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Bench Grinder Basics

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Forum topic by TheWoodenOyster posted 03-30-2015 02:41 AM 1603 views 1 time favorited 17 replies Add to Favorites Watch
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TheWoodenOyster

1275 posts in 1403 days


03-30-2015 02:41 AM

Topic tags/keywords: bench grinder

Hey guys,

I have been thinking about trying out a bench grinder for sharpening. I’ve always just sharpened by hand, but I want to give a grinder a try. Maybe the grass is just greener, but it seems like a very controlled way to establish/re-establish a bevel without having to go thru the whole honing guide process, which I don’t really care for. I do the Paul Sellers method right now, but I have my doubts as to the sort of edge it produces, as do lots of people (feel free to voice opinions on this). That said I would be sharpening plane irons and chisels mostly. I’m not turning yet, but I probably will eventually.

My main questions are:

1. Is low speed necessary?
2. Are the fancy wheels necessary?

Any other thoughts for a bench grinder noob would be appreciated.

Thanks

-- The Wood Is Your Oyster


17 replies so far

View lwllms's profile

lwllms

555 posts in 2749 days


#1 posted 03-30-2015 02:57 AM

no and no

You do need decent tool rests and coarse grinding wheels. Make sure and keep your wheels dressed because dull wheels grind slow and generate heat. One 6” high speed grinder is all most woodworkers need.

Just for fun, here are some of our grinders. We grind a lot.

View ElChe's profile

ElChe

630 posts in 804 days


#2 posted 03-30-2015 03:02 AM

No and yes to maybe. I use a 3450 rpm bench grinder with a Norton white friable wheel. I use the veritas tool rest as the std tool rest on my grinder was useless. The typical grey wheels grind too hot. I keep a cup of water and if chisel gets too hot I dip it. Gentle pressure and it is really easy to get a hollow grind. I finish up on a 4000/8000 water stone. I do use the grey wheel carefully but I prefer the white stone.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View jdh122's profile

jdh122

879 posts in 2285 days


#3 posted 03-30-2015 05:23 PM

I also use a high speed grinder with a white friable wheel and the Veritas tool rest. It works very well, as long as I dress the stone often enough.
I was also told that the wheels that come with grinders grind too hot. I’ve never tried using the wheel my grinder came with, but Old Street Tools, respected wooden plane makers, argue that a regular coarse stone works fine: http://www.planemaker.com/articles_grinding.html

-- Jeremy, in the Acadian forests

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TheWoodenOyster

1275 posts in 1403 days


#4 posted 03-30-2015 05:41 PM

Thanks for the input guys. I think I will probably splurge on a white wheel, and if I don’t I will practice on a crappy chisel first.

Looks like CL is the best cheap source for quality bench grinders. Is there a minimum HP I should be shooting for? And what about 8” vs 6”?

-- The Wood Is Your Oyster

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jdh122

879 posts in 2285 days


#5 posted 03-30-2015 05:45 PM

Ha – I wonder if lwllms is Larry Williams, one of the planemakers from Old Street Tools that I referenced in my post. Seems likely…

-- Jeremy, in the Acadian forests

View hotbyte's profile

hotbyte

844 posts in 2443 days


#6 posted 03-30-2015 05:46 PM

For going straight from grinder to stone, what grit wheel would be best?

View SirIrb's profile

SirIrb

1239 posts in 698 days


#7 posted 03-30-2015 05:51 PM

I would say to go to Lowes, look at all the bench grinders, take the money and go have lunch. Even the better bench grinders without jigs and very good rocks will leave you with a very very very rough edge. I have a 2X72 belt grinder for making knives, I sharpen all my stuff on a stone or paper.

Exception: Lawn Mower Blades…maybe.

(In British Monty Python voice: Run away, Run away!)

-- Don't blame me, I voted for no one.

View rwe2156's profile

rwe2156

2200 posts in 948 days


#8 posted 03-30-2015 06:03 PM

Speed + fine grit = heat.

If you want to grind with fine stones, you have to slow them down, period.
Also, remember the angular velocity increases with bigger stones, so an 8” wheel is actually going faster than a 6” at the same rpm. If you go with an 8” grinder, you definitely want variable speed.

My answer is yes to both questions if you’re planning on putting fine edges on fine tools.

Additional info:

1. The tool rests that come on most grinders are pretty useless so you’ll have to upgrade them somehow.
You didn’t mention it, but I think a guide is nice to have, like the Veritas system.

2. The lights on most grinders only work when the grinder is on so check that feature.
As far as I know, only the Craftsman and Portercable have independent light swithes.

You don’t need an expensive one, either.
I went with the Craftsman variable speed and I’m satisfied with it.
I figure for the same price, why not get one I can slow down if I want?

-- Everything is a prototype thats why its one of a kind!!

