Making A Mirror Grinding Tool By Allen Malsburry The average person would never think, I can make my own telescope. Most amateur astronomers believe, I can buy a better telescope than I can build. Neither is actually correct. For many decades now, amateur astronomers have been building their own telescopes.
Grinding On the picture below the machine is fine grinding an 8 inch mirror with an 71% tool (143 mm diameter) and 9 micron aluminium oxyde. The bent lines on the mirror are the effect of the tool turning - with respect to the mirror - faster at the central part of the mirror as compared to the edge zones.
I borrowed a few ideas from the Mirror-O-Matic mirror grinding machine, particularly how to mount the turntable on top of the pulley. Anyone building machinery for cold-working glass should have a look at the MOM web site and plans. There are lots of good ideas there. The large wood circle will become the base of the turntable.
Mirror grinding machine construction log I started thinking about building my own mirror grinding machine several years ago. Having been on the ATM list now since almost the beginning of it here on the web, I had lots of of inspiration reading of others projects and viewing their webpages
Sep 26, 2006 Grinding and polishing your own mirrors is a long, arduous process. Instead of lapping the blank by hand, Laurie Hall built this mirror grinding machine from scratch.
MIRROR GRINDING MACHINE. I made my first mirror grinding and polishing machine over thirty years ago. It used the working principle of the machine illustrated at A Fig.3, Page 163, Amateur Telescope Making Book 1. A bowl which rotated was fitted to the spindle. I also built another machine of the same type.
Oct 13, 2019 Re Building a fixed post mirror grinding machine. Update summary Lots of work to get to this point. Things I need to probably change or fix My gearing of the DC motor. I will need a slow speed for polishing (5 rpm), and faster speeds for hogging out and fine grinding (15-
Sep 20, 2019 Once I generate the curve on a mirror blank I switch to my fixed post machine and I can usually complete grinding the whole mirror in about 4 - 5 hours. Thats starting with 80, 120, 220, 320, 25. 12, 5, 3, 1. Polishing usually takes anywhere from 4 - 6 hours and thats allowing time for pressing, lap maintenance, etc.
Nov 01, 2011 Basically there are two types of grinding/polishing machine. The traditional type which involves the mirror rotating at a relatively slow speed, a few rpm for a big mirror (16-20 inches) with the tool moving across the mirror, from side to side, at a higher rpm depending on the size of the mirror and/or tool.
To control the shape of your mirror, you will have to use or build your own tools. A tool commonly used is the Foucault tester also known as knife-edge test. It is easy to build from materials available at the hardware store. A Ronchi screen is also a time saver tool. More complex tools such as
The mirror machine came to me as a result of astronomical horse-trading, swapping a large GEM mount and a 8 Newtonian OTA for the machine as it was and a start kit consisting of two 6 blanks and the grit, rouge and pitch to manufacture a mirror. The grinding machine had been built to the design of the mirror-o-matic design of Dennis Rech ...
In addition, a great deal of money will be saved a finished 24 scope will set you back $7,000 grinding your own mirror and building the mount yourself will cost you $2,000. Amateurs have made mirrors up to 41 by hand. A grinding machine relieves the labor, but is not necessary. A 24
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Mar 06, 2006 Making a homemade mirror grinding machine - posted in ATM, Optics and DIY Forum I want to make a motorized mirror grinder , any good info on this , i have a couple geared motors , low speed high torque. One more question ...will 1 1/2 shaft size pillow block
Aug 19, 2019 Re Building a fixed post mirror grinding machine. I I had a nice piece of 3/4 stainless dowel that was begging to be used. So I bought a cheap pillow block to provide the locator for the metal dowel, and then drilled the overarm to fit. These pillow blocks are $8 and come complete with a locking collar - great deal.
George Willis Ritchey built this mirror grinding machine at the Yerkes Observatory in Williams Bay, Wisconsin, in the late 1890s. Under the sponsorship of George Ellery Hale, the machine was used to grind a series of telescope mirrors starting with a 24-inch and then a 60-inch mirror for a telescope initially intended for the Yerkes Observatory.
