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Surface grinder coolant needed?

drcoelho

Stainless
Joined
Feb 19, 2017
Location
Los Altos
I'm in process of buying my first surface grinder. I'll be using it for prototype, not production purposes. I'd like to avoid going with coolant as I expect only intermittent use of the surface grinder and don't want the hassle. Assuming I solve the dust issue with a quality hood and HEPA collector, and that I'm willing to go slow, are their any disadvantages to not having coolant?
 
I was unable to dress my 8x18 chuck flat without coolant. Even taking .0002” passes and less and spraying with WD40, the chuck built up heat and distorted (.0008” low in the middle after cooling off if I remember correctly).

I use my grinder around once a month and have no issue with Blaser coolant in it.

For most of my work, a grinder without coolant would be almost useless.
 
I second that.

If it's a good grinder and was designed to run coolant, it will not make a mess or take you significantly more time than grinding dry. Actually will save you time by making the process simpler and work better. I have both coolant and a dust collector built into mine, and almost always use coolant.

FWIW my surface grinder is a Jones and Shipman 540 from the 1980s, 6" x 18"
 
The main disadvantage to not using coolant is heat. Even with a small or one-off job that doesn't require much time it can be a big factor. This will also depend upon the level of accuracy/tolerance/surface finish you're working to. If your work can tolerate .001 dip across the plate, for example, then dry grinding is probably ok. When working to .0001's on size/flatness you have to allow the piece to cool to a uniform temp. The smaller the x-section of the work the more heat will affect it. Heat can also easily distort the work if there's a lot of residual stress in the piece. You'll get done with the grind, pull the piece off the chuck and find out it's got potato chip distortion once on the surface plate. Most of the grinding I've done on the SG has been dry but plenty of times I had to rig up an ersatz coolant feed or have the spray bottle on hand to cool the work for the sake of time. Heat will build in a surprisingly short time even if you're only taking a skim cut. You can discover this yourself by grinding dry and allowing the piece to cool. Then either mark up the piece with a series of slashes across the piece with a magic marker and go from your last untouched downfeed setting a .0001 at a time. See how long it takes to completely clean off the marks. For most work I've done if the piece is warm to the touch it will change when it cools. You'll have to decide if this is important or not. You can even check the piece after cooling with an indicator on the surface plate. I prefer to grind with coolant when practical, the surface finish should also be more uniform and consistent. The material being ground can/will make a difference too. Grinding hardened D-2, CPM metals, or the M group steels for example, generate a lot more heat (wheel choice aside) than low carbon steel and it's easy to burn the piece and ruin the temper. If the piece is a cutter the heat can ruin how the cutting edge performs, Coolant isn't always required but when you need it you need it. Find out by experimenting with/without but I'd say you'll want to have coolant as an option.
 
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If you have a choice to buy coolant vs not. BUY it as you need not use it for small light work, but if you do some heavy grinding or large plate grinding and the occasional table and chuck top dress you have to use it as Hal and Bal said the heat will build up and the wheel will burn. Using a hand spray is not the answer and in my opinion a mister is better then nothing and a hand spray.
 
Having coolant is the best choice. You can build/buy a small system using a small pump and a small reservoir.
Very likely you will warp the chuck trying grinding it dry plus warping parts is another fate and then a big waste of time. Use a biodegradable coolant and so you will not have disposal problems.

Yes you likely will hear guys say it is not needed, and yes, I can grind dry with my many years in grinding but mark my advice wet is best.

Don't even think about grinding the chuck dry.

Plenty of advice about grinding a chuck here on PM. You might use a 46 or courser wheel. do wet and keep it cool with very small down feeds, incrementing across one way and going off chuck at both ends for a cool down rest. Best to not do it when you are still a green grinder hand.

Yes with some time in grinding you will still grind some/many jobs dry.
 
Consider other cooling schemes: mist coolant, or a cold air gun.
The grinding work I've done sorts out into two piles: large stock removal, and low stock for size and finish. First group always done wet, second always dry, occasionally with cold air cooling.

WRT grinding swarf, vacuum system with collector at machine feeding into a gravity separator (made from plastic trash can) to vacuum unit. Works for me.
 
I've talked to a couple machinists older than I that claim 90% of the time you shouldn't use coolant, but EVERY text I've read states the opposite that you should use coolant as much as possible and only not to when the material requires dry grinding (like graphite).

From my experience, coolant helps a bunch, even on small or one-off parts. In a lot of ways, those jobs will benefit the most from coolant as small thin parts are more prone to warp under heat and if it's a one-off, why chance messing it up? Coolant keeps the heat down and makes your work environment 100% cleaner as the fluid keeps all the dust and debris down in the table instead of letting it fly out into the shop or settle on the rest of the machine.
 
I cannot imagine doing surface grinding without a coolant - especially for precision work. Working with coolant is actually a much cleaner process, with no dust to settle on other machines (even though I have my grinding in a separate area some dust can always get through) and in the lungs, less heat, better finish, easier on the wheels and faster and less expensive in the long run.
 
I cannot imagine doing surface grinding without a coolant - especially for precision work. Working with coolant is actually a much cleaner process, with no dust to settle on other machines (even though I have my grinding in a separate area some dust can always get through) and in the lungs, less heat, better finish, easier on the wheels and faster and less expensive in the long run.
The lungs are the part I worry about.
 








 
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