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Looking for a reconditioning: surface grinding, possibly re-scraping?

I've old articles from HSM and other sources about hand scraping. I know that said tools were made from, I guess..."modified files"? They were hardened to my recollection.
Correct, files are glass hard as attested by the half files I own.
 
Sounds like you're a carpetbagger ? Us californians will go 60 miles for a good burrito. I had a customer in healdsburg who used to pick up parts and run them down to san leandro twice a week.

Heck, I'd run down to edwards not as often but plenty, in a van that shouldn't have been allowed across the street.
I never said I wouldn't go to where I could find a shop that could do it, just there are few machine shops up here. Mainly what I know of remaining are CNC shops. Whether or not any of them have surface grinding capabilities I don't know? I just know the last shop I worked at (a really long time ago) had a small room with a tool grinder, manual lathe and it was probably a Bridgeport and they just sat in there. No one used them. With the exception of the tool grinder(I think the only machine that got used regularly) the other two had so much dust and grit on them from sitting you could wipe it off like a layer of icing off a cake.
 
Love to, but I don't know where you are (geographically speaking).
I'm in Cottage Grove, MN. I see your in California. To bad you weren't a member a few years ago. I taught in Berkeley, Oakland, Vacaville a number of classes. I am to old now to travel as my health isn't as good, so I've decided to only teach 200 feet from my house. If you really want to come and can't afford it. I offer a hardship price. Basically I give you a big discount as long as you teach someone someday. Pay forward....I supply all the tools during the class, so no investment is needed. I'm teaching weekend classes so those who are still working. can come and not have to take off so much work time.
 
There is a shop north of Los Angeles that grinds..I forgot their name. A few years ago we did a list of grinding shops in the USA and their listed. Google, Large capacity grinding practicalmachinist Richard King...
 
Patience I have, the skills and knowledge (as well as the scraping tools). I don't.
Surface plate. 200-300 bucks, depending on size, new or used; I picked up a 2'x3' pink Starret grade B with a stand for 200, so bargains do come by. A scraper with a carbide blade about 80 to 100.
Or, you can buy these and make a handle.


Ink 10 to 20. bucks for each color that will last you an eternity. Pick contrasting colors like red and black or dark blue and yellow.


The only thing that is a bit dodgy is rigging up a low RPM sharpening thingie using diamond-lapping discs. I used a treadmill motor with a controller and some of these (or similar).



Something like a 600 to 1000 for shaping and a 3000+ grit for polishing.
will do fine. Diamonds do eat carbide :)
 
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Nice pic of dcsipo of his plate he scraped at the class he and PoaloMd took at Tocaho (spelling) museum in Easton MD. if you get a chance you have to go. It's an all ceiling belt driven machine shop. Paolo is holding the camera. Another Museum you should visit is the American Precision Museum in Springfield VT. Number 1 Bridgeport is there plus a lot of guns.
 

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Nice pic of dcsipo of his plate he scraped at the class he and PoaloMd took at Tocaho (spelling) museum in Easton MD. if you get a chance you have to go. It's an all ceiling belt driven machine shop. Paolo is holding the camera. Another Museum you should visit is the American Precision Museum in Springfield VT. Number 1 Bridgeport is there plus a lot of guns.
Ok, busted...
 
An ugly, but rather effective way to get closer to flatness fairly cheap is to stick 4 sheets of sandpaper to a piece of thick glass or a "granite" counter top and "lap" the plate by moving it in a figure-8 pattern, holding preferentially in the middle, in order to reduce the risk of grinding it convex.
You can do quick checks for flatness in different areas with a knife-edge straightedge or similar against the light. When you are satisfied with it, you can switch to finer grades of sandpaper.

True, it won't be perfect but it could be even flatter than a grinding job, if the plate were slightly deformed by holding it down on the grinder's table.

I can testify that Dee speaks out of personal experience: at the scraping class he brought a "camelback surface plate". If I recall correctly, that plate had a few thousands-high hump in the middle, as you can see by the sharpie marks delineating the step-scraping areas in the first picture.
The final result was way better.

