Do I Need A Universal Tool Grinder?

[Dan_S]

I've been into woodworking and metalworking for a while now, and I've been pondering some type of grinder build for a few years now. The other night I sat down and came up with a short list of tools that need to be ground. Some of them I do myself on a cheap 6" bench grinder, some I send out to be ground, and some are toss and buy replacements.

Woodworking

1. chisels (edges and backs)
2. had plane blades (edges and backs)
3. making/sharpening awl tips
4. making/sharpening marking knife/gauge blades
   
5. woodworking lathe tools
6. Forstner drill bits (would be nice to do myself)
   
7. brad point drill bits (would be nice to do myself)
   
8. regular drill bits
9. router bits (would be nice to do myself)
10. saw blades (would be nice to do myself)

Metalworking

1. hss lathe tool bits
2. brazed carbide lathe tool bits
3. regular twist drill bits (split point, multi facet)
4. spotting drills
5. center drills
6. endmill ends (would be nice)
7. endmill flutes (would be nice to do myself)
   
8. slitting saws (would be nice to do myself)
9. random other mill cutters (would be nice to do myself)

if I where to build or buy something like an old union grinder, would that work for all my grinding needs?
http://www.lathes.co.uk/uniontool&cuttergrinder/

 

[joshua43214]

Most of that stuff can being either free hand ground or touched up with a stone pretty easily. Stuff like the Forstner bit and Brad points are fixed on an oil stone. Flutes need a tool grinder. Slitting saws can be dressed by hand unless they are chipped, I send my saw blades back to Forrest and would even with a tool grinder since they re-tip and straighten them as needed.

All that said, you do need a tool grinder. You really do. Just think how awesome it would be to have one. Just tell the wife that it will make you happy, and that you will take her to Hawaii in exchange. (sorry, I just had to give you some goading ).

You can get them on Alliexpress for between $500.00 and $1k. They are a pretty big investment. You might get lucky and get your hands on a Deckel in good shape, they are pretty expensive new. I looked at the one from Northern Tools, every one seems to agree that it is not a good machine.
I am about to embark on making a Quorn. It wont save you much if any money, but it looks like a really fun project. You can get the complete set of castings (The updated version) from Martinmachine.com for about $400.00 and then you will need a motor, shafting, brass, etc and about 1500 hours if the rumors are correct. There is a dealer of the castings in Europe too, but I believe that those are not the updated version (the updated version has extra material around the clamp bosses for using keys rather than slitting the casting). Some folks have made them from bar stock, but I think this is a really bad idea, though there is no reason you could not make it from something like schedule 60 continuous cast iron. Not sure it would be cheaper though.

There are much simpler ones that can be built. All you really need is a precision shaft/bearing for the arbor - this can be a simple as a bronze bushing and a piece of drill rod or the motor itself. A precision linear shaft to mount the tool holder on - also can be done easily. A tool holder than can mount assorted cutters and be adjustable in 3 planes - more complex but doable.

-Josh

 

[Andre]

As Joshua stated, most of the above can be sharpened or stoned by hand.

 

[Dan_S]

I'm decent at hand honing, but I can't freehand grind complex geometries to save my life.

I've thought about single lip machines (Deckel), but they don't really work for woodworking stuff. a 6" diameter wheel is serviceable, but 8" wheels produce better results. putting something like an 8" d-way wheel on a Quorn, Brooks, or Stent grinder seems like an ER trip waiting to happen.
http://d-waytools.com/cbn-grinding-wheels

tool grinding is pretty expensive, a good 8" grinder is several hundred dollars new.
http://www.woodcraft.com/product/858829/jet-8-slow-speed-grinder-model-jwbg8.aspx

One of the things I've considered, is buying mini mill replacement components and then modifying them. little machine shop sells pretty much everything i would need, except a spindle.

I

 

[samthedog]

A Union would do what you need. You would need the various fixtures or at least make some. The range of items you want to sharpen is quite broad so you will need a broad range of vices and fixtures.

Paul.

 

[joshua43214]

I'm decent at hand honing, but I can't freehand grind complex geometries to save my life.

