# Surface plate support quick question



## expressline99

I just read in an excerpt from a early 1900's book that it's best to support your surface plate in a 3 point configuration. The part I read didn't go into any detail at all about what this was about. So is this valid or a typo? I'm sure it was referencing cast iron plates. (I think.)

Paul


----------



## MonkMan

*Found this on Rock of Ages site.

SURFACE PLATE SUPPORT*
In accordance to GGG-P-463c, Rock of Ages insures accurate readings of surface plates by supporting the plate properly on three support points.  Three points are preferred and are located 1/5 the length and width from the ends and sides. Three supports are used because it is the only way to consistently support a surface plate object without the weight shifting from one leg to another.  Any attempt to use more than 3 points may cause the plate to receive its support on various combinations of three points and the plate will settle differently and possibly deflect out of tolerance.

Rock of Ages provides various options for supporting surface plates:


stationary stands with leveling screws
stands with casters
stands with casters and leveling screws
All models with casters come with wheel locks as standard. Any working height can be specified to meet your application need.

- See more at: http://www.rockofages.com/en/industrial/products/surface-plates/#sthash.zSMXeVRf.dpuf


----------



## ewkearns

expressline99 said:


> I just read in an excerpt from a early 1900's book that it's best to support your surface plate in a 3 point configuration. The part I read didn't go into any detail at all about what this was about. So is this valid or a typo? I'm sure it was referencing cast iron plates. (I think.)
> 
> Paul



A plane is defined by three points, therefore is much easier to level. Personally, I would think one would find a surface plate on casters less useful than one carefully leveled and stable.


----------



## Tony Wells

Read up on Airy and Bessel points. It explains why.


----------



## Rustrp

ewkearns said:


> A plane is defined by three points, therefore is much easier to level. Personally, I would think one would find a surface plate on casters less useful than one carefully leveled and stable.



Given the weight and it's setup location, a surface plate on casters may expedite shop projects. Level isn't the primary purpose of a surface plate, although having one set up in the level position seems to jump out as important. My concern would be the possibility of it getting tipped over and damaged.


----------



## ewkearns

Rustrp said:


> Given the weight and it's setup location, a surface plate on casters may expedite shop projects. Level isn't the primary purpose of a surface plate, although having one set up in the level position seems to jump out as important. My concern would be the possibility of it getting tipped over and damaged.



Yeah, in my downsized shop, I'm looking at casters for a LOT of things, but I'm going to arrange them such that I can have a hardened point leveling the [_whatever_] against the floor.


----------



## Rustrp

ewkearns said:


> Yeah, in my downsized shop, I'm looking at casters for a LOT of things, but I'm going to arrange them such that I can have a hardened point leveling the [_whatever_] against the floor.



In many of the carts and movable frames I've fabricated I like the foot operated brake  that has about 3/4" of travel to use on the caster side of the table.


----------



## expressline99

So is there a possibility of tipping on a 3 point stand? I'm considering a 24 x 24 plate.  Probably the heaviest thing I would put on it would be 30-60 pound cross slides.


----------



## ferlum

Tony Wells said:


> Read up on Airy and Bessel points. It explains why.



This.

Also, I came across this recently, shows some configurations the OP might find useful (including examples of the three support points).

http://www.precisiongraniteusa.com/pdffiles/5502.pdf


----------



## ezduzit

On a small surface plate I wouldn't worry about 3-point mounting. And I likewise wouldn't worry about it tipping, using a 3-point mount, as long as there was a full support surface just beneath the 3 points. Mine is 12" x 18" (IIRC) and sits on a rollaway cabinet.


----------



## Rustrp

expressline99 said:


> So is there a possibility of tipping on a 3 point stand? I'm considering a 24 x 24 plate.  Probably the heaviest thing I would put on it would be 30-60 pound cross slides.



Three legged milk stools have been around a long time. 

As *ezduzit* stated, the support for the three points would be the important factor. Most of the signage I've seen on the work benches or carts in machine shops always detail a **DO NOT** preceeding a list, with some type of physical harm done if said action was ignored. I think by the very nature of the surface plate being a precision tool, logic says we treat it with care. With that said; I stopped using "Would you treat your tools that way?" years ago.

I've seen plenty of surface plates supported on work benches and carts. I don't think I would be inclined to place one on a three point stand. Many websites show the plate inset into or surrounded by a protective frame to prevent a **what if**. My experience in fabrication is the employee struggle with when to use a level versus a square. It isn't necessary for the plate support to be precicely level, just structurally sound.


----------



## expressline99

This is all great information thank you guys.
Paul


----------



## tertiaryjim

I would think a cart should have a frame slightly larger than the plate so the plate couldn't bump anything as it's rolled around.
You could still mount the plate on three points with a square or rectangular frame and support the frame with four wheels.


----------



## todd774

Rustrp said:


> Given the weight and it's setup location, a surface plate on casters may expedite shop projects. Level isn't the primary purpose of a surface plate, although having one set up in the level position seems to jump out as important. My concern would be the possibility of it getting tipped over and damaged.




Leveling could be an important factor if you what to do some static balancing. As with 2 knife edge straight edges.


----------



## Rustrp

todd774 said:


> Leveling could be an important factor if you what to do some static balancing. As with 2 knife edge straight edges.


Yes it would, but if the intent was to facilitate timeliness in a machining project(s) to save steps back to the surface plate, it isn't likely related to static balancing. There's multiple tasks where a surface plate needs to be level.


