Gregg MacPherson

Aaron, Assuming that the equipment is OK...... It's a good idea to control the loop sizes, and the position of the perf in the film gate, and the position of the claw. The mirror parking will leave the claw always in the same place. The manual mirror motor, you will have a routine that leaves the mirror and claw almost the same. When loading, while setting the loops, shift a perf in the gate so it's just below the claw. The claw will catch it every time, quiet starts and you will keep your ideal loop sizes. Like Dom says, manual inching to engage the claw is best. Make it part of your protocol. Get some clean scrap film to practice loading. You can run the loop tests/scratch test with the door off. Adjust your loading protocols as above and check that your method works. Then you can pull mags as often as you need without any concern over the loops. If you have any doubt about your mag or method, after mounting a fresh mag on the camera just pull the door and run a few frames. Have fun.

Really interesting work Aapo. How is shoulder mounting with the common view finders? There must be more space to include a shaped shoulder pad.

Well deserved David.

Thanks Dom, this is going to be a good reference thread. Duncan, The generic Arri-B/S to TS adapter in my prev pic above......Lens inserts to the flange, then twist a few degrees 'till it locks with a click. The metal button that releases the bayo lock also retracts the little tabs that hold the groove in the Arri-S mount. If the lens orientation feels off to the operator or focus puller maybe it's OK to rotate the rear of the adapter. The machining one assumes is perfect and there will be 4x90deg increment positions.

This is the common (generic) Arri-B/S to TS adapter I've had and seen photos of. Best I can do for now. It's cut from the pic on the cinemarketplace that I pointed to. The bayonet locks. It has a metal release button on the far side. When Sam Riley resurfaces he might take some better pics for us. One of the common industrial lens projectors uses the same adapters, I'm fairly sure. So that is a source of info, and maybe used adapters, so anyones guess on the supply and demand there.

You are a busy beaver. I'm sure that is not the standard Arri-B/S to TS adapter that was sold (contemporaneously) with the original cameras. I've had one or two and seen a few photos on the web or brochures. It has a plain, simple front face. I can't easily find a good photo, but there is one included in the ACL II kit I previously advertised on the Fleamarket. Not a close up, but you get the idea.. https://cinematography.com/index.php?/forums/topic/91893-eclair-flea-market/page/2/#comments So I don't know who made that one. Looks like a studious piece of work. Gregg.

Hey, well done. A thought on the rewinds...Most old ones had simple gears enclosed that gave quite a high rewind speed. Very useful. Not sure on the ratio, guessing maybe 3 or 4 to 1. You could make all that with your 3D printer maybe. Steel for the shafts and spindles. The gear teeth would be quite coarse.

Meant to add...Keep the PL mounts and screws, may be very useful later, and the lenses are more valuable with PL mounts. If someone is buying the good aftermarket PL mounts to convert, they're almost USD400 each.

I had to figure this out a while ago (screw length on Arri-B vs PL mount). In the end the simplest thinking was best. I measured the screw length from a factory PL mount on a 16mm format lens as 6mm. The screw for Arri-B was I think 5mm long. There isn't much thread engagement length at 6mm for the PL mount, but at about 7mm the screw is bottoming out. If you have 6mm screws, it may not be safe to use them on the Arri-B mounts. The screws are DIN 920 standard, M2 with coarse pitch=0.4mm. They have a 2.8mm diam cheese head, narrower than normal screws. Zeiss were helpful but didn't work out. ACCU in the UK sold us 50 stainless screws for about 25 Pounds, similar shipping. Very hard to find in small quantities. There may be lots of used 5mm screws left over from all the conversions from Arri-B to PL. The people selling you the mounts may have them. If you are searching, the screw spec will look something like DIN 920 M2x5, then maybe something specifying the steel and finish. Trimming the screw length is pretty easy for those with skills, familiar with tiny screws. Good luck.

Heikki, have you been through those web pages and scavenged for useful contacts etc, like on the camera service techs page..The first one I explored seemed a bit problematic, but there were some new names (for me). Steven, those ACL S16 conversion kits, I'm sure were intended for camera techs, not for DIY. (so I think we agree) Gregg

Andrzej is really busy. I had to wait a couple months for him to service two motors. But it's worth saying, he put it in his que and he was on time with the execution. Not bad really for a highly specialised (one man?) business. Re the shipping costs. You can strip down to the bare minimum that he needs

I think I remember Jean-Louis Seguin may have made those before. He may have some Jaeger connectors or an easy source. Anyone good at making up cables could probably make one, though I would choose someone experienced who knows the cameras and the specs well. The 4 pin Jaeger can be trickey if one doesn't have skill or experience. The standard cables with 4 pin Jaeger/Canon XLR4 I have seen in two versions. One with a coiled cable about 400mm long with connectors, and one with a straight cable about 250 long total, for the on board battery. For the length, copy a standard length, or consider it carefully. Andrzej at AZ Spectrum, commenting on current draw and V drop at higher fps, advised to keep cables short. So I guess one should also have adequate copper section area (cable size). The spiral cables are really useful though. I like the idea of the off board battery, and with the XLR4 connector on the camera, really robust, the old concern about stressing up the Jaeger connector is gone. Gregg.

It's good to emphasise the importance of properly fitting screwdrivers. Gunsmith sets are an interesting idea I never thought of. They are a bit expensive here. I used to have a specialist tool shop nearby and I could buy a selection of expensive good quality small size screw drivers. Since then I have found inexpensive, quite good quality sets of hollow ground screw drivers at the budget hardware and auto supply shops. Have a look at the shape of slothead screw drivers online....normal vs hollow ground etc... One problem is that the slothead screws on the ACL often have quite narrow slots , so without the perfect driver set, one sometimes has to use a smaller driver so as to fit the slot. Obviously a driver that fits the slot perfectly and is the width of the screw head is ideal.

I have sometimes taken a cheap screwdriver that was a little too big or thick and carefully ground it to size. Incorrect or inexpertly ground screwdrivers can easily cause a little damage. The screw on the feed side needs to be tightened, with the idler assembly in the correct position with the spring relaxed. Les Bosher might have experience with these mags. Any camera tech could fix the idler mounting, though he will wonder what the correct spring pre tension should be. Some experience may be required if there is a troublesome issue with the take up wind being loose or not tracking straight. As well as the possible causes for take up problems listed earlier, add... - Take up arm pre tension. There is a means of adjusting that on the feed side. Really needs a custom tool to rotate it. I have done it without that but sometimes scratched it. Needs a little skill, expertise. - The take up platter and guides on the door. The factory mags had 200' sized platters, and with a properly maintained mag the 400' roll takes up straight without the bigger platter to sit against. But if there are any tracking problems due to the rubber take up tyres then the bigger platter could help. But it's better to have the rubber tyres working properly. (Edit)..You platter is odd. Looks like the film might catch or scrape on the surface, especially if the take up tracking was not true. Where are you located?

So I had a look and one can, leaving the whole pully and idler assembly in place, adjust the spring pre tension by releasing the screw on the feed side. Rotate the assembly to the correct relaxed position, then tighten the screw. Very simple. Sorry I did not check earlier. I have a faint memory of having done it years ago also. I'm not sure what the correct spring pre tension is. The techs would have had a torque spec and a rule of thumb for the relaxed position of the assembly. I think I just guessed and was happy when the take up worked. Did you fix it?