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DIY ring lapping

26 May 2014
@ 07:30 pm (GMT)

Ken

Seems everything I read online requires the use of some fancy scope ring lapping tool, which got me thinking- can you just use and old scope?
Sorry if this is covered in your books Nathan, I'm waiting for a new card as mine expired and haven't been able to purchase your series

Replies

26 May 2014
@ 08:31 pm (GMT)

Quote this

Nathan Foster

Re: DIY ring lapping

Hi Ken, yes I have gone over this in the new book.

An old scope would not be that good due to two reasons. The length of stroke is too short. If the scope is very soft, it may already have been bent previously.

The most rudimentary tool would be a short length of 25mm (or 1") stainless tube for a 1" scope. This is would not be as true as a machined billet but is near enough to minimize any strain to optics.

It does pay to actually check whether the rings really do need lapping. Truth is, some of the talk about ring lapping is just bollocks. There are several ways to skin this cat as discussed in the book: Lapping, Plastic insert rings, use a one piece base, epoxy shimming the lower ring halves, brass and epoxy shimming under a base if using two piece bases. There is a lot to consider and jumping straight into lapping just because everyone else is doing it can be pretty much pointless if other factors are not taken into consideration. Where is the actual fault, its cause, what are the ramifications of the fault- will it strain the scope. And to those who think that DIY shimming with an old scope sounds like a silly idea- its good to see that you are stopping to think about it all and discuss it rather than rushing in and buying the latest kit.