Home Built Surface Grinder

Great information on the surface grinder attachment -- I'd not considered that you could build a magnetic chuck.

For those that have done this, how do you get the blade off the chuck? It seems like if you had enough magnetism to securely hold it in place for grinding then it would be a bear to get it back off. I started looking at how commercial permanent magnetic chucks work to see if there was an easy way to make s similar thing.
 
currenthill said:
Thanks for the inspiration guys!

I've been looking for a better way of surface grinding, my process today involves my belt grinder, disc grinder and surface plate. But it's time consuming and not really giving me the precision I'd like. So I came across O One Armed 's build, and then @KenH 's and knew I had to build one myself. I sourced the parts a while ago but haven't had the time to get it all together. But I managed to get it done today. It was a fun build with a lot of small challenges for a non machinist. I learned a lot making it. Thanks @KenH and @kuraki for the tips about milling, I sourced a 10mm 3 flute 45 deg helix carbide end mill made for aluminium, it was like cutting hot butter, even with my mini mill.

I'm also waiting for some 75x2000 mm (3" x 78") belts. I built the SGA with a 75x200 mm (3"x8") serrated wheel so I can take full advantage of the 60x400mm (2,36" x 15 3/4") magnetic chuck. A lot of my knives are 50-60mm wide. This means I don't have to track the belt up and down for full coverage.

The components I sourced:

Magnets
https://www.aliexpress.com/item/15-...Rare-Earth-Neodymium-Magnets/32398053200.html

Linear stage sliding table
https://www.aliexpress.com/item/Man...al-Linear-Translation-Stages/32612615636.html

Linear slide rail
https://www.aliexpress.com/item/1pc...ulti-axis-core-linear-Motion/32842691822.html

Contact wheel
https://www.aliexpress.com/item/200...isher-Wheel-Sanding-Belt-Set/32381815454.html

Chuck and plates
The magnetic chuck is made from AW-2007 aluminium. The holding plate for the chuck and the mount plate for the slide rail is made from O1 tool steel.

The linear stage sliding table was a little less precise than I wanted. If I were to build it again I would probably get this one instead:

https://www.aliexpress.com/item/GGP...4-Ball-Screw-Linear-Rail-CNC/32806395029.html

So I had to take it apart and lap the pieces for a tighter dovetail fit. I now have a runout of about 0.015mm (~0.0006") across the slide. And I decided to get a lot of magnets on the chuck since they're only 4mm. And it seem to have done the trick, the grip is fantastic.

I also put the two stops at the correct distance for quick and easy tapered tangs, just like Wuertz SGA.

And I decided to build the whole package on the same tooling arm for more rigidity.

Here are some pictures.

5adLvus.jpg

9fyjMrh.jpg

bSFCRuv.jpg

8RrVdAX.jpg

eNf0rIf.jpg

ZukjS0k.jpg

o5zEvJa.jpg

VgLLV6z.jpg

lSydVtI.jpg
Click to expand...


That is absolutely fantastic... Thanks for sharing.
 
jmcglynn said:
Great information on the surface grinder attachment -- I'd not considered that you could build a magnetic chuck.

For those that have done this, how do you get the blade off the chuck? It seems like if you had enough magnetism to securely hold it in place for grinding then it would be a bear to get it back off. I started looking at how commercial permanent magnetic chucks work to see if there was an easy way to make s similar thing.
Click to expand...

Natlek said:
Just slide knife on side .................;)
Click to expand...

Exactly, even though the magnets will hold a piece of steel rock solid, it's pretty easy to slide it off.

A friendly warning, be sure to also slide your steel onto it the same way you slide it off, don't try to smack it straight on. It will result in bloodshed, I guarantee it. Don't ask me how I know. :oops:
 
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.

PHBUw5h.jpg


xA0JolV.jpg


BoXHvRZ.jpg
 
currenthill said:
Thanks for the inspiration guys!

I've been looking for a better way of surface grinding, my process today involves my belt grinder, disc grinder and surface plate. But it's time consuming and not really giving me the precision I'd like. So I came across O One Armed 's build, and then @KenH 's and knew I had to build one myself. I sourced the parts a while ago but haven't had the time to get it all together. But I managed to get it done today. It was a fun build with a lot of small challenges for a non machinist. I learned a lot making it. Thanks @KenH and @kuraki for the tips about milling, I sourced a 10mm 3 flute 45 deg helix carbide end mill made for aluminium, it was like cutting hot butter, even with my mini mill.

I'm also waiting for some 75x2000 mm (3" x 78") belts. I built the SGA with a 75x200 mm (3"x8") serrated wheel so I can take full advantage of the 60x400mm (2,36" x 15 3/4") magnetic chuck. A lot of my knives are 50-60mm wide. This means I don't have to track the belt up and down for full coverage.

