Surface Grinder Restoration & Belt Conversion WIP

Salem Straub said:
Just as a voice to argue the other side, and not that I even have my own SG yet, it's common for makers to be able to remove .020" or even more in a pass with a belt converted surface grinder... as opposed to like .005" a pass with a stone wheel. That should get you there quicker. Ken Onion and some other folder guys were discussing this not long ago on USN like it was night and day...
Click to expand...

What is USN.
 
I'm with Don on this one.. For making knives, I *much* prefer a stone. I've used about half a dozen belt converted SG's, and while they're always convenient, and there's a big range of variance between the conversions and the machines themselves in terms of accuracy, none of them hold tolerances like my SG with a stone does.. I'm using probably the same Norton (gray) stones that Don uses primarily, and I can hog pretty well (don't usually take more than .004 though, but that adds up quick with an auto feed machine, and my stones are 1" or 3/4" thick) or leave an equiv 220+ grit finish on a ricasso, that takes seconds to lap up to 400 and then go to hand finishing. You can also dress the wheels to various effects like cutting in fullers, nail nicks, etc. etc. And with the right fixtures do all sorts of advanced machining, and usually, hold very tight tolerances with a good machine.


Yes a belt conversion is great for hogging with a 36 or 50 grit belt on there, but very few belt modded machines I've used will leave a very consistent finish even at higher grit, and most of them don't hold anything like 0.0005 tolerances, regardless of what their owner's say. And I gotta wonder what you need to be taking 0.020 swipes off of other than damascus.

IMHO, and to each their own, but the only justification for a belt mod is for extreme hogging in the case of stock reduction or damascus work. If your goal is "flat and parallel" a stone is a much better choice, cheaper, easier, and in most ways (other than just switching belts or using worn ones) more versatile.


YMMV of course.
 
Sorry for the late reply guys, Internet connection problems for the past week or so.

Thanks for all your help guys, much appreciated.

You are right Don, some sort of air powered auto feed. More pictures of it later and info as I learn more about it.

A lot of people have suggested giving wheels a try before I do the conversion and I think that it is sound advice. Not saying I won't do the conversion and I apologize in advance if I don't for misleading with the thread title. But it really is quite simple to try it as is first, especially since so many have good results with wheels. Plus, as javand said, I am not looking for hogging capacity (for now anyway) as much as for getting things flat with a reasonable finish.

What would I do without you guys. :thumbup:
 
Let's move this along.

First, the motor is shot. It runs very slowly for little while with almost no torque and then speeds up and heats up real fast. Not taking any chance and replacing it.



I have this motor lying around from a old belt grinder I had built. Nice TEFC too.



110V Specs, 1HP, 1725rpm. Previous one was 3/4HP and 1725 rpm.



Only down side is the color, kind of clashes. ;) Kidding aside, anybody see a reason this would not work?



Now a few pics of the custom power feed. Top view.



Front controls



And the “rocker switches” underneath. The middle parts pivots and trips the switches when the table passes by.



I would be glad if anybody could shed more light on the workings if this. I will get better detailed pics when I put the grinder back together and try it. Hopefully I can learn a bit more before then.

Here is another mod made by this gentleman. For those who are not familiar with this machine, the wheel is supposed to be horizontal, directly attached to the column leadscrew. A very ingenious way to move it to what must be an easier position to use it I am sure.



I removed the magnetic chuck and now that I am on a roll, might as well continue dismantling the grinder so I can do a proper cleanup and re-lube.



Table removed



And the saddle. They are quite dirty and since I don't have anything big enough to wash them in, looks like I am spending a lot of quality time with the toothbrush. ;)



And started with said toothbrush and some degreaser to clean up the base which I wont be dismantling. I would like to but I have to be realistic about the facilities I have and also the amount of time I can spend on this if I want to start making knives again any time soon. :( Isn't it looking better already? Lots more to do.



On a side note, here is the degreaser I use. Works really good, doesn't smell too strong (like to keep the few neurones I have) and is biodegradable.



And finally, a picture of the spindle. This is a little more complicated to dismantle but I really want to do it since it is on of the main parts of the grinder and sees a lot of work. It is nice that they put some instructions for removing it on the side but I will surely need you guys to help me when I put it back together again.



Thanks for watching.
 
Lookin good Patrice!

I've never dissembled the spindle on mine, so no help there. I'll be watching though.

The mods the guy did are nice!
 
Don, can I ask what is the speed of your motor? I post on a Yahoo group about this grinder and somebody said that the 1725 rpm motor might be too slow.
 
Patrice Lemée;12488548 said:
Don, can I ask what is the speed of your motor? I post on a Yahoo group about this grinder and somebody said that the 1725 rpm motor might be too slow.
Click to expand...

Mine is 3450 rpm. I also thought 1725 would be too slow, but you might be able to gear it up with pulleys?
 
Patrice, my Grizzly surface grinder is also 3450 but is direct drive.

Stan
 
Patrice Lemée;12488548 said:
Don, can I ask what is the speed of your motor? I post on a Yahoo group about this grinder and somebody said that the 1725 rpm motor might be too slow.
Click to expand...

Don Hanson III said:
Mine is 3450 rpm. I also thought 1725 would be too slow, but you might be able to gear it up with pulleys?
Click to expand...
Patrice, I was wrong! I just checked and mine is 1725 rpm. I also have the original 3 phase motor and it too is 1725. You will be fine with that motor.. Sorry for the miss-info...
 
