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Rob; hey just checkin to see how the grinding went last night, but hey also a question....do you do Stellefane???
Id think your 10 inch refractor would win a prize easily??

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First...the grinding went very well last night..pretty smooth surface..with just about an inch of edge that I am addressing today. Once I get the edge ground...I will run the tool back across the entire mirror surface to even the curve up........

Currently I have it working the edge with about a 1/3 overhang. That pulls the worked center and mid zones to the edge...finalizing the sphere.

I'll make sure I'm happy with this grind before I even think about changing grits. It usually takes about 1/2 of a Coke bottle of grit to get the job done....

Funny...now I'm down to making determinations based on Coke bottle volumes.. Is it half empty or half full.....

Rob

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www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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Funny...now I'm down to making determinations based on Coke bottle volumes.. Is it half empty or half full.....

Rob

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Depends....on if you've had a bad day or not,lol.

bad day= half empty
Good day= half full.
if its half empty, youll move on to the next grit, if its half full you might not,I hope its half empty...

Keep checking your video web page thingy too.Watch the 12.5 being ground and pretend its the 13inch...
Pretty much look the same Im guessing.

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12 inch Truss Reflector "John"
102mm Celestron C102HD " Carl "
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT "Wilma"
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.


60mm Telescope Club

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Are US pennies all copper? Canadian pennies were till it was switched to copper plated steel then copper plated zinc. Wouldn't want different types of metal on a tool?

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Right on...That is one thing I'm quite sure of. If I'm have older pennies I use them...younger..I use them.

I throw Canadian pennies away. I NEVER mix-n-match pennies.

Copper or Zinc. Then I always glue them down back up...or face down. I never permit them to be face or back at the same time. They work swell...and are the cheepest thing to use. The last 13" tool I made had less then a dollars worth on it. Try to beat that with glass tiles.....You can't. Plus they are smaller and adapt to the curve faster.

I like-em

Rob

--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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Funny...now I'm down to making determinations based on Coke bottle volumes.. Is it half empty or half full.....

Rob

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Depends....on if you've had a bad day or not,lol.

bad day= half empty
Good day= half full.
if its half empty, youll move on to the next grit, if its half full you might not,I hope its half empty...

Keep checking your video web page thingy too.Watch the 12.5 being ground and pretend its the 13inch...
Pretty much look the same Im guessing.

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Yeah..pretty much...I'm hurting too bad to spend much time on it today...I'll give it a rest for a day or so.

I was thrown from my horse yesterday. Dumb thing is barn bound...so after an hour of working her I decided to take her for a quick run through the field and up the drive to the main road. The GRAVEL drive passes right by her corral...well as we were clipping along(about 20~25 miles an hour)...she decided to quickly bolt to the corral gate....Well I went flying off.. head first(like a bullet) onto the gravel driveway. I protected my hands and tucked and rolled..but proceded to remove all the skin off my back/butt, both knees and both elbows.

I became unconscious...and my daughter(who was rinding with me) had to revive me about 4 times. I then woke up and in sever pain drug my shredded body to the house.

I was bleeding pretty good but had no broken bones..just a bruised kidney. The worst part was allowing them to WASH the rocks from each searing...intense cut.... Mommy!

After gettin home from the ER.....I went back out and got back on her and rode hor for another half hour.

It is very important you get back on after a serious spill....to calm the horse and yourself.

I couldn't sleep last night(you could imagine). Today..I am so sore with deep contusions (bruised kidney)..I look like a Devil.

I have never been thrown from a horse in my life...and I was raised with them.

So please be patient with me as I hobble around to do ANYTHING......I need meds now. Talk to you later.

Rob

--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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get some rest, take some good meds...lol.
Several years ago, I tryed to learn to ride a motorcycle, my cousin had an old 850 kaw, he let me ride it down a dirt road with a dead end blockade, got ot the end of the road and hit the back brake ,aint one, hmm he did'nt mention this, so I paniced and yanked on the front brakes, layed the bike down , drug my right leg , did I mention I was in shorts and deck shoes, for about 20 feet, missed smashing my head into the baracade bye ohhh 6 inches, angry as all get out, I picked it up, did I mention it was still running, stuck my bare leg on the hot muffler pipe, did I mention my bare legs??, ok, right leg has road rash bleeding all over, left leg now has a second degree, at least , burn on it, I road it back to my cousins house,in first gear and dropped in in his yard, and never got on a motorcycle again.
I wish Id had some one to tell me, "you gotta get back on Andy" ....

Just so you know I feel your pain, or ok well I did once.

Thanks for video, Ill watch it when I get home from work.

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Oh yeah..I failed to mention I was wearing a *T* shirt and shorts myself.....I hurt so bad....

I learned to ride a motorcycle when I was 8....I still ride.
Dirt bikes...of course.

The video should be up soon.

Rob(did you see I got my objective for my 10"f/15?)

--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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Rob(did you see I got my objective for my 10"f/15?)

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coooool

--------------------
12 inch Truss Reflector "John"
102mm Celestron C102HD " Carl "
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT "Wilma"
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.


60mm Telescope Club

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We rode ponys bare back as kids and teens.Had my share of barn door meets head,lol. Been kicked, stomped on , etc.One pony liked ot bite.

Rob ,coool video......now that was grinding I take it.How long does it take ot smooth out that edge???

I use something similiar to your polisher at my job.Only it makes em as flat as possible so I can look at the metal at 400x for microstructure work.

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Well..always remembering that we are after a sphere...the tool ...even though it is contoured to the sagitta of the mirror..you are still going to have zones initially...this meaning..parts of the mirror surface will polish out faster then other parts...ie..the center and about 2/3 from the center to the edge. It is all a matter of tool placement and stroke. Last night after I finished(after about 7hrs of grinding)..I have a pretty good beginning. The edge(IN machine polishing) tends to take extra care to pull in.

I ran the table fast last night and had lots of edge stroke...today..I'll slow the table down and focus my stroke(shorter too) on more of the 2/3 zone. Meaning..I'll grind out the slight donut that the inital grind created.

It's all about working all the zones to form a perfect sphere. We're also working the tool as well.

Wonce we put in ample time to form the tool agains the mirror..we can begin to work the sphere more accurately.

OH..one last thing. when we initially grind in the curve..it isn't necessarilly a perfect sphere..to being with.

Grinding the tool and mirror together FORMS the sphere.

Rob(sore..but I'll be at it today again)

--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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see if you stayed in the house all the time and di nothing even remotly dangerous you wouldnt be in pain now.....lol

Of course thats totally no fun

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Right! BEen working on the 13" today and have been grinding for some 4 hours..working on several zones to bring the sphere into completion.

Just about done with a full Coke bottle of grit......Whooohooo..

I'll check the mirror and see where we are at...and make any stroke changes then. We're getting there....


Rob

--------------------
www.goldmtobservingcenter.com
A great place for amateur astronomers, and ATM's to come and enjoy their hobby.

http://tech.groups.yahoo.com/group/HomemadeRefractorTelescopes/ My homemade refractor group.

www.vimeo.com/6014031

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