More than you wanted to know about a couple of gimbals!

Valvebounce

EOS 5D SR
Apr 3, 2013
4,200
166
52
Isle of Wight
Hi Folks.
Having just written this for a reply to a thread, I thought I would post it where others might find it and get something from it.

Just to clarify, I am using rotation to denote the horizontal travel and swing to denote the vertical travel.

I have 2 gimbals,
A Benro GH2, (£350 ish), lives on my tripod.
A Sevenoak SK-GH01 (£70ish), for sticking on various 3/8 studs like at the local hide. (And maybe forgetting to take home with me so didn’t want an expensive one. )
Why did I choose the Sevenoak, well because it was the cheapest gimbal that appeared to have the centre line of the clamp (and therefore the lens) in line with the centre of rotation, no idea if this matters or not but I have it in my head that it does! :unsure:

The Benro.
Nice needle race thrust bearing carrying the weight and acting as partial rotational location for the swivel, the rest of the swivel location is via a brass or bronze bush. The swing is a brass or bronze bush on the camera side and a plastic bush on the knob side which also acts as part of the brake (lock) system.


The Sevenoak
Probably a needle race, same fixing pattern as the Benro, and feels the same smooth rotation. Fairly poor double plastic bearing on the swing, way too much clearance and a serrated face on the spindle and a rubber disc for the brake, it had no finesse, it was on or off, and when off it was like a stick in a bucket, no location, lots of drop on the platform, the level in the camera could be set zero, then release the clamp and 3 or 4 bars which equates to 3 or 4° of tilt!

They both have a ball bearing thrust race under the lock knob for the swing.

Yes I have had both apart, a friend bought a very hard used Benro (we were told it spent its life holding up a Nikon 800mm f/5.6) for real cheap due to some play in the swivel, the thread lock had failed and the bolt that tensions the needle race had slackened.
Use steam to break down the glue holding the decorative cover and the thread lock holding it all together, if you don’t the thread lock might be strong enough to break the screws!

I improved the swing on my Benro by replacing the outer plastic with a bronze bush that I made. Probably £3 in materials and £50 labour, see below about the labour!

I improved the swing on the Sevenoak by completely reworking the swing with bronze bushes, removed the serrations on the spindle and replaced the rubber brake disc with 2mm Phenolic sheet, I now have two perfect gimbals, including my time and the materials, the Sevenoak cost me about £200 in total, so not the bargain I thought, however as the time was taken from my hobby time I like to discount it as I enjoyed the project and the materials were about a tenner! (Yes lots of time was spent fettling the original casting to align the bores in the top, one bore from each side so they were not aligned!)
I also replaced the M5 screws (just over 3/16 inch) holding the swing arm to the spindle as they were much too short, the holes were tapped 13mm deep and the screws engaged by about 2 turns, just about 1.6mm (1/16 inch), they are now in by about 8mm, (about the same as the Benro) the spindle is recessed in to the swing arm so the screws are not directly carrying the weight, but they are under some tension to hold the arm against the spindle. I’m much happier to hang heavy lenses on it now!

I thought I had some phone pictures of bits of this but I can’t find them, I may have them on my pc, if I find them I will add them.

T.L.D.R.
You definitely get what you pay for in many cases, including these!

Cheers, Graham.
 

Valvebounce

EOS 5D SR
Apr 3, 2013
4,200
166
52
Isle of Wight
Hi Joe.
At the moment, it is you and me both! I know I took some with something, old phone, new phone, old iPad, new iPad? They seem to have vanished, possibly in the backup / restore process surrounding new iDevices, I may yet find them if I can narrow down the date I did the work!
For now I’m going to have to consider that they are permanently gone, this is why I don’t take important photos with my phone, too easy (for me) to loose them!

Cheers, Graham.

I love to see the build photos

Joe