View TheFridge's profile

TheFridge

5765 posts in 954 days


#9 posted 03-30-2015 06:04 PM

Unless you plan on dropping a bunch of money into it, a grinder will only be good for rough work like setting the primary bevel.youll also need a wheel dresser or dressing stick (Amazon is where I got mine). I have a stock wheel and it’s pretty coarse.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View ElChe's profile

ElChe

630 posts in 804 days


#10 posted 03-30-2015 08:36 PM

I have an 8” 3450 with the white Norton wheel and even though it is technically more feet per minute than a 6” it works fine. The 6” 3450 is pretty optimal. I got mine for free if not i wouldve bought a 6”. My white wheel is 80 grit. l got it from spectrum supply where I get my handsaw blades as well. I hollow grind my chisels to 25-30 bevel. Then I sharpen the two reference points of the hollow grind at 4000 then 8000 Waterston’s. Then i get rid of the burr on the 4000. Works really well and much easier to register a chisel free hand compared to sharpening the entire bevel.

-- Tom - Measure twice cut once. Then measure again. Curse. Fudge.

View OSU55's profile

OSU55

1063 posts in 1457 days


#11 posted 03-30-2015 09:09 PM

For chisels and plane blades, a grinder is great for establishing the primary bevel, but probably only the Tormek waterstone rock (about $350 for the wheel alone) MIGHT provide an edge smooth enough to last any time. The edge will need to be honed either free hand or jig. A lot of turners use tools right of the wheel, and it varies how fine of a grit they use.

Since you don’t have a grinder, an 8” 1750 rpm with friable wheels is the best choice. I use a 6” 3450rpm with grey wheels only because I had it. Very difficult to not burn the steel once the edge gets very small. A white friable wheel is in my near future.

I use a Grizzly wet grinder for 01 steel blades/chisels. The wheel composition does not like A2 or HSS blades, loading up quickly and requiring constant dressing. It does do well the HSS turning tools, where only a small amount of steel is in contact with the stone at one time. I use the 6” grinder for relief bevels on the turning tools. I use mostly Tormek accessories on the wet grinder and bench grinder.

My honing method for chisels/blades is here http://lumberjocks.com/OSU55/blog/39391

View Wildwood's profile

Wildwood

1887 posts in 1602 days


#12 posted 03-30-2015 09:31 PM

Whether you buy a 6” or 8” grinder, with no load speed of 1725 or 3000+ RPM’s not important as buying locally. A 1/3 HP 6” grinder will sharpen or ruin a tool edge as fast as a ½ or ¾ HP 8” grinder. Reason for buying locally simple; lot easier to exchange or get a refund.

¾” wide wheel normally standard on most 6” grinders today. 8” grinder want one with 1” wheel verus ¾”.
You also need a diamond dresser for truing up wheels.

Friable wheels best to have a medium grit wheel for repair a cutting edge or changing a bevel angle (46 or 60 grit). A fine grit wheel for sharpening, resharpening, or touching up an edge (80, 100, 120 grit). They also sell 150 grit super fine wheels but personally would not buy one.

Jig already mentioned:
http://www.veritastools.com/Products/Page.aspx?p=128

I sharpen my turning tools on Norton 3x K hardness grade wheels they seem to last longer than I or J. A plain white wheel might suit you just fine.

http://www.sharpeningsupplies.com/Grinding-Wheels-C20.aspx

-- Bill

View lwllms's profile

lwllms

555 posts in 2749 days


#13 posted 04-02-2015 02:39 AM


Ha – I wonder if lwllms is Larry Williams, one of the planemakers from Old Street Tools that I referenced in my post. Seems likely…

- jdh122

That would be me but it’s been more than 15 years since I wrote or even read that article. I don’t often use a star-wheel dresser now, I either use a single point diamond or a multi-point “T” diamond dresser.


For going straight from grinder to stone, what grit wheel would be best?

- hotbyte

I prefer 24 grit. At $8.40 each, these are my choice:
http://www.victornet.com/detail/GWBE-6-3/4-C.html
Keep in mind that Victor Machine has a $25 or $30 minimum order. These wheels will grind faster and cooler than the white or 3X blue wheels. They’ll also last longer and hold their shape better than the high dollar wheels.

View TheWoodenOyster's profile

TheWoodenOyster

1275 posts in 1403 days


#14 posted 04-02-2015 12:16 PM

Wow. This is exactly what I was hoping for.

For clarity, I am not planning on doing any sort of final edge with this grinder. I will be referencing on my two points and freehanding with a 4000 then 8000.

Thanks for the tips guys!

Larrry – I read your article on bench grinder basics and it was very helpful. I am going to try a coarse grey stone as you suggest first before buying a white wheel.

-- The Wood Is Your Oyster

View Big_T's profile

Big_T

119 posts in 825 days


#15 posted 04-04-2015 04:56 PM

Very nice thread here as I was planning to learn about sharpening my own blades to save money. But it seems too complicated and expensive for a novice and will just keep paying the mobile service $5 for household scissors and $20 for tools every few months.

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