Poor Man's surface grinder

John, dummy me! My mind was in the wrong track. Of course, "disk grinder" among knife makers is a "disk grinder"... Works great for flattening surfaces from small imperfections. Got one myself that uses 8-1/2" X 11" sandpaper glued on, then cut in a circle.

I've wondered about your question also - I've got an 8" aluminum disk I've planned to rig up on the mill and see how that works. I suspect it will work better than the grinder disc I'm currently using on the mill. That grinder disc has a good bit of run-out on it. The disk from the vertical disk grinder would be MUCH less. I think it would be better..... I think.

Ken
 
I just wonder if the sandpaper will hold up. Someone mentioned that earlier- but if it does hold up then your idea has nearly limitless possibilities.


Sent from my iPhone using Tapatalk
 
I don't think sandpaper will hold up for removing much metal (stock removal?), but for putting the finishing touch I think it might give a better finish than the 7" grinding disc I've got. For sandpaper to work it would have a lot of the face of disk with sandpaper sanding at once - this is going to put more force on the blade than the current setup using the 7" grinding disc. Remember, this type of disc as a small cup to the face so there is only a small area actually touching the metal blade at a time.

The 7" grinding disc sure does put a lot of metal dust in the area - and this is NOT good for the ways of the milling machine. I make sure to do a good cleanup after using it in this manner. I also use the shop vac while grinding to catch as much of the dust as possible.

Later
 
Not great for the milling machine- but fairly insignificant for a drill press.... (Scratching chin)

Being that there is very little side load on the tapered chuck I'd like to see how it pans out.

Has anyone here ever JB Welded the tapered drill chuck in? A craigslist-special drill press could become a dedicated Hillbilly Surface Grinder.


Sent from my iPhone using Tapatalk
 
Just a word of caution guy's, when you grind on your mill be very careful of protecting the ways from the grit and dust. This fine dust will prematurely "grind" the precision surfaces that mate together. Not good for the machine. It can be done if you cover the ways with rags. Lots of cautions about this sort of thing in the machinist forums.
 
An update for this "Poor Man's" surface grinder. I reported ±.002" results with this setup using a "makeshift" type magnetic table. Well, I found a 6"X8" magnetic chuck for $135 shipped on ebay. Asking was $125 (plus $35 shipping), I made an offer of $100 plus shipping and it was accepted. I got the magnetic chuck (table?) today and must say it seems to work good. Clamped to milling machine table, ran an indicator from one end to other and there was no change. I had a backspring that needed a bit of grinding to finished thickness - finished product was about 1/2 thou from one end to other. I was impressed - maybe it's a fluke, but I'm pleased with this test.

Magnetic_Table-s.jpg
Forgot to post pic of setup! Thanks for asking question Jeremy.

Here's the one I purchased: http://www.ebay.com/itm/251952280755

Best I can tell, it's the same as this: http://www.ebay.com/itm/351003084171

Ken H>
 
Last edited:
Very cool-I'd say a 1/2 a thousandth is pretty darned good :). Might need to look around for one of those magnetic chucks. Guessing you're still taking really small "bites"? Any nervousness about the blades being thrown off the chuck without the pin setup?

Jeremy
 
Last edited:
I edited post to add photo - I forgot to add before. If you look close at the edge of magnetic table you can see an adjustable "bar" that provides a nice ledge that holds the backspring in place. Works better than the pin did. The bar is adjusted to be lower than thickness of metal, but still enough to hold metal from sliding off.

Ken H>
 
Jeremy, you didn't miss anything - I didn't realize I'd forgot the photo until you asked the question.
 
Ken, I know this an ancient thread, but I'm wondering if you are still using this setup and what, if any, changes you may have made.
 
Yep, it's an old post, and I do still use the same setup for my "surface" grinder. The first setup I posted was sorta of "made do", but once I got the magnetic chuck it all came together. The BIG concern I have that limits my use is the grinding dust that gets into the ways. While I try to do a good job of cleaning and protecting the ways to prevent damage I do feel this is the weakness with this setup. I would NOT recommend it for a full time operation, but for me who only makes a few knives it seems to work pretty good.

Ken H>
 
Excellent. In the time since this thread began I have outfitted my shop a good bit but I don't have a surface grinder. My mill is a little mini-mill, and there aren't a lot of exposed ways. I can easily tape a trash bag drape around my vertical ways and a good cleaning afterward should get all the dust off anyway.

Did you stick to the flat grinder disc, or did you adopt the cup style wheels? Do they need to be dressed (or can they be) ?
 
I'm still using the flat 7" disk grinder. I'd like to have a cup grinder wheel, but not found one at a price I'm open to paying {g}. The 7" disk works "ok", but is slow going since I tend to take off only a couple thou at a time. For the folder work I use it for mostly, it works ok. On a long 8" to 10" chef knife distal taper it would be slow. On my kitchen knives I'm using thinner material, .060" to .070" and those don't really need much of a distal taper at all.

Ken H>
 
You must log in or register to reply here.
Back
Top