Don't use thread adapters! (1 Viewer)

[Tringa45]

Many scope users seem to favour direct mounting of the scope into the tripod head. Some scope feet were compatible with the Manfrotto RC system and now later Swarovski scopes are Arca-Swiss compatible. Perhaps there was a fear that quick-release plates could come loose, but for many scopes a longer QR plate is almost indispensible.
The Nikon Fieldscope and Monarch 60s and also the Swarovski ATS/STS 65s are extremely tail heavy and would otherwise require excessive amounts of tilt friction to hold them in the horizontal. Some other scope families have the scope foot in the same position for different objective sizes, e.g. Swarovski 85, 95 and 115 objective modules and Kowa 77, 88, and 99, so horizontal balance for some of these will be less than ideal.

The scope manufacturers have unwittingly led us into the trap of using a fixture that may be adequate for static camera use but is completely inadequate for mobile scope use.
Most scope feet are tapped 3/8"x16 but are delivered with a 3/8" to 1/4" adapter so many use a QR plate with a 1/4" screw. Some adapters can have as little as one and a half thread turns, so it doesn't take much for everything to come apart, and as one cannot apply much torque to an adapter, one effectively has a loose connection from the start!
The answer is to junk the adapter and use a QR plate with a 3/8" screw. Even the suboptimal Manfrotto RC plates with their rubber mating surfaces were available with 3/8" screws and this applies to most Arca-Swiss compatible plates.

Moderate torque (for the thread size) with a coin slot, or even better with a 4mm Allen key can generate a high compressive load betweel the metal surfaces of plate and scope foot that nothing will come undone. There is then no shear load on screw or anti-rotation pin. The friction between the two surfaces is akin to that between a car wheel and hub, which carries the load and transmits braking torque. Loctite is completely unnecessary.
In almost 20 years of scope use with Diascope 65, ATM65 and Kowa 883 with Manfrotto RC and later Arca-Swiss compatible plates from Novoflex and Berlebach I have always used 3/8" connections and never had a plate work loose.

John

 

[forent]

Thanks, John, excellent advice! Actually, the few available QR plates with 3/8" screws seem to provide the most reliable solution.
An improvement over the ordinary adaptors does exist nonetheless: longer "screw over" adaptors that help to prevent the flimsy "one-and-a-half turn" connection. These adapters shown e.g. on this German webpage (https://etrion.de/shop/product_info.php?products_id=985) are available via e*ay or Ama*on.

 

[Hermann]

Perhaps there was a fear that quick-release plates could come loose, but for many scopes a longer QR plate is almost indispensible.
The Nikon Fieldscope and Monarch 60s and also the Swarovski ATS/STS 65s are extremely tail heavy and would otherwise require excessive amounts of tilt friction to hold them in the horizontal. Some other scope families have the scope foot in the same position for different objective sizes, e.g. Swarovski 85, 95 and 115 objective modules and Kowa 77, 88, and 99, so horizontal balance for some of these will be less than ideal.

Unless you use a head that allows you to balance tail or front heavy scopes, like e.g. the Gitzo 2180.

Most scope feet are tapped 3/8"x16 but are delivered with a 3/8" to 1/4" adapter so many use a QR plate with a 1/4" screw. Some adapters can have as little as one and a half thread turns, so it doesn't take much for everything to come apart, and as one cannot apply much torque to an adapter, one effectively has a loose connection from the start!

Not most scope feet, but many. There are scopes that are tapped with 1/4'', for instance the Nikon Fieldscopes. And there are 3/8'' to 1/4'' adapters that have more than one and a half turns. If you can't use a plate with a 3/8'' screw, make sure you get adapters with as many turns as possible. The ones I use have 2 1/2 turns minimum.

The answer is to junk the adapter and use a QR plate with a 3/8" screw. Even the suboptimal Manfrotto RC plates with their rubber mating surfaces were available with 3/8" screws and this applies to most Arca-Swiss compatible plates.

