Author Topic: Granite surface plate  (Read 12351 times)

Offline Joules

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Granite surface plate
« on: September 28, 2016, 06:24:16 AM »
Spent some more of my hard earned....  Since I have the mill conversion on the go I thought I would treat myself to a new granite surface plate.   Boy have prices come down at the low end of the market.  I got a 12" x 9" for well under £50 from ROTAGRIP.   Just given it a clean and added 3 cork pads under the stone where marked.  I know it should be sat on points but its sat on my flexable wooden desk.



OK Chinese granite 3" thick, some other outfits are selling 2" thick plates for more...   It's a nice slab of rock and should takes ages to suck  :lol:

My old granite tile can now be used as a lapping plate.  On a side note, since I have been doing a lot of blueing and using the computer, my keyboard started to turn oily blue.   After a quick clean the solution was to wrap cling film over it.  Easy to wipe clean or swap when its all gone Yuck, but clean keyboard underneath with no dross working its way under the keys.  Just got the streaky blue old iPad to sort out now.
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Offline DavidA

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Re: Granite surface plate
« Reply #1 on: September 28, 2016, 07:49:52 AM »
I also have been thinking of getting a surface plate. I do have a carefully milled cast iron plate that I use for the purpose, but it obviously isn't near enough flat to be called a surface plate.

I have been looking at some granite plates, but will probably finish up getting a traditional (but new) cast iron plate as I need something a bit bigger than the one you depict.

It's a hard choice these days.

And how do you ensure that the plate (either kind) is actually plane to within a few microns ?

Dave.

Offline Joules

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Re: Granite surface plate
« Reply #2 on: September 28, 2016, 08:19:04 AM »
Dave they do bigger granite surfaces, this was about as heavy as my desk would take.  They have an 18" x 12" that took my fancy.  The thing about the granite is none marking and more importantly, none rusting surface.  I may add the 18" x 12" to the workshop bench at a later date, and replace the pink granite worktop that sits there now.

http://www.rotagriponline.com/index.php?option=com_virtuemart&page=shop.browse&category_id=201&Itemid=29

Not sure how long they are on offer for.  It comes with a report but I don't really have a way of testing it, 1.3 microns rise in the middle of this plate apparently.
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Offline DavidA

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Re: Granite surface plate
« Reply #3 on: September 28, 2016, 08:57:05 AM »
1.3 Micron.  I could live with that.

The idea of a granite plate is very appealing. 12" X 18" would be about right.

I'll have a look at the site.

Thanks,

Dave.

Offline DavidA

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Re: Granite surface plate
« Reply #4 on: September 28, 2016, 09:11:11 AM »
Well, I did it.  For the price it is hard to resist.

And the carriage isn't too bad considering the weight.

And so begins the endless quest for better precision.

Dave. :thumbup:


Offline lesterhawksby

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Re: Granite surface plate
« Reply #5 on: September 28, 2016, 01:09:59 PM »
Another advantage of granite. If a clumsy idiot like me stands near a granite surface plate and drops a hard object that bounces onto it, the resulting small chip only subtracts material, it doesn't raise it. So you get a tiny area that is damaged, but very little reduction of the overall utility - if you only do it the once. (Verified by experiment  :doh: ).

Whereas with an iron plate, a ding or dent is quite likely to have a raised bit around it, that you have to stone flat, and then there is a larger patch of plate you'll never really trust again. (Thankfully not verified by experiment on a surface plate, but definitely happens to iron).


RobWilson

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Re: Granite surface plate
« Reply #6 on: September 28, 2016, 02:39:55 PM »
They are cheep Joules .


I may have to treat myself to one  :dremel:


Rob

Offline Will_D

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Re: Granite surface plate
« Reply #7 on: September 29, 2016, 05:08:55 AM »
These threads are getting as dangerous as the ones on our homebrew sites:

Yet another piece of shinny ss kit or worse still a new digital brew controller thingy!

At least in the machine shop we are not getting "and links via blue tooth to your smart phone so you can machine or monitor your cnc from the comfort of your arm chair or nearest pub"

Or do I jest too much? ?
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Offline Joules

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Re: Granite surface plate
« Reply #8 on: September 29, 2016, 05:48:16 AM »
Toooo much Will, none of your Bluetooth rubbish, it's full blown Wifi with streaming video and head accelerometer to detect tool load, collision or tool breakage.  The machine can email the pub and make sure your pie and pint are at the bar, whilst monitoring your progress to the pub via your phone gps....    Now that's what I call service.

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Offline DavidA

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Re: Granite surface plate
« Reply #9 on: September 29, 2016, 06:46:21 AM »
Will,

You have to look at the acquisition of a granite surface place as long term investment.

