What I need is an M42 male thread to M48 female thread less thickness than the 16.5mm ones I have. 12-15mm would be perfect!
Any leads?
Thanks!
Let us know how it turns out, please.UlteriorModem wrote: ↑Sat Jan 25, 2020 10:30 pm I have access to a belt and or disc sander. Also a large collection of sanding blocks in all kinds of grades. Should be easy!
I have access to one of those too. I just did not feel like driving over to the shop. I just sanded away while watching Netflix
If 1mm got the curvature from 41mm to 31mm maybe you need another 3mm to get the curvature to zero? Just a guess.UlteriorModem wrote: ↑Fri Jan 31, 2020 11:42 pm Well had a chance to test it and I need to shave off more or find some shorter rings.
Here is a star field I shot. Click it a couple of times to zoom in and look at the corners.
Field 1 by Tom Whit, on Flickr
Here is what ccd inspector had to say about it.
Curve 4 by Tom Whit, on Flickr
Here is a measurement before the shortening of about 2mm. There was some improvement!
Curve 1 by Tom Whit, on Flickr
It's super easy to overshoot the mark if you don't use the lathe every day.UlteriorModem wrote: ↑Sat Feb 01, 2020 4:20 pm I took the ring over to the shop and chucked it into the lathe. Only took a few minutes to turn it down to 12mm.
Once installed I found I overshot the reduction spacing which is now at 50.5 mm with is inside the 51.5 stated requirement for the Field Flattener. But hopefully it will be close enough.
Unfortunately it is not supposed to clear up until after midnight tonight. So maybe tomorrow (Sunday) I might get a chance to test it.
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