Nebro Handcross Lens hood and filter holder.

I have just bought an almost as new example of the accessory from the mid 1900s. Even the rubber protective sleeving on the clamp arms is in good condition.

I use an simpler version which I converted to take 52mm screw in filters, but this one would be much easier to use on my older film gear if I can find some filter glasses for it. The glass that came with it is 38mm diameter but is plain UV and so doesn't help me with monochrome.

Does anyone know of a supplier of filter glasses to size? I imagine 40.5mm filters will ahve glass around this diameter but don't have one to check so can anyone throw any light on this too?

I assume Heliopan would cut glass discs to custom size, in case one off the racks would not fit.

Thanks for the suggestion AgX which got me thinking and I have now bought some resin filters from SRB/Griturn in the UK which they cut for me and are a perfect fit.

SRB/Griturn

First time I hear of them. A short glance at their website though does not indicate that they make any filters themselves, thus I am surprised by that customizing.

They do a bespoke service for mounts, adapters and resin filters - no glass - but their website is not very clear about this service. Some digging is needed. They are very helpful, however, once past the various hurdles.