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View Full Version : buying a surface plate... how big to go



lowcountrycamo
04-11-2012, 12:05 PM
I am learning to scrape and might be reconditioning bridgeport a few years from now(as a HOBBY). I am getting ready to buy a surface plate. My question is, do I need a 24 by 36 or can I get by with one a bit smaller like a 24 by 18. What do you guys use? I know it is preferable to have a reference the same size as longest way, however, can it be done with a reference shorter. I would hate to buy a smaller and a couple years later realize that I should have bought the large one. I talked to a local supply and they quoted me 210 for a 24by36 and 350 for shipping. Yikes!

I see grizzly has one for 300 with shipping. So much for supporting local economy.

As always, thanks for any advise.

Dr Stan
04-11-2012, 12:30 PM
I'd go with the bigger one. BTW, since you do not need it ASAP take some time and keep an eye out on Craig's List for something fairly local. that way you could pick it up and avoid the outrageous cost of shipping.

You could also look at Enco and take advantage of one of their free shipping offers when available.

On edit:

"Enco free shipping on order of $25 or more, till May 31 2012 is NCCAPR"

metalmagpie
04-11-2012, 12:34 PM
In the Seattle area, surface plates often show up at auctions and it seems like they go dirt cheap. Usually the only bidders are headstone makers. I tried for months to sell a mint 18x24" Starrett pink plate with zero luck, not even a lowball. Basically most guys that want one already have a black import surface plate.

So my advice to you is to be patient and go to local auctions ready to bid. No way in h*ll would I buy one new, you'd just be throwing your money away.

lowcountrycamo
04-11-2012, 12:40 PM
metalmagpie, you don't happen to live in Jax fl. I saw an add for same plate a few months ago.

lakeside53
04-11-2012, 12:46 PM
+1 on local auctions... At a auction a year back, they has dozens - all in use and "pristine". My friend bought a 30x48x6 on a stunning custom table/drawer set for $100. The big unit (48x72x8 ) went for close to nothing... I was tempted to buy one for a garden step, but I'd have had to flame the surface to break it up for safety in the wet :D

At the machine shop estate sale where I bought my lathe they has a 24x36x6 pink Starrett. He'd heaped tooling on the surface so it was filthy and had minor scratches. Wanted $200, I offered $100... then I decided I really didn't want a pretty tombstone just yet.

Forrest Addy
04-11-2012, 01:17 PM
Size for a surface plate?

As a scraping reference about 2/3 the length of the longest surface. You can with care overlap the reference without sacrificing the accuracy imparted to the work. For precision layout and metrology ideally you want to place the work near the center of the plate and have access all around it for height gages, transfer gages, indexing head, toolmaker knees, jo block stacks, and other surface plate toys. Figure 8" to 14" margin all around.. So if you want the optimium, minimum width would be part size plus a couple feet. If I had my 'druthers'd, I'd have a 3 ft x 4 ft plate 10" thick . It's big enough to do anything automotive and for smaller work you can have several things going at once.

This is the real world. Most home shop types are pressed for space or budget and have to get by with less. For these I suggest a surface plate that's bench sized but muscleable if it needs to be moved. 18" x 24" for example. A strong man can carry one across a shop and a clever man will slide it on a castered cart whose top is bench height. 12" x 18" is usable but the working space is restricted. You spend a lot of time shuffling work and apparatus around to access all part features.

24" x 36" really is a better choice but at nearly 400 lb it's difficult to move. If it's on a cart the damn thing will be in the way when not needed in a crowded shop.

Good choices in affordable imports are available for either size.

Remember frieght. It usually cost more to ship them than to buy them.

Somewhere in the archives is a reccommended tool list for a turret mil re-scrape.

Black_Moons
04-11-2012, 02:17 PM
+1 on local auctions... At a auction a year back, they has dozens - all in use and "pristine". My friend bought a 30x48x6 on a stunning custom table/drawer set for $100. The big unit (48x72x8 ) went for close to nothing... I was tempted to buy one for a garden step, but I'd have had to flame the surface to break it up for safety in the wet :D


Blah, if you can't walk on a surface thats flat to within a thou without falling over, you deserve it! :P

Marty Feldman
04-11-2012, 03:25 PM
lowcountrycamo - As big as you can afford, have space for, and can muscle around. Used is fine if you can have some confidence in the surface flatness. Since you are or will become a scraper hand, you will be familiar with ways to check this. On the shipping cost, it is worthwhile to consider getting in your car and driving to a supplier for pickup. There must be one or two of the Grizzley type places within striking distance of Savannah. Buying a tankful of gas beats paying 300 bucks for the same thing.

