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# rough grinding mirror

### Joy of Mirror Making: Rough Grinding - BBAstroDesigns

31 行  2020-5-19  Rough Grinding The first milestone is putting a curve into the mirror face. The curve's depth dictates the mirror's focal length. The curve should be spherical. Creating the curve can be done by several methods: The curve is ground into the mirror face using a grinding tool. The curve is pre-generated for you.

### ROUGH GRINDING THE MIRROR -

2020-5-7  The rough grinding usually digs a depression in the center of the upper disc which gradually deepens and spreads toward the edge of the disc. It is a fairly simple matter, by regulating the extent of overhand, to arrange to have the curve on the mirror face reach its proper depth just as the edge of the ground out area reaches the edge of the blank.

### Rough Grinding of a Telescope Mirror Guy's Math

2014-12-15  One way: do about 8 circular strokes. Then center the mirror on the tool. Turn the lower piece of glass to the left by about 15 degrees (1 hour on a normal clock face); then turn the upper piece of glass about 10 more degrees. Then grind away for 8 more circular strokes.

### Stellafane ATM: Rough Grinding

Rough grinding is often called "Hogging Out", as your goal is to remove the majority of the glass needed to form the curve of your mirror. It is not particularly elegant work, being the noisiest and messiest part of the whole mirror making process. GOAL: You have

### - WOS - Wenk Observatory Solutions

2020-7-24  Rough Grinding When delivered, the mirror blank should be square on both sides. In the process of Rough Grinding one side gets the the desired sperical curvature using an abrading medium (silicon carbide) and a very simple grinding tool.

### Help ! rough grinding 16" mirror - ATM, Optics and

2014-7-13  Help ! rough grinding 16" mirror - posted in ATM, Optics and DIY Forum: Hello, Grinding a 16 blank, plate glass....I am currently 5/8 - 3/4 from the outside edge using a ring tool (7.5 lb. barbell plate, by hand) around a 55 gallon drum. I would like to get 1/4, or

### Mirror grinding - scope making

2007-2-13  Make 7 more strokes, rotate the mirror 60 degrees clockwise, and the tool 20 degrees clockwise. Don't think in degrees, nor numbers, just spin it randomly. Rough grit breaks up quite fast, You will know that the grit is used up when the loud , crushing

### Fast Mirror Grinding Polishing - The ATMs Workshop

2001-11-15  Rough grinding operations are most effective when the coarse grit rolls between the tool and the glass causing a fracturing of the surface. My grinding wheel method kept the grit from easily rolling under the rough textured tool. Secondly, the

### How to Build a Telescope - IUCAA Scipop

2016-4-6  Depending on the weight used, the technique, the grit etc. the rough grinding of a mirror 12.5 cm ï¿½ 20 cm diameter can be completed in 2-5 hours (with 12-15 wets per hour). 2.6 Fine grinding and smoothing. Once the rough grinding has been completed the mirror, tool, work plate etc. should be thoroughly scrubbed and cleaned using soap solution and an old tooth brush for example.

### ROUGH GRINDING THE MIRROR -

2020-5-7  The rough grinding usually digs a depression in the center of the upper disc which gradually deepens and spreads toward the edge of the disc. It is a fairly simple matter, by regulating the extent of overhand, to arrange to have the curve on the mirror face reach its proper depth just as the edge of the ground out area reaches the edge of the ...

### - WOS - Wenk Observatory Solutions

2020-7-24  Rough Grinding When delivered, the mirror blank should be square on both sides. In the process of Rough Grinding one side gets the the desired sperical curvature using an abrading medium (silicon carbide) and a very simple grinding tool.

### Mirror-o-Matic

2015-4-5  Rough Grinding. Rough grinding (hogging out) is the first stage of grinding performed on a new flat blank and tool. The purpose of rough grinding is to generate a ‘dish’ in the center of the mirror. This dish is deepened until the correct radius of curvature (R.O.C.) is produced.

### Help ! rough grinding 16" mirror - ATM, Optics and

2014-7-13  Help ! rough grinding 16" mirror - posted in ATM, Optics and DIY Forum: Hello, Grinding a 16 blank, plate glass....I am currently 5/8 - 3/4 from the outside edge using a ring tool (7.5 lb. barbell plate, by hand) around a 55 gallon drum. I would like to get 1/4, or 1/8 from the edge, if possible. Any tips or tricks ??? Prayers ??? ...

### Mirror grinding - scope making

2007-2-13  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 ...

