slow speed grinder

[Hangfire]

Hi all,

i have been dabbling with my lathe using carbide tools - lots of fun making pens etc - but am thinking of getting into more traditional tools to turn bowls etc.

what has put me off is the sharpening stuff.

that said i am thinking of pressing the button on a 200mm slow speed grinder - by no means are my pockets very deep here.

which of the following would people recommend (from the usual suppliers)?

Carbatec - Carbatec 750W (1HP) 200mm Low Speed Bench Grinder | Carbatec (https://www.carbatec.com.au/carbatec-200mm-bench-grinder-1450-rpm-slow-speed) - currently $254 - 750W

Timbecon - https://www.timbecon.com.au/sherwood-8in-slow-speed-bench-grinder - currently $239 - 375W induction motor (4 pole - apparently this is good??)

Hare + Forbes - doesnt seem to offer a slow speed grinder...

i am thinking of getting a basic HSS set to complement my carbides - then fleshing it out with the ones that i use a lot - (same as i did with my router blades)

what does the brains trust think?

[Chief Tiff]

I recently bought the Timbecon one to use with a Tormek adaptor on the RH wheel and an aftermarket grinder rest on the LH one. What really sold it to me was that it came with two white wheels (the RH one being 40mm wide) so I wouldn’t have to buy those as well, but the fact it was on sale and that weekend was free shipping so only costing $215 sealed the deal!

I haven’t actually got it set up yet so I can’t comment on the performance under load; all I’ve done is spin it up to make sure it worked. What I can say is that out of the box the wheels are not as balanced as I would like; both wheels have some wobble with the LH one being the worst. I’m hoping I can simply remount them and get them in true without having to rely too heavily on dressing tools but if I have to carve them up a bit then so be it.

[China]

Why a slow speed grinder it is a new fashion, I have been wood turning for 45+years ( 5yrs as business) as have may others never had the need for slow speed grinder.

[tonzeyd]

I don't have either of those machines, but do have an older 1hp full speed grinder. The left wheel is white oxide wheel right a CBN wheel. left on its own it takes some time for it to get up to speed, so i end up giving it a push before i turn it on to reduce the load on the machine. My point, is if i was to replace my grinder with one of the above models i'd go with the 1hp Carbatec unit.

Having said that if you're not planning on upgrading the wheels, the Timbecon unit with the wider wheel would be a good bet, but with either machine set aside some funds to upgrade the tool rests. I have the Tormek BGM-100 which is excellent if you sharpen an array of tools/knifes etc, but gets expensive once you start factoring the various jigs.

Also like China said slow speed are a new thing and i'm sure they're great, but there is nothing wrong with full speed grinder either once you get used to the machine.

[derekcohen]

Hi all,

i have been dabbling with my lathe using carbide tools - lots of fun making pens etc - but am thinking of getting into more traditional tools to turn bowls etc.

what has put me off is the sharpening stuff.

that said i am thinking of pressing the button on a 200mm slow speed grinder - by no means are my pockets very deep here.

which of the following would people recommend (from the usual suppliers)?

Carbatec - Carbatec 750W (1HP) 200mm Low Speed Bench Grinder | Carbatec (https://www.carbatec.com.au/carbatec-200mm-bench-grinder-1450-rpm-slow-speed) - currently $254 - 750W

Timbecon - https://www.timbecon.com.au/sherwood-8in-slow-speed-bench-grinder - currently $239 - 375W induction motor (4 pole - apparently this is good??)

Hare + Forbes - doesnt seem to offer a slow speed grinder...

i am thinking of getting a basic HSS set to complement my carbides - then fleshing it out with the ones that i use a lot - (same as i did with my router blades)

what does the brains trust think?

You do not need a slow speed grinder for lathe chisels, which are either M2 or M4 steel. The slow speed grinder is recommended for bench chisels and plane blades, which use steel that is vulnerable to heat.

I would get a standard speed 8" grinder. Cheaper and better for your purpose. Use CBN wheels to get the best performance.

Regards from Perth

Derek

[BobL]

+1 for a normal speed grinder and CBN wheels

[bruceward51]

Yes spend the money on a CBN wheel. The CBN generates a lot less heat and is easier to use. Expensive but very good.
Bruce

[chambezio]

As an Apprentice Carpenter our Tech teacher (TAFE), when showing us how to use a grinder in order to sharpen tools told us the best place for our fingers during the grinding part was to have the fingers close to the grinding site. He told us to hold the tool tight on the rest and slide left to right using only light cuts to the grinding wheel. Those fingers, he said, were the best temperature sensing instruments around. As soon as you feel the tool heating up dip it in water and go again until you get the desired face on the tool.