J Tiers
04-11-2012, 07:27 PM
Yep..... as big as you can deal with.

BUT

ALSO get a smaller one that is within your "lift and manipulate" range..... you will want it when the plate is lighter than the item you want to check.... combining straightedge with smaller plate is perfect for many things.

SteveF
04-11-2012, 09:04 PM
+1 on local auctions... At a auction a year back, they has dozens - all in use and "pristine". My friend bought a 30x48x6 on a stunning custom table/drawer set for $100. The big unit (48x72x8 ) went for close to nothing...

Those big ones don't seem to bring much because, at 166 lbs/cu ft, they are seriously heavy. That 48x72x8 would be about 2700 lbs.

lowcountrycamo - If you buy a used one realize that they do wear and, if not cared for properly, may not be what you want for a scraping master. I've got a 12" x 18" cast iron that looks like it was pounded on with a hammer for some bizarre reason.

Steve

oldtiffie
04-11-2012, 09:23 PM
Every body is talking about size - which is a sensible thing to do.

But the important thing about surface plates is the Class/Grade of flatness of the plate which may be determined by the size and class of flatness you want or need on the job that is to be scraped.

It is usually best to have the plate one Class/Grade higher than the work you want to do.

All plates of the same Class/Grade of the same size will be the same flatness but the same Class/Grade but diffrent sizes will not be as flat.

It is best to have a plate that had been calibrated and a printed "map" of the high and low points where it was calibrated.

http://www.starrett.com/metrology/metrology-products/precision-granite/surface-plates


http://www.tru-stone.com/pdf/FedSpecGGG-P-463c%20amendment%201.pdf

See pages 4, 6 and 7 for tolerance of different sizes and grades.

Note The flatness tolerance for metric grade AA plates listed in Table (III) (metric) are obtained from the following formula:

Total flatness in micrometers (um) is = 1 + 1.6D^2 x 10^-6

where D = diagonal or diameter of the plate in millimtres (mm)

The tolerances on the A and B grade plates are 2 and 4 times respectively those for Grade AA

Note that in 1 + 1.6D^2 x 10^-6 that D is the only variable and that all other terms are constants.

If D = 300 then D^2 = 300 ^2 = 90,000

but if D = 600 then D^2 = 600^2 = 360,000

which is why flatness for the same grade varies with distance "D"

It is also the reason that Grade must be increased if the sane flatness isw required for the same grade but different distances "D".

A Grade AA plate is 2 x flat as a Grade A plate and 4 x flat as a Grade B.

If the calibration "map" is available, the best path for best flatness is easily obtained.

Here are my "maps" for my Chinese Grade AA (their Grade 00) 630 x 630 mm and 400 x 300 mm plates:

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/630Platesheet1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/Surfplategradediag1.jpg

My granite square (Grade 00):
http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/Precgransqsheet1.jpg

And just some of the stuff that goes on or with them here - all of the squares and angle plates have been accurately re-machined:
http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/630SPandsq1.jpg

Note: 1 micrometer (um) ~ 40 micro-inches (ie 40 millionths of an inch) ~ 0.0004: (say 0.4 "tenths" of an inch).

So prepare and be wary and be warned when assessing or buying a surface plate.

JeffKranz
04-11-2012, 09:29 PM
I was lucky enough to purchase a used one from work. We had about 10 that were 48" x 96" x 10"thick and they even included the steel stand for free. Final bonus was they delivered it to my barn. Had to buy the guy across the street donuts and beer so he would bring over his fork lift and unload it. Move it on a set of machine skates to its new home in the shop and it hasn't move in 8 years. It probably have seen more woodworking stuff on it but it is a great foundation for that.

Oh yes, price was $180 total (silent auction) and after the bidding was over the guy with the highest price was only $75.00 so I over paid a little.

oldtiffie
04-12-2012, 12:08 AM
An indication in $US prices regarding grade, accuracy and price is at the Shars web site at:
http://www.shars.com/files/products/catalog2011/page138.pdf

dp
04-12-2012, 02:10 AM
I am learning to scrape and might be reconditioning bridgeport a few years from now(as a HOBBY). I am getting ready to buy a surface plate. My question is, do I need a 24 by 36 or can I get by with one a bit smaller like a 24 by 18.


