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Re: [ATM] General questions before getting starting on a 6F6.
Mike,
You mentioned that I should use a glass tool for my first mirror. How
critical is this recommendation?
The reason I ask is that I would like to gain some experience with the
hogging tool and tile tool techniques on a smaller mirror. I hope to
then use that experience later on a 10 F6 (or possibly faster) mirror.
Thanks,
-Anthony Anconetani
> -----Original Message-----
> From: atm-bounces@atmlist.net
> [mailto:atm-bounces@atmlist.net] On Behalf Of Mike Lockwood
> Sent: Monday, March 19, 2007 11:13 AM
> To: ATMList
> Subject: Re: [ATM] General questions before getting starting on a 6F6.
>
> Anthony,
>
> Anthony Anconetani wrote:
> > Mike, I stumbled onto your website from GotGrit. I really
> like your 10
> > F5.5 design. I hope to build something similar once I have a little
> > more experience. Anyway, from the first part of your Mirror Musings
> > page, here are some questions:
>
> Thanks. I was going to sell the 10" F/5.5, but it's so
> darned lightweight and fun to use that I may not.
>
> > You comment that one should read at least two other pieces of
> > literature, I've read Berry's book and I'm planning on purchasing
> > Texereau's from Willmann Bell. Do these seem like a
> complete selection?
> > I've noticed some things seemed to have changed over the years. For
> > example steel hogging tools and tile tools versus glass tools. Is
> > there a more recent text that I should consider?
>
> Those are what I started with. Combined with web resources,
> you should do fine. Just realize that Berry is not an
> optical expert, and Texereau is now a bit dated in terms of
> materials. We generally use aluminum oxide instead of emery,
> and cerium oxide polishes faster than rouge. We also use
> tile tools for pregenerated blanks, and when glass tools are
> too expensive.
>
> > I'm surprised that one would need to grind the back of a mirror and
> > tool to 320. How much extra 80, 120,180, 220 and 320 should
> I plan on
> > ordering for a 6 inch mirror?
>
> Grinding the back flat is most important on larger, thinner mirrors.
> With a 6" blank it's sort of optional, since the mirror cell
> will be a simple 3-point cell, and a rough mirror back will
> not cause too much problem. It's a nice touch if you have a
> flat tool.
>
> If you get a grit kit, you should have plenty of extra
> abrasive to do some work on the back, if you decide to.
>
> > I'm planning on doing the initial hogging with some kind of
> steel item
> > (I don't know what yet...) and then switching to a tile
> tool. Should I
> > plan on fine grinding the back of the tile tool? How well
> does dental
> > stone on the back of the tool hold up to direct grinding? Does the
> > tool need to go to 320?
>
> Really, I'd recommend two glass disks for this first mirror.
> The back of a tile tool will not work for grinding against
> the back of a glass disk. You'd have to make another tile tool.
>
> I guess I need to clarify my article a bit for this case.
> (It has changed from a figuring page to one with figuring and
> grinding advice.)
>
> > What are generation marks in a blank?
>
> Marks from using diamond tooling to make the blank concave.
> Saves a lot of work (and grit) on big mirrors.
>
> > And lastly, I took your advice on United Lens. They we're a really
> > nice bunch of folks. I look forward to seeing the blank.
> And I hope I
> > get a chance to send them more business.
>
> UL is great. If they haven't shipped your order yet, add another 6"
> disk to it for a grinding tool.
>
> Mike L.
>
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