Basic Surface Grinding

Hi Bernie...

The passes are pretty fast. That piece is about 6" long and if I had to guess, a full pass (going from L->R then R->L) is 5 seconds. To cover the part from top to bottom (on one side) is about 5 minutes. I'm sure You Tube has some live videos.

On a lathe, you don't do much at all. With this thing, your left arm is cranking back and forth like an organ grinder's monkey and every five seconds, the right hand makes a quarter turn on the infeed. You can easily fall into the trap of locking your body into a hunched-over and set position for a long period and before you know it, your shoulders are tight and stiff and lower back is aching.

BTW: I really should mention that full face protection could save your vision or life. I highly recommend wearing it.

... Good luck with your machine. What kind and size? BTW, if ever I had to get a different one, a 6x12 instead of a 6x18 would suit me fine... Autofeed... yeah, I'd love that.


Ray


I love this thread Ray!! Thank you! This lesson is right up my alley, since I am in the market for a Surface grinder, and think I found one.

How long do you take on each pass? Silly question, but I've never seen it done. What is tiring about it compared to lathe work? Is it that fine a feed per turn? The machine I'm looking at is also manual (or I couldn't afford it :)


Bernie

- - - Updated - - -

Yes, I never really notice much airblown dust on other machines nor does it build-up on my eyeglasses (unlike with my sand blaster). The trick is to get the draw tube lined-up right on with the direction of the projecting dust.

Ray
 
Thanks for this post. I use my koolmist with my grinder as well. I have not set up a dust collection system yet on mine. But you are right I desperately need to. I get that caked in the nose black dust and that can't be good for ya. I was thinking of using one of the Oneida dust deputes hooked to my shopvac. I have one on my blasting cabinet and it works great. Please post more on the surface grinder this is one area I am very weak. I would like to see how you set your coolant up and more on your dust system.

Jeff
 
Hi Bernie...

The passes are pretty fast. That piece is about 6" long and if I had to guess, a full pass (going from L->R then R->L) is 5 seconds. To cover the part from top to bottom (on one side) is about 5 minutes. I'm sure You Tube has some live videos.

Gotcha- that was what I pictured, having just turned the handles on the one I saw.. :) ...


BTW: I really should mention that full face protection could save your vision or life. I highly recommend wearing it.

... Good luck with your machine. What kind and size? BTW, if ever I had to get a different one, a 6x12 instead of a 6x18 would suit me fine... Autofeed... yeah, I'd love that.


Ray

Looking online at pics, it seems the one I found is a 6x12... Manual feed. I bought the lathe from this guy, and he seemed to find nice machines, and kept his machines tip top :)


Yes, I never really notice much airblown dust on other machines nor does it build-up on my eyeglasses (unlike with my sand blaster). The trick is to get the draw tube lined-up right on with the direction of the projecting dust.

Ray

I am all over keeping myself safe and my other machines clean. I use the same vacuum setup as your grinder when I am cutting cast iron on the lathe. I just don't have a clue how much dust really goes up when finish grinding like you did there.

I second Jeff's request for a part two of this post!!!! :)


Bernie
 
Thanks for this post. I use my koolmist with my grinder as well. I have not set up a dust collection system yet on mine. But you are right I desperately need to. I get that caked in the nose black dust and that can't be good for ya. I was thinking of using one of the Oneida dust deputes hooked to my shopvac. I have one on my blasting cabinet and it works great. Please post more on the surface grinder this is one area I am very weak. I would like to see how you set your coolant up and more on your dust system.

Jeff

You're welcome...

Well, assuming your grinder is nice and flat and in proper working order, the most important thing is to have a very well balanced wheel. I've shown my balancing setup many times here but if you need to see it again, here it is. That axle was specially made to fit the grinder hub and with it, the balance weights can be adjusted to statically balance the wheel. It makes a huge difference in the quality of the grind. A slightly unbalanced wheel will leave little cup-marks on the surface. Many hubs have no balancing mechanism. The ones that do cost over $600 each -so I make my own and have posted threads here on how I make them. I have no idea how anyone can do a good job w/o a balanced setup.

BTW: In the picture of the bearing balancer, you can see the black draw tube. It's a heavy plastic that bends and stretches -and most important, does not collapse when the vacuum is switched on. You can't use the tubing from a clothes dryer vent as it will just collapse immediately. Anyhow, the vacuum system is trivial. I just connect the tube to the unit (it fits perfectly) and use a telescoping stand to position the hose inlet right in-line with the grinding dust. Simple as that. The tubing is heavy enough to not start on fire and most of the dust settles in the tube and never makes it to the bag.

Balancer Arbor.JPGBackside Balancers.JPG

Next thing is to surface the wheel with a diamond. They cost about 40 bucks and last a long time. It's the small rod-like thing sticking out of the holding cylinder. The actual diamond is 1/4 carat and is embedded and silver-soldered into the rod. It is purchased that way. The holding cylinder is a piece of drops with a hole drilled to hold the rod/diamond and a bolt to hold the diamond in place. With the motor off, you clamp the holding cylinder with the mag base, move it very close to the wheel (but not touching), lock the x-direction of the bed, spin the wheel by hand and lower the head juuuust until it starts to touch, move the diamond away in the Y-direction then lower the head 1/2 thou. Fnally, turn on the motor and move the diamond across the wheel slowly. Keep lowering the head 1/2 thou at a time until the wheel face is even. -Takes all of a minute or two.

The vacuum should be on the whole time as the wheel kicks-up dust and that is aluminum or silicon oxide -not good for the lungs.

BTW: I'm using the XYZ coordinate system as in milling -and don't know if that's the correct ordinate system traditionally used in grinding. Feel free to clarify if I'm wrong. Also, I never learned grinding prior to the last few years so, this is all coming from the school of hard knocks.

sg8.JPG

After that, you just do what's mentioned in the first part of this thread.

At the surface (pun intended), it's pretty easy. In reality, many things can go wrong. Using the wrong type of wheel on a given metal, too much downfeed (good is 0.0001" for a finish pass and 0.0002 to 0.0003 is about right for rough passes), not recognizing when the wheel needs to be faced, too much infeed in one pass, heat buildup... Those are the easy things that go wrong. Then you get into the hard problems, like how to do thin pieces or holding pieces at angles... In the near future, I'll show some stuff about how I've tackled that.


Ray

Balancer Arbor.JPG Backside Balancers.JPG sg8.JPG
 
I have seen your balance wheel post before but now I need to go back and read them. I have seen the cupped finish you mentioned before and never knew what caused is. Looks like a wheel balancer and hub is in my future to build.

Jeff
 
Ray, thanks for the post. Very informative. Believe me, I can use all the instructions I can get. I ordered two 46 grit wheels, per your suggestion, and got them yesterday. I plan on spending some time with the grinder, hopefully this week. I am going to try to rig up a stand for my dust collector first and then look into your static wheel balancer. I will have to find that post, I know have seen it before. I will continue to follow your future post on the SG.

PS: I will contact you on helping me set up the VFD to variable speed.

Thanks much,
Sandia
 
Ray, you're not helping. I've been needing a bigger shop for some time. Now I have to find space for a surface grinder. :biggrin: And find a surface grinder. Nothing gives a finish like a grinder.

Good post. Thanks.
 
Yeah, I hear y'a... I'm fresh out of space too. Where there's a will, there's a way!

Ray


Ray, you're not helping. I've been needing a bigger shop for some time. Now I have to find space for a surface grinder. :biggrin: And find a surface grinder. Nothing gives a finish like a grinder.

Good post. Thanks.
 
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