Howdy, I am going to be joining the ranks of retired people on 12/31,and I am thinking about grinding another mirror. My first mirror is an 8/f5 that was done by hand. Since then I had to have surgery on my right shoulder,so I am wanting to build a grinding machine.
Apr 30, 2021 SkyBadger The mirror machine came to me as a result of astronomical horse-trading, swapping a large GEM mount and a 8 Newtonian OTA for the machine as it was and a start kit consisting of two 6 blanks and the grit, rouge and pitch to manufacture a mirror The grinding machine had been built to the design of the mirror-o-matic design of Dennis Rech.
Mirror-o-Matic was designed to be a very low cost astronomical mirror grinding, polishing and figuring machine. Its attributes are 1. It can be built for somewhere between $200 and $400. 2. It is constructed of hardware store items and it needs no machined parts. 3. It is constructed primarily of 3/4 inch plywood and has few close tolerances. 4.
Grinding a Mirror For it is true that astronomy, from a popular standpoint, is handicapped by the inability of the average workman to own an expensive astronomical telescope. It is also true that if an amateur starts out to build a telescope just for fun he will find, before his labors are
Grinding the secondary is just like grinding any other optic except in minature. I ground the secondary with the mirror on a workstand and worked the tool on top just like I would grind a larger mirror. This optic is small enough that a lens grinding machine could work well.
This is why you dont want to make mirrors to be worked on machines too thin. For 16 to 18 mirrors, 1.62 thick is the thinness I would recommend. There are several ways to support the mirror on a grinding and polishing machine turntable, but first make sure the turntable itself is rigid.
Products/Services for Parabolic Mirror Grinding Machines. Grinders and Grinding Machines - (984 companies) Grinders and grinding machines use an abrasive that is bonded to a wheel, belt or disc to remove material and improve surface finish. Devices can be pneumatically driven or
I finally decided it was time to build a machine to help me grind the edges of the blanks true and round. This is my home-built edge grinding machine for grinding down my home-cast mirror blanks. Click to see the whole project. This is a 12.5 inch diameter, 1.5 inch thick, light-weight honeycomb-back telescope mirror blank that I
Parabolic-mirror-grinding machine. Applications Claiming Priority (1) Application Number Priority Date Filing Date Title US86695214A US1171174A (en) 1914-10-16 1914-10-16 Parabolic-mirror-grinding machine. Publications (1) Publication Number Publication Date ...
A local machine shop would finish a 1 shaft and 1/2 steel plate for $115. Covington Covington Engineering Corp., P.O. Box 35, Redlands CA 92773 lapidary machines and supplies will sell me a 12 tapered iron plate for $163, a 1 shaft with bearings for $90 and a whole kit of
Large Thin Mirror Making by Mel Bartels. Grinding Machines. Mirror-o-matic. Tom Waineos Desktop Grinding/Polishing Machine. Ken Liljas Grinding Machine. Grinding Machine. Figuring. Figuring a Paraboidal mirror by thermal predistortion. Optical Testing.
I want to make a machine to grind a 20 mirror. If I remember rightly, I circled the circular bench every 10 mins or so (motion A), and each back and forward stroke took say two seconds (motion B). Motion (A) just repositioned the stroke, and motion (B) did the work. To make a motorised machine to do something similar would be fairly easy.
A good starter size is the 150 mm (6) mirror. A 200mm (8) will also work. Most ATM books and websites recommend a Pyrex mirror blank, but in my opinion, annealed plate glass is better for this first, learn and practice mirror.It is cheaper, it is softer and grinds faster, needing less abrasives and with these small sizes, the low expansion glass like Pyrex has no practical (visible at ...
With the Mirror on top, the tool on the bottom, and coarse grit in between, we start grinding with the mirror overhanging the tool. We rub the center of mirror against the edge of the tool, and this wears a depression in the center of the mirror (the edge of the tool wears down also, so that the tool becomes convex (a
Nov 06, 2020 telescope mirror grinding machine. Build Your Own Telescope, Mirror-O-Matic grinding machine When I decided in 2009 after a ten-year break to get into mirror making again, . Get More mirror grinding machin - ATM, Optics and DIY Forum, Get Price.