granite dresser tops for a surface plate or for lapping?

Savarin it happens that i have a good interest for optomechanical measuring devices.May be we have to open a
new thread for discussing these.I am a little confused with the new software and i don't know how to open.So you are burdened with
this difficult task taking the opportunity to present your projects,including photos of course.
Waiting impatiently
Ariscats
 
My knowledge level is minimal so please keep that in mind. I went the Craigslist route and bought a Starrett 24" x 36" x 6" "A" Grade with Starrett table for $400. It required ten hours of driving to get it home. I purchased mine from an electronics design company. The engineer I spoke to said that when the company formed, the lead engineer they hired insisted they buy the plate. The engineer went on to say that they never purchased any other measuring equipment as they used CAD and sent the designs out for prototype work. It was certified about eight years ago. I couldn't see any marks or blemishes on the plate. A friend has a mold shop nearby so I stopped by on the way home where he checked it out and said that with the measurements he could do, the plate did seem to be unused.

I watched eBay and Craigslist for about two years before running across this ad. I must have been lucky that day because they said I called within ten minutes of the ad going up. I was thinking of going the countertop route but kept hoping I would run across a real plate that I could afford. Time wasn't a big factor for me as I am still gathering equipment from a list I started two years ago when I decided I wanted to start a machinist hobby in my garage.

Regards.

Bob
 
MARVIN GARDENS said:
My knowledge level is minimal so please keep that in mind. I went the Craigslist route and bought a Starrett 24" x 36" x 6" "A" Grade with Starrett table for $400. It required ten hours of driving to get it home. I purchased mine from an electronics design company. The engineer I spoke to said that when the company formed, the lead engineer they hired insisted they buy the plate. The engineer went on to say that they never purchased any other measuring equipment as they used CAD and sent the designs out for prototype work. It was certified about eight years ago. I couldn't see any marks or blemishes on the plate. A friend has a mold shop nearby so I stopped by on the way home where he checked it out and said that with the measurements he could do, the plate did seem to be unused.

I watched eBay and Craigslist for about two years before running across this ad. I must have been lucky that day because they said I called within ten minutes of the ad going up. I was thinking of going the countertop route but kept hoping I would run across a real plate that I could afford. Time wasn't a big factor for me as I am still gathering equipment from a list I started two years ago when I decided I wanted to start a machinist hobby in my garage.

Regards.

Bob
Click to expand...
Well done Marvin.I was driven to the counter top solution because in Greece a good plate is absurdly expensive,probably because of the weight.Have fun
with your's.
Ariscats
 
ariscats said:
Savarin it happens that i have a good interest for optomechanical measuring devices.May be we have to open a
new thread for discussing these.I am a little confused with the new software and i don't know how to open.So you are burdened with
this difficult task taking the opportunity to present your projects,including photos of course.
Waiting impatiently
Ariscats
Click to expand...


Hi Ariscats,
My current project is here http://www.hobby-machinist.com/threads/80mm-long-focal-length-refractor.26212/
but I never made the lenses.
The next one will be the 12" binoscope where I will grind and polish the glass and will show the equipment in that blog when I start it.
What I find so astounding is that a simple measuring system made with a couple of really cheap overflow store micrometers and some scrap can measure such tiny amounts. The magnet holds the razor blade or Ronchi screen, the wheel holds 6 different coloured led's, (I wondered how different wavelengths would affect the readings) the two stages are controlled with the micrometers and the peep hole/screen plate moves up and down via a long thread.
Test3L.jpg
I may build a Bath interferometer to test the 12" mirrors but as I am polishing to spherical then flexing to final shape its not really needed as a simple null for the sphere should be sufficient.
 
savarin said:
Hi Ariscats,
My current project is here http://www.hobby-machinist.com/threads/80mm-long-focal-length-refractor.26212/
but I never made the lenses.
The next one will be the 12" binoscope where I will grind and polish the glass and will show the equipment in that blog when I start it.
What I find so astounding is that a simple measuring system made with a couple of really cheap overflow store micrometers and some scrap can measure such tiny amounts. The magnet holds the razor blade or Ronchi screen, the wheel holds 6 different coloured led's, (I wondered how different wavelengths would affect the readings) the two stages are controlled with the micrometers and the peep hole/screen plate moves up and down via a long thread.
View attachment 97329
I may build a Bath interferometer to test the 12" mirrors but as I am polishing to spherical then flexing to final shape its not really needed as a simple null for the sphere should be sufficient.
Click to expand...
I went through your project with great interest.The tensioning elements in the tripod ringed a small bell in my memory.Are you building boats too?
Ariscats
 
I was at an Auction 2 weeks ago and they had an inspection plate they were trying to auction off.
I believe it was 8" thick 36" x 48" on a very sturdy steel stand.
The owner said it was .0005 accurate and weighed 1200 lbs.
I could have got it for $50 but had no way to move it as it had to be out by end of day.
 
roadie33 said:
I was at an Auction 2 weeks ago and they had an inspection plate they were trying to auction off.
I believe it was 8" thick 36" x 48" on a very sturdy steel stand.
The owner said it was .0005 accurate and weighed 1200 lbs.
I could have got it for $50 but had no way to move it as it had to be out by end of day.
Click to expand...
Can you send it to Greece By Airmail Parcel Post and i will send to you $50 LOL
 
Sure thing ariscats, LOL
I know the Auctioneer as he did my father's auction and he kept trying to get me to bid on it because he knew I work with wood and metal in my shop.
I told him I would take it if he could get it loaded into the back of my truck. I could get it unloaded no problem at the house.
Needless to say, it did not sell. Even at the ridiculous low $50 bid.
 
You must log in or register to reply here.
Back
Top