using a surface grinder --

[Burchtree]

Any good tutorials out there on how to use a surface grinder? I'm picking one up, but have truthfully never used one. What are some good wheel choices, safe cutting depths, etc? It is a Boyer Schultz 612.

Thanks --

 

[gspam1]

Michael:

Most general machining text books have a section on surface grinder useage. You can pick these up very cheap off eBay or a used book service like Abe Books or Amazon. There are books dedicated to surface grinding as well.

George

 

[tmickley]

I was surprised at how slow it can be to use one. Higgy has said a dozen times, they aren't for taking off a lot of stock, they are for making things flat.
You don't want to take off more than .002" and probably .0015" is better at a swipe. If I want a very smooth finish, I'll just take .001" or so. Each successive pass might be 1/2 or 1/3 of a turn of the wheel that controls the table in/out. Watch for heat as it will warp the part and you won't get a flat surface. I initially went with a cheap mag chuck and then had to go back and get a fine pole mag chuck for the small folder parts I use it on. My HF has an oiling mechanism that slowly puts oil on the tables ways. I've found this really messes up your cuts as the table floats and then settles on the oil. You can surface grind dry if you control your cut. A good wheel is $30, a cheap one is $15, get the good wheel. Grit's for wheels are nothing like grits for grinding belts. The wheel should ring like a bell with lightly struck. If it is dull, throw it away as it might have a crack and when you see how fast that thing goes, you'll know why you don't want one of those exploding on you. Nice, even, smooth cranking on the wheels for a smooth finish. If you stall while moving, you will burn a spot, if you go too fast the finish will be rippled. Dress the wheel at least every other use.
Hope that helps...Have fun.

 

[steierknives]

A good grit to use on the wheel is 46. You can use a 60 grit to get a smoother finish, but the wheel will load up a lot faster and burn the work. Norton is a good brand of wheel, but will be more expensive. I have a grinder vise which comes in very handy to hold parts. An angle dresser comes in handy. You can dress a certain angle on your wheel, then grind this angle on your part. I use the angle dresser and grinder vise to grind the dovetail on my bolster and locking surface on the liner lock blade.

 

[J. MacDonald]

You need to learn patience. Surface grinding is a zen type endeavor. Slow and steady gets the job done.

A set of books called Machine Tool Operation by Burkhardt would be a good addition to your shop. They were school shop text books published by McGraw Hill. There are two volumes. Volume 1 has a grinding chapter. I think I bought my set on the used book section on Amazon.

Congrats on the new addition.

 

[jhiggins]

Good advice above. :thumbup:

Never go for more than .001 cut.

rig up a vac system downwind to catch the debris coming off the wheel and take very light cuts.

Technique: Lets say you are going to flatten a blade blank.

1) Deburr the edges and layout dye both sides. Once you get the hang of what you are doing, this step is unnecessary.

NOTE: You should only be taking quick light passes across the workpiece, not slow deliberate passes. That builds heat. Heat is your enemy on any SG setup. Never try to completely cross your workpiece in one pass. Always advance across your work using half of the width of your stone. For instance, if you stone is .500 wide, you need to take .250 advancements across your work. This promotes the fastest and most-consistent flatness.

2) Skim just enough off one side to flatten it. You can leave some dips and flaws at this point. All we want right now is flatness across the width and the length. The dye will show you where you need more work.

3) Flip it over and now flatten this side completely to your liking, bearing in mind how much you will need to remove from the opposite side to make it to within your specs.

There is nothing as rewarding as making a lockback or a slipjoint and flattening the spring AND the blade to the same thickness.

That's it! Like Tracy said, easy does it.

 

[Fox]

You can really simplify your life and convert it to use 2" x 72" belts!

 

[Burchtree]

You can really simplify your life and convert it to use 2" x 72" belts!

That is something I'll probably end up doing with this if I get another SG down the road. Now for a few really stupid questions -- how to dress a wheel? Also, someone spoke of "regrinding" the chuck. What is that all about? And one generic question -- a good oil for machinery for protecting and lubricating?

It isn't in place, but at least it is in the shop!

 

[Mark Nelson]

Looking at your folders at Blade Michael, I would have guessed you had a surface grinder. I look forward to what you do with that beast.

 

[steierknives]

To answer you question about regrinding your chuck. You will only need to do this if you are getting tapered parts. If you attempt to do this, turn the magnet on. Feed down until you barely get a spark off the chuck.(Start on one edge.) You want to take as small a cut as possible, so you do not generate much heat. If you have coolant, run it. Take a slow cut accross the chuck. One toolmaker told me to feed down about 2 tenths at a time. Continue this process until the chuck is cleaned up. You might even make the last couple of passes without feeding down at all. This will take off high spots that weren't taken off. When the wheel quits sparking you have all the high spots.
To dress the wheel, place the diamond which is mounted in a flat piece of steel, on the chuck. Turn on the magnet. I always lower the wheel so it is on the back side of the wheel. In case I forgot to put on the magnet it won't be pinched between the wheel and the chuck, just pushed away. Bring the wheel down until the wheel touches the diamond. With the crossfeed move the diamond away from the wheel. Once it is clear, feed down a few thousandths. With the crossfeed move the diamond to the other side of the wheel. Continue doing this until the bottom of the wheel is flat.
Hope this helps.

