Arca Swiss plates...

From your description, if it were me I would get rid of those Slik heads ASAP. They sound really poorly designed and ripe for catastrophic failure on the job. How much would it cost you to repair or replace a camera/lens? A lot more than a decent tripod head, I suspect.

Actually the clamps that can screw off is not a bad thing, because then you can use the same clamp on another Ball Head preferably one which has an independent panning base.

The reason I mentioned the camera crashing down to the floor, is because when those Paning Bases I purchased earlier seized on me, it wasn't the panning base that was moving when I panned the camera, but the actual clamp unscrewing from the base of the Ball Head. Good thing I noticed, or it could have been a disaster.

Many ball heads these days come with repaceable clamps. Some manufacturers use a special type of glue so the clamp won't unscrew from the base, but its easy to get by that if you put enough pressure on it.

But how many turns does it take to twist those arca style clamps off?

A lot of things, including cameras and the quick release plates you might attach to them, are fastened using things that release when twisted. That is not poor design or being ripe for catastrophic failure. Screws, threads, are proven to be quite good for what we use them for.

A quick release plate on a camera is a bit different--you know that you screwed it on so you are aware that it can come off easily and are likely to check it periodically, and it will be loose (the camera will rotate slightly) before it actually falls off. The head design cited by the OP is different. I would expect a part like that to be permanently attached and I would never expect it to come loose under normal use. When I attach a tripod head to one of my Manfrotto tripods it screws on and then there are 3 grub screws that further anchor the head to the tripod. There are also indents in the tripod head base that prevent the head from turning even if the grub screws worked a bit loose for some reason. In 40 years of regular use these heads have never come off and have only loosened a couple of times, but well before they would have come off. The fact that there is nothing to prevent this piece of a tripod head from unscrewing is evidence of poor design as far as I am concerned.

A quick release plate on a camera is a bit different--you know that you screwed it on so you are aware that it can come off easily and are likely to check it periodically, and it will be loose (the camera will rotate slightly) before it actually falls off. The head design cited by the OP is different. I would expect a part like that to be permanently attached and I would never expect it to come loose under normal use. When I attach a tripod head to one of my Manfrotto tripods it screws on and then there are 3 grub screws that further anchor the head to the tripod. There are also indents in the tripod head base that prevent the head from turning even if the grub screws worked a bit loose for some reason. In 40 years of regular use these heads have never come off and have only loosened a couple of times, but well before they would have come off. The fact that there is nothing to prevent this piece of a tripod head from unscrewing is evidence of poor design as far as I am concerned.

That's why I reverted to using the older version of Slik SBH-280 Ball Head(which was my first BH) where you can't unscreew the clamp, or does it have a Quick Release Plate, or does it have an annoying little switch that you have to press to attach/remove the plate from the clamp. For the work I do, it's one less thing to worry about ! Here is a picture of the older model:

where you can't unscreew the clamp, or does it have a Quick Release Plate, or does it have an annoying little switch that you have to press to attach/remove the plate from the clamp.

The illustration clearly shows it has a nasty little rectangular QR plate that releases using the small 'trigger' lever at the right side.

As this thread progresses, I'm less and less persuaded to buy anything branded 'Slik'.

The illustration clearly shows it has a nasty little rectangular QR plate that releases using the small 'trigger' lever at the right side.

 

As this thread progresses, I'm less and less persuaded to buy anything branded 'Slik'.

Manfrotto uses similar locking levers. No problem.

Manfrotto uses similar locking levers. No problem.

Indeed. Some of Manfrotto's cheaper heads use a similarly small and nasty rectangular QR plate. Worse still, they come in at least 2 different fittings that are non-interchangeable but visually near identical. Wouldn't use one of those either.

Thankfully, most of my tripod heads have a simple 1/4" or 3/8" bolt fitting, and date from an era before QR plates became inexplicably 'de rigeur'.

"Let's insert another fiddly fixing underneath the perfectly good fixing attached to every camera. What a brilliant idea that is.... NOT!"

Agree that quick release plates are not really necessary.

But they aren't bad either. Those cheap, small and nasty couplings keep your gear quite secure.

Indeed. Some of Manfrotto's cheaper heads use a similarly small and nasty rectangular QR plate. Worse still, they come in at least 2 different fittings that are non-interchangeable but visually near identical. Wouldn't use one of those either.

 

Thankfully, most of my tripod heads have a simple 1/4" or 3/8" bolt fitting, and date from an era before QR plates became inexplicably 'de rigeur'.

 

"Let's insert another fiddly fixing underneath the perfectly good fixing attached to every camera. What a brilliant idea that is.... NOT!"

The Arca Swiss Plates come n handy when you need to constantyly change your camera from horizontal to vertical, but with that you also need an L bracket. Otherwise, they are not mandatory. Here is another alternative. I found this at the very bottom of a bag in my dungeon. I'ts a beast, but for its size and weight, can only handle 15 lbs ! Come to think about it, I think this was my first BH ? It does come with an intependent panning lock, however it can be finnicky to set up.

Manfrotto 3055

Are all Arca-Swiss plates the same or do they come with different sizes ? I want to replace my quick Arca-Swiss plate with one I saw on eBay that has vertical and Horizontal bubble levels. Is this possible ?

Arca plates vary by a few thousandths of an inch between manufacturers. If you use the convenient lever operated clamps, they should be made by the same company. Screw operated clamps are more forgiving. Adjustable lever clamps are likely to be out of adjustment at inconvenient times.

As I know they can be different, but I'm not sure.

The original Arca Swiss style plate dimensions were not patented, although RRS, Arca Swiss, Kirk, Wimberley are identical dimensions to my knowledge and experience.  They will work well with lever or knob tightening clamps, but other plate makers with different dimensions may not fit the lever clamps well. Ed Ingold's advice to use all plates from the same maker(anyone in my list, above) with lever clamps solves all problems. Some ball heads with lever clamps can have the plate acceptance dimensions changed in the field.

Finally found a viable replacement for my old Slik SBH-280 ball head. Actually, the reason I needed a replacement was that my Slik Tripod + Ballhead were stolen the other day.  I left the Tripod + Ballhead at one of the properties I photographed by mistake one day. Two days later after I realized it wasn't in trunk of my car, I went back to the property, but by then it had dissapeared ! This new/used Vanguard SBH-100 holds more weight, has 2 boubles just like I wanted and has the Pan-Lock. It's not as nice looking as my old Slik, but it will do. Now I have to find a replacement Tripod...   

Having become a recent convert to the Arca-Swiss plates, I purchased this to go on my Giotto CF tripod :

as the least expensive pan head I could find with Arca-Swiss compatibility (never got on with ball heads). Although it is reasonably small and lightweight, upon testing it I was pleasantly surprised to find that the clamps will take a Sigma 150-500 lens attached to a Pentax K3 with battery grip, and hold them securely. Obviously, using the A-S compatible foot of the lens, not a plate or L-bracket attached to the camera ! Being a fluid head, the movements are very smooth, it has internal spirit levels and well-marked panorama indications. Best £40 I have spent for sometime !

12 hours ago, Tony Parsons said:

Best £40 I have spent for sometime !

Wow! That does sound like an absolute bargain. Congrats on that find. 

If I didn't have far too many tripods and heads already (and an aversion to QR fittings) I could be well-tempted by that.