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Forum topic by hookup posted 02-26-2019 09:21 PM 356 views 0 times favorited 7 replies Add to Favorites Watch
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hookup

17 posts in 177 days


02-26-2019 09:21 PM

I am a new member and a really really new turner. the question i have has to do with sharpening with a cbn wheel .
everything i see shows using a slow speed grinder. I have a 6in skill grinder which is not slow speed or more than 1 speed. can a reostate (sp) be added to this grinder to get a slower speed. Trying to spend wisely by not having to buy a new grinder and there are 6 in cbn wheels that are a bit less also.


7 replies so far

View TheDane's profile

TheDane

5666 posts in 4116 days


#1 posted 02-26-2019 11:27 PM

No … rheostats only work on universal motors (e.g. routers, etc.). Grinders use induction motors … trying to use a rheostat on could cause the motor to overheat, damaging it.

Many people use 6” grinders, but be advised that they create a deeper hollow on the bevel than an 8”. Some like it, some don’t.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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Andre

2695 posts in 2259 days


#2 posted 02-26-2019 11:35 PM

Pretty sure the rheostat will not work, slow speed grinders are 1750 RPM as compared to 3450 regular grinder, so just a lot less wheel contact time. I use the White cool stones on both of my grinders and also have one on a hand powered grinder, too much money invested to switch to the CBN but from what I’ve heard very tempting.
I was taught if you can touch the steel without burning yourself good to go! You see blue/black colouring, temper gone!

-- Lifting one end of the plank.

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Lazyman

3712 posts in 1840 days


#3 posted 02-26-2019 11:49 PM

It seems like I’ve heard that you have to use a variable frequency drive (VFD) to make an induction motor variable speed. By the time you add that you could get yourself a good slow speed grinder plus a few other tools to go with it. You can probably sell your old ginder for a few bucks to help offset the cost of the new grinder.

You can probably use your regular grinder but you have to use a light touch and frequent breaks to prevent overheating, though I don’t know if there are any other problems with the CBN with higher speed.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Gittyup

184 posts in 2409 days


#4 posted 02-27-2019 01:09 AM

A lot of guys sharpen on a 3450 grinder. The trick is not to overheat your tools. I could never seem to do it, especially on thin-edged tools. So, rather than ruin expensive chisels, I bit the bullet and went with a slow speed grinder and CBN wheels. So much easier for me. I use my high speed grinder for carbon steel (lawn mower blades and such).

-- tel

View hookup's profile

hookup

17 posts in 177 days


#5 posted 02-27-2019 02:25 AM



I am a new member and a really really new turner. the question i have has to do with sharpening with a cbn wheel .
everything i see shows using a slow speed grinder. I have a 6in skill grinder which is not slow speed or more than 1 speed. can a reostate (sp) be added to this grinder to get a slower speed. Trying to spend wisely by not having to buy a new grinder and there are 6 in cbn wheels that are a bit less also.

- hookup

thanks folks. the answer is as I expected. well off to raid the piggy bank

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moke

1402 posts in 3229 days


#6 posted 02-27-2019 03:56 AM

IMHO, CBN wheels are a forever purchase, I would spend the extra to get a slow speed 8” if I was going to spend the money. I have two grinders, a 10 year old Delta slow speed with Norton wheels and a two year old Rikon Slow speed with CBN wheels. You used to be able to pick up the Rikon’s for around 100.00 on sale occasionally, I’ve lost track recently, but they must still be reasonable. CSUSA has some new cheaper CBN wheels ( KJR brand- still 110 to 120.00 each ) and they are also lighter for quicker start up.

6” wheels yield a more hollow grind on tools. High speed grinders heat tools up more….even though CBN wheels run some what cooler. Having said that the best turner in our club uses a 6”- 3450rpm Buffalo grinder with old gray wheels and has beautiful grinds on his tools…..IMHO it more about the person than the equipment. It’s just I can use all the help I can get, so I bought that Rikon and CBN’s.

-- Mike

View TheDane's profile

TheDane

5666 posts in 4116 days


#7 posted 02-27-2019 04:14 AM

Woodturners Wonders often has deals on Rikon grinders equipped with CBN wheels. Check them out … https://woodturnerswonders.com/

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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