----------



## todd774

I suppose you could seat the knife edges on 4 posts. 3 of which are adjustable. 
 The reason I even mentioned it was because I just very recently purchased a surface plate. I was thinking of how I should mount it. While planning it out in my  head I realized I could 
Balance Harley Davidson fly wheels with that kind of set up. My original purpose of purchasing the plate was to scrape the ways of a cheap Chinese milling machine.
Mine will also be on a heavy duty cart with casters.


----------



## expressline99

Static balancing... well it's gone over my head again. lol


----------



## Rustrp

expressline99 said:


> Static balancing... well it's gone over my head again. lol


Imagine a round rod placed in the mounting hole of a lawnmower blade so you can tell which side needs to be ground down to balance the blade. Something requiring more accuracy might be the stone/wheel for a surface grinder. Static balancing would be the least expensive way to check for an out of balance condition, but it's also a quick way to answer a vibration question. e.g. vibrating bench grinder.

PS. Okay, I just assumed you had balanced a lawnmower blade, or that you had lawn that needs mowing.


----------



## Rustrp

todd774 said:


> I suppose you could seat the knife edges on 4 posts. 3 of which are adjustable.
> The reason I even mentioned it was because I just very recently purchased a surface plate. I was thinking of how I should mount it. While planning it out in my  head I realized I could
> Balance Harley Davidson fly wheels with that kind of set up. My original purpose of purchasing the plate was to scrape the ways of a cheap Chinese milling machine.
> Mine will also be on a heavy duty cart with casters.



I did chuckle. I imagine a guy sitting on a Harley thinking; Hmmm, maybe my flywheel is out of balance.


----------



## todd774

If ya think about it, if you didn't know better the first time you sat on a Harley you'd probably say:
 "Hmmm, maybe my flywheel is out of balance. Maybe I need a surface plate"


----------



## Dabbler

All of the higher end Standridge stands use two adjustable elevator bolts, and two more on a rocker arm, making the leveling as per a 3 point system, but supporting on all 4 Bessel points.  For long term flatness, the surface plate (especially large ones) need to be supported equally on all 4 Bessel points. (.2204 from the edges, as I dimly recall)


----------



## expressline99

Dabbler said:


> All of the higher end Standridge stands use two adjustable elevator bolts, and two more on a rocker arm, making the leveling as per a 3 point system, but supporting on all 4 Bessel points.  For long term flatness, the surface plate (especially large ones) need to be supported equally on all 4 Bessel points. (.2204 from the edges, as I dimly recall)



>.2204 from the edges... are you a suspect for photographic memory? 

So after re-reading all this is it a yea or nay for 3 points? It sounds like on the large plates (3'x3' Or bigger?) that they need 4. At the largest I would have a 3' x 3' . I just wonder at what width or thickness would it start to flex, twist or distort. If I'm using it to scrape small ways my wooden workbench might not be where I want to set this thing up. I know my garage floor is bowed like >insert anything you want here< . I know I won't have a Harley in there.  So I guess I'm still up in the air on this.  Then it gets back to will I ever get my work to a level quality that would require this amount of OCD in advance.  Perhaps!

Paul


----------



## ddickey




----------



## Dabbler

I have 3 surface plates, and here's what I'm doing with them:

-  an 11"X 9"X2.5" (unknown grade) from China - used only as a bench plate, for lapping only. supported by bench. stored in a drawer.
- a 12"X18"X3", (B grade) - just unmounted it from its stand, because I'm reusing the stand. It will be mounted on 3 points, just because it's easier.
- a newly acquired 18" X 24" Mitutoyo A grade plate.  see below...

... first a short story: I have a friend that bought a Mitutoyo AA grade surface plate in the 36 X 48  X 5 inch size - and mounted it using the 4 corners...  After 36 years, it has dropped about .006 in the centre.  It is now worse than a shop grade plate.  I wouldn't take it if he gave it  to me.

So being a little OCD and/or anal-retentitive (yes it _does_ have a hyphen BTW), and because I'm not from Standridge Granite I am mounting my new surface plate on a rolling Tool and Die cart, also recently acquired, which is made of 10 gauge pressed steel.  The plate will be mounted using 4 Bessel points with a pivot...

The best advice I can give to you is that if you are mounting it on a non-movable table, make the feet of the table adjustable so ti is properly supported( so the table won't twist) . No use twisting your surface plate for the lack of 1$ worth of leveling bolts.  If it is on a moving base, the your plate's sub-base must be overly rigid, so as to support the plate properly.  No matter what, the plate has to ber very rigidly supported to maintain calibration.

3 or 4?  your choice - if your manufacturer won't commit, I'd use 4.  If you go with a Standridge 24 X 36, they explicitly say use 3 because they calibrate them that way.  I hope this is more helpful than confusing,...


----------



## expressline99

ddickey said:


>


This guy is great. I'm surprised he wasn't on my subscribed to list. 
Paul


Dabbler said:


