Modified Sigma 150-600 C Foot

[Compuwight]

I got fed up with the Sigma foot and adaptors, not staying square, not able to adjust for balance,......
So out with the tools, drill and tap, fitted brass screw and hey presto it works a treat......

 

[ecoleman]

I had a long plate on my foot but it more rubber then yours seems to have. It never moved

 

[sk66]

I did similar with my 120-300/2.8... couldn't believe they only put one threaded hole on that lens foot. So I drilled/tapped it and added a second 1/4-20 thread insert.

But you need to be careful, that brass screw is likely to become welded into the foot due to galvanic corrosion. If you want to use a brass or stainless screw you are best off adding brass or stainless thread inserts and using a thread locker compound on it. Otherwise, I would get a zinc or aluminum screw; even a nylon screw would probably suffice.

 

[Compuwight]

I did similar with my 120-300/2.8... couldn't believe they only put one threaded hole on that lens foot. So I drilled/tapped it and added a second 1/4-20 thread insert.

But you need to be careful, that brass screw is likely to become welded into the foot due to galvanic corrosion. If you want to use a brass or stainless screw you are best off adding brass or stainless thread inserts and using a thread locker compound on it. Otherwise, I would get a zinc or aluminum screw; even a nylon screw would probably suffice.

Thanks for the Info, intend to replace with a stainless hex but only had a brass one in the garage !

 

[sk66]

Thanks for the Info, intend to replace with a stainless hex but only had a brass one in the garage !

Stainless is only a little better than brass. You could use a thorough coating of a weak threadlocker (loctite 222) as barrier to help, or PTFE tape. Of course, if it stays dry (low humidity, etc) there's no issue even with the brass screw.