Home Built Surface Grinder

Kevin McGovern said:
yes. Think about the force of the compound table and the counter force of the contact wheel/ belt. You want a point load situation where those points are pushing directly into one another. If it's not in line, you are introducing a force that is working against a cantilever (in this case, the linear rail). In my mind, that is introducing a stress, that while I can't be CERTAIN will negatively impact precision, I wouldn't want to risk it. I think using a 1/2" thick aluminum plate to mount the cross feed table on will be more than ridged enough. In fact, I considered it, but then remembered that my grinder tilts. ( I knew I built that into the grinder for a reason)
Click to expand...

Thank you for more information. I understand what you are saying now.

My plans are to make my KMG horizontal, so I may just make the surface grinder on the single tool arm for now. Even if its going to be awkward using it in the vertical position for the time being.
 
On the axis of slide rail being in center of contact wheel - I do think that is best, and do plan to change my axis so it will center. I first built my grinder using existing contact wheel in upper tool arm slot, with SGA in bottom slot. With grinder in horizontal position that put the axis in center. Once I mounted the contact wheel on same tooling arm as slide rain, that put the axis off about 1-1/2" or so. It seems to be working - I just ground this 11" chef knife



Ooops, that's a BIG photo

OK, here's the tip at
[
Tip.jpg
[/url]

Measurement at middle

Middle.jpg
[/url]

and at butt of tang.
Tang.jpg
[/url]

Pretty darn close with only .00015" difference - even impressed myself with that one. I'd LOVE to say that's normal, but .001" is more normal..... or maybe I'm just getting better? {g}
 
Ken H> said:
On the axis of slide rail being in center of contact wheel - I do think that is best, and do plan to change my axis so it will center. I first built my grinder using existing contact wheel in upper tool arm slot, with SGA in bottom slot. With grinder in horizontal position that put the axis in center. Once I mounted the contact wheel on same tooling arm as slide rain, that put the axis off about 1-1/2" or so. It seems to be working - I just ground this 11" chef knife



Ooops, that's a BIG photo

OK, here's the tip at
[
Tip.jpg
[/url]

Measurement at middle

Middle.jpg
[/url]

and at butt of tang.
Tang.jpg
[/url]

Pretty darn close with only .00015" difference - even impressed myself with that one. I'd LOVE to say that's normal, but .001" is more normal..... or maybe I'm just getting better? {g}
Click to expand...
Very impressive!

And I think you're right, you do get better at it. It's like using every other tool in the shop, the results get better with experience.
 
While 400mm should work, it is a tad on the short side, really needs 500mm. I used 600mm.

As to those rails - YES - I do think they will work just fine. Normally they're used with CNC machines where the tracking has to be MUCH more precise than on this SGA.
 
Looks like they make these in various lengths, I found a 600mm long version.

Did you find something ready made for the depth adjustment which works out of the box, or one has to make his own from scratch?
 
jeness said:
This topic is a goldmine for me, I am in the process of making a similar surface grinding attachment for my belt grinder. Did you look at these linear rails, insted of the SGR20? I would think that these would give a bit more support, and would have less play in them:

https://www.aliexpress.com/item/12m...id=5064908d-4809-4254-bad5-6bd79ad26f5e&tpp=1
Click to expand...
Honestly, ilike the simplicity of the rails we used and the ease with which they can be slid off for cleaning and storage. I have had no issues with how Ridgid they are.
 
Jesse Latham said:
The only issue with rigidity is when you want to switch from horizontal to vertical.
Click to expand...
Mine only works horizontally, unless I want to stand on a ladder to grind. Regardless, I don't see how switching from horizontal to vertical would make a difference.
 
With a 600mm rail (Google says thats 23.622 inches :) ) what is the longest blade you can grind
 
Well, that depends more on the length of the magnetic chuck you build. Most of us seem to be building around 12" chuck. The blade could extend an inch over each end and still grind pretty good - I think anyway - making it a 14" blade. The purpose of the longer rail is to allow the chuck plenty of room to extend past the belt. I think 500mm will give all that's really needed. I didn't know, asked the vendor about the 600mm, he made one for me at same price as the 500mm.

I think the attraction of the above linked pair of rails is the cheaper cost. Those above for 400mm are only $37 shipped while the ones we used are about twice that price. The advantage of the SGR20 set is the lower profile making it easier to rig up.
Here is the set I used, except these are 500mm: https://goo.gl/XDH1NP

Somebody asked about the feed adjust system - here's where I wrote about the one I built.
https://www.bladeforums.com/threads/sga-feed-adjust.1563170/#post-17950531
 
What size and where did people get the aluminum pieces for the magnetic chuck and the other pieces that attach it together? That's something i havent seen mentioned.
Wish we had a wip broken down barney style for those like me lol
 
Spalted said:
With a 600mm rail (Google says thats 23.622 inches :) ) what is the longest blade you can grind
Click to expand...

I have the 600mm rail, combined with a 400mm magchuck (around 15.7"). It's a little tight at the ends, but the whole magchuck will clear the wheel. On this setup I have surface ground blades up to 395mm/15.5 inches. No problem. :thumbsup:

If it may help someone figuring this out, here's an exploded view of my SGA.

gTorvDE.png
 
That is a VERY good drawing of your SGA - Thank you for taking the time to draw it up and present it to us. Your feed adjustment looks interesting - I like it.

Valnut - you asked about source for the aluminum for building. There are several sources around. If purchasing it all at one time, perhaps https://www.industrialmetalsales.com/ is one of the best sources around. Also, ebay has many suppliers of aluminum. I had a good bit of aluminum on hand, so ordered the 1X2X12" for magnetic chuck from ebay. This seller seems to have a good selection at a decent price. https://www.ebay.com/itm/360679563368?
 
Quick question, how are removing the metal grindings from the magnetic chuck? Thx
 
They wipe right off fairly easy. I put a layer of 2" wide scotch tape on chuck to protect the blade from being marked on magnetic chuck and that seems to make it easier to wipe metal grinding dust off.
 
Im contemplating going a different route but it seems way more complicated and expensive so i may not. Im thinking of making a benchtop surface grinder.
Basically use the rack and pinion design of the drill press, with the 2wheel design and belt of a 2x42 ,with the tracking and tension of a 2x72. And a milling table underneath
Just picture the milling table underneath this
JwmVQAP.jpg
 
This is a fantastic thread. You guys have inspired me to build one as well. Ordered everything I need yesterday.

I had a thought though. The one like Stromberg Knives Stromberg Knives made, it looks like if you take that top black plate and mount it to the side of the aluminum magnetic chuck instead of the bottom you wouldn't have to mill any of the tooling arm off and it could bolt right up. Depending on the thickness of your plates I suppose.
 
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