Surface Grinder - surface grinding attachment

KenH

Well-Known Member
You did really good with that build, and good with the photos. I especially like the contact wheel mounted to the tooling arm. Since I saw OBG's setup with his contact wheel mounted to contact arm I've been thinking about doing the same thing. BUT - I'd have to resurface my magnetic chuck. Due to the slop in the tool arm holders when my system is mounted the magnetic chuck wasn't exactly square to the contact wheel. Once I surfaced the magnetic chuck it's now square, but I'm not sure the "slop" will come out to exactly the same every time. I might just move my contact wheel to the tool arm like you've got. I do think that's best.

Again, GREAT JOB!

Ken H>
 

currenthill

Member
Awesome work currenthill! Clean, CLEAN build! That's 3 of us now. Just normal guys with a passion,(and not a lot of money in my case!), and KNEW they could build this! Warms my heart to see people sharing my love for building things. I'm so happy to have posted here.
I totally agree! I’ve looked at SGAs for a while but thought it would be too hard to build one myself.

I really do appreciate you sharing your build, it was very inspiring!
 

currenthill

Member
Hi guys!

I've been using the SGA with 3 inch belts for a couple of days now. It's great! I can do all my pattern sizes without tracking the belt. It's nice to be able to flatten tangs so quick and easy now, no more hand rubbing on the surface plate. But then it struck me, I still need to hand flatten the scales on the surface plate.

So, back to the drawing table. I made a quick and dirty prototype holder this morning. It works perfect, I might make some minor adjustments and make it a little prettier. But it flattens my scales superfast and precise. It's a real time saver!

It's got a 2mm (5/64") steel backplate for attachment to the magchuck. It can do scales up to 60x140mm (2.4"x5.5"). Minimum depth in this configuration is 5mm (0.2"), but I could grind it thinner.

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KenH

Well-Known Member
I see you're like me - the more you use the SGA, the more uses you find for it. That's a good looking attachment and a good idea. Does the 3" belts work good with the normal 2" (usually 2-1/4") tracking and drive wheels?
 

currenthill

Member
You're correct, the 3" belts would be too wide for the standard wheels (or rather, the belt would hit the grinder when centered).

So I cut them at 2.5". That way it covers the 2.4" magchuck perfectly, while it'll still fit the wheels fine.
 
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KenH

Well-Known Member
Currenthill, got a question for you - when you move the slide .003", make a couple of passes so it seems to be ground good, does that .003" movement remove .003" from the metal?
 

currenthill

Member
Currenthill, got a question for you - when you move the slide .003", make a couple of passes so it seems to be ground good, does that .003" movement remove .003" from the metal?
That is actually a really good question. I have so far solely been measuring relatives, not absolutes. I would have to do some test passes to know.

What is your experience on the matter?
 

KenH

Well-Known Member
I've not done any real testing - had to take the dial indicator off to use elsewhere. BUT - the little bit I did it seemed sorta like .006" feed might get an honest .003" of actual metal removal? I was thinking the metal removal would be closer to feed distance, but perhaps wear on belt? Perhaps not making enough passes grinding to remove all metal to the depth of feed? Not sure, that's why I was asking you :)
 

Smallshop

KNIFE MAKER
Anyone thought about the need to build one with compound ability? (tilt in two directions) I haven't really used mine but keep thinking if I could taper along the blade as I taper across the blade would be handy.

Currenthill's build turned out so clean I had to go look at his knives...and understood immediately....
 
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Thanks for posting your build, this was on my wish list, and has now just become affordable as diy build. I think it will have a million and one uses being i don’t have room for a surface grinder, nor are we blessed with the massive second hand market like you gents have in the US for machines and tools.

Can I please ask a few questions:

o) Do you afix the magnetic chuck to the top tool steel plate only ?
o) with the tool steel plates, does it need to be heat treated? And what thickness did you use 3/8?

I am just in the process of ordering the bits, as it will take me some time to get these out of China.

Thanks in Advance,
.adrian
 

tex

Member
hi there I am building a surface grinder attachment.
how do you prevent the magnet jumping onto the adjoining magnet when glueing into position.
any help regarding the magnetic bed will be much appreciated. thank Tex in South Africa
 

KenH

Well-Known Member
Hello Tex, what part of the world are you in? That's where filling out the profile really helps with folks that might be local to help.