### Fast Mirror Grinding Polishing - The ATMs Workshop

2001-11-15  More than that range warrants curve generation, less is adequately handled with the normal ring tool grinding methods. Mirror Polishing Techniques . After grinding the back of my 17.5" blank flat, I decided to polish it to make the detection of pits on the front surface easier.

### Stainless steel processing: from rough sanding to

2009-11-10  Stainless steel processing: from rough sanding to mirror polish. 10 November 2009. ... customers can choose from two stainless steel sets while there are six sanding polisher sets for grinding, satin-finishing and polishing. FEIN’s pipe sanders and straight grinders and GRIT belt grinders round off the stainless steel range from FEIN.

### Large Thin Mirror Making - BBAstroDesigns

2012-7-3  Preparation before grinding. Throw rough grit around the rim of the mirror, wet it down, grab a piece of metal, and grind in a nice rounded bevel 1/12" wide. Do this for the back side of the mirror also. As grinding proceeds, maintain the bevel.

### Hubble Error: Time, Money and Millionths of an inch

2011-1-17  mirror’s performance. However, the Teacup Affair had cost Rigby another six weeks. A year had been allowed for the rough grinding in Wilton. The mirror had been scheduled for delivery to the Danbury plant for fine polishing in early September 1979; it didn’t arrive until late May 1980.

### Stellafane ATM:Mirror Making Myths

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 "hill" in the center) and ...

### ROUGH GRINDING THE MIRROR -

2020-5-7  The rough grinding usually digs a depression in the center of the upper disc which gradually deepens and spreads toward the edge of the disc. It is a fairly simple matter, by regulating the extent of overhand, to arrange to have the curve on the mirror face reach its proper depth just as the edge of the ground out area reaches the edge of the ...

### - WOS - Wenk Observatory Solutions

2020-7-24  Rough Grinding When delivered, the mirror blank should be square on both sides. In the process of Rough Grinding one side gets the the desired sperical curvature using an abrading medium (silicon carbide) and a very simple grinding tool.

### Help ! rough grinding 16" mirror - ATM, Optics and

2014-7-13  Help ! rough grinding 16" mirror - posted in ATM, Optics and DIY Forum: Hello, Grinding a 16 blank, plate glass....I am currently 5/8 - 3/4 from the outside edge using a ring tool (7.5 lb. barbell plate, by hand) around a 55 gallon drum. I would like to get 1/4, or 1/8 from the edge, if possible. Any tips or tricks ??? Prayers ??? ...

### Mirror-o-Matic

2015-4-5  Rough Grinding. Rough grinding (hogging out) is the first stage of grinding performed on a new flat blank and tool. The purpose of rough grinding is to generate a ‘dish’ in the center of the mirror. This dish is deepened until the correct radius of curvature (R.O.C.) is produced.

### Mirror grinding - scope making

2007-2-13  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 ...

### Newport Glass Works, LTD. Grinding, Polishing and

2014-7-21  Rough Grinding . Once you have the back of the mirror ground flat through 220 and the face reasonably flat, you're ready to start roughing the curve into the mirror. I recommend #60 carborundum for rough grinding. By the way, as in all optical work, be sure that you always maintain bevel on the edge of the mirror throughout grinding.

### Ed Grinds a Mirror - scopereviews

2002-1-25  -Ed 5/29/00) Chapter One: Rough Grinding, May 28, 2000 I arrived on a cool Sunday afternoon in May, and started grinding with five other club members in a local barn. Right away, there was pressure on me; I had missed the first two-hour grinding session and everyone was well ahead of me on the coarse (80) grit.

### Astronomy: Making a Mirror - El Camino College

In order to achieve a desired focal length, it is necessary to periodically measure it during rough and fine grinding. An easy way to measure the focal length is to let the sun reflect off the mirror and measure the distance from the mirror to the image of the sun as shown below.

### Stainless steel processing: from rough sanding to

2009-11-10  Stainless steel processing: from rough sanding to mirror polish. 10 November 2009. ... customers can choose from two stainless steel sets while there are six sanding polisher sets for grinding, satin-finishing and polishing. FEIN’s pipe sanders and straight grinders and GRIT belt grinders round off the stainless steel range from FEIN.

### Issues with Rough Grinding - ATM, Optics and DIY

2021-1-27  Issues with Rough Grinding - posted in ATM, Optics and DIY Forum: Hi, I am in the process of rough grinding a 12.5 diameter x 1.5 thick F6 mirror blank that I cast myself in a kiln and need some help/advise. I am using a 9 diameter tile tool (see pic below) mounted to a patio block, 60 grit silicon carbide and spinning (TOT) at about 50 RPM.