> I have 3 surface plates, and here's what I'm doing with them:
> 
> -  an 11"X 9"X2.5" (unknown grade) from China - used only as a bench plate, for lapping only. supported by bench. stored in a drawer.
> - a 12"X18"X3", (B grade) - just unmounted it from its stand, because I'm reusing the stand. It will be mounted on 3 points, just because it's easier.
> - a newly acquired 18" X 24" Mitutoyo A grade plate.  see below...
> 
> ... first a short story: I have a friend that bought a Mitutoyo AA grade surface plate in the 36 X 48  X 5 inch size - and mounted it using the 4 corners...  After 36 years, it has dropped about .006 in the centre.  It is now worse than a shop grade plate.  I wouldn't take it if he gave it  to me.
> 
> So being a little OCD and/or anal-retentitive (yes it _does_ have a hyphen BTW), and because I'm not from Standridge Granite I am mounting my new surface plate on a rolling Tool and Die cart, also recently acquired, which is made of 10 gauge pressed steel.  The plate will be mounted using 4 Bessel points with a pivot...
> 
> The best advice I can give to you is that if you are mounting it on a non-movable table, make the feet of the table adjustable so ti is properly supported( so the table won't twist) . No use twisting your surface plate for the lack of 1$ worth of leveling bolts.  If it is on a moving base, the your plate's sub-base must be overly rigid, so as to support the plate properly.  No matter what, the plate has to ber very rigidly supported to maintain calibration.
> 
> 3 or 4?  your choice - if your manufacturer won't commit, I'd use 4.  If you go with a Standridge 24 X 36, they explicitly say use 3 because they calibrate them that way.  I hope this is more helpful than confusing,...



Unreal how multi-million year old granite moves in a few years. This does help me quite a bit. I'll have to buy some really ridged box tubing to weld up once I select a plate. I've got a lot of measuring equipment to purchase going forward. Seems the surface plate is the base point for being able to measure with accuracy. 

Being as new to it as I am I've got a long way to go. Since there is never an end to the learning on this topic I think I've picked the perfect hobby.

Paul


----------



## Rustrp

expressline99 said:


> Being as new to it as I am I've got a long way to go. Since there is never an end to the learning on this topic I think I've picked the perfect hobby.



Yes there is! Door #3 has a tunnel with an infinite length filled with infinite cubby holes just waiting for someone to say; "I didn't know that." 

Now, I'll say I was with him up to the point where he puts a beam on the third support. I still think we get stuck thinking **level** when all we are really striving for is flat. The plate is certified (if it is of certifiable quality) and it needs to be supported so there's no force or tension on any specific point.  I don't think there's been proof that a plate supported on three points ends up with to of the corners drooping. I think if we replace the word support with suspend we arrive where we need to be. 

With that said, I wouldn't want the workbench or support to be out of level to a point where things roll off the plate.


----------



## Tony Wells

I think if I ever get room and need for a larger plate, I will build a heavy stand with leveling feet, just because it may have to move some time in the future.....never know. But I will build the top as a tray and fill it about an inch deep with self leveling floor compound. That stuff seems to flow out really nicely and should give even support. HOWEVER, the catch is that there is no guarantee that the top and bottom of any plate are parallel, nor that the bottom is actually flat. But if I time it right and sit the plate in the compound just before it sets up, then I would have virtually 100% contact and therefore support for the entire plate. It wouldn't matter so much if it weren't perfectly level at that point, as I would adjust it with the feet. It doesn't have to be level, but it sure is nice at times to have a known level surface. And I mean really level, so close I could use it (to a degree) to calibrate levels. Like the one I'm about to build as soon as I talk Ken into scrounging me a piece of nice, aged CI.


----------



## ezduzit

TW--that is bound to fail as changes in the mounting surface will impart stress on the surface plate. If that were a workable solution, the big guys would be using it already.


----------



## expressline99

ezduzit said:


> TW--that is bound to fail as changes in the mounting surface will impart stress on the surface plate. If that were a workable solution, the big guys would be using it already.



OK to take this a step beyond this.  Could you mount the surface plate support system in a way that it would be stabilized and protected from vibration. Much like they earth quake proof buildings? Almost in a stiffened rubberized mount that would take the stress or any expansion of the bench material?


----------



## Rustrp

expressline99 said:


> OK to take this a step beyond this.  Could you mount the surface plate support system in a way that it would be stabilized and protected from vibration. Much like they earth quake proof buildings? Almost in a stiffened rubberized mount that would take the stress or any expansion of the bench material?


There's no such thing as an earthquake proof building. 

....but we do keep trying.


----------



## expressline99

Rustrp said:


> There's no such thing as an earthquake proof building.
> 
> ....but we do keep trying.



Oh I know. I lived over there in the 90's and early 2000's. It's more of a let's try to over do it comment. At 10 Richter scale nothing survives.  Probably much lower down the scale even.


----------



## Tony Wells

Actually I worked with a company near me that had a design that used a cross meshed array of pure Boron wires that functioned as bearings under each column supporting the building. The idea was to allow the foundation piers to move around while the building slide around on the bearings allowing the inertia of the building to keep it more or less stationary.

And as far as all the "big guys" using it, they don't always go for the ideal solution due to cost constraints. That and ease and speed of installation. And of course people are creatures of habit, so once a method is established, it can be hard to change. I'm not saying that method would be perfect, but I think I see some advantages to it.


----------



## Dabbler

There are very good reference works on surface plates and mounting them.  If you  'fully' support the bottom by potting it in the floor compound, it will not be as per the calibrated accuracy.  If you only care about thousands, and don't mind your plate being a few thousands out, then got for it!  A good surface plate (not shop grade) will be locally accurate in tens of millionths of an inch, and over the entire surface in tenths of a thousand of an inch.

I am trying to answer the question -correctly-, there are a lot of ways to 'make do'.  A pivot is on one side of the plate to ensure that all four contact points have exactly the same pressure on them.  This way the plate will experience minimum flex if they are on the 'Bessel' points. I prefer to build once, the best I can, so I don't have to do it over.  Oh and yes, an improperly supported plate will flex and you can see it on a tenths indicator.


