less than 4mm thick so even that's not easy. At least they are brass so fairly soft to drill. Perhaps some Plusgas squirted down the holes might free them a bit allowing a misfitting bit to budge them? I have a Draper security bit set and the largest spanner bit (which has two prongs) does get a slight grip on the screws. However, I can't see how even the proper security bit could work because the design on the screw head has slopes and unless you can press down with a lot of force, the bit would just slide out. At the other end are captive 'nuts' encased in plastic. Three of mine actually broke and I've had to epoxy them back in place.

When I reassembled my unit, I cut slots in the original screws and can now undo them with an ordinary flat head screwdriver.

 

[Poignard]

Trend GRAB/SE2/SET Grabit Damaged Micro Screw and bolt remover 4pc set

These are supposed to work with screw diameters as small as 3mm

 

[Daydream believer]

Get a piece of rod or a brass bolt or the head of a bolt of the same diameter of the hole that the bolts sit in.
Then place it in a vice & using a sharp 3mm drill bit drill a hole dead centre of it. You may have to have a couple of tries to get it right. Drop the piece of rod down the hole. This gives you a nice guide for drilling a hole dead centre.

At this point a LH drill bit (MSC Industrial) should be used to drill down your guide into the bolt. It will either start to turn the bolt to bring it out or it will give you a hole for an easy out. You could follow up with a 3.4mm drill but by this time you are getting near the threads.
Instead of making a guide you might actually find a nut that drops down the hole & this may help you guide your drill bit.

for the other bolts get someone to hold the guide in place with some mole grips to give your drill a start
Buy some replacement A4 ( 316 SS)socket head screws from Westfield fasteners which you can get in small numbers.

 

[Graham_Wright]

It looks like a proper security screw that can only be driven right hand. They are designed to be irremovable.

Drill them out and replace with ordinary.

 

[Dipper]

It looks like a proper security screw that can only be driven right hand. They are designed to be irremovable.

Drill them out and replace with ordinary.

I think you may be right. It should be possible to drill off the heads and lift the cover off.

 

[Poignard]

It looks like a proper security screw that can only be driven right hand. They are designed to be irremovable.

Drill them out and replace with ordinary.

How would the factory remove them in order to repair the unit, or are they non-repairable?

 

[Plum]

View attachment 126458
Does anyone know the name for these anti tamper screws please?
I need to open my very elderly autohelm ah800 analogue, to see why it has started stuttering instead of running smoothly.
TIA
Chris

There is a security version of Torx:
sourcingmap 1/4-inch Hex Shank T25 Torx Security Screwdriver Bit 25mm Long 4pcs : Amazon.co.uk: DIY & Tools

Otherwise, this set may be worth a gamble: https://www.amazon.co.uk/Rolson-306...473OARU/ref=pd_lpo_2?pd_rd_i=B00473OARU&psc=1

Www.solocoastalsailing.co.uk

 

[Dipper]

[QUOTE="Plum, post: 7851113, member: 169"}

Otherwise, this set may be worth a gamble: https://www.amazon.co.uk/Rolson-306...473OARU/ref=pd_lpo_2?pd_rd_i=B00473OARU&psc=1
[/QUOTE]

I've tried my set on the screws and only the spanner size 10 bit stands a chance of gripping anything.

 

[snowbird30ds]

If you thinking of drilling get a left hand drill bit, chances are it will bite and bring the screw out long before it goes through anything, tracy tools online do them.
But use minimal pressure and very low speed so you can feel it push back when it bites.

 

[Thistle]

Does anyone know the name for these anti tamper screws please?
I need to open my very elderly autohelm ah800 analogue, to see why it has started stuttering instead of running smoothly.
TIA
Chris

Something like https://www.amazon.co.uk/Kuptone-Pr...VFBBK4/ref=psdc_1939023031_t2_B07ZDFN1K3?th=1 may help ... and would be a useful addition to a toolkit.