If you place the magnets in every other slot they will usually stay in place. I also took an aluminum bar and tapped 1/4-20 screws at each slot and as the epoxy/magnet was placed in slot, snugged the screw against the magnet to hold in place. That works pretty good and doesn't take long to tap the bar.

Good luck.
 

KenH

Well-Known Member
Thanks for posting your build, this was on my wish list, and has now just become affordable as diy build. I am just in the process of ordering the bits, as it will take me some time to get these out of China.

Thanks in Advance,
.adrian

Sorry Adrian, I missed your question until now. If you still need answers, let me know. I've tagged this thread to notify me of any posts so I won't miss any new posts. Also, feel free to email or PM me any questions.
Ken H>
 

tex

Member
OK, I got the 2" wide aluminum bar to make new magnetic chuck. When I made the first 2.5" wide chuck I had a hard time holding the magnets down in slot. This time I made the following jig to hold magnets down where they should be. OneArmed, when you epoxied your magnets into slots, how did you hold those down? BTW, this might be a good reason to use a steel bar - the magnets should hold themselves tight into slot due to magnetic pull.

Magnet_Chuck_Jig.jpg
thanks for solving my problem, in South Africa I can only get 50 mm x 10 mm x 10 mm very strong will set them 3 mm below the surface.
any other info on the magnetic chuck will be greatly appreciated tex.w@webmail.co.za
 

tex

Member
Hello Tex, what part of the world are you in? That's where filling out the profile really helps with folks that might be local to help.

If you place the magnets in every other slot they will usually stay in place. I also took an aluminum bar and tapped 1/4-20 screws at each slot and as the epoxy/magnet was placed in slot, snugged the screw against the magnet to hold in place. That works pretty good and doesn't take long to tap the bar.

Good luck.
 

tex

Member
Hello Tex, what part of the world are you in? That's where filling out the profile really helps with folks that might be local to help.

If you place the magnets in every other slot they will usually stay in place. I also took an aluminum bar and tapped 1/4-20 screws at each slot and as the epoxy/magnet was placed in slot, snugged the screw against the magnet to hold in place. That works pretty good and doesn't take long to tap the bar.

Good luck.
thanks for the help, good idea, I am just a bit worried the the magnets are to strong. I am 77 years old living in Cape Town South Africa, a long way from America. nice to be part of the group
 

tex

Member
thanks for the help, good idea, I am just a bit worried the the magnets are to strong. I am 77 years old living in Cape Town South Africa, a long way from America. nice to be part of the group
 

KenH

Well-Known Member
in South Africa I can only get 50 mm x 10 mm x 10 mm
I need to read closer, right there in your first post you mentioned South Africa. 10mmx10mm, that's a nice magnet. You might not need so many of those, but again depending of strength of magnet. If N52 they gonna be strong! Can you order from www.aliexpress.com? If so, here's a link to 10x 5mm magnets which is what we normally use. https://tinyurl.com/y38da74o

Those N52 rare earth magnets are really STRONG for sure. They WILL pinch your fingers and leave a bruise if not careful. BTW, here's another idea I really like: www.amazon.com/dp/B003FWERRC/? This option is a tad more expensive as two of the magnets are needed, but you can turn them OFF and ON with the lever. These are used by https://blackfoxknifeworks.com/knifegrinder/black-fox-glide-surface-grinder on their SGA. I'm not sure which of these lever magnets Black Fox uses. The one I linked to is the 95 lb pull, and for $10 USD more they have a 150 lb pull magnet.
 

tex

Member
I need to read closer, right there in your first post you mentioned South Africa. 10mmx10mm, that's a nice magnet. You might not need so many of those, but again depending of strength of magnet. If N52 they gonna be strong! Can you order from www.aliexpress.com? If so, here's a link to 10x 5mm magnets which is what we normally use. https://tinyurl.com/y38da74o

Those N52 rare earth magnets are really STRONG for sure. They WILL pinch your fingers and leave a bruise if not careful. BTW, here's another idea I really like: www.amazon.com/dp/B003FWERRC/? This option is a tad more expensive as two of the magnets are needed, but you can turn them OFF and ON with the lever. These are used by https://blackfoxknifeworks.com/knifegrinder/black-fox-glide-surface-grinder on their SGA. I'm not sure which of these lever magnets Black Fox uses. The one I linked to is the 95 lb pull, and for $10 USD more they have a 150 lb pull magnet.
Thanks for the info have changed to two magnets per slot 20 x 10 x 5 IE 40 x 10 x 5 end to end. will post picture when done
 
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