----------



## Ulma Doctor

Tony Wells said:


> Actually I worked with a company near me that had a design that used a cross meshed array of pure Boron wires that functioned as bearings under each column supporting the building. The idea was to allow the foundation piers to move around while the building slide around on the bearings allowing the inertia of the building to keep it more or less stationary.



(sorry OT)
i worked on a crew doing a few seismic retrofit projects.
on one job in San Francisco at the PG&E building, on Market St, i was out there for eight months.
we took a 17 story building and one at a time chopped out a 6' hunk out of the base of each column and inserted seismic vibration dampening devices , kinda like giant hockey pucks.
the work was the most interesting stuff i have ever been a part of.


as far as supporting your surface plate on 3 points, it's a sound principle and i use the method myself


----------



## Tony Wells

Dabbler, I was only thinking out loud and rambling. I'm a firm believer in following the Federal guidelines for mounting plates. I've been around them quite a while and some large enough to park cars on. And even cases where more than one plate had to be aligned with another accurately enough to be used as one. I'm very familiar with them. 

If one were to be bedded/potted, it would have to be lapped back into flatness specs anyway since that's not how it was held for manufacture, and I doubt temp variations in an average shop would let you get away with it to any great precision. A cleanroom maybe, but since there are established support standards that everyone accepts, that's what should be used. They all move when you load them anyway, it's just a matter of how much and whether it makes it possible to maintain the desired accuracy. I've done some testing with instruments on plates with and without loads and found that they move more than most people probably think.


----------



## Dabbler

Tony,I misunderstood your previous post as a recommendation - I apologize for sounding heavy-handed.  The friend in my above comment is a highly skilled toolmaker that ignored the recommendations that you endorse.  It is all too easy to follow the recommendations, if a little picky.

I agree that if you do an alternative, some recalibration will be required.  I've heard of aligning plates to use as one, but have never seen it in any shop I've worked.


----------



## Tony Wells

It might make for an interesting experiment someday, if I get the instruments again. I kind of doubt it, but in an odd sort of way it makes a bit of sense to me to give it 100% support and have it lapped. I may shoot an email to a couple of old friends and see what they say about it. Obviously it's nonstandard, but there is something nagging in the back of my mind (where it probably ought to stay) that if you used some high durometer/Shore RTV about 1/2" thick to set the plate in, it would spread any load over a larger area than the standard points. I know for a fact that if you load the corner on the single pad end of a plate, it moves the entire plate. It would seem to me that there would have to be a positive effect to have some support under the whole plate. Setting it in while the potting is still setting would prevent uneven pressure from underneath, so how could it not help? What am I missing?

But, I'm just rambling again.


----------



## Dabbler

If you were to try the potting experiment, it would be vital that the foundation under the RTV would support the RTV evenly as well...  Perhaps a network of vertical ribs?


----------



## Tony Wells

Well, yes and no I think. That's where I get a little unclear about it. Since the objective would be to distribute the weight away from the typical 3 (or 4) points, you would have to gain some ground on how much the plate distorted under load by spreading the weight. It would definitely be different from needing a strong support under a single one of the 3 (or 4) points. In my mind, a reasonably heavy steel plate with perhaps 4 equally spaced angle, channel or I-beam cross bars would be needed, depending on the size of the plate, of course. I could see that quickly the construction complexity and expense would exceed the normal approach. What I am mulling over is whether it would actually be superior in any way. I'll have to keep thinking about it. 

And then there is another angle. Instead of "soft" (relatively) RTV, use something self leveling, but pourable, like concrete or maybe just portland cement. Sort of like grouting in a machine. That wold give 100% support, conform to the underside of the plate, and not be very flexible. 

Mentally,  I may be simply trying to get around using soft supports on the common points, knowing that they do allow some weight driven distortion.  The obvious answer is to just get a thicker plate.


----------



## Dabbler

I once found a 'free' surface plate on the internet....  > 2000 miles away, weighing 12t.  --but it was 16" thick!  Of course I passed.  Having had a little experience in ferrocement boats, concrete flexes more than you might think.  Perhaps a solid concrete base, say 30" high?  Now that would be rigid!


----------



## Tony Wells

Yeah, shop planning would become paramount. Kinda tough to move a plinth like that. 

Oh well, I just enjoy metal exercise and hypothetical situations.

That "free" one would not have stayed free when you hauled it!


----------



## Dabbler

What about upgrading a good plate by using RTV to support it with an old worn out or cheap shop grade plate?  Doubling the thickness will halve the deflection, no matter how it is supported.


----------



## ezduzit

Dabbler said:


> What about upgrading a good plate by using RTV to support it with an old worn out or cheap shop grade plate?  Doubling the thickness will halve the deflection, no matter how it is supported.



This is about the only way I see to make the bedding idea (possibly) work. Otherwise the surface plate is being used to try to stiffen an inferior structure. But it would likely create an even bigger problem with the 2 bonded plates acting as bi-metals and each warping the other from thermal changes.


----------



## Tony Wells

Seems you'd need to use a powdered granite epoxy slurry to bond them, and scarify top and bottom. By the time you went through all that you could probably buy a nice, thick Starrett pink


----------



## Dabbler

touche.


----------



## projectnut

Most cast iron surface plates come with a 3 point bearing pads.  I have 2 surface plates, a 10"x18" no name, and a 24"x36" Challenge.  Both have 3 load bearing points built in.  Here's some text from the Challenge Precision website concerning their cast iron surface plates:

"Three point surface plates provide a precise reference surface for tool making, layout, or checking the accuracy of other surfaces. The three point bearing pads and rigid ribbed construction permit support by less accurate surfaces without disturbing the surface
accuracy. Wooden cover supplied with each plate."