I have used this method ever since (52 years now.....I'm old) and rarely "burn" a tool while grinding. When using turning tools a trip to the grinder is needed regularly depending on the hardness and make up of the timber being used. You NEED to have sharp turning tools!!! I have never used a slow speed grinder but a build up of heat with one would "burn" a tool just the same as a full speed wheel.

The under lying method in either grinder would be to have a "light" touch to avoid any burning

This will make you cringe.....we had an exercise to show that we were competent with the tool grinding process. The TAFE store man would issue us with a plane blade that he had just attacked the cutting edge with a Warrington Hammer (OUCH). I think he had great delight in the job. These plane blades would have "dings" 3mm deep and maybe 2 or 3 of them on the cutting edge. It took a while to remove enough metal to get the cutting edge ready for the sharpening stone

[jack620]

Agree with normal speed grinder (2800RPM) plus CBN wheels. However, there's nothing new about slow speed grinders. They are just four pole motors and have been around for decades. But with the reduced heat generated by CBN wheels they lose their advantage.

[addyau]

I recently bought the Timbecon one to use with a Tormek adaptor on the RH wheel and an aftermarket grinder rest on the LH one. What really sold it to me was that it came with two white wheels (the RH one being 40mm wide) so I wouldn’t have to buy those as well, but the fact it was on sale and that weekend was free shipping so only costing $215 sealed the deal!

I haven’t actually got it set up yet so I can’t comment on the performance under load; all I’ve done is spin it up to make sure it worked. What I can say is that out of the box the wheels are not as balanced as I would like; both wheels have some wobble with the LH one being the worst. I’m hoping I can simply remount them and get them in true without having to rely too heavily on dressing tools but if I have to carve them up a bit then so be it.Funny, I bought one recently as well, and I'm thinking about taking it back because there is significant wobble. At the 40mm wheel, about 0.15mm front to back, and 0.4mm side to side.
Just not sure about sharpening where the wheel doesn't constantly touch the tool.

Sent from my Pixel 3a using Tapatalk

[KahoyKutter]

The consensus seems to be to get a normal-speed grinder with a CBN wheel. I'm going to go against the grain but keep in mind that the following advice is coming from a relatively inexperienced woodworker so take it with a grain of salt.

If there's even the remotest of chances that you'll be using the grinder to sharpen non-HSS tools (e.g. bench chisels, plane irons, etc), I recommend getting a slow-speed grinder with CBN wheels. I've just been restoring a couple of antique planes and I've managed to change the colour on the tip of one of the original irons using my VicMarc CBN grinding (slow) station. The plane blades are quite thin especially at the tip and it didn't take long to overheat it. And if you are going to use it for bench chisels and plane blades/chip breakers/lever caps, I would advise choosing the VicMarc CBN wheels over the other brands because their sides have a 40mm CBN band that can be used to give a flat grind and also to roughly flatten the backs of plane blades and chisels (e.g. removing bellies or rust pits). That's my 2cents.



Cheers,
Mike

[Backyard Shed]

I have also purchased the Sherwood (Timbecon) slow speed grinder recently. I also has a wobble in the wheels. Once I dressed the wheels they are running true. I have sharpened a few of my HSS lathe tools and have been happy with the results so far. Still fairly new though.

I also agonised over the regular speed and CBN, this ended up cheaper for me and works out of the box. I figure I could upgrade one of the wheels to a CBN at some stage of I end up using the lathe to an extent that it justifies the extra money.

Also a very new turner, so keep that in mind.

[jack620]

The consensus seems to be to get a normal-speed grinder with a CBN wheel. I'm going to go against the grain…

Fair enough. Certainly won’t hurt. I have the Vicmarc CBN wheel with the 40mm flat band and I don’t think I’ve turned anything blue yet.

[Skew ChiDAMN!!]

I wouldn't bother with a slow-speed grinder for turning tools, but they can be very handy for other bench tools. Bench tools need to be sharp but turning tools lose the majority of their sharpness on first contact with the wood. Getting the bevel angles right is more important as they're what determines how long what's left of the 'edge' will last, giving you a longer cut time.

Sharpening turning chisels is all about lots of quick trips back to the grinder for light, quick touch-ups so you're still cutting and not grinding the wood away. ;)

Shaping them is a different matter. ie. changing the profile or bevel angle to a significant degree. Then a slow-wheel is handy.

Appropriate tool for the appropriate job.

For HSS turning chisels all you need is a normal grinder and AlOx wheel. It's bloody hard to blue HSS. Good to learn the light touch on. Buy a batter quality wheel as and when you can afford, but AlOX is cheap and effective.

