Surface Grinding

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ctwo
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Re: Surface Grinding

Post by ctwo » Wed Nov 22, 2017 5:34 pm

I really did not want to, either...

But I had to laugh at Nelson's avatar. (it's the despised ant)
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

John Evans
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Re: Surface Grinding

Post by John Evans » Wed Nov 22, 2017 6:02 pm

What Glenn & Harold said! From personal experience get one with 2 axis power fees and coolant,your body will thank you !
www.chaski.com

Harold_V
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Re: Surface Grinding

Post by Harold_V » Thu Nov 23, 2017 2:33 am

John Evans wrote:What Glenn & Harold said! From personal experience get one with 2 axis power fees and coolant,
While I agree, not all tool makers do. Many prefer the manual machines, and often grind dry.
I worked as a tool maker for several years. When surface grinding was required, I did it with a machine such as you described. Yeah, it's a little bit harder to do it with power feeds, as they tend to hide the "feel" of the machine, but I preferred that to hand cranking, which makes it much more difficult to achieve the type of finish I prefer.

Coolant.

Again, some won't agree, but there's no way in hell I'd operate a surface grinder dry, no more than I'd operate a cylindrical grinder dry, especially when grinding stainless. It just complicates things too much for my liking, especially when one is trying to hold a couple tenths, which isn't all that uncommon when grinding.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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ctwo
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Re: Surface Grinding

Post by ctwo » Thu Apr 26, 2018 2:25 pm

There is a Brown&Sharpe grinder with chuck - a bit rusty. There are several more - all prided about $250. I'd have to burn a day at work, rent truck with lift (which I think lift gates will not handle this, maybe over 2000# ?). I'd buy it sight unseen if he'd bring it over. He will for another 800.

I might convince a friend to haul it on his car hauler trailer. Then to get it off...?

https://sfbay.craigslist.org/search/sss ... r&sort=rel
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

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GlennW
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Re: Surface Grinding

Post by GlennW » Thu Apr 26, 2018 3:40 pm

ctwo wrote:
Thu Apr 26, 2018 2:25 pm
a bit rusty.
That's an understatement!
c2.jpg
Run away as fast as you can...
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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ctwo
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Re: Surface Grinding

Post by ctwo » Thu Apr 26, 2018 9:33 pm

Can't these pretty much fix themselves, I mean as long as the table still glides smooth?
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

Harold_V
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Re: Surface Grinding

Post by Harold_V » Fri Apr 27, 2018 1:25 am

Depends. I purchased a 6 x 18 B&S grinder off ebay. It had been removed from service by the owner, but was now owned by a used machine tool dealer. It came equipped with a very nice profile dresser (worth more than I paid for the machine, including shipping), and cost just $1,200, including shipping from the East to the West coast. There's more to this story, as I was gifted with a couple dozen wheel hubs for my Cincinnati cutter grinder, along with the tools and manuals for the machine, all from the original owner (a large corporation in Pennsylvania). I found them because they had left their lubrication schedule in the machine, and it included their name and address. A quick phone call yielded excellent results, with no expense to me aside from paying for the phone call.

The grinder didn't display that much rust, but it was not rust free. The chuck was fine, but the column faces were rusted, as they are in Glenn's attached picture. Problem was, it had been worked on by someone without a clue. They had assembled it such that when the column traversed, it tilted because the hydraulic cylinder and the screw had both been installed in the wrong attitude. To add to the problems, the bed ways had been rescraped, but without paying attention to parallelism. I found .005" difference from one end to the other between the V and flat ways. That condition makes it impossible to accomplish acceptable work. My plan is to rescrape the ways, a project I hope to pursue as quickly as I get my induction furnace operational Fortunately, the ways for the column (the entire column moves for saddle feed. The saddle is stationary) appear to be in very good condition. I do not regret buying the machine. I could have done better in many respects, however.

Don't lose sight of the fact that grinders are intended to be precision tools. They are not the least bit similar to lathes and mills---neither of which are normally capable of (reliable) work in tenths. Grinders do that routinely, but in order to do so, they must be in respectable condition. If the grinder you select has issues, you most likely won't be happy with the results achieved.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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ctwo
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Re: Surface Grinding

Post by ctwo » Tue Jun 12, 2018 9:28 am

Looks like the guy got a pressure washer and some evaporust and now has the grinders listed for two grandages. They look so much better and are selling.
Standards are so important that everyone must have their own...
To measure is to know - Lord Kelvin
Disclaimer: I'm just a guy with a few machines...