  Here's a link to the Challenge Precision cast iron surface plates:
http://www.challengeprecision.com/products/plates/threepoint.htm

The 24"x36" plate came from our machine shop at work.  It weighs 475 lbs.   It has spent it's entire 50+ yearlife on an angle iron stand with a 3/4" plywood top.  You would have to run into the stand with a fork lift or Mack truck to tip it over


----------



## expressline99

projectnut said:


> Most cast iron surface plates come with a 3 point bearing pads.  I have 2 surface plates, a 10"x18" no name, and a 24"x36" Challenge.  Both have 3 load bearing points built in.  Here's some text from the Challenge Precision website concerning their cast iron surface plates:
> 
> "Three point surface plates provide a precise reference surface for tool making, layout, or checking the accuracy of other surfaces. The three point bearing pads and rigid ribbed construction permit support by less accurate surfaces without disturbing the surface
> accuracy. Wooden cover supplied with each plate."
> 
> Here's a link to the Challenge Precision cast iron surface plates:
> http://www.challengeprecision.com/products/plates/threepoint.htm
> 
> The 24"x36" plate came from our machine shop at work.  It weighs 475 lbs.   It has spent it's entire 50+ yearlife on an angle iron stand with a 3/4" plywood top.  You would have to run into the stand with a fork lift or Mack truck to tip it over



So do they diamond lap cast iron plates? Or how do they get them to the proper grade? I have a decent understanding of how they do this on granite. 

I can't believe they have handles for those huge plates... there is even a handle for the 900+ pound version. Must be machine lifting points?

Paul


----------



## Wreck™Wreck

ezduzit said:


> This is about the only way I see to make the bedding idea (possibly) work. Otherwise the surface plate is being used to try to stiffen an inferior structure. But it would likely create an even bigger problem with the 2 bonded plates acting as bi-metals and each warping the other from thermal changes.


My hovercraft is full of eels.


----------



## Dabbler

Since 2008, Standridge has been  using 3 point instead of 4 point supports (which it did previously) ...  Now this has gotten me really interested!  I'm going to call Standridge tomorrow and see if I can find out why.  If it makes sense, I'll relay the conversation here.


----------



## Tony Wells

That's curious.


----------



## projectnut

expressline99 said:


> So do they diamond lap cast iron plates? Or how do they get them to the proper grade? I have a decent understanding of how they do this on granite.
> 
> I can't believe they have handles for those huge plates... there is even a handle for the 900+ pound version. Must be machine lifting points?
> 
> Paul



I'm not sure how the "precision ground" surface plates are finished.  I do know a hand scraped one costs about 1/3 more than the same size precision ground one.  The list price for a 24" x 36" precision ground one is about $2,000.00.  The same size hand scraped one is about $3,000.00.   As for the handles, there is typically a lifting tool that slips over them.  The tool is then raised by a crane or lift.  Here's a link to a smaller plate available on e bay.  Note the lifting tool that comes with it.

http://www.ebay.com/itm/CHALLENGE-1...urface-Plate-Very-Nice-W-Hanger-/351891804736


----------



## BROCKWOOD

Short answer is the table that the surface plate & it's '3 point rest system' can sit upon any table supported with as many casters as you like.  The 3 point leveling should only be of such height as to avoid any interference from said table top. 2" should be plenty.  Carry on!


----------



## ezduzit

projectnut said:


> ...a hand scraped one costs about 1/3 more than the same size precision ground one.  The list price for a 24" x 36" precision ground one is about $2,000.00.  The same size hand scraped one is about $3,000.00...



That would be 50% more.


----------



## Dabbler

Okay, here goes:  I called Standridge Granite today, and talked to one of the technical people...  Apparently in living mempry they have always used 3 points to calibrate and mount surface plates.  My information from a website misidentified Standridge where it was another company.

Now for why:  This all goes to a Federal standard.  If you do work for the government (military, etc) you must use a calibrated surface plate that meets very specific criteria - chiefly that it uses a 3 point support system.  Standridge and others calibrate and prepare surface plates to use this system.  For extra money, Standridge will calibrate to 4 points - which is not allowable in the Federal standard.

Mathematically, 4 points is better.  From a business POV, 3 is better.  For a small shop, what-you-want.  My new plate will be calibrated and supported on 4 points. My Mitutoyo, it turns out, must be on 3 points (!).

There is a lot of good stuff on cleaning and maintenance in the standard, so by the grace of Standridge (who sent it to me) here it is:


----------



## expressline99

OK guys my 24x24 plate is on it's way from Standridge. I need 3 levelers to build into the top of a stand I'm going to make for it. You guys may have pointed me to a place to buy them but I can't find it for the life of me. .125 walled box tubing should work for the stand shouldn't it? 

Paul


----------



## Tony Wells

You can use machine leveling screws upside down, and they are available with rubber cushions or solid delrin type plastic. I would avoid that because od the slippage factor. The rubber feet would grip and not allow the plate to slide around on the mounts. Easy enough to weld nuts the crossmembers of the frame. And yes, that tubing is sufficient for your stand. You gave only the wall, but I am guessing it's at least 1 1/2" square.


----------



## expressline99

Tony Wells said:


> You can use machine leveling screws upside down, and they are available with rubber cushions or solid delrin type plastic. I would avoid that because od the slippage factor. The rubber feet would grip and not allow the plate to slide around on the mounts. Easy enough to weld nuts the crossmembers of the frame. And yes, that tubing is sufficient for your stand. You gave only the wall, but I am guessing it's at least 1 1/2" square.



