Grub screw blanking. 1

[ricksmetalbits]

Hi Everyone,

I have just joined today and could really do with some help?

I am trying to find out whether anyone knows if grubscrews are used in any kind of application and then blanked of to prevent tampering or removal.

If anyone has any information regarding this i would be most grateful.

Rick

 

[byrdj]

staking to damage the threads to prevent backing out

 

[AaronH]

I have seen fasteners marked with a paint or wax to indicate tapering in cases that would void warrantees.

You could use permanent loc-tite (requires heat to remove).

Someone out there must have tamper proof set screws. A quick google found a lot of hits, but no one actually shows a tamper proof set screw on their website. These guys can probably make them:

http://www.brycefastener.com/products.htm

Regards,
Aaron

 

[drawoh]

ricksmetalbits,

I hate set screws. They damage the parts they are clamping. Their holding torque (force?) is limited. They are not reliable in a variable torque application.

If you want a permanent shaft assembly, apply retaining compound like Loctite 680. The set screw makes a good fixturing device. It won't matter if someone removes it later. Read the Loctite instructions. A lot of materials are inactive and require primer.

My set screws are impossible to remove because I do not use set screws.

JHG

 

[KENAT]

I swear I answered this already. I vaguely recall, though can't be sure, some setscrews (or maybe it was similar screw pads) used on bomb tails being filled with P38 or P40. Now this was likely also to do with aerodynamic reasons but there you go.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[MikeHalloran]

So, Rick, the answer to your very strange question is:

Yes.

Why did you ask?


Mike Halloran
Pembroke Pines, FL, USA

 

[ricksmetalbits]

Hi Mike

Thanks for the response.

It is regarding a patent.

We supply a device that fits with grubscrews into a HGV fuel tank to stop diesel being stolen.

One of competitors has filed a patent basically preventing us using grub screws in our application.

Our lawyers are trying to get as much evidence as possible showing grubscrews being used in a similar manner on other applications i.e a tube within a tube secured by grubscrews or other fixings and then blanked off.

If you know of anything and can be of help I would be most greatful.

Rick

 

[AaronH]

Can you get around the patent by adjusting your design slightly and using something other than the screws? Let's say rivits? They're cheap, easy to install, and can be flush. Another thought would be to mechanically stake the two tubes together. Similar to riviting, but without actually using a rivit. You could also resistance weld the tubes together or use some sort of epoxy. Also, I have seen designs that have an O.D. groove on the inner tube, a matching I.D. groove in the outer tube, and a snap ring that is compressed at assembly. When the tubed are correcly aligned the snap ring expands into both grooves and prevents disassembly.

Just my $.02.

Regards,
Aaron