The components I sourced:

Magnets
https://www.aliexpress.com/item/15-...Rare-Earth-Neodymium-Magnets/32398053200.html

Linear stage sliding table
https://www.aliexpress.com/item/Man...al-Linear-Translation-Stages/32612615636.html

Linear slide rail
https://www.aliexpress.com/item/1pc...ulti-axis-core-linear-Motion/32842691822.html

Contact wheel
https://www.aliexpress.com/item/200...isher-Wheel-Sanding-Belt-Set/32381815454.html

Chuck and plates
The magnetic chuck is made from AW-2007 aluminium. The holding plate for the chuck and the mount plate for the slide rail is made from O1 tool steel.

The linear stage sliding table was a little less precise than I wanted. If I were to build it again I would probably get this one instead:

https://www.aliexpress.com/item/GGP...4-Ball-Screw-Linear-Rail-CNC/32806395029.html

So I had to take it apart and lap the pieces for a tighter dovetail fit. I now have a runout of about 0.015mm (~0.0006") across the slide. And I decided to get a lot of magnets on the chuck since they're only 4mm. And it seem to have done the trick, the grip is fantastic.

I also put the two stops at the correct distance for quick and easy tapered tangs, just like Wuertz SGA.

And I decided to build the whole package on the same tooling arm for more rigidity.

Here are some pictures.

5adLvus.jpg

9fyjMrh.jpg

bSFCRuv.jpg

8RrVdAX.jpg

eNf0rIf.jpg

ZukjS0k.jpg

o5zEvJa.jpg

VgLLV6z.jpg

lSydVtI.jpg
Click to expand...
Great buid. What kind of tolerances are you seeing? Mind posting some pics of a ground blade?
 
knife to a gunfight said:
Great buid. What kind of tolerances are you seeing? Mind posting some pics of a ground blade?
Click to expand...
Sure, I'll snap some photos when I'm at it the next time.

I just measured a blade I surface ground with a 120 grit belt. It measured 1,86mm all around, my caliper is good for 0,01mm (0.0004") with 0,02mm (0.0008") accuracy. So it looks like I would have to get myself a micrometer for a more accurate measurement.
 
Toni Oostendorp said:
Looking good! Working on mine at this moment. Wenn it is done I will post a picture. I was wondering what ratio you used on the two bolts for the tapering, 1/4?
Click to expand...
Not sure what you mean. The two stop pins are 3/8" heads. They are just butted up against the rail to allow me to insert feeler gauges in so I can replicate the taper I want.
 
Kevin McGovern said:
Not sure what you mean. The two stop pins are 3/8" heads. They are just butted up against the rail to allow me to insert feeler gauges in so I can replicate the taper I want.
Click to expand...

Kevin, what he's asking is where are your pins located so if you use a feeler gauge between the pin and the bar what ratio it would give you. What taper per inch of grind.

If your pin is 3" away from the pivot center and you use a .1" feeler gauge it would be .1" per 3" of grind. if your other pin is 6" from center of the pivot with the same gap it would be .1" per 6" of grind.

You would want to know this so you can properly calculate what shim to use to get the exact taper ground on a tang you want.

 
Last edited:
I hadn't even measured it. i was planning on just putting a stop on the mag chuck at the right hand (away from the pivot pin) stop pin. Then use a feeler gauge the thickness i want to remove on the first side of the tang and 2x the thickness i want to remove for the other side of the tang. For what it's worth, the pin near the pivot is 5cm away from the pivot, and the other pin is 21.5cm away.
 
Ok, so you're planning on shimming between the tang and the chuck when tapering if I'm reading you correct?
 
KnuckleDownKnives said:
Ok, so you're planning on shimming between the tang and the chuck when tapering if I'm reading you correct?
Click to expand...
no, between the stop pin and the chuck. but putting the end of the tang at the far right stop pin, and using a feeler gauge between that stop pin and the mag chuck attachment that is the thickness I want to remove. Then flip the blade over and use a feel gauge on the same pin that is 2x the thickness of the first feeler gauge. Make sense?
 
Kevin - you're doing good with your machine work - looks really good. You're going to LIKE the grinder.

Toni- be sure to post some photos. We all LOVE to see work from other folks.

Ken H>
 
Kevin McGovern said:
no, between the stop pin and the chuck. but putting the end of the tang at the far right stop pin, and using a feeler gauge between that stop pin and the mag chuck attachment that is the thickness I want to remove. Then flip the blade over and use a feel gauge on the same pin that is 2x the thickness of the first feeler gauge. Make sense?
Click to expand...
Your build is looking good! :thumbsup:

And yeah, it makes sense. I put mine at 150mm and 300mm from the pivot point, but the only advantage of this setup is that you don't need the 2x thickness feeler gauge, you just use the same gauge at the pin closer to the pivot point for the other side. So not a major issue I would say. :D

I just did a taper test on a piece of steel, and it's a super quick setup for making tapered tangs. That's for sure! :cool:
 
Yes it is not a problem, just noticed the spacing between the bolts and was wondering about it. Cool thread and builds!
 
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