Bench Grinder For Grinding Lathe Tools: Advice Needed

[Nogoingback]

I'm thinking about learning to grind my own lathe tools and need a bench grinder
to do it with. (Up to this point I've been using HSS insert type tooling.)

Baldor's are probably out of my budget, but a decent
older USA made machine is what I have in mind. Is there a minimum HP I should look for, and
what motor RPM is best? (Or are they all the same?). What
grinding wheel diameter would be best in terms of performance, availability and cost? Any particular
brands or models? Any other considerations?

 

[Charles Spencer]

Virtually any bench grinder should be able to grind HSS bits.

I have three bench grinders and two stationary sanders. I usually rough out bits on one of the bench grinders, but I finish on a Harbor Freight mini tool grinder.

 

[mikey]

I'm thinking about learning to grind my own lathe tools and need a bench grinder
to do it with. (Up to this point I've been using HSS insert type tooling.)

Baldor's are probably out of my budget, but a decent
older USA made machine is what I have in mind. Is there a minimum HP I should look for, and
what motor RPM is best? (Or are they all the same?). What
grinding wheel diameter would be best in terms of performance, availability and cost? Any particular
brands or models? Any other considerations?

I suggest at least 3/4 to 1 HP if you can. Grinding on a wheel requires pressure and you will bog down a weak motor. Most grinders will run in the 1800 rpm range, although there are slow speed grinders as well.

As for wheel size, I would go for an 8". Wheels are common and there is less of a curvature to the grind so your edges last longer. If I were you, I would definitely consider a CBN wheel for tool grinding - something coarse in the 60-80 grit range. A slight radius on the corner of the with a CBN wheel on one end and maybe a fine finishing AO wheel on the other or a fine CBN wheel if I could afford it. Check this guy out: https://woodturnerswonders.com/collections/rikon-grinders

A grinder as above is for tool grinding only. I don't think I would use a CBN wheel for everyday grinding.

I use a belt sander.

 

[Doubleeboy]

You can rough grind using a cheap angle grinder like one from HF for cheap and then finish on a small grinder. I have two Taiwan 8" grinders, plus a 1" belt plus my angle grinders. When I want to rough a large bit, I take the angle grinder outside clamp the bit to wood bench and go to town with angle grinder, very fast way to rough IMO.

 

[Nogoingback]

OK, good useful information. It sounds like an 8" is the way to go, and I'll make sure I don't go too low on power. I already have an angle grinder and a 1" belt sander so I suppose
I could rough out with those, but in the long run I'd rather have the right wheels to do it all on one dedicated machine. Then, I can use the other machines for everyday grinding tasks. mikey,
thanks for the info on CBN wheels: they look expensive but if they last a long time and don't need dressing I imagine I could stretch for one of them. I haven't priced out regular wheels,
so I don't know how they compare. While we're on the subject of grinding wheels, who makes good ones, or does it matter? (I know, it almost always matters...)

Charles, with 3 bench grinders to choose from, do you have one you use the most?, and if
so, why?

 

[Uglydog]

Old arbor grinders are cheap if not free! Bushings or bearings can be replaced easily.
If it doesn't have a guard and rest you can make one easy enough.
Any motor will work.
You don't need to spend lots of dollars to have a good time and do good work.

Daryl
MN

 

[Nogoingback]

Old arbor grinders are cheap if not free! Bushings or bearings can be replaced easily.
If it doesn't have a guard and rest you can make one easy enough.
Any motor will work.
You don't need to spend lots of dollars to have a good time and do good work.

Daryl
MN

That's kind of the conclusion I've drawn from trolling CL. Around here older USA or USA branded Taiwan machines usually run between $50.00 to $100.00 if they're
decent. Right now the closest to what I'd like is a Taiwanese Dayton 1/2 hp with 7" wheels for $60.00. I'm not in a hurry to buy one, so I can afford to take my time and look
for a bargin.

 

[Uglydog]

If you are willing to pay shipping and supply a motor and new bushings I'll send you a grinder arbor/stand free.
However, you might be better off waiting for rummage/estate sales.
These sort of machines show up in the Free Box, or you can negotiate to nearly free.

Be careful of used grinding wheels. Learn how to "ring" them, and stand back on start up!

Daryl
MN

 

[mikey]

mikey,
thanks for the info on CBN wheels: they look expensive but if they last a long time and don't need dressing I imagine I could stretch for one of them. I haven't priced out regular wheels,
so I don't know how they compare. While we're on the subject of grinding wheels, who makes good ones, or does it matter? (I know, it almost always matters...)

I don't use CBN wheels but @Dan_S does. Maybe he'll chime in here.

 

[Nogoingback]

If you are willing to pay shipping and supply a motor and new bushings I'll send you a grinder arbor/stand free.
However, you might be better off waiting for rummage/estate sales.
These sort of machines show up in the Free Box, or you can negotiate to nearly free.

Be careful of used grinding wheels. Learn how to "ring" them, and stand back on start up!

Daryl
MN

Thanks for the offer Daryl, but I might just wait for something local. The shipping and a
motor could add up to just as much as buying the complete machine.

What's the Free Box?

When you ring a wheel, are you just tapping it and making sure it doesn't "clunk" due to a crack or imperfection?