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View Full Version : 8" bench grinder purchase advice



bellyup
24th June 2011, 02:36 PM
G'day All,
I'm looking to upgrade my 6" bench grinder to an 8" jobbie. My first thought was a Scheppach bg-200 but a quick search here on the forum gave the Scheppach a thumbs down. Anybody purchased a resonable 8" grinder lately?
Thanks,
Bruce.

brendan stemp
24th June 2011, 03:06 PM
First question: why do you want an 8"? Second question: have you looked at

http://www.cws.au.com/persistent/catalogue_images/categories/creusonslowgrinder.jpg

Its a 6" grinder that travels at half speed limiting the chance of burning your tool edges.

bellyup
24th June 2011, 03:14 PM
My Ashley and Abbott 6" runs HOT - the windings are on the way out and I rather fancy one of those diamond grinding wheels every one has ( I feel so left out!) and figure 8" would give a "flatter" grind.

robyn2839
24th June 2011, 04:31 PM
have had an abbot and ashley 8'' for years ,cant fault them ,i also have a 6''a&a as well both excellent..............bob

Sturdee
24th June 2011, 05:22 PM
First question: why do you want an 8"? Second question: have you looked at

http://www.cws.au.com/persistent/catalogue_images/categories/creusonslowgrinder.jpg

Its a 6" grinder that travels at half speed limiting the chance of burning your tool edges.

I recently got one of those and I'm really impressed with the quietness and vibration free operation.

Peter.

NeilS
25th June 2011, 01:24 PM
On 6" vs 8" vs 10" wheels vs flat grind and fast vs slow grind.

Many highly experienced turners have used 6" bench grinders effectively for decades. Can't remember any of them ever saying when they got an 8" grinder that it was a significant improvement, but worth noting that many of us began with carbon steel which was more suited to the slower surface speed of a 6" grinder.

Most of us now use 8" grinders. With HSS tools the higher surface speed of an 8" is not (should not be) an issue. The larger diameter of an 8" wheel does change the geometry of the bevel. If you have never used anything else other than a grind off an 8" wheel this is not an isuue. Some of us that have used both 6" and 8" grinders prefer the larger radius of the 8" grinder.

The 10" wheel on the Tormek-like wet grinders produce a flatter hollow grind yet again. Haven't used one myself so can't comment on any difference in the grind, but speculate that the durability of the edge off an 10" wheel may be slightly enhanced regardless of other claimed benefits of a slow-wet grind.

Some advocate a flat grind on belts grinders and claim that it has made a significance difference to their turning. Again, I haven't tried this yet so can't comment. Belt grinders/sanders have a slower surface speed than both fast and slow bench grinding wheels, if that is seen as any benefit, which I don't with HSS. Here (http://www.bigtreeturnings.com/articles/sharpening2.html) is one advocate for the method and an earlier thread (http://www.woodworkforums.com/f8/sharpening-question-48834/) about this on this forum.

One of these days I'm going to experiment with wet-flat diamond grinds on something like this (http://gemcuts.com.au/prod1794.htm), just because I like to play around with sharpening things, but don't anticipate that it will be a significant improvement over the 8" diamond wheel I mainly use now... :U
.

WOODbTURNER
25th June 2011, 02:35 PM
If you are looking for a diamond wheel checkout the CBN wheels also. Iv'e got both in 8" and if you are mainly using it for HSS I highly recommend the CBN wheels. (IMHO) I found out from use, that the diamond wheel seems to clog up where as the CBN always seem to be clean and sharper. The only downside is they are a bit dearer. I got mine from Dave Swietzer(?) of http://www.d-waytools.com/tools-diamond-grinding-wheels.html in the USA. The postage was $us47.00. There is information on the net re pros and cons of CBN and Diamond wheels.

bellyup
25th June 2011, 03:53 PM
Thanks Woodbturner,
What do you think of the wheels and what grit do you use?
The prices arn't that scary when you look at replacing Tormec wheels and the like - these are supposed to last a lifetime arn't they?
Bruce.

NeilS
25th June 2011, 05:28 PM
If you are looking for a diamond wheel checkout the CBN wheels also. Iv'e got both in 8" and if you are mainly using it for HSS I highly recommend the CBN wheels. (IMHO) I found out from use, that the diamond wheel seems to clog up where as the CBN always seem to be clean and sharper. The only downside is they are a bit dearer. I got mine from Dave Swietzer(?) of www.d-waytools (http://www.d-waytools) .com in the USA. The postage was .00. There is information on the net re pros and cons of CBN and Diamond wheels.