Quite right. And make sure you get rid of the rubber (or cork) mating surfaces on your adapter plates in necessary. Metal on metal often works a heck of a lot better.

In almost 20 years of scope use with Diascope 65, ATM65 and Kowa 883 with Manfrotto RC and later Arca-Swiss compatible plates from Novoflex and Berlebach I have always used 3/8" connections and never had a plate work loose.

I've been using 1/4'' connections with my Nikon fieldscopes for well over 20 years. No problems either.

Hermann

 

[Bill Atwood]

This is just utter rubbish, the 3/8 screw doesn't work any better.

 

[Tringa45]

This is just utter rubbish, the 3/8 screw doesn't work any better.

It was your statement that QR plates "suck" that provoked this thread.
You have obviously failed to read, inwardly digest and comprehend.

John

PS:- As Hermann pointed out, if the scope foot is tapped for 1/4" x 20 that would also work satisfactorily.

 

[Binastro]

The Slik 88 tripod, of which I have several, has a small stud that provides the only connection between scope and tripod head.

It always works loose, i.e. it unscrews itself.

So, I check and retighten every time I use a scope.

Why do I use this system?
It is so simple and I leave a stud in place on the bottom of each scope, checking each time.

It is 1/4 inch.

Also I use the handle backwards so it doesn't stick in my eye.

I use everything up to a 127mm Maksutov on the tripod.

For larger scopes I use larger tripods.

Regards,
B.

 

[wllmspd]

1/4” should be no worse as long as you’ve got enough turns of thread to pull stuff together “good and tight”. For big scopes I want >= 2 screws/pins, so stuff can’t rotate and unwind itself. Latest scope I popped on a tripod plate I used 3x 1/4” screws tightened with a large coin…. Something else will come off long before that joint goes bad! The long tripod plate allows me to slide things about to tune the balance as I change the elevation.

Peter

 

[Tringa45]

The Slik 88 tripod, of which I have several, has a small stud that provides the only connection between scope and tripod head.

It always works loose, i.e. it unscrews itself.

So, I check and retighten every time I use a scope.

Why do I use this system?
It is so simple and I leave a stud in place on the bottom of each scope, checking each time.

It is 1/4 inch.

Also I use the handle backwards so it doesn't stick in my eye.

I use everything up to a 127mm Maksutov on the tripod.

For larger scopes I use larger tripods.

Regards,
B.

Some tripods suitable for birding scopes have a reversible 1/4" and 3/8" stud (e.g. Gitzo, Novoflex), but as most suitable heads are tapped 3/8" it would be advisable to use that end.
Top plates are often around 60 mm diameter and have a thin layer of cork or synthetic friction material and, because of the large area and the ability to apply more torque than on a QR plate, compliance is not a problem. If one locks the panorama function on the head one can apply sufficient force with the panorama lever to secure the head to the tripod and nothing should come loose. Some tripods however have one or more grub screws on the underside of the top plate to lock the head.

Regards,
John

 

[Merlin]

I always use a thread-lock 'Locktite' on all QR plates, it is not a total solution but it does help considerably.

regards
Merlin

 

[Bill Atwood]

It was your statement that QR plates "suck" that provoked this thread.
You have obviously failed to read, inwardly digest and comprehend.

John

PS:- As Hermann pointed out, if the scope foot is tapped for 1/4" x 20 that would also work satisfactorily.

Lol, your advice here is still rubbish. And plates still suck.

 

[tenex]

I wonder: do most people really prefer QR plates, or is it just too hard these days to find a head without them? I've never used them myself, for camera or now scope. My Gitzo head has a 1/4" screw (with accessory nut for tightening) that I find simple to use, and because I've just tightened it each time it's not going to come loose. I suppose I could imagine a situation where this took too long, but haven't encountered one yet.

 

[Hermann]

Lol, your advice here is still rubbish. And plates still suck.

You quite obviously don't know what you're talking talking about.

