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Can you say Surface Grinder!!!!
- Thread starter Hankins
- Start date
I just got my SG three weeks ago and these are the things that folks told me here on this site and another.
You have to actually cut the surface of your magnetic chuck so it is square and flat to the stone. When I got mine set up I started cutting the chuck and it was cupped from being used over the years. Although you could not tell by looking at it alone, the grind marks told the story.
One thing that I learned is that heat WILL warp blades real fast. Get the coolant set up before you get to it. And actually use the marks on the wheels. I thought I could just take a half turn on the front/back axis and not burn the steel, didn't work out so well. and the same goes for the z (up and down) axis. I always get my X and Y mixed up... Flip the piece often (relative term) and eventually you will get flat and parallel.
I use a white 46 and 80 grit stone, K hardness. That may not be what is the perfect setup, it's what came with my grinder. Some folks are gonna ask when you are gonna go with the contact wheel and belt conversion.
Others have mentioned that depending on the speed that you move the dresser across the stone determines how rough the surface is. I know 46 grit is 46 grit but I am talking about the actual profile of the flat. I take off a little at a time and go slow (as in 2 sec total) across the wheel.
Is this a single phase motor? It also has been mentioned that cause single phase motors start so hard the wheel ends up out of round from the space of the wheel arbor hole and the shaft. I dress my wheel a hair after I start it up just to make sure cause mine is single phase. You might not have that issue, I dunno if I do, I just dress the wheel. Maybe you have a soft start. Throwing a 3 phase motor in and using my VFD is in the future so I can get the soft start.
I went to the practicalmachinist forum and asked questions over there, they were extremely helpful. Just an outlet if you cannot get an answer here. They have an abrasive machining subforum.
You have to actually cut the surface of your magnetic chuck so it is square and flat to the stone. When I got mine set up I started cutting the chuck and it was cupped from being used over the years. Although you could not tell by looking at it alone, the grind marks told the story.
One thing that I learned is that heat WILL warp blades real fast. Get the coolant set up before you get to it. And actually use the marks on the wheels. I thought I could just take a half turn on the front/back axis and not burn the steel, didn't work out so well. and the same goes for the z (up and down) axis. I always get my X and Y mixed up... Flip the piece often (relative term) and eventually you will get flat and parallel.
I use a white 46 and 80 grit stone, K hardness. That may not be what is the perfect setup, it's what came with my grinder. Some folks are gonna ask when you are gonna go with the contact wheel and belt conversion.
Others have mentioned that depending on the speed that you move the dresser across the stone determines how rough the surface is. I know 46 grit is 46 grit but I am talking about the actual profile of the flat. I take off a little at a time and go slow (as in 2 sec total) across the wheel.
Is this a single phase motor? It also has been mentioned that cause single phase motors start so hard the wheel ends up out of round from the space of the wheel arbor hole and the shaft. I dress my wheel a hair after I start it up just to make sure cause mine is single phase. You might not have that issue, I dunno if I do, I just dress the wheel. Maybe you have a soft start. Throwing a 3 phase motor in and using my VFD is in the future so I can get the soft start.
I went to the practicalmachinist forum and asked questions over there, they were extremely helpful. Just an outlet if you cannot get an answer here. They have an abrasive machining subforum.
Last edited:
- Joined
- Dec 2, 1999
- Messages
- 9,910
You're goin to love it! I dont think I can even make a knife anymore without mine. It will take some getting used to but once You do a whole new world opens up. Congrats!
- Joined
- Sep 15, 2009
- Messages
- 117
My surface grinder is one of my favorite tools! It is sooooo nice to be able to make things flat, especially when forging damascus 
Bruce,
On your shop tour pics you show a really nice milling machine. Why would you need a surface grinder? Please excuse my ignorance. Love your dog by the way!
Dean
It looks kinda like mine. You need to put the small nut back on and hopefully you have a spanner wrench with two pins to go in those two holes, and the collar spins. Here's the kicker. Mine has backards threads. Righty loosey lefty tighty. My smaller nut releases the arbor (lack of a better technical term?) that holds the whole shebang in the spindle. It has a taper cut in it. Mine is stuck and I have to get one of those arbor removers specifically for my machine.
This is what mine looks like.
This is what mine looks like.
- Joined
- Jun 25, 2007
- Messages
- 898
It looks kinda like mine. You need to put the small nut back on and hopefully you have a spanner wrench with two pins to go in those two holes, and the collar spins. Here's the kicker. Mine has backards threads. Righty loosey lefty tighty. My smaller nut releases the arbor (lack of a better technical term?) that holds the whole shebang in the spindle. It has a taper cut in it. Mine is stuck and I have to get one of those arbor removers specifically for my machine.