Sorry about that. Yes I was thinking either 1.5" or 2.0" square. I'm watching Shandon HKW make his now.  Looks pretty straight forward. Also he mentions there are stand instructions included on the back of the Standridge certification.


----------



## expressline99

It occurred to me today that leveling my plate could be  a challenge as my garage drink/beer fridge has been out there for years and is so out of level the door swings open after you let go....


----------



## Dabbler

If you aren't doing static balancing on it there are a few woodworking (yes, woodworking) levels that are accurate to .004 per foot.  I ended up buying several over the years, but I have now forgotten which of my woodworking levels are that accurate!  (I guess I could check if you can't find one).  Buying offshore machinists levels have some problems:  the one I bought was so far out and nearly impossible to make right.  It took a bunch of hours to free the gimbals, and more to calibrate it, due to the very coarse adjustment screws.


----------



## expressline99

Dabbler said:


> If you aren't doing static balancing on it there are a few woodworking (yes, woodworking) levels that are accurate to .004 per foot.  I ended up buying several over the years, but I have now forgotten which of my woodworking levels are that accurate!  (I guess I could check if you can't find one).  Buying offshore machinists levels have some problems:  the one I bought was so far out and nearly impossible to make right.  It took a bunch of hours to free the gimbals, and more to calibrate it, due to the very coarse adjustment screws.



Bob has offered to lend me his level short term to level the lathe once I get the legs and the pan together. Although like the plate I'm leaning towards buying one. I'll have to level the mill soon as well. So I will need it several times. Sounds like enough to warrant buying it. ....and maybe a 4"...a 6"...an 8"...a 12"


----------



## expressline99

OK since this blends with the other thread a bit. Currently waiting on my level to arrive. Today I picked up all of the 2" square tubing .120 and made all my cuts for my stand. I'll be welding that up this week hopefully.


----------



## expressline99

Ack! I forgot to get weldable nuts. Zinc no bueno.  And I know better. oh well. Add another day to making the stand.

Paul


----------



## expressline99

It occurred to me a couple of days ago that this stand probably would hold over 1000 pounds without any problems. I think I may have fallen past the overkill line again.


----------



## Dabbler

Overkill for a surface plate stand is one of those things that's very hard to do.  The stiffer and bigger it is, the less twist and other variations you will get.  Not overkill.  Just 'extra sturdy'.  Look t the better commercial ones.  They hold a 500lb surface plate using 2X2X3/16" tubing.  With extra bracing!


----------



## expressline99

I am getting close... I did  a lot of welding today. Let me tell you what I'm a great grinder. Hopefully get this thing painted this weekend. Ever closer.


----------



## dlane

Long thread with no pics?


----------



## expressline99

I promise to get some listed this weekend. Gotta pretty up the last welds. Then some pictures before painting.


----------



## expressline99

OK So I am ready to paint after today. 













Picture of the simpson strong-tie bearing plate 2"x2" 5/8" hole



__ expressline99
__ Jul 8, 2017



						Cheap at home depot! I think I paid 44 cents each. They are around the concrete bag area. LBP...
					
















Close up of the leveling feet.



__ expressline99
__ Jul 8, 2017



						I used 2" square 5/8" hole simpson strong-tie Bearing plates. You can get these at home depot...
					
















The bottom leveling feet.



__ expressline99
__ Jul 8, 2017



						All of the welded nuts on this are 1/2" x 13tpi totally common and plenty strong enough.
					
















Franken corners. These were made to be removeable corner brackets for the plate.



__ expressline99
__ Jul 8, 2017



						They had to go over the attachment points...OK nuts.This will allow me to remove two corners in...
					
















I added 4 "attachment" points to the 4 corners of the stand.



__ expressline99
__ Jul 8, 2017



						I figured I may want to attach something to the stand in the future for an odd project... or...
					
















The base of the stand



__ expressline99
__ Jul 8, 2017


















Close up of the 3 point mounting system.



__ expressline99
__ Jul 8, 2017



						Super complicated...OK not really Just has to be right where the manufacturer requires them for...
					
















The stand has a 3 point bessel leveling setup. These points are exactly as the manufacture requires.



__ expressline99
__ Jul 8, 2017



						As per Standridge instructions on the certification sheet that comes with the plate.
					
















Overall view of stand



__ expressline99
__ Jul 8, 2017



						I built the stand using 2"x2" .120 wall square tubing. Overall width is 25".
					



There ya go.
I will paint it Dark Machine Gray like my lathe tomorrow.
Don't get all excited about my welds I know they aren't great.

Paul


----------



## Dabbler

the welds will do!  Very nice work!


----------



## 4GSR

expressline99 said:


> ..............
> Don't get all excited about my welds I know they aren't great.
> 
> Paul


Nice job Paul!

Welds are better than any I can do!  

How much would charge to make one for my rock?


----------



## expressline99

4gsr said:


> Nice job Paul!
> 
> Welds are better than any I can do!
> 
> How much would charge to make one for my rock?



Thanks. I uhhmm If you bring the stuff over we can just make it. But plan on two weeks of evenings. LOL!

Here are some pictures with it painted. 













Painted!



__ expressline99
__ Jul 10, 2017


















Painted 2nd view.



__ expressline99
__ Jul 10, 2017


















This little girl appeared inbetween pictures. Really wanted to be in the pictures!



__ expressline99
__ Jul 10, 2017


















This little girl appeared inbetween pictures. Really wanted to be in the pictures!



