Dressing grindstone wheels

[Deejay]

Evening all

I'm taking up woodturning as a retirement hobby.

I've just bought a Record six inch bench grinder, an RSBG6.

I have a question about dressing the wheels, which are both slightly eccentric.

The grinder is now mounted on a fairly sturdy and heavy base but I'm having difficulty dressing both the wheels with a 'devil stone'.

What is the best technique to use? Should I push the devil stone forwards using light pressure to take off the high spots, or heavy pressure to force them into a circular shape?

Am I using the best tool available?

Given that the grinder cost thirty quid with a five year warranty, would you advise me to replace the wheels?

The wide white wheel is graded A80 PV and the coarse wheel is an A36 PV.

Any advice would be appreciated.

Cheers

Dave

 

[PowerTool]

Hi Dave - I've got the Perform wide-wheel grinder;pretty sure the white wheel on that is 80 grit also,so I think the wheels on yours are quite suitable.
Not certain of the right way to true up the wheels - I use the devil stone lightly to take off the high spots,then sharpen tools on any remaining high spots,then re-dress with the devil stone - so it's a bit of a slow process,but can't bear the though of removing too much usable wheel at once.. :wink:

Andrew

 

[beejay]

Hi Dave,
I think someone posted about a similar problem with Record grinders recently. It may not be the wheels that are causing the problem.
Record are excellent at handling customer complaints. I would call them as I'm pretty sure they'll send you a replacement grinder.
The 80 grit is fine for touch up and keeping the edge on your tools by the way.
Some prefer 100 grit wheels for this but I don't think its necessary.
Some go for 60 grit on the coarse wheel which is mainly for regrinding/shaping but the one supplied with the Record is OK.
Trust you've got everything ready to go now and that you enjoy your new hobby.
regards, beejay

 

[duncanh]

I use the devil stone for cleaning the wheel but not for bringing it to round. To do that I use a diamond dresser similar to this one from Axminster (mine is narrower)

To hold it and get the wheel true I use the Trugrind jig that I also got from Axminster

Duncan

 

[Deejay]

Thanks for the replies.

I took Beejay's advice and mailed Record.

To do this I had to register with them and found out that you get access to their knowledge base.

That suggests using a star wheel dresser for wheel shaping.

I'll let you know what Record say.

Cheers

Dave

 

[TEP]

Hi Dave. I would be very wary about dressing the wheels if the machine is new. IME and whether cheap or expensive all new grinders should come with round and balanced wheels. It would be very unusual to have to dress the wheels unless you have used them for quite a bit.

If the wheels are eccentric and the grinder has not been used enough to cause that eccentricity, and is new. I would do as has already been suggested and get Record to sort out the problem.

 

[lurker]

I agree with TEP.

Also be aware that reshaping a wheel (as opposed to dressing) is bloody dangerous! Chances of a shatter are very high, particually with the cheap (sub £!00) chinewanese wheels we all use.

I've seen a wheel shatter and it scared the **** out of me.

I now always use a full facemask when using a grinder.

 

[Deejay]

Hello all

Thanks for the replies.

Record got back to me and gave some advice.

They said that the wheel should be trued by passing some form of cutter (I have a devil stone) across the grinding face, i.e. parallel to the axis.

Apparently the cutter just follows the existing shape if it is pushed in line with the plane of the wheel.

It makes sense when you think about it.

Furthermore, it works. The wheels are now much better. They aren't perfect (yet) but I may be trying too hard. I'll Take Andrew's advice and use it for a while.

I'll keep my eye out for a diamond tool, as Duncan suggested.

Lurker made a good point about using a full face mask. I wouldn't like the last thing to go through my mind to be a piece of grinding wheel.

Cheers

Dave