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John Stan
12-06-2010, 8:02 PM
Hi -
I am getting a grinder. My use will be mostly plane irons and chisels. Seems the 6 inch Baldor comes in two speeds - 3600 RPM and 1800 RPM. Can anyone think of why one speed would be better than another? I would imagine with the slower speed you would be less likely to overheat or mess something up. Is there a downside to the 1800 RPM grinder?

Thanks,
John

Don Dorn
12-06-2010, 8:14 PM
If it's primarily for plane irons and cutting tools, I think the slow speed is your best bet.

Todd Hyman
12-06-2010, 8:15 PM
John go with the slow speed and you are correct the slower speed doesnt heat up your plane balddes or chisels as quickly. Not sure about Baldor ginding wheels, but i have the Norton blue grinding wheels and they are great.:o

Larry Williams
12-06-2010, 11:29 PM
The down side of the slow speed grinder is that it's more difficult to true and dress the wheel. A well dressed coarse wheel is the secret to grinding tool steel without overheating. At slower speeds the dresser tends to follow an out of round condition rather that true it. I think it's better to get the high speed grinder and put coarse wheels on it. Spend your money on a dresser rather than those high dollar wheels and learn good grinding technique.

What ever way you go, getting a grinder and learning to use it is a critical step in success with hand tools. I hate to discourage anyone from getting a grinder unless it's one of those Tormek types. It's a little known fact that Rip Van Winkle really didn't sleep all that time, he just decided to grind a couple plane irons on a Tormek in one setting. :D

Johnny Kleso
12-07-2010, 1:29 AM
Dressing is not that hard if you have the right tool..

One of these works great..
http://www.leevalley.com/en/wood/page.aspx?p=55075&cat=1,43072,43080&ap=1

http://www.leevalley.com/en/images/item/woodworking/sharpening/70m5003s1.jpg

Just hold it down in place tight and let the wheel true it self up slowly..
You could clamp it to the tool rest and lightly tap the tool rest or just push on it to true the wheel 100%..

When grinding do not dwell the cutter when near the corners of the blade..
They will turn blue quickly as there is no extra steel to heat sink the heat away like the middle..

On really bad blades blunt the edge square to remove chips and breaks, grind at 20º till 2/3 up the blade then grind at 25º the top 1/3 This way your not grinding the whole edge at once..

Hi or Low is up to you..
Low is cooler- slower
Hi is Faster - hotter

If your not skilled go slow or think you will pick it up fast go fast..
I say get a White 46 grit H,I or J hardness wheel slow
If you do a turning get a 60

David Weaver
12-07-2010, 8:04 AM
I use a dresser like johnny shows. If you watch a video of Larry Williams taking mass amounts of material off a while, the cheap T grinder won't do that comfortably, but I've had mine for a couple of years, and it does very well at dressing stones and if you take your time with it, it will shape them fine. Loses a little of its *smartness* after you've had it for a while, but it still cuts, and I don't see any evidence of diamonds coming out or electroplate letting loose on it.

Side note for buying the baldor, I *found* a 3x wheel with spacers and an old white wheel with spacers in my piles of stuff yesterday, and replaced the wheels that come with the baldor grinder. The ones that came with it were awful for balance - they just had one 1/2 inch hole, and now the grinder is really smooth. I found that out last night after ordering a balancing system from oneway :rolleyes: We'll see if it makes it even smoother.

McMaster Carr sells the wheels with spacers for about $13 for econo and $18 for premium, all aluminum oxide wheels that will be good for sharpening, and a huge array of grits.

I personally would go with a high speed grinder for 6 inch, but you can definitely burn edges with them, and you probably can burn edges even with a pink wheel if you want to use heavy pressure. If you have no experience, you may burn an edge or two and have to take a couple of minutes to undo your handywork by grinding out the blued steel. But i think in the long run, you'll appreciate the high speed wheel more.

Adam Cherubini
12-07-2010, 8:53 AM
Hi -
I am getting a grinder. My use will be mostly plane irons and chisels. Seems the 6 inch Baldor comes in two speeds - 3600 RPM and 1800 RPM. Can anyone think of why one speed would be better than another? I would imagine with the slower speed you would be less likely to overheat or mess something up. Is there a downside to the 1800 RPM grinder?

