Truing grinder wheel

[tapemonkey]

Hi all

I am trying to true (if that is the correct terminology) my grind wheel, but I just seem to be making worse. It is ok with side to side movement, but it is very bad in forwards/backwards. I have tried to dress it to get it concentric, but it is just getting worse. Why can't I get rid of the high point? Any help would be appreciated as I am obviously doing something very wrong.

Thanks

 

[CHJ]

Is the wheel located firmly on the motor spindle with no central boss slackness?

What type of dressing device are you trying to use?

How are you controlling the traverse across the Wheel?

Most likely cause is that the truing device is not firmly located in relation to the tool rest and is just following the wheel surface instead of removing the high spots.

 

[tapemonkey]

Stone is secure.
Using a dressing stone (bet this isn't good enough is it?)
Just holding the dressing stone.
So what do I need to remove the high spots?

Thanks

 

[CHJ]

A dressing stone is not the best method of truing up a grinding wheel, works reasonably well on a true wheel.

The problem you are getting is more than likely due to how you are using it though.

If you are just pressing it up against the wheel it is just following the surface of the wheel and due to 'bounce' as the high spots come round you are accentuating the highs and the lows, you are removing material from the low points.

The dressing stone needs to be held firmly against the rest so that only the high spots on the wheel touch as it rotates.
Do this by rotating by hand using the stone or a pencil point to see what I mean.

One of the main problems you have if it is well out of true (and balance) is that the machine will vibrate heavily and make it difficult to hold your dressing stone still on the rest.

 

[Finial]

Once the wheel starts to get out of true it gets worse and worse because of the vibration in the whole machine. Try running it up to speed then switching off and do the truing as it runs down. That may help you skip the low spots and just take off the high. Something more aggressive than the stone might help, a star wheel dresser or a single point diamond. When it is reasonably true you can keep it ok with the wheel running at full speed. Wear eye protection!

 

[sometimewoodworker]

Stone is secure.
Using a dressing stone (bet this isn't good enough is it?)
Just holding the dressing stone.
So what do I need to remove the high spots?

Thanks

I made the mistake of removing a wheel and after replacing it had very bad vibration. Tried a star wheel dresser and it was not good enough.

Picked up a single point diamond wheel dresser and within 60 seconds the vibration was gone.£5.00 Inc VAT

 

[tapemonkey]

Stone is secure.
Using a dressing stone (bet this isn't good enough is it?)
Just holding the dressing stone.
So what do I need to remove the high spots?

Thanks

I made the mistake of removing a wheel and after replacing it had very bad vibration. Tried a star wheel dresser and it was not good enough.

Picked up a single point diamond wheel dresser and within 60 seconds the vibration was gone.£5.00 Inc VAT

Do you think a single point is better than the block type? http://www.axminster.co.uk/axminster-di ... prod21896/

 

[CHJ]

[Do you think a single point is better than the block type? http://www.axminster.co.uk/axminster-di ... prod21896/

Yes, but a qualified Yes: To get a good flat and square surface on a wheel, a single point dressing diamond needs a carrier to allow a controlled traverse across the wheel. See attached homemade Jig or look at the dresser used on the Tormek.

The block if used with care and avoiding the problems of bounce facilitates the flat surface requirement which is hard to achieve freehand with a single point tool.

 

[wabbitpoo]

You might want to check to see if the spindle on your grinder is running true - if it isnt (many dont) wont you struggle to get a smooth running grinder?

I speak from experience

 

[tapemonkey]

I'll check everything out on the grinder and I like the look of that jig. I'll see if I can knock something up. Thanks for all the replies.

 

[tapemonkey]

Ok, I know it is a bit of a late update, but I got a diamond dresser and things are a lot better now. Thanks for the advice guys.