And when you die you can have it engraved and use it as your tombstone. A cast iron one will rust away.

How about that for dual-function.

Dave.

Offline Joules

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Re: Granite surface plate
« Reply #10 on: September 29, 2016, 06:52:32 AM »
 :lol:
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Offline tom osselton

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Re: Granite surface plate
« Reply #11 on: September 29, 2016, 02:36:36 PM »
I can see that!!

        Here lies Johnny
        Loving husband
          Loving father
        Cheap bastard

 :lol:

Offline Joules

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Re: Granite surface plate
« Reply #12 on: September 29, 2016, 02:48:13 PM »
Jeez Tom, they charge by the letter...

    RIP J
 
Will do, I spent all the money on granite.
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Offline tom osselton

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Re: Granite surface plate
« Reply #13 on: September 29, 2016, 03:13:40 PM »
Well if you are going cheap there is the air chisel or if really cheap just a piece on scrap iron and a rock!
If they charge by the letter go with Ocupied or In use.
 You can always sell the scrap!

Offline krv3000

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Re: Granite surface plate
« Reply #14 on: September 29, 2016, 06:21:49 PM »
hi rob watt happened to the one that wanted grinding flat

Offline Will_D

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Re: Granite surface plate
« Reply #15 on: September 29, 2016, 06:25:10 PM »
Will,
You have to look at the acquisition of a granite surface place as long term investment.
And when you die you can have it engraved and use it as your tombstone. A cast iron one will rust away.
How about that for dual-function.
I love the logic here!

So as I am 6' 3" and 100 kg as my auls mum used to say, "if you're going to have one have a big one"

I'd best order a Big One!

On the same vane of thought:

Anyone have an e-bay link for "shrouds with pockets"

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Offline Pete W.

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Re: Granite surface plate
« Reply #16 on: September 30, 2016, 05:29:06 AM »
Will,

You have to look at the acquisition of a granite surface place as long term investment.

And when you die you can have it engraved and use it as your tombstone. A cast iron one will rust away.

How about that for dual-function.

Dave.

Best to check the local regulations.  My mother is buried in the churchyard in a Dorset village.  There were definite regulations regarding gravestones, marble and granite were not permitted.  I was offered the choice between Portland stone or Purbeck stone - as the latter had recently doubled in price because planning regulations prevented quarries from increasing in extent, Mum lies beneath a Portland stone marker. 
Best regards,

Pete W.

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Offline Joules

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Re: Granite surface plate
« Reply #17 on: September 30, 2016, 06:53:09 AM »
I'll be kept in the freezer till November 3, then done on the bonfire on the 5th, granite surface left on embers the following day, sorted....

A load of ally and iron swarf and whats left of the lathe oil should get the temperature up.  Bonus being it will have that authentic workshop smell as it all burns, and they can play doubleboost out takes   :thumbup:
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Offline mcostello

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Re: Granite surface plate
« Reply #18 on: September 30, 2016, 03:46:14 PM »
If anyone would see My tombstone the "cheap" part would be expected without needing it carved in. Anything else and they would think it is someone else. :beer:
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Offline awemawson

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Re: Granite surface plate
« Reply #19 on: September 30, 2016, 05:53:01 PM »
I have a friend with a BIG post hole borer - I'm going to be set standing up in a hole on the farm  :lol:
Andrew Mawson
East Sussex

Offline tom osselton

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Re: Granite surface plate
« Reply #20 on: October 01, 2016, 12:08:56 AM »
I'm not sure I'd want to spend eternity standing on my feet! A nice recliner maybe or the loo!

Offline smiffy

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Re: Granite surface plate
« Reply #21 on: October 01, 2016, 03:54:32 AM »
There is a grave on the top of Boxhill  a famous landmark in Surrey where an eccentric Victorian  man is buried standing on his head

Offline tom osselton

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Re: Granite surface plate
« Reply #22 on: October 01, 2016, 12:18:35 PM »
They probably didn't realize the " This end up sticker had shifted!"

Offline Will_D

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Re: Granite surface plate
« Reply #23 on: October 01, 2016, 04:39:40 PM »
Reminds me of a very old graveyard joke.

The headstone was leaning over at an angle so the family pulled it back with some straining wire.

Next day two people walking past, one said "He always was a posh B'tard, now he's gone and had a telephone installed!"

That joke is © about 1960!!
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Offline DavidA

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Re: Granite surface plate
« Reply #24 on: October 18, 2016, 05:45:05 PM »
Well, the surface plate arrived; all 32 Kilo of it.

According to the spec sheet the greatest error is 0.7 Micron.  I make that about 0.039 Thou"

Am I right ? Having a Senior calculating moment.

It's still a whole lot flatter than the cast iron table I was using. I'll relegate that to assembly plate duties.

Dave.