Thanks,
John
I bought the 8" woodcraft. There's alot I don't like about it. But I'm finding that most of my grinding is freehanding curved irons, gouges etc. So the quality of the tool rest doesn't matter so much to me.

The 8" slow peed grinder is a nice compromise between fast and slow 6". The surface speed is faster than a 6" slow speed and slower than a 6" high speed.

Larry is probably dead on when it comes to production grinding. But for limited use like most of us will experience, the stock white wheels are fine. I don't use the fine wheel. I tried a 3x and it made such a mess I took it off. Larry is also dead on about keeping stones (not just grindeing stones) clean. I dress mine often, but I use Joel's approach, dressing a slight camber on the wheel.

Since I got a decent diamond stone, I no longer use the side of my grinding wheels for flattening backs. That's an unsafe practice anyway and I haven't been wholly successful with it anyway.

Next chance I get I'm going to try and possibly buy a Tormek for grinding carving tools. The whole "speed of cutting" discussion (involving not only grinding wheels but also whetstones) is a bit unhelpful in my opinion. If you are grinding a large flat surface you need media that removes material quickly. But if you are detailing a small part, slower cutting stones/equipment can be better.

I say save your sharpening dollars. Get a cheap woodcraft grinder, a DMT diasharp xx-coarse diamond stone, good dressers (I've never used the single point dresser Larry uses, I have the little tee handled thingy), then the stones of your choice. If you are doing alot of rehabbing, a belt sander can be helpful, but don't think you can't overheat a tool on a belt sander.

That's my 2 cents

Adam

David Weaver
12-07-2010, 9:04 AM
Belt sanders are definitely nice to have, especially one that flips straight up, even a cheap 4x36 one like the one home depot has. they run about 2000 feet per minute, which is enough to remove metal pretty quickly, but with an 80 grit belt, lots cooler than a wheel grinder. The metal roller on the end of the belt is very handy for anyone who ever decides to make a metal plane, too.

Tormeks are great tools, just not so great for blunting an iron and grinding a lot of it back. A cheap belt sander and a tormek is a good combination, though, for someone who is afraid of burning edges.

The only trouble with cheap belt sanders (as opposed to quality purpose-made belt grinders) is that they dub the corners of wide irons, and where you don't want to do that, it creates the need to hone back to get past the dubbed edge. They are HIGHLY useful for cambered irons, though, you can grind those older woodie irons without heating them too easily. Much more friendly than doing it with a grinder, at least in my experience - and I'm sure some of those old high carbon plain steel laminated irons start to lose their temper at a pretty low temperature.

The 3x wheels must all be slightly different. The $10 one I got a while ago is definitely harder than my white wheel, which yields to the diamond dresser like powder.

Johnny Kleso
12-07-2010, 9:47 AM
I'd like to agree with Adam that while a Baldor is a great grinder, the WoodCraft grinder I think will last you a lifetime and its dual speeds..

Edit:
I see WC no longer sells the dual speed WC but does sell dual and variable speed Delta Grinders..
IMHO I think either of those would work find and spend the extra money on other sharpening tools..

David Weaver
12-07-2010, 10:04 AM
And having spent the money on a baldor grinder, I can't say that it's really a necessity. I don't know that it's necessarily any smoother than a foreign grinder with good balanced wheels.

I saw three grinders at HF this weekend, two were duds and one of them rolled like a cadillac. If you're really looking for cheap, you can go through HF grinders until you get one you like.

It's (the baldor) an indulgence for people who like such things in their shop, especially with the cast parts, which dampen a lot. I hollow ground a chisel last night and walked across my shop, and honed the chisel and lapped the back before the wheels stopped turning.

David Weaver
12-07-2010, 10:07 AM
Edit:
I see WC no longer sells the dual speed WC but does sell dual and variable speed Delta Grinders..


I have a hunch the grinders are very similar to the WC dual speed grinders, though that's just a guess.

Johnny Kleso
12-07-2010, 12:08 PM
David,

For those that can afford it nothing better than the best but I see a bench grinder as just one tool on a long long list of tools to pick up on my way down the slope :)