Conrad_R_Hoffman
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Re: Surface Grinding

Post by Conrad_R_Hoffman » Wed Jun 13, 2018 8:38 pm

I don't consider myself an expert on grinding, yet I've been around surface and OD grinders for 30+ years and have had my own for a year or so. Boyer-Schultz 612, 7" wheels. On safety, you always ring the wheels and you always use blotters (add 'em if the labels are missing). You do have a full wheel guard, right? You always ask your self, "in the worst case, what could possibly go wrong?" If the work slips and shoots out the back, have you got something there to cushion it a bit or are you going to take the full ricochet? Is there anything on the work (shelf or protrusion) that will blow the wheel when that happens? Is the part magnetic? Did you remember to flip the magnetic chuck lever? Are you running the wheel within its maximum speed limit (that increases as it gets used up and the diameter goes down- Norton (I think) says so)? Are you going to run into the rear guide when you go over the back of the part? If the part is small and could slip, do you have it blocked with a piece of sheet steel? This is a biggie- if the part is tall, is there any way it could tip and blow the wheel? It needs to be secure in a big grinding vise, or up against an angle plate. No doubt that list is incomplete.

All that said, I've seen very few mishaps with small surface grinders over the years. Mostly shooting things out to the left because they weren't secure. The risk is greater if they start to get hot or burn. I've never seen a wheel blow. I don't have a coolant system, but have found that just brushing the surface with a suitable oil or coolant does the trick. Usually Cool Tool II for steel and WD-40 for aluminum. Yes, I grind aluminum quite often. Works fine with a standard white wheel, though SiC would probably be better. IMO, the absolute maximum that should be taken on a small surface grinder in conventional grinding is about 0.002". Maybe a bit more if the surface is milled and the grinding isn't continuous yet. I do sometimes creep feed small vertical features, and that might be a lot more, say 0.030" if necessary.

I use a VFD and love it. You can vary the effective hardness of the wheel with RPM. You can also use wheels with ratings below the full speed of the grinder. I have some very narrow wheels useful for slots and reducing the diameter of tap bodies that are only rated at 3400 RPM. No problem on my 3600 RPM grinder. I'm not set up for over-speed, but if you are, you can keep the same SFPM as the wheel diameter goes down. Note that a surface grinder gets turned on well before you want to use it, and it gets left running until you're done with the immediate task.

Most people seem to dress their wheels too finely, too slowly and in multiple passes. Don't do that- you'll just burn your work and grind inefficiently. Last dressing pass should be maybe 0.0005" and feed quite quickly across the wheel. If you're worried it's not fine enough and not smooth enough, it's probably about right. You should have a good reason for using anything finer than a 46 wheel, like holding a corner radius.

I do find balancing necessary for best results when using a dense wheel. With my narrow wheels no. With my 46 white wheel, not usually, though I can tell the difference. My Norton SG5 60 wheel is useless without balancing. It's dense, and will give a rippled finish unless balanced. I had great expectations for it (and they're expensive) and was surprised at how difficult it was to get decent performance out of it.

FWIW, I thought I'd use a surface grinder only every now and then. After getting one, it seems like something needs to be ground for me or for somebody about every other day of the week. And I don't even have an end mill fixture yet!
Conrad

1947 Logan 211 Lathe, Grizzly G1006 mill/drill, Clausing DP,
Boyar-Schultz 612H surface grinder, Sunnen hone, import
bandsaw, lots of measurement stuff, cutters, clutter & stuff.


"May the root sum of the squares of the Forces be with you."

earlgo
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Re: Surface Grinding

Post by earlgo » Thu Jun 14, 2018 8:48 am

First off, let me reiterate that I know less about surface grinding than anyone.
I have had this old Delta T&C grinder since 1985 when I bought it to sharpen threading dies. Think Rigid or Oster pipe threaders.
Since I didn't have a job or 3phase power in the garage, I bought and installed a 240V single phase 1/2hp motor, apparently against the laws of the gods and nature. I also mounted the grinder on rubber shock absorbing feet. I used and have used Norton 5SG-60-KVS wheels almost exclusively on the M2 tool steel dies. The ground surfaces were rippled, whether it was due to unbalanced wheels, single phase power or grinding a surface that is interrupted by triangular cutouts, I do not know.
After I was gainfully employed again, I used the grinder for a lot of projects, and eventually got better at learning how to do things, but I still used the Norton wheels for everything except carbide for which I bought a green wheel, and later a diamond wheel was given to me.
In cold weather the original v-belt drive had to be warmed up or the set in the belt would add to the ripples.
Recently I had a project that required a slightly better finish, so I bit the bullet and bought a HF link belt to drive the wheel.
Link Belt 6_2018 small.jpg
Link Belt
Amazingly it took some of the vibration out of the machine. I made a trial cut on a piece of scrap CRS and after a couple of spark outs, found the finish much improved.
Link Belt first cuts small.jpg
trial cut
For me, at least. Others would not think so. This whole monolog is to say that the link belt is a good addition for a belt driven grinder.

--earlgo
Deja Poo - The feeling you have seen all this crap before.

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GlennW
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Re: Surface Grinding

Post by GlennW » Thu Jun 14, 2018 9:44 am

That looks like a mighty nice finish for CRS!
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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SteveM
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Re: Surface Grinding

Post by SteveM » Thu Jun 14, 2018 10:24 am

earlgo wrote:
Thu Jun 14, 2018 8:48 am
First off, let me reiterate that I know less about surface grinding than anyone.
ALMOST anyone :-)

Steve

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