You don't need a big one now so save your money and use it to by the add-ons you're going to need later. Examples:
http://www.gaging.com/trustone.htm

And get a good brayer and place to store it so it doesn't get flat spots.

You will need these accessories later and they're not cheap. Later on you can buy an appropriately sized surface place and your accessories will be right at home with it, and you will have been able to use all your accessories on the smaller plate to learn the ropes in the mean time.

Greg Q
04-12-2012, 10:55 AM
I bought a dozen plates a few months ago for a group buy down here. Larger plates are hard to find, and the prices are stupid. i ended up getting plates labelled as Grade A from Enco, with very reasonable shipping to my forwarder in Indy.

We got 24" X 36" plates which were the best value on the size/cost curve, and a great aize for both survey work and mastering 3' straightedges etc.

BTW, I checked three of the plates at random with my Taylor Hobson Talyvel and they did indeed meet the grade A specifications. Who knew?

Greg...previous owner of an 18 X 24, very happy with the extra real estate. Oh- I made a stand that also houses a roller cabinet full of metrology tools and shelves for all the plate accessories. With a plywood cover for the granite it is my best little work table when the granite is not in use.

TexasTurnado
04-12-2012, 02:54 PM
Apparently places like Enco (MSC) get deeply discounted prices on truck shipping: I bought one of Enco's grade A plates in 36 x 48 x 8 size while on one of their sales and the shipping was only $250 for 1140 lbs. I made a custom stand for it and a plywood cover so I could use it for a work table for lighter objects. Being 3 x 4 ft, the diagonal is 5 ft, so I am able to check my 6 ft camelback using it.

The most interesting observation: it was shipped from MSC in Atlanta....:D

TexasTurnado
04-12-2012, 04:57 PM
Note: 1 micrometer (um) ~ 40 micro-inches (ie 40 millionths of an inch) ~ 0.0004: (say 0.4 "tenths" of an inch).

So prepare and be wary and be warned when assessing or buying a surface plate.

Hmm, I do not believe this computes :D :

40/1,000,000 = .00004 inch

It seems a zero got lost.....:eek:

.RC.
04-12-2012, 06:33 PM
size matters..... :D

Greg Q
04-12-2012, 06:54 PM
The most interesting observation: it was shipped from MSC in Atlanta....:D

All of our plates had MSC labels too, TT. From Harrisburg and Elkins mostly, but thats because my freight guy is in Indianapolis.

I'd like to find a good price on a bunch of granite knees too, and some camel back castings.

One more reason for a large plate: you can spot an entire lathe bed on one. The 2 X 3 size works well for something like a Rivett 608 bed, which just happens to be my first project lined up. Well, that and a couple of mills, straightedges and another lathe.

Greg

oldtiffie
04-12-2012, 07:44 PM
Hmm, I do not believe this computes :D :

40/1,000,000 = .00004 inch

It seems a zero got lost.....:eek:

Thanks TT for picking me up on that - it was a silly thing for me to do - but while the 0.0004 was short a zero the "0.4 tenths" was still OK.

sasquatch
04-12-2012, 07:47 PM
"BIN" that one!!:p

oldtiffie
04-12-2012, 07:53 PM
I bought a dozen plates a few months ago for a group buy down here. Larger plates are hard to find, and the prices are stupid. i ended up getting plates labelled as Grade A from Enco, with very reasonable shipping to my forwarder in Indy.

We got 24" X 36" plates which were the best value on the size/cost curve, and a great aize for both survey work and mastering 3' straightedges etc.

BTW, I checked three of the plates at random with my Taylor Hobson Talyvel and they did indeed meet the grade A specifications. Who knew?

Greg...previous owner of an 18 X 24, very happy with the extra real estate. Oh- I made a stand that also houses a roller cabinet full of metrology tools and shelves for all the plate accessories. With a plywood cover for the granite it is my best little work table when the granite is not in use.

Thanks Greg.

That made my day.

My guess is that all were Chinese (each with its own plot/map) and as you say all checked locally (Australia) as being Grade A.

