Home Built Surface Grinder

BubbaW said:
The problem is that a 5" long 1/2" bolt only has 1-1/2" of threads, not enough to go through the tool arm
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Buy a longer bolt. There is no reason the bolt has to thread into the tool arm. I think it's better not to anyway. Threaded in you are relying on straight threads. Drilled through you're relying on the surface of the tool arm and hardened washers as a spacer.
 
So after trying to go through the 29 pages of this thread, I’ve seen a few guys mention the sgr20n vs the sgr20 linear rail most guys used.

Has anyone actually bought and used the sgr20n and if so, how did it turn out?
 
The SGR20N is a tad more narrow than the SGR20, and I like all the width possible for stability.
 
That was my concern aswell, however from what information I can gather, the only difference between the sgr20 and sgr20n is the amount of material on the outsides of the rail. The bearings, and rods are the same diameter. Which should not change the rigidity/stability. That’s why I was hoping someone who has used both could give a definitive answer.

First picture is the sgr20n second pic sgr20

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If you'll take a look at the specs does the "20n" have 47mm width while the "20" as 60mm width?
 
Yes, 13mm total difference in width of the rail 6.5mm on each side - which I believe is the difference shown in my comparison pictures. The thickness is the same, the rods are the same, the rollers are the same. Man I wish I could see them side by side....
 
I ordered the 20N. When it arrives, I will happily take measurements to compare against the 20. The only reason I gambled on the 20n is I'm in Canada and found one for a good deal. Hopefully it works.
 
Getting a good deal can make things work sometimes. The difference is only 1/2" so I expect it to work ok for you.
 
I think that centering the face of the magnetic chuck to the height of the rollers would be way more critical than the width of the rail for reducing deflection.
 
My 20N rail arrived, and I am pleased with it. If anyone is interested in any real life measurements to compare it to the standard 20 I would be happy to help.
 
Now I need to find a decent contact wheel. So after everybody’s experimenting, the ideal size is what?
6” diameter x 3” wide?
Serrated vs smooth?

Is there a decent source for these besides aliexpress? I have bought anything from there and would prefer not to if possible.
 
You mention you'd prefer not to purchase from Aliexpress - did you have problems with them? That's where I got my 3"X6" wheel.

Good luck on the build - you're going to really ENJOY the SGA.
 
I have not ordered from them. My fear is based only on what I have read - and to be fair many reviews were positive. I’m just very cautious....

So the 3x6” wheel is the one a guy wants? Smooth or serrated? How hard?
 
double gun said:
I have not ordered from them. My fear is based only on what I have read - and to be fair many reviews were positive. I’m just very cautious....

So the 3x6” wheel is the one a guy wants? Smooth or serrated? How hard?
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Serrated, and as hard as possible. 80+ duro preferably.

You don't have to be cautious, I have hundreds of purchases from Ali and nothing went wrong with items which were at least 3$ in price :) L-paladin is the contact wheel guy, you can order any configuration from him and will charge almost no extra for it. His prices are a fraction of what you would pay elsewhere. And a lot of retailers are selling his wheels with a hefty markup anyway.
 
So, I’ve made the magnetic table, attached to the slide, and my contact wheel arrived this morning.

So I need to make the slide that brings the table closer to the wheel. I see most guys were buying a little linear slide from China but I would prefer to machine my own. First thought was to machine a dovetail slide with adjustable gib - but thought I would see if anyone has taken apart the actual slide on the store bought surface grinder attachment to see how they were made. From the basic pictures I’ve seen - I don’t see a dovetail...

Anybody willing to share?
 
double gun said:
So, I’ve made the magnetic table, attached to the slide, and my contact wheel arrived this morning.

So I need to make the slide that brings the table closer to the wheel. I see most guys were buying a little linear slide from China but I would prefer to machine my own. First thought was to machine a dovetail slide with adjustable gib - but thought I would see if anyone has taken apart the actual slide on the store bought surface grinder attachment to see how they were made. From the basic pictures I’ve seen - I don’t see a dovetail...

Anybody willing to share?
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I bought one off eBay that’s “American made” of that means anything now adays. If I remember correctly it is dovetailed and also has a couple set screws per dovetail to adjust our any slop.
 
KNelson said:
I bought one off eBay that’s “American made” of that means anything now adays. If I remember correctly it is dovetailed and also has a couple set screws per dovetail to adjust our any slop.
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Do you have a link for the ebay item? Cost? Is it still available?
 
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