Home Built Surface Grinder

KenH, thank you for the link to your detailed pictures and write up. Yours looks very similar to the store bought version.
I started machining a dovetail slide yesterday and will see how it goes. Hopefully it works out

KNelson, I too would love to see the one you bought.
 
I finally finished my sg attachment, and wanted to say thank you to the guys who took the time to help me out answering my questions.
Since there have already been a bunch of really good posts showing a standard shopping list, I figured I would only mention the differences I went with:
-I used the sgr20N rail instead of the sgr20
-the wheel is obviously non-serrated (3x6” 90A)
-and lastly I made my own adjusting slide

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Looks good - I see the way you did the slide adjustment. Good idea. Is the support at the rear threaded to provide pull/push for the slide? OR - is the slide have the threads? I'd sure like to see some detail how you handled that.

Boy, these SGA have really taken off with lots of folks building.
 
Ken,
the threaded "pusher" is 1/2-20, then the end flares out to 9/16" since that is the od of the bronze washers I had. The shaft is then reduced to 1/4-28 and goes into the top slide. About 1/2" in from the end I milled a pocket from the bottom side which has another bronze washer and two nuts.

Yes the back support is threaded so it can push and pull. A little playing around with the nuts (that doesn't sound good) you can take out all but the smallest amount of backlash.

The slide itself was made of two pieces of hot rolled steel 3/4"x3"x5" long. The slide was slightly recessed into my tooling arm, and the roller bracket was also recessed into the top of my slide so there is very little chance of torquing in those areas.


The one other thing I did differently is I used locktite retaining compound to glue my magnets into their slots. It's easy to use and clean up, and I usually have it on hand.
 
The 1/2"X20 TPI is a good thread, that gives .050" per revolution. I really like the way you did your slide adjustment - and your explanation is about what I was thinking. I like the way the bevels hold the plate down rather than the "tee" groove I've got. Slick.
 
Size of contact wheel . . . .what you guys think is better , bigger one or small one ? I m ready to start to build this ....
 
I had mine made by the same guy Ken suggested. I had him make it smooth, harder than standard and non standard bearing seats. But it cost me considerably more money and higher shipping (I'm canadian).
 
what are the standard sizes of the stone wheels on a regular surface grinder ? that may clue us in on the best size. but if anyone knows, i would love to know the advantages/disadvantages of small and large wheels on a surface grinder.
 
Gentlemen! A question to those of you who have been using the sga on a regular basis for some time, did you have to resurface the aluminum chuck yet? Does it wear visibly over time?

All of my parts arrived to make my sga, but I am a bit hesitant to use aluminum for the chuck, and am thinking about steel for longevity. You constantly rub hardened P36-P120 finished steel against it, does it hold up in the long run? I would like to make mainly folder parts on it, so it would be nice to keep the precision without regularly resurfacing the chuck. One other consideration is holding power. The less distance between the magnets and the blade, the bigger the holding power. But than you have less material left for resurfacing with time, till you have to make a new chuck.

Let me know if I am too ocd, and I am worrying for nothing :)
 
john april said:
what are the standard sizes of the stone wheels on a regular surface grinder ? that may clue us in on the best size. but if anyone knows, i would love to know the advantages/disadvantages of small and large wheels on a surface grinder.
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John, sorry I missed your question about wheel size. Seems like surface grinders use stone wheels in the 7" & 8" size range. It's been almost 50 yrs since I worked in machine shop where I used surface grinders so my memory can well be faulty. I took a look at Travelers site and they show 7" as most common, with sizes all the way up to 10", and some even larger.

I use a 6" wheel on my SGA, but have used 8" also. The larger wheel has the ability to make a smoother finish, but by moving the slide slowly there will be no real difference in a 6" or 8" finish. I've not used a 4" wheel, it would be slightly less expensive to purchase. My feeling is a 6" wheel is a decent size to use.

Your question about wear on chuck by parts rubbing & sliding on aluminum. I can't imagine that happening. For final finish I usually put a strip of scotch tape over chuck so the finish on blade doesn't get damaged by sliding on chuck. The final pass with 400 grit belt does leave a nice finish. If you were worried about damage to chuck the scotch tape could be used all the time and replaced.

Ken H>
 
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jeness said:
A question to those of you who have been using the sga on a regular basis for some time, did you have to resurface the aluminum chuck yet? Does it wear visibly over time?
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I'm told a steel chuck provides slightly more holding power than does aluminum, but I'm not sure. My aluminum chuck has N52 magnets spaced perhaps 1/2" (3/4"?) apart and holds pretty good. On small folder parts I do have to put a block for the blade & backspring to slide up against, but this isn't a problem. The "block" is just a thin strip of steel that goes on top of a recessed magnet and sticks up about .050" above the surface to provide a stop. I've also drilled a 3/32" hole in chuck with a brass pin sticking up a tad so the pivot hole in blade will fit over pin to provide extra holding. Either method works just fine.

I use aluminum for most of my stuff because I like working with aluminum and my small mill likes aluminum better than steel. Aluminum is lighter and less expensive than steel when ordering.
 
I have no issues at all with wear. At least none that I am seeing. I am using the same spacing Stromberg Knives uses and it works too good. I put a layer of Duct tape across mine and replace the tape as it wears. If I do not do this, its almost near impossible to get the blade off. Sliding it off can sometimes cause a scratch so the tape helps. I imagine that is why I am not getting any wear on the aluminum as well. I ordered my magnets from the same source as everyone else, but man the ones I have a STRONG. Anything at all across two or tree of those magnets is almost permanent on mine. The least of my worries is it not holding, my biggest worry is trying to remove it once I have done the surface work lol.
 
Greg.Norcal said:
Hello everyone.
I have a question for the masses. I am in the processes of finishing by belt sander/grinder and want to make more attachments for it. A surface grinder is on my list. So, the question, what do you thing about this table for a base for the y axis? https://www.aliexpress.com/item/328...5.0&pvid=c6710ece-8503-4634-b532-62b24cfc8c5d
Please let me know. Thank you to everyone on the forum for all of your awesome ideas.
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I bought one similar to that. It works ok but with the ball screws you only move the handle a very little (tenth of a turn) bit at a time. The other issue was I had to put a brace on the guide rods to limit flex. I wouldn't buy mine again.
 
Jesse, what is the diameter of the guide rods? Guide rod flex is something I'd never considered. Me being the old titewad I am I've made my slide adjustment tables.
 
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