mapstar

Cheers Faulksy just wish it was finished like the scope was before writing.

Hopefully, although it's not finished before putting a thread together unlike the scope build. I've been on with this whilst doing the scope builds so its been a bit of a slog! Yet to start the scope wood work but that's another thread although won't be as long as the last one ;-)

Cheers Stu, hopefully you'll get to see it by the end of this year!

Fingers crossed, Unfortunately Rich I'm battling a turned edge? It's taken a week up to now and its steadily moved outward although I think I'm hitting a bit of a brick wall as it doesn't seem to be changing now? Not sure if it's the slight warp on the table thats caused it?

Cheers Calv Notice you added the word "when"! I'm getting there but it's slow going as I'll get to in the thread

Hi Ron I was initially aiming for F3.9 but as I'll be detailing later this changed to nearer F3.7 It's an ambitious goal but with time and dedication its steadily progressed. There have been plenty of ups and downs

Hi all, I began this journey way back in Oct 2013 so it has taken a while to get to where I am at present but thought it about time I put my experiences down. Wanting a larger scope than the 8" I had and after discussing with my good friend Rich (Crashtestdummy) we both decided to find out about mirror making. There is a mine field of information out there on the subject some of which is useful but not much in the way of practical experience except what I'd read about on here (Rustysplit 14" and Rick M 20") So when a seminar was advertised on SGL by Glasspusher we both decided to book in and attend. As many know Glasspusher is John Nichol and he took us through a little bit of history on himself and mirror making in this country which is sadly not as prolific as it used to be, his experienced friend Jack also popped in to talk of the many years he'd spent at Grubb Parsons ( ) . After an informative and enjoyable few hours with John we left with thoughts of big bits of glass and lots of work ahead (I mean lots) On returning it took us a couple of weeks to decide what size we were going to go for. Hunting for a glass supplier in this country leads to Spectraglass in Scotland and Rich ordered the two 22" blanks. Here's one with a cup for size! The blank was 44mm thick and weighed in at 22kg! There was a small defect near the edge which I decided would be the back Whilst waiting I'd put together a couple of grinding tables so we could make a start To make a start I had to bevel at 45 degrees the edges of the blank to about 5mm with a carborundum stone. Each side took an hour! On a blank this size it is important when you turn it over you lift it completely or roll it on something flat. I didn't initially and caused some shelling of the surface. This would later be ground off but valuable lesson learnt. Next was to flatten the back with the 80 grit carborundum. This was done using a steel ring about 12" in diameter. It was quite nerve racking due to the blank having concentric rings on the face I was flattening so each time it skipped over these really does not sound nice This took 11 hours in total so quite a while. I tested as I went with a straight edge and finally finished with 220grit although I think John is convinced I used 400grit as it's really smooth Total grit usage up to this point was 2.5kg 80 grit and 0.1kg of 220grit. The blank had also lost weight, just under 1/2 kilo and 2mm from it's thickness so was 42mm. Turning the blank over I then made a start on the curve generation using a barbell weight of approx 11". Damian

Good to read an update and looking forward to seeing the new lap. Damian

Completed my new lap today Crash so hopefully it will polish the centre out after a good press. Damian

Nice to have another entry from you Rich. You've had a bit of a rough ride with the health lately. I'm looking for definite at a new lap as it's down to less than 2mm on the edges. I'm at about 12 hours polish but due to the lap thinning the contact has been poor so it is hazy in the middle but getting better. Looks like I'll be making the trip up to see John to hopefully acquire some more pitch just hope he's got some? On another note the aluminium for the scope truss poles is sat in my lounge ready for the scope builds. I have also ordered the focuser so tin itch to start the builds is getting nearer Just wish I was a little nearer the end of the mirror Hopefully your MoJo and health will return soon as mine as you know has had it's big ups and downs Damian

Still very much alive and being taught by those that don't want our history to disappear

I had the 25, 15, 8 and 5mm BST's and for the balance of price and views I think they're very hard to beat and a fantastic upgrade to the standard eye pieces that come with most scope's. Well designed and as you say extremely comfortable to use. I was using them in an 8" F5 newt. Some have said the 25mm is the weakest of the range I found it nice to use. Highly recommended from me

Shame that Rich. I need to send some Ronchi images to John see how he thinks mine should progress? I am thinking of ordering the ply and truss poles for delivery next week fella so will be able to make a start on the dual build so I'm sure you'll have the mirror sorted before its finished! Damian

Nigel Not sure if you've got confused but Rich like myself is doing a 22" mirror. Mine is definitely under polished and 2hours of long centre through strokes today has helped a little Damian

Heres the scratches and a bit of reflection I mentioned fella

Firstly nice bike fella and well done on the job front down there, it looks like you'll be well away on that I wish I could ride to work but its a proper set of dangerous roads to get to my place of work. Back to the grinding and nice to chat on the phone and work out where I've been picking up the silly scratches from. It's nice to finally see some polish on the surface and the blank nearing the final stages. I think your under estimating the progress you've made up to now Rich as not just anyone could get to where you or both of us are now (me with my scratches and chip and all that!) As you say it has helped both of us doing it at the same time as there have been plenty of times when morale has been lacking but we've kept at it. Well done up to now and be nice to eventually have the scopes finished and side by side, but will like all three together eventually just for a few photos as it will be the only time they'll ever be together. Keep up the good work and riding as its a great pass time I'll be able to throw the mountain bike in too now!