__ expressline99
__ Jul 10, 2017
__ 1






Paul


----------



## expressline99

Two coats of primer, two coats of dark machine grey, and then two coats of crystal clear enamel.


----------



## Ulma Doctor

Hi Paul,
looking great man!
looks like you have a shop gnome too!

my shop gnome puts stuff away for me.
as cute and respectable as it is, the problem is that i'm the only one who know where stuff is supposed to go ! 

i look forward to seeing the plate!


----------



## expressline99

Ulma Doctor said:


> Hi Paul,
> looking great man!
> looks like you have a shop gnome too!
> 
> my shop gnome puts stuff away for me.
> as cute and respectable as it is, the problem is that i'm the only one who know where stuff is supposed to go !
> 
> i look forward to seeing the plate!



Thanks Mike! I was wondering what it was called. Seems my shop gnome likes to say "NO!" a lot. She's 4 and in the last month has gone to an enormous amount of 'why are you doing that?" Or "What are you doing?" questions which is good. She was on a milk crate a couple of days ago with her P.P.E. watching me drill holes on the drill press.  Getting her to wear glasses is easier than getting her to wear shoes! 

The plate might get put in it's resting place this week. I visited it in the shop today. It looks lonely.


----------



## Ulma Doctor

she's cute as a button! the questions from her get tougher from here!

my son(6yo) loves to put on the PPE stuff- he says he's like Bob the Builder!

can't wait to see the plate!!!


----------



## Dabbler

Glad to see your progress!  You guys remind me of the days that my little ones took to trying to do their own projects with my chisels and hammers!  Heart racing, they never did too much damage to the shop or kids.


----------



## expressline99

OK so here's how it went down! My wife through a fit over me wanting to spend another 200$(or more as I wanted to buy a lifting table also) to unload my "secrete" surface plate I had some how acquired... So what I ended up doing was buying (8) 2x4's to build a ramp from the truck to the plate. I put the plate on an extra pallet I had at the warehouse and loaded it in the truck. This gave it enough height to be above the grade of the stand.  I only used (4) of the 2x4s... some 3" and 2-1/2" screws...and some rope a bike hanger and a single pulley. (I want to warn you this particular pulley almost killed me in 2010 when I pulled a water heater down from a loft by myself...and it was full of rust...it weighed more than I did and I got to fly through the air like that story you've read on the internet about the bricks falling..the rope...yadada. Anyway, it's on it's stand and I've tried to describe what I did on each photo in the title. Here it is.  20 more photos for your viewing pleasure.

Paul












What I had to do.



__ expressline99
__ Jul 15, 2017



						This is as close as I could get the van. It's so tall (9 feet) I couldn't get it closer.
					
















I had the plate on it's shipping pallet... plus One more pallet that I had in the warehouse.



__ expressline99
__ Jul 15, 2017


















Just another angle of the garage from where I was moving the plate...



__ expressline99
__ Jul 15, 2017


















This is where I got the idea of where I could put rails to slide it on. So it needed a cleat. See next pictures



__ expressline99
__ Jul 15, 2017


















I added a ledge for the rails to sit on directly to the shipping pallet the surface plate was on.



__ expressline99
__ Jul 15, 2017


















There was a slight slope from the truck to the stand. Roughly 6" of drop. These are the rails I attached to the ledge I put on the stand.



__ expressline99
__ Jul 15, 2017



						This was exactly 8' so no cutting of those two 2x4s! Great! Less work!
					
















I made sure the rails were as wide as the stand. Which I made an inch wider than the plate for room to move. So it needed a couple of 25" spacers.



__ expressline99
__ Jul 15, 2017



						These were attached to the bottom then flipped over to finish the "ramp"
					
















I placed a single support under the center. I made sure that the 2x4s were directly supporting the load.



__ expressline99
__ Jul 15, 2017


















A view of how the rail looked attached to the ledge on the pallet.



__ expressline99
__ Jul 15, 2017


















Another view of the rails on the stand. The mounting screws are turned down below the level of the sideways 2x4s



__ expressline99
__ Jul 15, 2017


















There are mounting pads on the bottom of the plate. These had to fit between the rails. I had to keep adjusting as I slid it.



__ expressline99
__ Jul 15, 2017


















A close up of the factory installed mount pads. Had to make sure these didn't get pryed off while sliding it down the rail.



__ expressline99
__ Jul 15, 2017


















Starting to slide it down the rail was the hardest part. As the plate went from flat to sloped. A little more lifting than I wanted.



__ expressline99
__ Jul 15, 2017


















The plate didn't slide easy...so I thought I'd attach a pulley to the bench. I used a single pulley and a bike hanger. Screw in type.



__ expressline99
__ Jul 15, 2017


















The particular setup was 1 to 1 on leverage so It didn't work just pulling on the rope.



__ expressline99
__ Jul 15, 2017



						BUT! Pulling on the rope with one hand while pushing on the back of the plate with the other...
					
















The plate made it! The last couple of inches I had to remove the bike hanger and pulley. Then push it the rest of the way. Which was easy.



__ expressline99
__ Jul 15, 2017


















At this point the plate is still sitting on the slide rails.



__ expressline99
__ Jul 15, 2017


















Now to remove the rails just lift the plate via the 3 mounting points until you can see light between the rails and the plate.



__ expressline99
__ Jul 15, 2017


















The plate made it to it's new home!



__ expressline99
__ Jul 15, 2017


















The plate in it's home another shot from the end of the garage.



__ expressline99
__ Jul 15, 2017


----------



## francist

Yay, good job! I almost want to see that photo sequence set to music.... 
Seriously, glad you finally got it done.   

