Surface Plates - Granite

[EmilioG]

I've been researching and looking up various surface plates for a height gage datum.
The prices range from high to low, new and used.
Is it better to buy a new granite surface plate that is less expensive or a good used one, like a Starrett
or DoAll ? I only need a small one, maybe 12 x 12 or 12 x 18. I make small parts and need a good
level surface to take measurements. Would I also need to be an angle plate to rest the parts against when
scribing and measuring? I thought I would only need a height gage, but like most tools for machining, you buy one thing
then quickly realize that you need several other accompanying tools! Please advise, thanks.

 

[darkzero]

Well for home shop/hobby use, IMO a cheap one is fine, even if it's grade B. But if you can score a Starret or other high name brand for a great price then go for it. Although I already have a small surface plate, I watch CL often for surface plates. Often they go for cheap cause people want to get rid of them, the larger they are, generally the harder to sell them cause moving them can be an issue. I even see huge ones go for dirt cheap but don't move cause many home shop guys can't move them or have space for them.

I have a 12x18 grade A (well import) that I'm happy with. I got it from Enco when they used to run sales on them, $37 & free shipping (the same p/n costs $115 now!). I would like something bigger but I really don't have the room for. If I do find a bigger one for cheap I'll make room. But the 12x18 has been fine for me for a while now but I don't need it for anything large, not yet anyway.

 

[george wilson]

I lucked out and got an Accupro cheap. I also have 2 USA granite squares and a granite straight edge,USA. For work,I bought a Chinese granite square. Surprisingly,it checked out pretty well with my expensive American made one. Even a blind pig finds a truffle sometimes!!

 

[EmilioG]

Thanks.
What are the ledges for? I see that some have a ledge or a step. Can you clamp things to a surface plate?
Are they fragile? Can they be refurbished?

 

[Holescreek]

Ledges are for clamping.

 

[darkzero]

I assume the ledges are just for lifting purposes. Mine is 80lbs so that's not something you would want your fingers caught under when placing it down on it's resting place. I suppose the ledges could be use for clamping but I would think the lifting/hand safety purpose is more appropriate.

 

[Uglydog]

I wanted a plate that could use for my 48inch camelback.
Found this 36"x36" on a factory stand on CL for $100.
The guy just wanted her gone. ASAP.
New she was probably .0005.
I can still see the scraping marks in the center, so she's not quite worn through.

Point is identify what you are looking for and try to wait patiently.
Something is likely to pop up!
Eventually.

Note, the pic makes it look like the photo is on it's side.
Reality is that all the weight has caused the garage floor to shift.


Daryl
MN

 

[Holescreek]

[h=2]SURFACE PLATES[/h] STANDRIDGE granite surface plates provide an accurate reference plane for work inspection and for work layout. Their high degree of flatness, overall quality and workmanship also make them ideal bases for mounting sophisticated mechanical, electronic and optical gauging systems. The size and capacity of our modern facility allows us to manufacture to nearly any custom requirement.

All of the granite we use has been carefully measured to establish the modulus of elasticity, allowing us to comply and exceed federal specifications and user requirements.

Our granite surface plates are manufactured in three ledge types as well as standard sizes and grades.
Plates that have ledges are used for clamping purposes only.

Clamping. Of course it is nice to not crush your fingers too.

 

[Terrywerm]

Note, the pic makes it look like the photo is on it's side.
Reality is that all the weight has caused the garage floor to shift.


Daryl
MN

So now your mill and lathe are hanging above your head, right?? Kinda hard to reach that way aren't they??? :lmao:

 

[chips&more]

I have a Starrett 24” X 36” with threaded holes in the top surface. At first, I thought the holes would be more problematic than for their actual intent. But I was wrong, I use the threaded holes for many applications and I wonder now how I would do anything without them. You may also want to think about get a plate with threaded holes in it…Good Luck, Dave.