Agree with you WOODbTURNER on the CBN. As far as I know, Dave is the first to supply them at a competitive price. If they had been available at his prices when we went for the bulk buy I would have gone with them, but the CBNs were at least twice the price when we were looking at options and at 2x the cost of the diamond wheel it was out of the price range of most of us.

I'm planning on replacing my Diamond wheel with a CBN.... when it wears out in about 20 years... :doh:

Not that I have found the need for it yet, but has anyone found a better method than Carbide for cleaning their diamond wheel?
.

TTIT
25th June 2011, 09:35 PM
My old home-made grinder (washing machine motor for it's low speed) gave up the ghost a few months back and I was going to buy a low speed job from C'tec but they were out of stock and I was in a hurry so I bought a Makita 8" from the local hardware and couldn't be happier :U. Very quiet, vibration free with balancing do-dads for the wheels, lights over each wheel etc etc. Put the diamond wheel from our bulk buy on it and attached my all-in-one jig - love it! Another plus is that it's more compact than most and easy to move around.

Best bit was it put me in the draw for a Makita bar fridge - and I actually won it!! :)(:brava

WOODbTURNER
26th June 2011, 12:10 AM
Bellyup,

Got the 180 grit and so far it's much better than the diamond wheel and as I said it hasn't started to clog up yet. Just feels good. A higher grit will be too smooth I think. Horses for courses I suppose.

TITT,
Good onya! Worked out cheap.

INVENTOR
26th June 2011, 09:22 AM
Having owned a variety of 8" grinders, fast and slow. The big advantage with the slow ( albeit they are usually more expensive to buy) is they 1. remove material slower and hence give you more control of what is being sharpened and
2. most machines running at 3000 rpm are subject to more vibration due to unbalance etc the slower the speed usually the less vibration. less vibration means more control, less 'bouncing around' on the wheel.
My dream bench grinder would be a variable speed unit, for even slower speed. they do sell them in the USA I believe.

Hope this helps.

bellyup
27th June 2011, 11:10 AM
Thanks everyone. So at this stage it looks like a Makita 8" ($195) with a D-way180 grit CBN wheel ($185us) - I can buy Makita locally which will save freight costs. (When you live in the bush, freight costs impact on everything BUT I do get to have access to lots of fantastic timber).If the postage from D-way is $40 I might look at getting a couple of tools at the same time, I like the look of the beading tools.
Bruce.

WOODbTURNER
27th June 2011, 03:18 PM
Bellyup,

There was quite a bit of space left in the usps box to fit other gear in as it was a cube box slightly larger than the 8" wheel diameter. Ask Dave when you buy it.

rsser
27th June 2011, 05:10 PM
Onya Vern. Nice to get a bonus.

Neil asked about cleaning diamond wheels ... with light clogging, a rubber stick at run-down speed.

And Norton seeded-gel wheels are now available locally from Jim Davey. Worth reading up on.

As for burning tools, seems acc. to our metalworking brothers on the forum that with HSS you need to get to dull red in natural light before you b*gger the temper.

robo hippy
5th July 2011, 05:47 AM
I looked closely at the CBN wheels from D-Way, and will be getting them shortly. You never have to spin balance them, or true them up. Huge advantage. I would think that they will ship fine in the flat rate US Post boxes. Big one is about $20 for international shipping with a 20 pound weight limit. The CBN wheels that I now use (for 5 years) are like the Woodcraft diamond wheels with a 'matrix' of CBN bonded to an aluminum wheel. The D-Way wheel is much more affordable, though not cheap. Like some one once said, "Buy the expensive tool, and cry once. Buy the cheap tool and cry every time you use it."

Another sharpening system I saw at the symposium is a new one from Stuart Batty. If you are a knife maker, their belt grinders are about $1800. Stuart designed one that will work for knives, and also for woodturning, and any other type of metal grinding you can think of. Reversable motor, flat belt on one side and about a 10 inch wheel on the other side. You can tip the whole motor set up, and have a flat platform with the belt running at 90 degrees to that. I don't know the exact cost, but the 2 wheel model will be about $1800. Not cheap, but after really checking it out, it is a very well thought out piece of machinery. Kind of what I think I would come up with if I had a couple of years to think about it. I think he has pics up on his web site now.

robo hippy