Poor Man's surface grinder

K

KenH

Well-Known Member
Since I don't have a surface grinder, I've been using the milling machine with a 7" grinding disk to make do. While it doesn't hold near the specs of a surface grinder, it will hold a typical 10" blade within ±.003" or so. Cleans up a good bit. Just took a 5/8" stud bolt screw to disk with a jam nut to lock disk in place. Chuck up in mill, spin up to max mill speed, and feed at .005" cutting depth. Make a few passes and it tends to clean up blade side pretty good. In the image below, I put a 1/16" rod under one end to get a distal taper to blade.

SurfaceGrind.jpg
 
Oh, forgot to mention that. If you look close to the top aluminum bar that is 1/4" X 2" wide. I drilled several 1/2" holes and epoxied rate earth magnets so the top of magnet is just flush with top of aluminum. There is also a 3/32" brass pin located in each end of the 1/4" aluminum plate that helps hold the blade. There's a hole thru the tang that fits over the pin at other end. So far, it's worked pretty good. Is it as good as a real surface grinder? No way - but it sure helps.

Ken H>
 
I try not to curse much, but that's f$@&$ng genius, lol! I will try this, can you post a picture of the hold down system without the blade in place,thanks.

Wayne
 
Sure, I'll try to get a couple of photos tonight... Which disk did I buy? I just pulled one from the drawer of disks for an angle grinder. I'll get photos tonight to show better detail.

Ken
 
OK, here's a couple of photos that might explain better what I'm doing here.

GrindingDisk.JPG

That's the disk I'm using - nothing special about it, just of a box of some I had on hand. I suspect there would be other disks better for the use. I just screwed a 5/8" stud into disk, then used a jam nut to lock in place.

PlateView.jpg
Here is blade laying on magnetic holder.

PlateView-2.jpg
This is a view with blade laying to side and you can see face of magnetic holder with the magnetics inlayed in 1/4" bar.

Ken H>
 
Thanks for the additional pics, answered my question. With it spinning I couldnt tell if it was a regular disc or pad with abrasives.
 
Thanks to all for the nice words - do remember, this is NOT as good as a surface grinder, but it does help keep the two sides parallel better than grinding flat on platen. Once I clean up both sides, they are usually within ±.003" which is a good bit better than I can do on the platen.

It also does a distal taper better than I can do flat grinding on the platen. As I said, truly a "Poor man's surface grinder"...

I did try a pad with sand paper first, but the soft pad didn't work as good as the hard disk. Too much give in the pad, perhaps a harder pad might have worked better.

Ken H>
 
Certainly could be a good go ahead for many ! I haven't got the milling machine and am some concerned to set up my drill press to do this. Maybe, just maybe, my disc grinder might handle an adaptation. Yes, this "poor man's" disc grinder could be very helpful even to a guy like me who has been doing this by hand for over thirty years. The getting close thing is what takes so much care.
With much respect for your thread.
Frank
 
Now thats a SUPER idea! Even though I have a surface grinder, I can see a lot of uses for that type of setup.....thats the kind of idea sharing that will make you a legend! :) I can just see 5/8" bolts flying outta the hardware stores now!
 
What is everyone's thought on doing something like this on a drill press with a cross slide vice? I know it wouldn't be as accurate as doing it on a mill, but might yield acceptable results. I don't know if the lateral stress would be too much for the bearing.
 
I think it might work - there is VERY little side stress on the spindle with this method. Remember, you're only taking a very few (5 to 10 depending on RPM and feed rate) thousandths of an inch at a time.

Let us know how it works for you.

Ken H>
 
Ken, I think you've started something. I picked up a 7" disc today to try it, but I've still got to build a hold down table of some kind. Have you tried this with one of the flap discs? I use them sometimes around the shop and they leave a pretty nice finish on steel. I saw that they had those in 7" too, but they're $10 ea. Some of my laser cut parts have a slight cup in them and they're pretty tedious to flatten on a disc grinder, so I'm hoping this way will be a little faster.
 
The only issue I can foresee if this is done with a drill press is rigidity.....any movement via "flexing" of anything could get you in serious trouble in the blink of an eye.
 
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