while grinding. Use a tool sharpening stone, wet it with water, and grind at 45 degrees, around the disc, A 2 mm bevel is enough Making a tile tool "In the old days" it was usual that a mirror kit is delivered with 2 glass blanks. One as the mirror, and the other as the tool.

Making a telpe mirror. To start, a new mirror blank is "sanded" down to create a precise parabolic curve in a process called grinding. To do that, the blank is paired with a device called ...

small mirrors, plate glass will work fine too. Telpe mirrors are relatively thick. The concave shaped face is made by repeatedly ... There may be a very thin film of plaster over some the tile faces, this will grind off in the first few grinding sessions. ...

Welcome to my channel - in this video, we will begin to make a telpe mirror from scratch! I'll be showing you the basics of telpe mirror grinding!Her...

Mel Bartels, a well respected west coast amateur, recommends on his Large, Thin Mirror Grinding web page starting with something between 30 and 60 grit, and then 120, 220, 500 (=25 micron) and finishing with 9 micron. This is just a 5 grit sequence, as opposed to 8 to 10 for the more traditional sequences usually recommended for novices.

A mirror mount is needed to hold the mirror during testing. If the mirror is a 'thin' mirror (i.e. the thickness is much less than 1/8th its diameter) then the mount must hold the mirror without deforming it. The weight of the glass can deform a thin mirror. In my case, I was making a full-thickness mirror, which is a mirror whose thickness is 1/8th the diameter or more, so mirror …

Thin Telpe Mirrors . Abridged from an article appearing in Telpe Making #12 Provided: Courtesy of Astronomy Magazine Article's Author: Bob Kestner . Part I - Grinding . For many years, amateur astronomers and telpe makers thought it essential that glass for telpe primary mirrors be at least one-sixth as thick as its diameter.

Still grinding your own mirror is a key skill that makes you a real telpe maker. To grind a telpe mirror by hand you simply attach a glass tool the same size as your mirror blank to the top of a small, strong stand. You apply grinding compounds to the …

Grinding an 8″ F/10 Telpe Mirror – gordtulloch. Grinding an 8″ F/10 Telpe Mirror. For this project (my first time ever grinding a mirror) I ordered an 8″ Black Vitrified Ceramic (BVC) blank without a pregenerated curve from ASM Products in Ste-Basile PQ. Ordering from Canada is always cheaper once you factor in all the taxes ...

Any mirror that is less than 6:1 thick is referred to as a thin mirror. Thin mirrors cost slightly less, weigh less, and cool down quicker. But they are much more susceptible to problems with ground in astigmatism and distortion due to support in the telpe unless additional precautions are taken.

THE AMATEUR TELPE MAKER Conducted by ALB E R T G. IN GAL L S W E ... the mirror, constituted our grinding ma­ ... A piece of thin sheet melal was mounted as a band around part of the mirror's circumference. One end of …

Showing grinding work on a super-fast 10" F2 telpe mirror. Gordon shows fine grinding by hand using the powered turntable.

Page 1 of 3 - Thin Mirrors - Enabling Technologies - posted in ATM, Optics and DIY Forum: Hello everyone, Im considering grinding a thin mirror. Im just curious what the Diameter/thickness limit is in the ATM world. Is the limiting factor the actual manufacture of the mirror, or supporting it in a telpe? Im hoping to stir up a bit of discussion on the …

Welcome to King Telpes Not an impressive website. However, we are not in this for a profit. Our intent is to provide a source for lower cost, mirror blanks, and supplies for grinding your own telpe mirror. If I had known as a kid how, well not easy, but indeed not as hard as I would have expected to grind my own mirror.

Grinding and Polishing a Meniscus Mirror. In many respects, the grinding and polishing stages of fabricating a thin meniscus telpe mirror are not different from any telpe mirror. There are lots of resources, online and in print, describing that. This article will focus on the specific issues introduced by working on such a mirror.

Making a telpe mirror. ... over the mirror by hand while the mirror rotates on the grinding machine. ... Techno-Fusion mirrors feature an open central structure consisting of two thin glass ...

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 …

FORCE When grinding thin mirror blanks, be conscious of downward pressure, which if excessive, may bend the mirror blank momentarily out of shape. While this is not a problem during rough grinding (as the amount of flex is exceedingly small) the effect becomes important as you reach the later stages of making your telpe mirror.

The problem with thin mirrors is that they flex more easily during grinding and polishing, making it hard to achieve the required surface precision. They also need a more complex mirror cell (additional support points). Plop is a useful software to let you calculate the number of points needed based on the diameter and thickness of the glass:

spin grinding a slumped mirror - posted in ATM, Optics and DIY Forum: so after taking a few years off from the hobby to get my wife well i have completed my spin grinder and am ready to tackle the 14 honeycombed mirror that you see as my avatar i had it fused to shape many years ago and it is slumped to an F5 curve. i have not used a spin grinder as yet all my …

Thin Telpe Mirrors . … I can buy it easily and get all the starting work done on diamond-grinding machines – something most of you don't have access to. Mirror grinding machine – Hack a Day. ... Telpe mirror grinding machine Mirror making and optical testing … The images below show the completed grinding machine in it's new ...

Mirror-O-Matic grinding machine. When I decided in 2009 after a ten-year break to get into mirror making again, it quickly became clear to me that I would need to construct machine, as hand grinding big mirrors is not something very beneficial for the hands of a musician.

In this video I am showing you how to make a DIY telpe mirror! This is the second part in the series, showing fine grinding in a step by step tutorial.

All blanks test Buy mirror blanks for telpe making,Purchase Mirror Blanks; Grinding Thin Mirrors; Contact Us; New Discount Items; Purchase telpe mirror blanks here. We provide 6 inch, 8 inch, 10 inch, and 12 inch telpe mirror blanks in standard 3/4" thickness, and larger mirror blanks up to 20 inches in 1" thickness.

The first phase of rough grinding my 8.5 inch Pyrex disc into a telpe mirror. Including beveling the edges, measuring sagita (central depth), and grindin...

Telpe Mirrors, Blanks, Secondaries, Grinding Materials, Testers, Aluminising, Making Advice Information. ... Fused silica between thin blanks supports the mirror and also keeps the weight to a minimum. ... per kilo $40AUD Tin oxide grinding powder per kilo $30AUD Pumice grinding powder per kilo $30AUD 80 Grade grinding powder per 8" mirror ...

The design must also account for back focus distance or the distance from the primary mirror to the focus plane behind the telpe to accommodate the focuser, star diagonal, and eyepiece. Considering the primary mirror focal length, the shortest, or fastest focal ratio generally accomplishable by an advanced ATM is f/4.

I know it is bordering on the edge of extremely thin with a 32:1 thickness ratio but it is possible as John Dobson has been known to successfully grind a 24" mirror 3/4" thickness. We have decided on an F/6 with a .25" sagitta it allows .5" center thickness.

For a discussion on the fabrication of thin mirror blanks please refer to the following article in: Kestner, Bob, "Grinding, Polishing and Figuring Thin Telpe Mirrors, Part 1 - Grinding", Telpe Making 12, Summer 1981, pp.30 -35.

Now that I have several blanks made, it is time to grind and polish one into a telpe mirror and test it out. I can use one blank as the mirror and another as the grinding tool, and have a couple in reserve in case something goes horribly wrong during the grinding and polishing operations. I'll post an update once a mirror is completed.