-frank


----------



## expressline99

francist said:


> Yay, good job! I almost want to see that photo sequence set to music....
> Seriously, glad you finally got it done.
> 
> -frank



How about this...I know it fits me so well. 



Paul


----------



## Rex Walters

Tony Wells said:


> That's curious.



WreckWreck was joking that he didn't understand your post -- it sounded like something from a Hungarian phrase book.

This should clarify:


----------



## expressline99

Rex Walters said:


> WreckWreck was joking that he didn't understand your post -- it sounded like something from a Hungarian phrase book.
> 
> This should clarify:



LMAO I had to go back to see if I was offended. That's great. 
Paul


----------



## Rex Walters

expressline99 said:


> LMAO I had to go back to see if I was offended. That's great.
> Paul



Wreck's comment cracked me up because I caught the reference, but he was replying to ezduzit not Tony.

Anyway now that I've explained someone else's joke and confused everyone by getting the quoting and attribution wrong, nice job on the plate stand!

I really need to get a decent plate and I'll definitely be building something similar.


----------



## expressline99

Rex Walters said:


> Wreck's comment cracked me up because I caught the reference, but he was replying to ezduzit not Tony.
> 
> Anyway now that I've explained someone else's joke and confused everyone by getting the quoting and attribution wrong, nice job on the plate stand!
> 
> I really need to get a decent plate and I'll definitely be building something similar.



I was going to put up the cut list and supplies list here later this week. Will make it super simple for anyone wanting to do the same thing.

Paul


----------



## 4GSR

Paul,

It would be much easier if you made the stands for us.

Ken


----------



## Wreck™Wreck

I use a 96" X 48" X 24" granite surface plate at work. have no idea how it is supported, it seems to work well.


----------



## expressline99

Wreck™Wreck said:


> I use a 96" X 48" X 24" granite surface plate at work. have no idea how it is supported, it seems to work well.



I think your work might be a little more serious than my wildest ideas are.  That rocks gotta be 10,000 pounds...

Paul


----------



## expressline99

4gsr said:


> Paul,
> 
> It would be much easier if you made the stands for us.
> 
> Ken



The 2nd one would probably be faster to make and prettier. But I have to get my mill head mounted...and move on to documenting the table rebuild...and handle the lathe remounting on legs and get a new pan made. Oh and help my wife for the next 6 months while she recovers.  Oh and handle the kids...oh yeah and run my business. If I keep listing these things I might have to do some of them!  

Paul


----------



## Dabbler

That rock which 'Wreck Wreck' uses, at 170lbs/ft3 is a 'mere' 5,440 lbs.  I once had offered a 'free' surface plate from Kentucky - but I had to pay shipping to Alberta, and it weighed 8,000 lbs!  (for some reason I passed it up)


----------



## Wreck™Wreck

Looked at the tag today, 6400+ Lbs.

We rarely have parts that large but it certainly is handy when we do the occasional wiper knife for a plastic sheet manufacturer, they want them straight.


----------



## Tony Wells

I should have mentioned this earlier, but you might have been better off using "elevator bolts" both for the feet and the mounting points instead of plain hex cap screws.


Oh, and by the way, I am half blood Hungarian and there is at least one Hungarian member here. Please be mindful of the different cultures and try not to post anything offensive.


----------



## expressline99

Tony Wells said:


> I should have mentioned this earlier, but you might have been better off using "elevator bolts" both for the feet and the mounting points instead of plain hex cap screws.



Oh well it's OK. It leveled just fine. I had just the right amount of struggle.


----------



## patmat2350

OK, I just read through 4 pages of discussion on this "quick question"... mostly it reinforces my belief that you can take any subject, and there's an encyclopedia of information about it, and I usually didn't have a clue about any of it!

But I'm still not sure what to do about my small surface plate, purchased on a whim (it was cheap and easily available). It's a 12x18x3 B grade (or worse, totally undocumented), purchased with an eye towards shop work like lapping and/or marking out parts. It's just laying on my nice solid workbench with no support, other than the bench top itself.
If I have to move it, I'll just slide it around like some millstone.

Should I feel bad or ashamed about it? 

I've got no welder, and I'm not about to purchase a purpose-made table that costs 20x what the rock did... not sure what else I'd do to support it, but frankly, I'm not too worried about a chunky thing like this sagging.


----------



## Dabbler

Hello Pat!  I have a 12X18X3 rock that I've been using for about 20 years now, just as you are.  Small surface plates such as this are sometimes known as 'bench plates', because due to their thickness versus their overall size they have very little (hardly measurable) deflection.

I get very accurate results on my offshore, not NIST traceable, cheap 12X18 plate.  I won't ever make a stand for it, because it is too handy sitting there on my bench.  Note I don't do work to tenths on it either.  but for scribing, layout, etc it is better than fine!

For bigger plates (I'm thinking 24" X 36" and above) it is essential you properly mount your plate, but a little one like that is just fine on a bench. My bigger plate is in the grey area, but I'm going to properly mount it with a 3 point suspension, just because I can (read: anal retentive )

I hope this helps.


----------



## expressline99

my quick questions go forever. But keep in mind I jump overboard in 60 seconds or less. Most people have theirs mounted on a workbench...frequently with just a plywood frame for a cover. If you aren't scraping in parts I wouldn't think sag is going to be of any concern. However, for any precision I would keep grit as far away as possible from the stone.   

I don't see any issue or reason to feel bad. But I would keep the grit off of it. 

Paul


----------