I've thought about single lip machines (Deckel), but they don't really work for woodworking stuff. a 6" diameter wheel is serviceable, but 8" wheels produce better results. putting something like an 8" d-way wheel on a Quorn, Brooks, or Stent grinder seems like an ER trip waiting to happen.
http://d-waytools.com/cbn-grinding-wheels

tool grinding is pretty expensive, a good 8" grinder is several hundred dollars new.
http://www.woodcraft.com/product/858829/jet-8-slow-speed-grinder-model-jwbg8.aspx

One of the things I've considered, is buying mini mill replacement components and then modifying them. little machine shop sells pretty much everything i would need, except a spindle.

I

The Quorn and other like it take wheels closer to 4". They are a very good size for grinding tooling. No need for an 8" grinder since you use cup wheels for any flat faced grinding. You only grind on the edge when form grinding. You can do things like grind threads, or even grind hobs, just about any contour of forming bit, make or sharpen reamers, etc on a Quorn. There is really no commercial equivalent until you get into many thousands of dollars. The head itself is modular and can be removed and installed on other machines to double as a tool post grinder, surface grinder. You can even attach it to a mill spindle and grind weird contours on the mill.

I would not consider that Jet to be a good grinder
A good 8" bench grinder runs ~ $1k

 

[Dan_S]

The Quorn and other like it take wheels closer to 4". They are a very good size for grinding tooling. No need for an 8" grinder since you use cup wheels for any flat faced grinding. You only grind on the edge when form grinding. You can do things like grind threads, or even grind hobs, just about any contour of forming bit, make or sharpen reamers, etc on a Quorn.

how would you grind something like a chisel or plane blade on a Quorn? The way I learned to sharpen them was, what using the periphery to form a slight hollow in the cutting face, so when you honed them on oil or water stones you had to remove very little metal. The video shows what i mean.

My dad recommend that i find or build a machine like this. Apparently it's what he worked with back in the 70's when he was a tool & die guy.

 

[JimDawson]

Is there even a question about this? Of course you need a new machine!

 

[joshua43214]

how would you grind something like a chisel or plane blade on a Quorn? The way I learned to sharpen them was, what using the periphery to form a slight hollow in the cutting face, so when you honed them on oil or water stones you had to remove very little metal. The video shows what i mean.

My dad recommend that i find or build a machine like this. Apparently it's what he worked with back in the 70's when he was a tool & die guy.

A tool grinder is for grinding machine tooling, not generally for hand tooling. I cant think of a single hand tool that would be made on a tool grinder, except maybe some odd shaped scrapers, or maybe making shaper blades for an old profiling plane.

I don't grind plane irons. The real issue with grinding is that the heat causes the metal on the edge to expand, and when it cools you get micro cracks as the metal shrinks. Elastic metals like stainless and HSS do fine, but the high carbon steel that plane irons are made from suffer badly. They should only be sharpened on a stone or a very slow bench grinder - ideally one of those with a horizontal wheel and a water drip. It is about impossible to not over heat the edge on a high carbon blade with a conventional bench grinder.
I grind chisels on the bench grinder if I hammer on them, I use stones for hand chisels and gouges. I always free hand grind wood lathe tools.

Hollow grinding is irrelevant to wood working. It does nothing good for you, and potentially does bad. Even Japanese chisels have most of their hollow grind stoned flat and only have a small hollow area. Hollow grinding is for knives.

All that being said, the Quorn will sharpen plane irons, chisels, convex skews, incannelled gouges, saw blades, etc. It is probably the most versatile tool grinder out there. They are not more common because they are expensive to build, take a long time to build, and have some very challenging machining operations.

Either way, JimDawson just weighed in. He also agrees that you need this new machine

 

[Dan_S]

Is there even a question about this? Of course you need a new machine!

It's more a question of how many and what type.

1. buy a better bench-top grinder and then buy one or more commercial tool grinders to cover everything else.
2. buy a better bench-top grinder and then build a Quorn, Brooks, or Stent grinder
3. go off the deep end and design & build an all in one myself.

I'm leaning towards #3, but then I am a little odd.