Again, not speaking about perfect job, but something reasonably close, especially if you intend to use the plate for layout work and similar, although more tedious and requiring more thinking to interpret the measurements, you can finish up the plate by scraping even without using a spotting master (i.e. another surface plate or a camelback straightedge): all you need is a parallel (at least 18" long) and a dial or test indicator reading tens of thousands. You place the parallel on the plate resting on shims at precise locations and, with the indicator, you map the whole surface. You need to do it from at least 4 locations (2 parallel to the long side, two parallel to the short one), process the data to even out the inconsistencies (i.e. the shims under the parallel might be in a low spot or in a high spot, as you can determine by surveying the plate from the second parallel location, and the plate could be shaped like a saddle, with two diagonally opposite corners high and two low, therefore the need to surveying from orthogonal positions), and you can mark the areas that need one or two rounds of scraping (after which you would need to redo the mapping).
It is a laborious, time consuming, and error-prone process, unless you pay the utmost attention to interpret correctly the calculations.

As Dee and others have pointed out, a 12x18" granite plate is reasonably cheap and it does not need a dedicated stand (and, with some effort, it can be stowed out of the away when not needed).

Paolo

PS A few more pictures from that class of eight years ago

I am still volunteering at Tuckahoe and, most Saturdays I am at the Machine Shop Museum. The first Saturday of every month from May to November, all Museums of Talbot County, MD are open to the public. If you want to visit at any other time, just contact me and we can arrange it.
 

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Surface plate. 200-300 bucks, depending on size, new or used; I picked up a 2'x3' pink Starret grade B with a stand for 200, so bargains do come by. A scraper with a carbide blade about 80 to 100.
Or, you can buy these and make a handle.


Ink 10 to 20. bucks for each color that will last you an eternity. Pick contrasting colors like red and black or dark blue and yellow.


The only thing that is a bit dodgy is rigging up a low RPM sharpening thingie using diamond-lapping discs. I used a treadmill motor with a controller and some of these (or similar).



Something like a 600 to 1000 for shaping and a 3000+ grit for polishing.
will do fine. Diamonds do eat carbide :)
Expanding on Dee's post, I have built my favorite hand scrapers for carbide inserts using 1/8" 1018 or equivalent steel bar, milling at one end the pocket for the insert (either Sandvik or, more recently, repurposing some cheap blades from Amazon) and brazing a piece of 1/4-20 all-thread at the other, in order to secure a flap disk (to push the scraper with the body). Here is a link to another thread with useful info regarding making scraping gear on a budget.
 

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QT Op Blanchard? What would they be able to grind the plate to tolerance wise? Hopefully better than .001?.
:likely .0003
Here is a typical claim for Blanchard

 
Damn. Why do I live in the wrong province. Wouldn’t mind having a Blanchard shop nearby, not to mention the size of stess relief furnace Anchor has. Thanks for the link- will be contacting them soon for a quote.
 
Do let us at PM know what the quote is.
I suspect at a major Blanchard shop it will be $100 or more for an hour job.
I would likely set it flat side up and skim where it sets, and then skim the top side.

Don’t mean to give the wrong idea. I’m interested in getting some medium size steel sections Blanchard ground and stress relieved, not a surface plate. My tolerances are +/- 5thou. Have re scraped several surface plates in the past and have tools and ability to do that again if needed. I don’t know if a Blanchard would get to the flatness I can achieve by hand scraping?

Sorry for the topic wandering.
 
There used to be a blanchard guy in Hayward that would’ve done that plate for 50 bucks if you paid cash. looks like he’s out of business now though. Who can pay rent in the Bay Area on a $50 minimum?

There are plenty of shops still open if you take the time to look. Maybe give these guys a call:
 
I highly recommend the American Precision Museum at Springfield, Vt. It well worth the trip, no matter where you are.
I was there a couple of years ago and am ready to go again.
JC
 
If it's a Brown & Sharp plate it probably is sitting on 3 points. If you have it ground (which I wouldn't do unless there were deep gouges in it) I'd set it on the 3 points and block around the outside. Then kiss the top. Use flood coolant.
 








 
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