Hermann

 

[Tringa45]

Lol, your advice here is still rubbish. And plates still suck.

If they work for Hermann, work for me and lots of others, but not for you, then someone must be doing something wrong.

John

 

[Tringa45]

I wonder: do most people really prefer QR plates, or is it just too hard these days to find a head without them? I've never used them myself, for camera or now scope. My Gitzo head has a 1/4" screw (with accessory nut for tightening) that I find simple to use, and because I've just tightened it each time it's not going to come loose. I suppose I could imagine a situation where this took too long, but haven't encountered one yet.

The raison d'etre of QR plates is that repeated use of screw connections is really not a good idea, and not very convenient either. I once heard that all those expensive titanium bolts in Formula One end up on the scrap heap after a single usage. I guess though that everything is torqued to yield.

Regards,
John

 

[wllmspd]

I had a plate once that the threads had stripped out of… may have been through reuse or just a crappy metal choice. Some screws are meant for multiple uses, some are designed to go on once and not undone/reused.

Peter

 

[tenex]

The raison d'etre of QR plates is that repeated use of screw connections is really not a good idea, and not very convenient either.

I had a plate once that the threads had stripped out of…

I suspect Gitzo may have had such issues in mind when designing this big knurled nut under the plate for final tightening. It avoids the screw going all the way in, or applying high torque directly to it and the threaded socket. I've used a head like this for many years without a problem, although I'm sure I use a tripod less freqently than some others do.

 

[Vixen_893]

Many scope users seem to favour direct mounting of the scope into the tripod head. Some scope feet were compatible with the Manfrotto RC system and now later Swarovski scopes are Arca-Swiss compatible. Perhaps there was a fear that quick-release plates could come loose, but for many scopes a longer QR plate is almost indispensible.
The Nikon Fieldscope and Monarch 60s and also the Swarovski ATS/STS 65s are extremely tail heavy and would otherwise require excessive amounts of tilt friction to hold them in the horizontal. Some other scope families have the scope foot in the same position for different objective sizes, e.g. Swarovski 85, 95 and 115 objective modules and Kowa 77, 88, and 99, so horizontal balance for some of these will be less than ideal.

The scope manufacturers have unwittingly led us into the trap of using a fixture that may be adequate for static camera use but is completely inadequate for mobile scope use.
Most scope feet are tapped 3/8"x16 but are delivered with a 3/8" to 1/4" adapter so many use a QR plate with a 1/4" screw. Some adapters can have as little as one and a half thread turns, so it doesn't take much for everything to come apart, and as one cannot apply much torque to an adapter, one effectively has a loose connection from the start!
The answer is to junk the adapter and use a QR plate with a 3/8" screw. Even the suboptimal Manfrotto RC plates with their rubber mating surfaces were available with 3/8" screws and this applies to most Arca-Swiss compatible plates.

Moderate torque (for the thread size) with a coin slot, or even better with a 4mm Allen key can generate a high compressive load betweel the metal surfaces of plate and scope foot that nothing will come undone. There is then no shear load on screw or anti-rotation pin. The friction between the two surfaces is akin to that between a car wheel and hub, which carries the load and transmits braking torque. Loctite is completely unnecessary.
In almost 20 years of scope use with Diascope 65, ATM65 and Kowa 883 with Manfrotto RC and later Arca-Swiss compatible plates from Novoflex and Berlebach I have always used 3/8" connections and never had a plate work loose.

John

I completely agree and I fail to see the reason for adopting Arca-suisse fittings anyway - they aren't as robust as the good old Manfrotto 128RC kit nor the now difficult-to-find Gitzo 1720 and 2720. Personally I find the latter designs the best ever but I think their initial price put many people off.

The 3/8-to-1/4 adapters are a disaster waiting to happen, unless you can get sometone to manufacture one from mild steel with 4 - 5 threads. I always insist on using 3/8 screws, which can be acurately cut to length to acheive the maximum thread surface area coverage.

