Bench grinders?

[Display Name]

Any body use bench grinders for knife grinding. If so what specs do you recommend. Horsepower, amperage etc... also what wheels do you guys use. 

[rockstar.esq]

Display,

I tried using an 8" variable speed bench grinder for knife grinding.  That experience really showed me why belt grinders are used for knife grinding.

The commonly available abrasive wheels for bench grinders will tend to wear down fairly quickly which plays havoc with grind lines.  As the stone wheels diameter changes, so too does the shape of hollow grinds.  The variable speed models allow you to add a bit of speed as the diameter decreases so it cuts consistently.

I have seen some conversion kits out there that will make one arbor into a mini belt-grinder.

 

[Kozzy]

Once you go belt grinder, you never go back (for controlled stock removal).  I doubt I've even touched anything to the grinding wheel on the actual bench grinder in a couple of years.  I use the wire wheel side once in a while but not the grinding wheel.

The same is mostly true regarding grinding discs in angle grinders too.  The flap disk wheels are soooo much better that it's tough to put an actual abrasive grinding wheel back on.  The only time I do it is for bad scale when I don't want to muck up the better discs.

I suppose that if backed into a corner you could make knife grinding happen on a bench grinder but I sure would advise avoiding it.  A bad belt grinder is still probably better than a good bench grinder for controlled metal removal.

[C-1ToolSteel]

If you can't afford a belt grinder, an angle grinder is WAY better for bevels.

[JHCC]

13 hours ago, C-1ToolSteel said:

If you can't afford a belt grinder, an angle grinder is WAY better for bevels.

For example, here's a knife-in-progress that's been ground entirely with a Harbor Freight angle grinder. 

[rockstar.esq]

While I agree on the angle grinder comments, I think it's contingent on using paper backed with a fiber/plastic disk. 

Trying to get nice bevels with a stone wheel in an angle grinder isn't that easy.  Flap disks are nice for rounding things off and softening transitions.  If you wanted a convex edge like an axe, they're really good for that. 

If you're looking to grind flats with an angle grinder, the paper backed fiber/plastic disk works really well.  Before I got my belt grinder, I roughed in flats with the angle grinder.  Then I switched to using a big felt-tipped marker and a coarse file.  Inking the surface let me know if the file is cutting the entire bevel flat.  Once I've got the bevel flat, it's a whole lot easier to progress through grits without messing it up.

Another approach is to ink a surface then rub it with a good straight edge. The high spots get wiped clean, which is typically where I need to cut more.  I find I'm able to get things true and flat much faster when I use the ink.  Part of that might be because the edges of the high spots are easier to spot with the ink.  That keeps me from hogging out a crater in the center of a large high-spot.  I used to spend a lot of time chasing high spots.

[Steve Sells]

you are saying you want to make knives, but not spend any money for tools.  that leaves you with files, then hand sane it to finish .

A bench grinder is not doing to get you  very far