For old Carbon Steel turning chisels (which are very easily blued but often hold a better edge) I'd recommend a better wheel (perhaps CBN) but same grinder. And never, ever dip it in water during grinding. Put it on a block of metal or blow on it to cool it off if you feel the need; it won't take any longer to cool down than it did to heat up.

FWIW, I don't use Tungsten Carbide tools, except when I'm roughing out large pieces and speed's more important than quality of cut. I don't blunt enough tips in a year that there's any economics to my investing in sharpening 'em, so I can't offer advice there.

But yeah... it's a good idea to buy a good set of HSS tools, even if only so you can do cuts a TC won't. Don't buy too cheap though, as steel quality drops off quickly at the lower prices.

[BobL]

To touch up carbide a 6" diamond coated wheel can be purchase for about $10 and attached to the same spindle as an 8" wheel like this.
The grinder is a 240V 3Phase 1HP running on a VFD from a 240V Single Phase GPO.
513229

I use it mainly to sharpen TIG welder tips but it comes in handy for touching up carbide tips for the MW lathe. I've also use it to shape glass. I replaced the side mirror of our Subaru by cutting a piece of mirror glass to rough shape and then rounding it off using this wheel and some water as a lube. Of course the mirror did not have the wide angle view of the standard mirror but it was good enough to enable us to sell it.

[bruceward51]

I think there is a key issue here that some of us miss. Those who have trade training have been taught by experts and can do everything with a rough grey wheel on a high speed grinder. But those of us learning by doing in a home workshop will never do enough grinding to get to that level of skill. As an amateur woodworker I found it very hard to get good results without burning tools. I find it A LOT easier with a CBN wheel.
Before I got the CBN wheel I had a slow speed grinder, which was a easier than a high speed machine, but the CBN wheel made more difference. I have my CBN wheel on a slow speed grinder but have used one on a normal grinder as well.
Since I have moved to Vic, my new Men’s Shed has an identical set up to mine but with white wheels so I can see the difference my CBN wheel makes. I still get much better results at home!
Bruce

[NeilS]

For HSS...

+1 for full speed

If also sharpening non-HSS...

+1 for CBN

If doing a lot of sharpening, for economy...

+1 for CBN, as it will eventually pay for itself in reduced loss of good steel.


PS - no amount of bluing at the wheel will soften HSS, different story with carbon steels.


On tools...

As Skew has pointed out, most woodturning tool 'sets' are of a lesser quality. My view on them is, if you don't know what you really need, buy as cheap a set as you can find (eg W302 - WT-6 HSS Wood Turning Tools - 6 Piece Set | Hare & Forbes Machineryhouse (https://www.machineryhouse.com.au/W302)) and be prepared to throw most of them away (usually into the back of a bottom drawer) as soon as you know what you really need.

One disadvantage of going cheap and nasty to begin with is that they might hold your learning process back. But, the advantage is that you will make the change sooner and buy quality individual tools, one tool at a time, and appreciate the difference when you are ready to know the difference.

[Hangfire]

for some reason i stopped getting notifications so didnt see much of this discussion...

i bought the carbatec 8 inch slow speed - along with their toolrest and basics turning tool rests

i bought a basic HSS set of lathe chisels from timbecon along with a diamond dresser for the alox wheels

not going to get the chance to unpack it all etc for a while, but it was surprisingly big at the showroom

[The Spin Doctor]

Why a slow speed grinder it is a new fashion, I have been wood turning for 45+years ( 5yrs as business) as have may others never had the need for slow speed grinder.

Woodwork/turning is like that. The number of techniques to carry out the same job are as varied as there are craftsmen...

There is no right way, there's the way you like to do it... Derek, though he probably doesn't know it, taught me that well over a decade ago.

You see I've been at it as long as you but a couple decades as a professional turner in Canada and I love slow speed grinders. I first rediscovered it, there is no new techniques there is only rediscovery of knowledge that was probably lost hundreds of years ago, in the early 80s and have been using it ever since. I would never go back to a regular grinder - ever. Mine spins from 1 to 3000rpms and I usually grind tools at about 200 or less, but rpm is less important than surface speed to that varies on diameter. When I was using 6" wheels it was about 300rpm.

To try to explain in writing isn't something I care to attempt, it would take pages and seems to offend the "experts" out there (not including you in that just in case you were thinking :U. Just past experience with trying to talk about it). The odd time I've shown someone, it takes about 15 mins and they're very surprised at how well it works and how easy by hand complex grinding can be.

But like I said if you like grinding at 3000rpm then that's fantastic. And if someone likes grinding at 1800 or 300, or likes to buff the ends that is also fantastic! As long as you're enjoying it.