No problem Don, thanks for checking for me. I thought I remembered that the original was 1735 rpm but it is good to have confirmation from an original motor.

I've been thinking a lot about the wheel vs. decision. The thing is, this can take 1” wheels which is what I wanted to use as a contact wheel anyway. Since the rest of the modification (arm and tensioning/tracking pulley) doesn't interfere with the wheel operation, couldn't I just pop off the contact wheel and put an abrasive wheel on there? Best of both world and as simple as changing the wheel.

I was thinking that starting with the wheels would be cheaper at first but I need a dressing tool for that which is around 225$ I think plus at least one wheel which is something like 35-50$ depending on where I looked. I got a quote for a 1” wide contact wheel at 175$ and the rest I can scrounge up in the shop or make it. So both options are about in the same price range...but I am sadly all out of play money for now. :-( I think I can at least fabricate the arm while I wait for funds to become available and proceed with the cleanup and rebuilding.

Speaking of cleanup, it looks like it will be a little more thorough that I had first planned. I just can't bring myself to clean parts of it and leave other parts still dirty. Plus I am pretty sure I have to remove the head to remove the spindle and at that point all that will be left is the column and legs and table. I am not setup to clean to bare metal and paint but with with the individual parts I can at least do a proper cleanup with the degreaser. And might as well do it now cause when it is back together I won't be taking it apart again any time soon. And of course in the back of my mind I am thinking about how nice it would be for the previous owner to see his machine in the best condition I can get it.

Thanks again for all your help guys.

PS: Don, can I ask the size wheel you use? (width and diameter)
 
A side note about magnetic chucks.

This is the chuck that was on the machine. Haven't tried it actually grinding but it look to still have a lot of holding power.



What can I do to it, maintenance wise? I know I am not suppose to disassemble it cause I will most likely loose magnetism. There is an oiling hole underneath so I guess a good exterior cleaning and lube is all I can do? What about these “channels” in the surface.



Don't know if it will show in the pic but there is what looks like a metal buildup in there. Is trying to clean them up a good idea and will it even change anything? Or should I just leave it as is? I know I will probably have to true it up on the grinder once it is working.

Any light you could shed on this would be greatly appreciated.
 
Patrice, you only need a "Single Point Diamond Dresser" or "Phono Point Diamond Dresser" ($10-$30 USD) and something to mount it in.

For single point dressing, you orient the diamond at 90deg vertical under the wheel and down-feed, then cross.


I made my "fixture" out of single point dresser and a piece of 1x4x4" scrap, with a hole drilled vertically through the center of the cross-section. The diameter of the dressers is usually 3/8" and tapered. All you have to do is drill a 3/8" hole in something steel and big enough for the mag chuck to hang onto.


Total cost of my square "Dresser" setup was $15. On top of that you can get radius dresser fixtures on ebay all the time for $100-$200.
 
Next, regarding your chuck, for accuracy, you need to "Grind in" your chuck to your spindle. Essentially, you need to surface grind your chuck, with the grinder. They're made for that.


There are a few methodologies for this, depending on whether or not you have flood/mist/etc coolant (I don't think you do), and which wheels you're using. You *need* to grind that in eventually if you want real accuracy, but you can probably start without it. You're likely better off not trying this procedure before you're comfortable using the feeds on your grinder, since one (literally) wrong turn can screw you up.


You grind the chuck with your machine's spindle so that it's parallel relative to your spindle and your table travel. When you clean up the table ways, you need to be careful not to use abrasives, as that can throw variance into the accuracy.. Clean precision surfaces *only* with #0000 steel wool and non-acid cleaners or solvents.
 
Patrice, listen to Javand. If I told you all I know about this, I'd be repeating most of what he just said.

Here are some photos of mine and to answer a couple of your questions.

Less than $50 for diamond point dresser and holder.

1/2" x 7" x 1-1/4" wheel. You do not want or need a 1" wheel. You start at the edge of the piece you are grinding and work across it's surface. You are not going to run the full width of the wheel across the surface in a single pass, with stone or belt. Hope that makes sense.

You can switch back and forth from belts to stone wheel. But once you try a stone and learn how to use it, I doubt you will want to.;)


Also, if I were to set up a belt on one of these. I'd use a 1" wheel and split the belts. 2" is not what I'd use.





 
When you say "vacuum system" you mean like a dust collector? Any chance we could see some pictures of that set-up? Pat is a fanatic/fiend on "GREAT" dust collection as we've noted in the past so you'll get him good and cranked up on this....................... He'll be spinning at 3600rpm for sure.

Since I am, both, learning to use and contemplating doing many of the same mod things with the Boyar Schultz 612 I "acquired" I'm very interested in these tips and techniques. I also thought I wanted to do the belt conversion but I've been using a wheel and it's working like a charm (I had to get over my initial SERIOUS fear of that sucker). Mine came with a "shopvac" collector as part of the deal but I've always worried about the sparks. Good news is there's no wood dust or aluminum collected in that one to make life interesting. There's always more to learn.

Thanks Pat, Don and Javand for sharing so freely.

Corey "synthesist" Gimbel
 
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Corey, I'll get a picture later. I'm using a Grizzly vac system and have it piped outside.

Every knife I makes runs through the SF, so too much grinding to not have a vac hooked up.
 
Some of ya'll may have noticed, I love heavy old cast equipment. That surface grinder is something special. I love it.
 
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