The "China knockers" - in the USA mainly - may well won't believe you or doubt your methodology - or both.

I bought my 630 x 630 Grade AA (or 00) from MTI in Melbourne and while it was expensive, I am very happy with it.

oldtiffie
04-12-2012, 08:32 PM
Just to keep our 'merican China-knocker friends happy, the reason I used http://www.tru-stone.com/pdf/FedSpecGGG-P-463c%20amendment%201.pdf is that it is metric and update the previous "inch" version.

So Starret and NIST have been using metric for surface plates at least since the date of the up-date dated 12 September 1973. (See the front page).

So while the previous "inch" version is still valid, if you want to "get/be with it" - metric is the way to go.

The varying limits of flatness for plates of the same Class/Grade of plate which increase with plate sizes (diagonal or diameter) would suggest that the limits can (and do?) allow for curves and/or "waves" as well as ("dead"?) flats.

So those "dead flat" surface plates may not be.

It should be noted that the "highs" and "lows" (within accuracy limits) can be anywhere at random and so the differences between adjacent or rear points can be quite remarkable.

Hence the need for the plate "plots/maps" as it enables the operator to pick the places or lines that best suit him.

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/630Platesheet1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/Surfplategradediag1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/Precgransqsheet1.jpg

It seems that the nearer the plate size is to the job in hand to nearer/better the accuracy of the plate (and the job?) will and may well be better than small(er) jobs on big(ger) plates.

Paul Alciatore
04-12-2012, 11:51 PM
size matters..... :D

Some decades ago when I was in the Army, I was stationed at Redstone Arsenal. One day we toured the labs and shops and in one of them they had a SURFACE PLATE. If I recall correctly, it was about 8 or 10 feet across. They were quite proud of it. I was impressed.

I wonder what it weighed.

.RC.
04-13-2012, 01:33 AM
...ffs....

.RC.
04-13-2012, 01:34 AM
Some decades ago when I was in the Army, I was stationed at Redstone Arsenal. One day we toured the labs and shops and in one of them they had a SURFACE PLATE. If I recall correctly, it was about 8 or 10 feet across. They were quite proud of it. I was impressed.

I wonder what it weighed.

I believe the manufacturers could make them as big as you wanted...

precisionmetal
04-13-2012, 01:55 AM
In the old days of Westec in L.A. (70's), someone (can't remember who) would always bring in a plate that had to be at least 15' long. Maybe it was even longer.

They would always have a scantily clad woman at each end, and they would slide a granite block back and forth on that big plate. (like being on an air hockey table).

Anyone remember that?

PM

oldtiffie
04-13-2012, 05:57 AM
With regard to this Grade 000 plate:

http://i200.photobucket.com/albums/aa294/oldtiffie/Surface%20plate/630Platesheet1.jpg
which has a difference between high (1.3um) and low (0.0um), my workings out for Grade AA (USA) and 000 (Metric) for this 630 x 630 plate with a diagonal of 890mm less 50mm = 840mm (from edge) which equals "D" (see page 7).

From the equation which equals flatness tolerance (in um):

1 + (1.6D^2 x 10^-6)

= 1 + (1.6 x 840^2) x 10^-6

= 1 + (1.6 x 1128060) x 10^-6

= 1 + 1128960 x 10^-6

= 1 + 1.13 x 10^6 x 10^-6

= 1 + 1.13

= 2.12um

The chart at page Table 3 page 7 shows 2.2um which is pretty good for a Class AA (USA) or Class 000 (metric).

Now using the charts:

A Class AA (USA) or 000 (metric) limits are 2.2um

A Class A (USA) or 00 (metric) limits are 2 x Grade AA (4.4um)

A Class B (USA) or 0 (metric) limits are 4 x Grade AAA = (8.8um)

What that (seems to) mean is that for a "top of the line" Class AA ("Laboratory" Grade) plate can have any amount of highs and lows so long as the difference between the highest an lowest does not exceed (2.2um x 0.00004") = 0.000088" or just less than 0.9 "tenths" (of an inch).

And it twice that for a Grade A (Test /Metrology Grade) (4.4 x 0.00004" = 0.000176" ~ 1.8 "tenths") and four times that for a Grade B (Tool-Room or workshop grade) = 8.8um x 0.00004" = 0.000352" ~ 3.54 "tenths".