This is what mine looks like.
If you have left hand threads you need to have your grinder spindle running clock wise. If you have it running counter clock wise the nut will loosen and that can be rather dangerous.
I'm waiting for my chuck and wheel dresser to arrive then my surface grinder will be running also. :thumbup:
- Joined
- Dec 7, 2008
- Messages
- 2,936
Thanks Gixxer and Dan
It is a CW rotation, sort of figured it wasn't that easy.
Will have to make a spanner for mine but I have plenty O steel around the shop.
The gentleman who delivered it suggested getting a VDF drive for variable speed. Not too sure if I am ready to go that far yet.
RPM is 3600 on a 3/4hp motor
It is a CW rotation, sort of figured it wasn't that easy.
Will have to make a spanner for mine but I have plenty O steel around the shop.
The gentleman who delivered it suggested getting a VDF drive for variable speed. Not too sure if I am ready to go that far yet.
RPM is 3600 on a 3/4hp motor
- Joined
- Apr 7, 2007
- Messages
- 67
Okay, surface grinders, unlike the usual bench grinder, use hub-mounted wheels for precision.
The idea is to mount the wheel to a hub, mount the hub-and-wheel combo to the grinder, dress the wheel (which makes it concentric to the spindle) then dismount the combo and balance it. (Some hubs have movable balance weights, and there's ways to balance even without them.)
This way, you can have multiple mounted wheels, and when you swap them out (say, for different hardnesses, or if you have form-ground wheels for grooving or chamfering) they'll run true and smoothly without having to go through the dress-and-balance each time.
Now, typically a knifemaker doesn't need a wide range of wheels- you're almost always grinding about the same hardness of steel, and looking for about the same surface finish. So there's no reason you can't just buy one wheel, mount and dress it, and leave it alone 'til it wears down too far to use.
But, there's a reason the surface grinders use that hub arrangement- know what it's for, and take advantage of it. Just as you wouldn't use just one grit of belt or one grit of sandpaper, depending on whether you're going for stock removal or a smooth surface finish, you shouldn't stick to just one grit or hardness of grinding wheel.
Doc.
The idea is to mount the wheel to a hub, mount the hub-and-wheel combo to the grinder, dress the wheel (which makes it concentric to the spindle) then dismount the combo and balance it. (Some hubs have movable balance weights, and there's ways to balance even without them.)
This way, you can have multiple mounted wheels, and when you swap them out (say, for different hardnesses, or if you have form-ground wheels for grooving or chamfering) they'll run true and smoothly without having to go through the dress-and-balance each time.
Now, typically a knifemaker doesn't need a wide range of wheels- you're almost always grinding about the same hardness of steel, and looking for about the same surface finish. So there's no reason you can't just buy one wheel, mount and dress it, and leave it alone 'til it wears down too far to use.
But, there's a reason the surface grinders use that hub arrangement- know what it's for, and take advantage of it. Just as you wouldn't use just one grit of belt or one grit of sandpaper, depending on whether you're going for stock removal or a smooth surface finish, you shouldn't stick to just one grit or hardness of grinding wheel.
Doc.
- Joined
- Dec 7, 2008
- Messages
- 2,936
Me and Electrical wiring just don't mix...
Anyhow just found a 90vdc motor Variable speed I had buried in the shop. Can use for this thing instead of the 3phase thing to 220v Etc
This thing will get tricked out here soon. Variable speed motor with maybe a conversion to using 2x72" belts, should be sweet when done
Now if i could just find a 90vdc controller
Anyhow just found a 90vdc motor Variable speed I had buried in the shop. Can use for this thing instead of the 3phase thing to 220v Etc
This thing will get tricked out here soon. Variable speed motor with maybe a conversion to using 2x72" belts, should be sweet when done
Now if i could just find a 90vdc controller
- Joined
- Apr 7, 2007
- Messages
- 67
Do not replace the motor on a surface grinder unless absolutely necessary. They're specially balanced, often as a unit with the pulleys and spindle.
It's much easier and better to pick up an inexpensive VFD and run the thing on it's native 3-phase motor, than it is to try and swap motors and rewire.
Doc.
It's much easier and better to pick up an inexpensive VFD and run the thing on it's native 3-phase motor, than it is to try and swap motors and rewire.
Doc.
- Joined
- Mar 7, 2000
- Messages
- 1,048
Yep. No one ever told me that- I learned the hard way.