Gregg MacPherson Posted May 11, 2022 Share Posted May 11, 2022 I have some PL mounts I bought from Slomo Digital and I want to check the fit and find the screws. It's for a Zeiss 8mm-T2.1 and a set of 5 MKII (S16) superspeeds. I have a 50mm-T1.3 MKII Zeiss with factory PL mount here for reference. Do you have to buy the screws from Zeiss or somewhere like P+S Technik. I read on a forum (somewhere) that someone ordered from P+S T and got the wrong screws...I'm wondering if the screws are to a DIN or similar standard and easy to find once specified as such. They are almost the same as DIN84, but the cheese head diameter (dk) is 3.8mm for DIN84 and 2.8mm for the original screws with the factory PL mount. Prob'ly not relevant, but I noted that the screws for the Arri-B mount on the 8mm are length (l)=5mm, while the superspeeds have l=4mm. The screws from the factory PL mount on the 50mm I'll list dimensions here. I'm just going to ignore the manufactured tolerance for now. M2, so nominal d=2mm. Pitch=0.4mm. Length l=6mm. Cheese head diameter dk=2.8mm...(sample screw from Slomo had dk=3.0mm.) Cheese head height k=1.3mm. Slot width n=0.5mm (just giving DIN84) Slot depth t=0.6mm (DIN84) One of the screws had 2mm of unthreaded shank, the rest were fully threaded. Thanks for any ideas. Gregg. Link to comment Share on other sites More sharing options...
Gregg MacPherson Posted May 12, 2022 Author Share Posted May 12, 2022 I found some old parts drawings for the 8mm distagon (Arri-B), and some of the 35mm format lenses with PL mount (thanks Tom Jensen). The small cheese head screws are DIN920, and the PL mounts show screws with 8mm length. One can see the end clearance available. But no drawings for the 16mm format superspeeds. My 6mm length sample screws from the 50mm planar PL mount may not be correct. Their length of thread engagement is only 2mm. Searching for "m2-0.4x6mm din920" showed that Aspen Fasteners sold 500 for $293 Zeis in Germany have almost enough, but plenty with length of 8mm (these were the cheapest, available in packs of 50, and have a nice 2mm unthreaded grip length ). Duclose have stock. Cheers, Gregg. Link to comment Share on other sites More sharing options...
Premium Member Dom Jaeger Posted May 12, 2022 Premium Member Share Posted May 12, 2022 The site accu.co.uk sells them in small batches, ie 50 for £19, but the postage is £30 to NZ. https://www.accu.co.uk/reduced-slotted-pan-head-screws/65323-SFPR-M2-8-A2 Link to comment Share on other sites More sharing options...
Gregg MacPherson Posted May 13, 2022 Author Share Posted May 13, 2022 Thanks, I saw that one. Zeiss are about the same price for 50 pc. We'll see what shipping is. Am i right to choose 8mm screw length? I suppose I can remove a screw on each lens and see if the end clearance for the screw is consistent. Gregg Link to comment Share on other sites More sharing options...
Gregg MacPherson Posted September 15, 2023 Author Share Posted September 15, 2023 I did buy 8mm long screws from Accu in the end, a few months ago. This length I took from a Zeiss drawing for a standard speed. Earlier I had found the screws for the 16mm format, 50mm superspeed factory PL mount to be 6mm long, but I foolishly bought 8mm screws thinking they would have better thread engagement. Of course they were too long..! Luckily Accu screwed up the shipping so I didn't pay for that. When I look at the screws that Accu supplied, the last 1mm or so is not well formed, so this decided me on trimming the screw length rather than ordering more screws, which is surprisingly easy. The available space in the threaded hole on the (16mm format) s'speeds may actually be something like 7mm, but I decided I would (should) just use the screws of the same length as the sample, 6mm. Bit of a screwup really..ha. Gregg. Link to comment Share on other sites More sharing options...
Steve Switaj Posted September 16, 2023 Share Posted September 16, 2023 How about this series of JIS screws at McMaster-Carr https://www.mcmaster.com/catalog/129/3396/94387A514 They're JIS standard, which means the heads are a bit thinner and less wide than the typical metric series (1.3 x 3.5mm versus 1.7 x 4.0mm) I use them for installing Nikon and Canon lens mounts on the specialty optics we build at work. In 2x6mm they're about $4.71/50 Link to comment Share on other sites More sharing options...
Gregg MacPherson Posted September 16, 2023 Author Share Posted September 16, 2023 The DIN 920 standard is a 2.8mm diam cheese head. The recess for the screw heads in the Zeiss PL mount is designed to take those screws.I don't know if all the 3rd party PL mounts copy that exactly. There isn't much metal there to make the diameter much bigger. The sample screws I got with the 3rd party PL mount from Slomo were I think 3mm head diameter, They fitted their mount, but I didn't try them on a zeiss mount. The DIN 920 screws are absurdly cheap in large quantities, and absurdly expensive in small quantities, with silly shipping costs. Cheers, Gregg. Link to comment Share on other sites More sharing options...
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