240mm G Claron reassembly order.

[Geoffrey Poulton]

I'm slightly reluctant to ask this question as I ought to know better.
I have dismantled my 240mm G Claron for cleaning, but on reassembling the lens I found that one of the spacers within the lens elements has a lipped edge and the other is flat. When I took the lens apart I did not notice that they were different until it was too late, and now I'm not sure of the orientation of the lip edged washer. I believe it is probably placed nearer the shutter than the flat washer (but I'm now not 100% sure of this), but I don't know whether the lipped part faces the shutter or the front of the lens.
I know there are some folks on here who will know for sure. At present the lipped edge is facing the shutter with the back element sitting within it, however there is a little rattling noise if I shake the lens so I'm doubting now that even this is right.
Help !!!

[EdSawyer]

6-element type, presumably? Did you check for cross section diagramson google?

[ic-racer]

This may or may not help:
134181

[Geoffrey Poulton]

6-element type, presumably? Did you check for cross section diagramson google?

Hi Ed
Yes it is the 6-4 plasmat type and I did look around for diagrams, but with no luck. I see that IC Racer has found a diagram that I did look at, but unfortunately there are not washer details showing on it as far as I can see.

I assembled the lens in a few different ways as far as the two washers are concerned. I think there are only three ways in which it can be done. All but one had the smaller rear element rattling after reassembly. One of the ways secured the group without rattling. I had assumed taht the lip on one of the washer was for securing the rear element, but I think it was for placing in postion for the main front element. By positioning this way, there is no rattle so I'm assuming, or hoping this is the correct way.

Very frustrating really.

[Geoffrey Poulton]

This may or may not help:
134181


Thanks for this diagram, this should really have been the last word on the layout, but unfortunately there are no washers detailed. It's a little bit frustrating.

In fact, the casing that it illustrated is nothing like the actual lens either. I think the trial and error method that I've tried with regard to the rear element being secure and not rattling, is as good a way as any................I'm hoping so. At least everything is secure. I had thought that the lipped edge of one of the washers related to the back element, but it doesn't secure that element when assembled, it allows movement, but if I use it in a position for main front element, it does secure the rear when tightened on assembly.

[EdSawyer]

Sounds like you have it figured out. Retaining or spacing rings with lips on them are usually for centering and retention of the element within the group. Definitely shouldn't be any rattles.

[Tony Lakin]

If you fail to reassemble it to your satisfaction you could always sell it on Ebay:eek:

[Kevin Crisp]

Geoffrey

Sounds like you have it figured out, I agree the lip is usually to help center an element. If your lens still has any issues, send me a private message on Tuesday, I've got an unopened 240 and I can open it up and check for you.

[Geoffrey Poulton]

Hi Kevin
Thanks so much your kindness. I wonder if you would just look to see if I have it right by opening yours, it would certainly put my mind at rest. I could see me using this wrongly for the next ..... number of years!

The comments made by Ed and yourself regarding the centering is really helpful. I've been thinking in terms of spacing, but once you think about centering it throws a few of the concerns out of the way. I'd be so grateful if you were able to take a look at yours. I hope it's the same way as I've assemble this one!

[Geoffrey Poulton]

Thanks Tony ;=) I might have expected that from someone with three legs!

[Geoffrey Poulton]

Sounds like you have it figured out. Retaining or spacing rings with lips on them are usually for centering and retention of the element within the group. Definitely shouldn't be any rattles.

Thanks Ed, the idea of centering instead of spacing certainly assuages a few of my concerns, and I can see how I've been thinking wrongly now. Kevin has offered to open his 240mm next week and see how it's assembled, that will be really helpful and put my mind at rest. I guess I won't be making the same mistake again.

[Geoffrey Poulton]

The help here has been fantastic, it's my first post on this site and the response has been great. Thanks everyone.

[Kevin Crisp]

I won't be able to until Tuesday. Just I'm clear on it, you have disassembled the REAR component by turning the slotted ring counter clockwise. Then took out the outermost cemented group and now you're not sure how the spacers below (behind) that larger rear group are supposed to go?

[Geoffrey Poulton]

Yes, that's it Kevin. At present I have assembled the group so that the washer with a raised edge lip facing toward the rear of the front element so that it cups the rear of the front element. The flat washer is put in place over the smaller rear element, when the whole thing is tightened there is no movement, or rattling of the elements.

I've assembled the front the group the same way too, both front and rear groups have the same arrangement.

[Kevin Crisp]

OK, I meant to do this last night but didn't get around to it. I will check tonight. I'm 99% sure you have it right now.

[Geoffrey Poulton]

Thanks Kevin, that will be great. It will be so reassuring to know if I have got it right, it won't be a mistake I make again, I'll be more observant next time.

[EdSawyer]

Glad to help out. I have an unmolested 240 G-claron I can open up if need be too.

[Geoffrey Poulton]

Thanks Ed, that would be really helpful. I think I have it right, but I'm not 100% sure and it would be such a pity if I had it like that for years! If it's not trouble and you do, I'll let Kevin know that you've done that.
Best regards,
Geoff