 

[Burchtree]

Thanks again for all the advice -- I've been reading over there in "The Practical Machinist," and will probably pick up some books.

 

[Burchtree]

With the crossfeed move the diamond to the other side of the wheel. Continue doing this until the bottom of the wheel is flat.
Hope this helps.

So basically, this gives you new "grit" and squares up the wheel? Also, when grinding is it better to move the table left-to-right, vice versa, or does it matter?

 

[steierknives]

Not sure what you mean about left to right. You do most of the moving of the table left to right. Then with the crossfeed index the table about an eight of an inch or so between passes. You are right about squaring up the wheel and getting new grit. It will also remove any unwanted material you picked up while grinding. I get a lot of nickle buildup when grind damascus. Dressing will take this off. This material will cause the work to burn if you don't get it off.

 

[fitzo]

Michael, before you do any grinding on your mag chuck, make sure you test indicate the thing to see how out of flat it is. Mount your indicator base on the wheel cover, start at one corner as "zero" on your dial, and check flatness from corner to corner and on the diagonals. If you have to grind much more than a couple thou off to square it, consider shimming it from underneath with thin brass shimstock. If you do grind, like Steier said, SMALL bites.

If you didn't have a dial indicator and base already, this would be a relatively inexpensive addition to your shop and useful with milling, lathe, and SG. While made in USA is always nice, Chinese will do.

If you can get by a machine shop, ask them to show you manual surface grinding. It's a cool little coordinated motion that puts you in a trance, machineshop-Zen.

 

[JCaswell]

You can really simplify your life and convert it to use 2" x 72" belts!

Amen to that!!
I don't know what kind of tollerance you're looking for, but I have a hard time caring beyond half a thou on pieces I'm likely to be surface grinding and can do that or better with a fine belt and quick, light cuts.
Plus, you put a 36 belt on that baby and clean up/square up a forging like magic. No set up, no stone dressing .... If you need/want .00005 then by all means, use a stone. The advice given previsouly seems top notch (as usual) for that.

 

[Dan Gray]

I can't add much other than
I'll also dress the wheel for the last two passes, and you need only take a very little off te wheel.
as with any grinding stone they are for ferrous medals only, unless the stone is rated other wise..
you can load them and cause them to go ,,,BOOOMMM

If you need/want .00005 then by all means, use a stone.

make sure the wind isn't blowing and you don't breath on it.
.00005 not in most shops...unless its a climate controlled shop anyway

 

[JCaswell]

I can't add much other than
make sure the wind isn't blowing and you don't breath on it.
.00005 not in most shops...unless its a climate controlled shop anyway

That's for sure.
I have a stainless pivot pin sitting in front of me as I write that comes in at .1855 at night and .1860 in the daytime.
Nope, plus or minus half a thou is good enough for me most of the time. Am I gonna sweat .0002 on a surface grinder just to loose that much when the peice cools off? If .001 is good enough, you can get that with a good belt conversion without a problem.
Still, a lot of hard-core guys like grinding with stone wheels, so I guess there must be something to that too.

 

[J. MacDonald]

Michael,

Cograts on the new tool. She looks like a beauty. My little old Yuasa 6x12 is jealous

I don't think you're likely to find a SG converted to a belt in my shop. To me the whole idea of an SG is precision grinding and a belt will never be as precise as a rock. But I can see how the belt conversion can be a real time saver for flattening forgings and stuff. I'm not trying to restart that old argument, it just goes against my training, even if that was a long time ago.

Of course, if it's good enough for Allen Elishewitz, who am I to question.

Now a nice 6x18 with hydraulic X and Y feeds and flood coolant and ball bearing ways, that I could get real excited about!

 

[Dan Gray]

Michael,

Cograts on the new tool. She looks like a beauty. My little old Yuasa 6x12 is jealous

I don't think you're likely to find a SG converted to a belt in my shop. To me the whole idea of an SG is precision grinding and a belt will never be as precise as a rock. But I can see how the belt conversion can be a real time saver for flattening forgings and stuff. I'm not trying to restart that old argument, it just goes against my training, even if that was a long time ago.

Of course, if it's good enough for Allen Elishewitz, who am I to question.

Now a nice 6x18 with hydraulic X and Y feeds and flood coolant and ball bearing ways, that I could get real excited about!

mine's an old brown&sharp with belt driven X and Y feeds
it's sure better than with-out it..

hydraulic X and Y feeds, flood coolant and ball bearing ways
that's a big 10-4 for sure:thumbup:

 

[Daniel Koster]

Now a nice 6x18 with hydraulic X and Y feeds and flood coolant and ball bearing ways, that I could get real excited about!

Ray Kirk has one of these...man, it is fun to watch. I don't think I'd save any time, cause I'd just sit there and watch it. Maybe after a few years I'd get bored with it...but it's mesmerizing.


There was one for sale in Tulsa, OK (2 hours away for me) on ebay....got outbid in the last 10 seconds...man, how 10 seconds can change one's mood... :grumpy: