grinder speed question

[Dale Gregory]

Just got home from Woodcraft. Based on what I've read here, most use a 1725 rpm slow speed grinder and Wolverine jigs for sharpening turning tools. So I bought them both. After reading through the Oneway Wolverine setup instructions there is a paragraph titled "Grinder Tip" recommending an eight inch grinder and high speed 3450 vs. 1725 rpms based on optimum grinding speeds of 6000-8000 surface feet per minute. They go on to show that the 8" wheel at 1725 rpms = 3612 sfpm - Too Slow! I guess I'm confused now and want to make sure that buying the 1725 was not a mistake. Who uses the 1725 rpm grinder and what is your take on how well it sharpens your tools in leu of Oneways statement above?

Dale

[Burt Alcantara]

I have a Harbor Freight 3450 grinder. I found that Richard Raffan and Earnie Conover suggests using the faster wheel because, with HSS, they cut faster.

Judy Ditmer uses the faster wheel but suggests using a slow wheel if you're just starting out.

I also have the $10 set of turning tools to make stubs with. I plan on learning to sharpen free hand, just because I'm that sort of person. At that price I can buy a few more sets and practice until I get it right.

Sharpening is a personal experience. Probably doesn't matter what method you use as long as you stick to it and learn how to get the sharpest edge possible.

I'd suggest to stick with what you have and don't go chasing the "best."

[Jason Morgan]

I did the same exact thing in the same order and wondered the same thing. Ive been sharpening on my for quite a while and it seems to work really well. I think most folks are more worried about wheel type and grit than they are with speed. I remember when I asked the majority of people said slow speed was fine or preferred.

My $0.02 worth

[Ken Fitzgerald]

Dale.........I bought the same stuff last year based on recommendations here. They work well.

[David Walser]

This is a hot topic of debate. A 1725 rpm grinder will definitely get the job done. A faster grinder will get it done faster. There's not a right or wrong here. With high speed steel tools, the faster grinder will not take the temper out of your tool. The slower grinder is most likely easier to learn on. I will note two things:

1. The AAW's "how to sharpen" video has several well-known turners each show you how to sharpen. None of them do it the same way. Most of them recommend the slower speed grinder.

2. I've got a high speed grinder. I'll trade you for your slow speed version.

[Bernie Weishapl]

Dale I think you will be ok. I went with the recommended 3450 rpm since oneway, Raffan, Conover and Mahoney all said that is the way to go. I don't think you will have a problem.

[Steve Schlumpf]

Dale, I think you made a wise decision.

I have a 3450 rpm 6" grinder and the Wolverine system. It works fine but I do plan on getting a slow speed 8" grinder one of these days. Reason for me is 8" has a wider stone, offers slightly less of a hollow grind and takes off just a little less metal.

[Ken Fitzgerald]

Dale.....I was told when I bought mine last year....You won't hurt the HSS with either one.....but the slowspeed grinder will take longer.....slows down the grinding process so a beginner sharpener/turner will do less damage to his/her tools as they learn to sharpen. I know now that I can sharpen much quicker that when I started last spring and take off less steel doing it.

[Dick Durbin]

I also have the slow speed Woodcraft grinder and the UPS man delivered my Wolverine jig about 7 p.m. yesterday. I can't imagine a better setup. Remember, when you are sharpening, you aren't removing much steel at all so the slow speed is just fine.

I pulled out a couple of roughing gouges, set the jig, made one pass on each tool and ended up with a perfect bevel on both of them. Sharpening has always been a really weak point for me in woodworking. I am pleased to have a setup that allows me to get a clean, sharp edge so quickly.

[Matt Meiser]

A few other things I've found with grinders. IMHO, a fast grinder is more suited to utility stuff than a slow speed, for example sharpening mower blades, grinding down the head on a bolt, etc. Also, for sharpening tools a lower powered grinder is fine, but for utility stuff it is easy to stop the wheel on a low powered grinder. My Woodcraft slow speed grinder was great for sharpening fine tools, but when I got out of turning I sold it as I didn't like it other stuff. I've been using a cheap 6" grinder, but finally broke down and bought a Wilton 7.7 amp 8" grinder -- most of the less expensive ones are around 3-4 amp. So I guess what I'm saying is that you should consider what else you plan to use the grinder for in your decision.

[George Tokarev]

Who uses the 1725 rpm grinder and what is your take on how well it sharpens your tools in leu of Oneways statement above?


As you can see, lots of people use 1725 grinders. Some even use Tormeks:rolleyes: rotating much slower. We're a weird bunch, we turners. We buy breakaway bond wheels and slow speed grinders to grind our heat-resistant HSS tools, worry about whether lack of a thousandth of an inch of metal between the ends of a bevel destroys a cut as if the wood knows the difference, and discuss how important it is to remove steel rapidly when what we want is to remove only enough to freshen an edge.

I think it has something to do with the stroboscopic effect on the turners' brains of interrupted light off natural-edge turnings.

Reason most of us use grinders is because it takes too much time to hone harder HSS with a gouge stone, and there's little risk of bluing and annealing an edge by pressing too hard on the wheel as was possible with carbon steel. Expedience. There are better ways to grind metal away, and better edges available through honing, it's just that this works well enough.

[Mark Pruitt]

Woodcraft 8" Slow Speed Grinder with Wolverine here; no complaints. Speed is perfect.

[Jim Becker]

I use a typical 3500 rpm 8" grinder for my sharpening. No problem with HHS and a light touch is what you want anyway. That said, the slower speed grinders are a little more forgiving for folks new to sharpening as they tend to not have the "light touch" which takes practice.

[Dale Gregory]

Thanks all for the collective reassuring pat on the back. I used the grinder for the 1st time last week and it worked great! I can see where the slow speed grinder will aid in this newby's tool fund. Even with the slow speed I was a bit over aggressive and sloppy with one of my 1/4" bowl gouges and ground a bit off before I realized I was pushing instead of letting the weight of the tool do the work. There is a big learning curve in turning, especially hits the old wallet pretty hard initially! Thanks again for the input.

Dale

[Richard Madison]

Several folks hit the target. The biggest advantage of the 1750 grinder is that you have a few more milliseconds in which to stop screwing up before you screw it up even worse. Beyond that, there seems to be little if any real difference.

[Ron Chamberlin]

Several folks hit the target. The biggest advantage of the 1750 grinder is that you have a few more milliseconds in which to stop screwing up before you screw it up even worse. Beyond that, there seems to be little if any real difference.
I'll Amen to that. I have a Sears adjustable speed 6' grinder that I keep running slowly for tool sharpening, by hand using a homemade tool rest. If I want to reshape something, like for instance a scraper, I can turn it up faster.
Ithink it is just what you get used to. Saw the Tormek demonstrated at the Columbus Oh wood show last week, but for $400, I'll keep my Sears.