So, saying or assuming that any surface plate is "dead flat" or "accurate to "millionths" (0.000001") is a bit presumptive.

Equally, it applies to parts that are scraped to a plate.

Also equally, a different accuracy of a part scraped to a surface plate may vary between plates of the same size and grade and the more so as plates are enlarged and between larger plates of the same or different grades.

Similarly different Inspectors may grade a scraped job differently.

There is a whole lot of subjectivety in scraping and scraped surfaces.

I have a 630 x 630 mm (~25" square) and a 400mm x 300mm (~15.75 x 11.8") surface plates as both suit my work very well.

Some people may need to reconsider some long-held beliefs and "known facts".

For most stuff that needs to be "pretty flat" I use a tempered "float glass" plate which is flat to with 0.0001" per inch which is pretty good on my mill table:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Surfaceguage1.jpg

Frankly my 600mm digital height guage is a PITA and gets in the way.

I prefer my surface guage with a good dial indicator as both these methods suit me very well:

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/Surfaceguage4.jpg

I sometimes just use the tables on my milling machine, surface and T&C grinders of just a magnetic base on a machine table or even on a bench.

Its simply knowing what degree of accuracy or flatness you really need and which "flat" suits the job in hand.

My guess is that there are a lot of large and small surface plates either rarely used and/or are assumed to have a surface that may not be as flat as they think (or hope?) it might be.

In many cases I'd just simply opt for a surface ground face as a good surface grinder will get as good a flat surface as hand-scraping to a surface plate will.

With a good universal T&C grinder and a lot of set-up care, a very good job can be made of oblique surfaces such as dove-tails etc.

Greg Q
04-13-2012, 09:17 AM
Just to be clear, I surveyed my plate with particular attention to the variation in surface compared to the certificate that came with the plate. The certificate was USELESS...had zero bearing to the actual topography of the surface and was, I believe, made by a random number generator.

Lest my methodology be suspect, I was using a recently calibrated Talyvel (admittedly not your typical hobbyist tool), and confirmed the findings with a likewise recently verified Wyler level, which provided the same readings as my Starrett 199. The spirit levels ( or: wasserwage in the case of the Wyler :) ) were used on parallels BTW.

I regret passing on a beautiful Nikon auto collimator that Don R had for sale at the intial Seattle scrapefest. And that Rann Planicator that was on ebay a couple of years ago.

oldtiffie
04-13-2012, 08:11 PM
Thanks Greg.

Even as the plot was suspect, it seems that the Classification was correct (Grade A) on those plates selected at random from a sizeable sample number.

My main point was to re-focus on the OP's request for "how big and how much (cost)" but he did not mention Grade (accuracy):


I am learning to scrape and might be reconditioning bridgeport a few years from now(as a HOBBY). I am getting ready to buy a surface plate. My question is, do I need a 24 by 36 or can I get by with one a bit smaller like a 24 by 18. What do you guys use? I know it is preferable to have a reference the same size as longest way, however, can it be done with a reference shorter. I would hate to buy a smaller and a couple years later realize that I should have bought the large one. I talked to a local supply and they quoted me 210 for a 24by36 and 350 for shipping. Yikes!

I see grizzly has one for 300 with shipping. So much for supporting local economy.

As always, thanks for any advise.

I simply pullled all the strings together and told him - in essence - to buy to least size plate with the highest grade to suit his job and his pocket.

I set about giving him an objective answer based on credible data and references (including Starrett) while eliminating subjectivity and wild ar$e-ed guesses.

I gave him worked examples as well so that he could verify it in his own way in his own time.

I also set about showing that there are degrees of "flat" on surface plates and that bigger (and lower Grade/s) may be OK for most shop work but he will really need to determine how big and how accurate his surface needs to be and to work through the reference to get his size and grade and then see if it suits his budget.

There may well need to be compromises made.

I also tried to show that there are some other pretty flat surfaces around the shop that can be used in many cases - as I do.

If it were me with his mill table and if it really needed to be re-conditioned, I'd have it ground (for flatness) and hand scrape it for effect or looks or aesthetics and for lubrication.

But I'd buy and evaluate the mill first and see what needed sraping or grinding and size and grade the surface plate feom there for scraping etc. - ie use logic and order.

