new hole - old foot?

[postcardcv]

I was wondering how easy it is to drill a new threaded hole into the foot of a lens/scope. The problem is that a 1/4 hole has had the thread stripped, so I was thinking of getting it drilled out to 3/8.

Anyone know how easy this is and where I might be able to get it done?

[yelvertoft]

Any competent small engineering company should be able to do this for you. A threaded insert, usually referred to as a "Helicoil" can be set into the hole to get you back to your original 1/4" thread.

Have a look in your yellow pages for "Engineers".

Duncan.

[Ant]

You will also need a threading tool, but as far as I'm aware there are none that will match that of a camera/lens/etc-tripod thread.

I had to make a thread on my scope, unable to find a threading tool of the correct type I had to use a bolt cut to lengh to hold it onto my tripod quick releace plate.

And I had access to all the tools in a large engineering company, my grandad afterall does work for a company that makes horse boxes and cattle trucks by hand.

[robski]

I would try and track down the correct Helicoil kit first - ring around nut and bolt suppliers - About ten years ago I had to use a kit for a couple of american threaded devices. It's not that difficult to do.

This is the sort of thing your looking for

https://www.namrick.co.uk/browse.asp?PCID=28

[nirofo]

You can ream out the hole using a 1/4" to 1/2" tapered hand reamer or similar, then tap out the hole to the new thread size using a 3/8" whitworth tap. Any good tool shop should be able to supply these tools. Be careful when reaming out the hole, don't make it too large or you won't be able to cut the thread deep enough for a secure fit to the tripod head, 5/16" diameter is plenty. If you use the 1/4" x 3/8" whitworth threaded insert make sure it is a good fit in the newly tapped hole. If you cannot get the reamer to go in far enough due to proximity to the lens, then you'll have to revert to drilling the old thread out, make sure you obtain the correct drill size for a 3/8" whitworth tap, I think it's 5/16". Make sure you cover all the various parts of the lens to prevent metal swarf from entering, tape it if necessary.

nirofo.

[Leif]

My old Slik tripod head came with a 1/4" to 3/8" adaptor. I suspect that Slik will stock them. I was able to obtain replacement items without difficulty. If not try Warehouse Express and Speed Graphic. The latter is expensive but they have a huge selection of hard to find items.