Import surface plates

[sic semper tyrannis]

I found a pink 12x12 starett late in 2011 at a industrial tool shop here in richmond. Grab it for 75.

I use it all the time it seem. Marking something, measuring. Very handy. Small enough that it doesn't take a bunch of space.

Maybe I will grab a granite floor tile and put it on the plate with some blue and see if I can tell just how flat it is.

 

[Kevin45]

First, another stupid Nelson newbie question:

What are surface plates commonly used for in the home shop?

Next, a practical question due to cost:

Are import" surface plates any good?

[This question was asked on another forum, but the thread abruptly closed without an answer due to the word "import"]

Almost all of the plates on ENCO and other sites are import brand.

Also for rubbing the ways on a lathe or other narrow strips can you use the side of a surface plate, or are there purpose built plates with a narrow flat surface for this application?


Thanks,


Nelson

Import plates can be good enough for home use. Surface plates should be checked yearly if your work is precision work that you are doing. Granite tiles and pieces of glass are just not flat enough for precise work. Almost all of our plates where I work are within .00001 across the entire surface.

What are you doing to the "ways" that you would want to rub them down with a surface plate? To do anything like that, you want to use a stone designed for it and not a surface plate.

 

[flatbelter]

You probably could, using the 3 piece method of lapping, but unless you had a good way to gage your progress, it would be difficult to impossible to rival a bonafide surface plate. One guy I worked for started his first shop with a blank tombstone. I doubt it was certifiable, but evidently was sufficient.

After having hand ground a telescope mirror, I can honestly say that making optical flats is within the relm of the home shop machinest. The 3 plate lapping method works surprisingly well, and a quick sharpie marker testwill make your surface plates flat to some impressive specifications. It does take some time to get it done right but we're talking hours to a couple of days, not that bad. (assuming the plates aren't that big) :biggrin:

 

[arvidj]

... What are you doing to the "ways" that you would want to rub them down with a surface plate? To do anything like that, you want to use a stone designed for it and not a surface plate.

Kevin,

Could you provide additional information, suggestions or links on how to do it correctly with "stoned designed for it". I am interested in both the 'how to do it' and the 'where to get stones".

Thanks,
Arvid

 

[Mid Day Machining]

First, another stupid Nelson newbie question:

What are surface plates commonly used for in the home shop?

Next, a practical question due to cost:

Are import" surface plates any good?

[This question was asked on another forum, but the thread abruptly closed without an answer due to the word "import"]

Almost all of the plates on ENCO and other sites are import brand.

Also for rubbing the ways on a lathe or other narrow strips can you use the side of a surface plate, or are there purpose built plates with a narrow flat surface for this application?


Thanks,


Nelson

You must have been on Practical Machinist. I posted something I thought might have been interesting there 3 or 4 months ago, and was immediately banned with a note that said ban to be lifted, NEVER. Thost people need to get a life outside the machine shop.

 

[gunboatbay]

I bought one of Enco's 9x12 import surface plates several years ago and frequently use if for a lapping/sharpening surface. I drilled four equi-distant holes along the 12" surface on each side 1/2" from the edge. (The granite drills quite easily with a cheap carbide masonry-bit in the drill press). I epoxied rare-earth magnets in these holes, making sure the magnets were completely encapsulated in the epoxy and slightly below the surface. To use the surface, I lay a full sheet of wet-or dry abrasive paper, grit side up, on the surface and hold it down with two 12"long pieces of 5/16" cheap keystock placed over the magnets. I have the whole thing submerged in a polyethelyne 'tub' of water, which keeps the abrasive paper from loading up. Depending on what I'm trying to do with the workpiece, I use anwhere between 80 and 1200 grit paper. The plastic 'tub' has a snap lid and is great for storing the surface plate in when not in use. This isn't my idea originally; I found it somewhere on the internet.

Art

 

[BRIAN]

For years I used a window from a van as a surface plate, but now as I live in Sicily I have a large plate of marble. A bit soft, but it works well for me.

The question is just how acurate do you Need to be ????? Think of the cash you could spend elsewhere.

Regards BRIAN:

 

[donthack]

In regards to the plate it should has somewhere stated in the documentation, either with it, or in the advertisement of the standard it was made to. Your needs and finances will dictate the rest. Buying them used can be dicey, I know a shop that used theirs for a lapping plate for years and never had it re-certified. Make sure it came from a home that it was loved in.

 

[Tony Wells]

Buy new, or reconditioned plates, with certs, keep them clean, and distribute the wear by moving the work around, and they will last quite a while. There are some sophisticated instruments used to certify the plate, but you can do a fair job of spotting bad wear with a surface gage and a good DTI. By good, I mean at least 0.0001 resolution, preferably better. You can sometimes see low spots developing where the plate is used most. then you want to avoid those spots. Eventually it will need lapping, but it all depends on your accuracy demands.

I've been this process many, many times yearly on plates up to 5 a 8 feet. Those cost a bit, if you want them flat and repeatable to a high standard. Sometimes it's needed, sometimes not. Unless you have a climate controlled environment, it's not work getting a AA plate.Most home use gets by with a grade b just fine.