In my opinion, there is no point in putting the cart before the horse.

luthor
04-17-2012, 07:56 AM
I bought a dozen plates a few months ago for a group buy down here. Larger plates are hard to find, and the prices are stupid. i ended up getting plates labelled as Grade A from Enco, with very reasonable shipping to my forwarder in Indy.

We got 24" X 36" plates which were the best value on the size/cost curve, and a great aize for both survey work and mastering 3' straightedges etc.

BTW, I checked three of the plates at random with my Taylor Hobson Talyvel and they did indeed meet the grade A specifications. Who knew?

Greg...previous owner of an 18 X 24, very happy with the extra real estate. Oh- I made a stand that also houses a roller cabinet full of metrology tools and shelves for all the plate accessories. With a plywood cover for the granite it is my best little work table when the granite is not in use.


Greg, do you have any plans of doing another group buy in the near future?
What did they end up costing each?

dian
04-17-2012, 04:03 PM
tiffie, how come your float glas is so flat? did you scrape it in?

how did you determine 0.0001"? glass seems to have a modulus close to aluminum. so i suspect, you get the above by just breathing on it. besides it is wraping around the table by its own weight. not to mention anything substantial that you put on it.

jdunmyer
04-17-2012, 08:10 PM
Tiffie,
You mention your "tempered float glass" being flat to within .0001". I worked in a glass plant for several years, and found that tempered glass was about anything BUT flat. If it was not tempered, it would probably be pretty good...

sasquatch
04-17-2012, 08:13 PM
Maybe he flycut it?

Going to be a "CRASH" when he "BINS" that!!:D

oldtiffie
04-17-2012, 08:15 PM
http://bbs.homeshopmachinist.net/showpost.php?p=492764&postcount=66

jdunmyer
04-17-2012, 08:53 PM
Tiff,
Your link describes float glass as being as flat as all but the best surface plates. But, that's not tempered. The tempering process will generally cause the glass to be warped in one way or the other. It's often very noticeable, as in stuff that went through a "tong" type furnace. Glass tempered on a roller hearth furnace will also be warped; even glass run through a "float" type of tempering furnace won't be flat. In fact, the latter is used when the desired product is curved, as in automotive side- or back-lites.

dian
04-18-2012, 04:08 AM
in principle float glas is pretty flat, although 2 microns might be stretching in a bit. its easy to check it with a beveled straight edge (00). but is has to be supported in a uniform way, on a piece of foam for example, because it has no rigidity. lets say you put it on a milling table that has two humps in in (like mine), you will have to carefully shim it to keep it straight.

edit: please disregard this, i didnt read the other thread.

Greg Q
04-18-2012, 04:43 AM
Greg, do you have any plans of doing another group buy in the near future?
What did they end up costing each?

I don't Luthor...it was only a way to amortise the shipping enough to make my plate affordable. I got them from Enco when they had a discount going, and shipped them all with a car importer. I think the price break happens for as few as five plates. The price difference between grade A on sale and grade B is only $15 per plate. 2' X 3' seems to be the best bang for the buck, size- wise. It is also the sweet spot for survey, spotting 3'+ straightedges, and general shop layout.

I have a plywood cover over mine most of the time in order to reclaim six sq feet of shop space. I cringe whenever I see uncovered plates stacked high with shop flotsam. Most auction plates that I have seen have been rendered useless by uncaring shop neandrethals...but I guess that's why the shop is being auctioned off. (I have learned to avoid insolvency sales...they go broke for a reason)

Greg

luthor
04-18-2012, 06:40 AM
Thanks for the information Greg, I am looking at bringing a couple over, did you go with or without ledges?

Greg Q
04-18-2012, 09:51 AM
Without, definately. Ledges are for clamping objects to the plate for layout and related duties. A monolithic plate of four to six inches thick is ideal. Enco is not the only supplier, but they seem to be the only ones who have regular discount coupons.

Let me know if you need my shipper's details. They are in Indianapolis.

Greg

luthor
04-19-2012, 10:49 PM
Greg, I would like to get the details of the forwarding company that you used and get a quote from them as well as from a company in California that I have used before to see who offers the best deal.

Regarding ledges on surface plates, when I worked in the machine shop of one of our nations airlines they had and probably still have a 6' x 4' granite plate, with ledges on the long sides, which were very handy for clamping components and tooling for inspction, but for my own shop I will go for the plain version mainly due to the difference in price.