Over the years, I've used a couple of ploys which stop adapter plates working loose. Applying a single layer of heavy-duty double-sided adhesive carpet tape between 'scope foot and adapter plates reduced movement considerably. The other ploy (not recomended if you're concerned about the resale price of your 'scope) is to tap the locater pin hole on the 'scope foot with an appropriate thread size so that the plate is now attached to the scope by a 3/4 screw, a smaller screw in place of the locator pin and double sided tape. I have used this combination on one of my larger 'scopes and the plate hasn't moved in 10 years!

Mike Hannah

 

[Vixen_893]

It partly depends on the material from which the adapter insert is made. Some of them are manufactured from brass, which is not sufficintly robust, especially if you want it to hold 'scope the weight of a Swaro ATX115. For maximum grip, a mild-steel 3/8 bolt cut to the maximum allowable length is by far the best option. For a given depth, the thread and head contact areas for a 3/8 bolt are greater than those of a 1/4 and the bolt can be safely tightened to a higher torque. Horses for courses and basic engineering tells us that for greater secuity and heavier loads, we need larger diameter bolts.

For heavy kit, you could argue that using aluminium or magnesium for the tripod ring and 'scope foot is pushing your luck - they are probably the most common cause of mechanical problems, either through structural failure or stripped threads. Given the option, I'd have mine made from stainless steel - the wieght penalty would be minimal.

Mike Hannah, retired Chartered Engineer

 

[Tringa45]

Some of them are manufactured from brass, which is not sufficintly robust, especially if you want it to hold 'scope the weight of a Swaro ATX115. For maximum grip, a mild-steel 3/8 bolt cut to the maximum allowable length is by far the best option.
Mike Hannah, retired Chartered Engineer

Mike,
I used to build bicycle wheels as a hobby. Spoke nipples are made of nickel-plated brass (occasionally aluminium). They have a 2 mm thread less than 12 mm long and are subjected to millions of cycles of fatigue loads.
I usually tensioned front wheel spokes to 900 N and the drive side of rear wheel spokes to 1300 N or aproximately 130 kgf and AFAIK have never had a failure.
It's not the material that's the problem but the clumsy solution of an adapter.
Btw, bolt thread length is not an option as this is dictated by the scope manufacturers with the available depth of a blind thread which is inacceptably shallow by engineering standards.

John

 

[Vixen_893]

Mike,
I used to build bicycle wheels as a hobby. Spoke nipples are made of nickel-plated brass (occasionally aluminium). They have a 2 mm thread less than 12 mm long and are subjected to millions of cycles of fatigue loads.
I usually tensioned front wheel spokes to 900 N and the drive side of rear wheel spokes to 1300 N or aproximately 130 kgf and AFAIK have never had a failure.
It's not the material that's the problem but the clumsy solution of an adapter.
Btw, bolt thread length is not an option as this is dictated by the scope manufacturers with the available depth of a blind thread which is inacceptably shallow by engineering standards.

John

Agreed about the spokes, but you're talking about (almost) vertical loads (compression/tension). If the 'scope is always horizontal on a tripod, there's no problem but the turning moment on the 'scope/QR plate interface is appreciable for a 2 kg 'scope, when it is being carried in an other-than-horizontal position and being bounced about.

A friend of mine, who is an authorised dealer for all the major manufacturer's products, says that the majority of 'scope failures are based around the mounting system. I would still prefer a more robust material for the tripod attachment but I agree - this is the area which lets pretty well all 'scopes down.

When you consider the hardware used to attach a small camera or a Nikon ED50 to a tripod is also used by many people for a Swaro BTX115 is a nonsense. In the latter case, to rely on a 3/8-to-1/4 adapter with only 2-3 threads making contact is rediculous. The blind hole in the foot should ideally be about 15-20 mm deep. You are right - the manufacturers of optics are partly to blame but they arn't helped by the makers of tripod heads!