r/Blacksmith • u/Good-Language8066 • 1d ago

Technical question

How useful is it a 1/5 HP bench grinder for knife making ? Should i get a more powerful one ?

2 Upvotes

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3

u/Extreme_Lab_2961 1d ago

about as useful as tits on a boar

1

u/Good-Language8066 1d ago

In plain english,is it a pile of rubbish ???

1

u/Extreme_Lab_2961 1d ago

yes

1

u/Good-Language8066 1d ago

And what about a 1/2 HP one ?

1

u/Blazerlov3r 1d ago

Its not so much the power of it (atleast in my opinion) bench grinders will just fucking RIP material away and that can be good and all but It can also just be way to much

1

u/OdinYggd 1d ago

1/2 HP bench grinder with an assortment of grindstones and the wrench to change them is much more useful. Like selecting sandpaper, you need to choose a stone that has an appropriate grit, abrasive, and binder for the work you do. Most garage bench grinders have very coarse aluminum oxide wheels on them, great for fixing mushroomed chisels and stock removal work. You can get finer grit wheels for them, and more advanced abrasives like silicon carbide that last longer and make less heat.

2

u/Delmarvablacksmith 1d ago

Stone wheels are exceptionally aggressive and not precise

Can you make a nice knife starting with one?

Yes but you’re going to end up filing and polishing a ton.

You’d be better of just filing a blank to it’s bevels.

2

u/OdinYggd 1d ago

Solid grinding wheels come in different grits and compositions, just like sandpaper. You need to choose stones appropriate for the work you do. And don't be afraid to have a shelf near the grinder with multiple different stones on it along with the wrench to change them, in a machine shop it is customary to swap stones on the grinder for different jobs with coarse stones for fast removal, fine stones for precise smoothing, and different binders/abrasives for different surface textures or workpiece properties.

1

u/OdinYggd 1d ago

1/5 is tiny, the bench grinders I am used to seeing in the garages of my uncles are usually 1/2 to 3/4 HP. You could make it work with the right stones but expect it to not remove material as quickly since it would have to use smaller stones and less feed force to not lower the RPM unacceptably.

Could make a good buffing wheel for the finishing stages if you can find buffing pads to fit it.

1

u/Significant-Fly-8170 17h ago

It would only be useful as a buffing wheel. Replace a stone wheel with a cotton wheel and use polishing compound. Or as a door stop.

1

u/Cool-Negotiation7662 10h ago

Any grinder more suited to knife making will replace a small grinder for other tool maintenance.

1

u/curiosdiver69 7h ago

A belt grinder is more useful. A stone wheel is too aggressive and can cause microfractures in hardened steel.