Well im still not getting as much grinding done as I would like due to a combination of having the worlds most unreliable car,a long distance relationship and a day job that leaves you with little motivation in life but the grind is coming along now.Im currently at about 8.5mm sagittal so there's a well defined curve now although my phone camera wont show it too well but will try and get a better picture next weekend.currently the mirror grind stands me at 46h 15 minutes with 31h 45 minutes of that being spent grinding the front.currently the mirror is a 22" f4.1 with the current depth but obviously this is a rough curve and I would lose 2mm of that in second stage grinding.for my desired f3.6 I need a 9.75mm sagitta for the finished mirror so I need to get down to about 12/13mm to allow for shallowing up with second stage grinding.hopefully I can get first stage grinding finished next week as I have the weekend away from the girlfriend so both days free although I have front and rear brakes,a diesel particulate filter and half the front suspension to replace on my car,hopefully which will be possible in a day leaving me the other day to grind.then its tile tool time and another bit of research on second stage grinding.have to start thinking about making a ronchi test rig soon too.
here is a grainy pic of an 8.5mm sagitta
Im also coigning a new term for the medical journal GRINDERS ELBOW!!!! after an hour of heavy grinding your arms are getting pretty tired.i can manage 2 hours but most of the time I do 1 to 1 1/2 hours to preserve my body.i usually get 3 or 4 nights a week to grind as one night is usually out climbing and Friday night is travelling down south where I live on a weekend.
another update next weekend hopefully.
cheers for looking
clear skies Rich