Alexis,
I very nearly liked one of your previous posts because I agree that Arca-Swiss is an available sytem that works. However, your mention of "boutique European brands" (who could you mean by that?) and the assertion that an anti-rotation lip is superior deterred me
.
The latter may certainly have advantages for cameras without a pin socket, but for a scope is in no way superior to a pin of the right diameter. Without either even the inadequate three or four thread turns of a loosened screw would not result in equipment loss. Perhaps both sytems are better regarded as a positioning aid.
As regards materials, there is no difference in rigidity of the same design made of different aluminium alloys.
All aluminium alloys have approximately the same modulus of elasticity. The alloy with the higher yield strength will experience a plastic deformation at a higher load, but we are not hanging tons on a QR plate! I fell for this myth years ago when I had a commuter bike frame made of Nivarox steel. 25CrMo4 (4130) would have done the job just as well for a lower outlay.
Bolts and anti-rotation pins should not experience shear loads if sufficient torque is applied. All loads are carried by the friction of the metal interfaces just like that between a car wheel and its hub.
Lastly, that RRS adapter looks better than most, but why use an adapter if you can use a 3/8"x16 screw?
Regards,
John
John,
Thanks for setting me straight--I'm not schooled in engineering so I fear I used some technical terms incorrectly or too loosely.
As for boutique European brands, that was a lazy way of referring to some of the brands that I tried a long time ago that didn't seem so good but that I can't remember for sure. Otherwise, I wouldn't hesitate to name names. Arca-Swiss was among them, maybe Novoflex too, but I'm not absolutely certain.
My preference for lips over pins is based on the fact that (1) most scopes don't have pin sockets, (2) some scopes with pin sockets don't have them in the right location, or else the plate doesn't have the pin in the right place for the scope foot, (3) many pins are too narrow and so do not prevent a bit of wiggle and thus loosening over time, (4) many plates from Manfrotto and Gitzo have spring-loaded pins that are somewhat loose in their housing so have lateral play and thus do not prevent a bit of wiggle and thus plate loosening over time. Sure, a good plate with a good pin can work well. I just haven't met many that do, and generally they are combined with a rubberized surface which, again, allows for a bit of wiggle and thus loosening over time. I guess this brings up a point. For me, a good plate not only prevents rotation, it also doesn't loosen over time. I have never had a plate from RRS or Kirk become loose.
Ever. And I've been using them for 20+ years. On a related topic, I've also never had a screw-action QR clamp from any manufacturer (RRS, Kirk, Gitzo, Neewer...) loosen or lose its grip on the plate, so I have no interest in the various "safety retention" pins and releases that some systems offer. If possible, I remove them for convenience.
As for better materials of mounting rigs, I wasn't thinking so much in terms of different aluminium alloys in plates and more about RRS's near exclusive use of machined metal parts for brackets and such, so that all joints and fittings are metal to metal, never metal to plastic or rubbery material, as some others do (e.g. the irritating macro rail system I got from Bogen/Manfrotto many years ago).
On the material or precision of bolts etc, I guess I shouldn't have used the word shear. What I was thinking about is that I have have never had issues with the material quality of RRS fasteners, whereas with other brands, I have sometimes found the following: (1) soft metal that allows the head of the bolt to twist off--admittedly, probably when over-torqued, but still..., (2) soft metal or poor precision or shallow depth of socket sizing in the heads of bolts such that the screwdriver slots or hex key socket is a slightly imperfect fit and thus distorts and become damaged over time, (3) the threads of bolts or thread adapters being ever so slightly undersized such that they thread into sockets but still have a bit of lateral play in them and aren't really tight until they are screwed in very firmly. Such fittings seem vulnerable to breaking free and loosening when subjected to shocks or vibrations.
I use 3/8" bolts and screws when I can, but some tripod bodies and other mounting hardware come with fixed (nonreplaceable) 1/4" threaded parts for attaching tripod heads etc, hence my use of the adapters here and there. They seem to cut some vibration or flex that can occur when, e.g. a head is threaded onto the mounting bolt of a tripod or clamp stud using an adapter that only encloses 2.5 or 3 threads worth of length of the bolt, as is the case with many cheap adapters.
Sorry for being so obsessive about this. Although I figured out what actually works a long time ago, it was a long time in coming, so I never take my solid tripod and other brackets etc for granted. I always appreciate how well they work and I never forget how much trouble I used to have. It's such a blessing to have solutions that do the job so well that persistent problems are laid to rest entirely.
--AP