Tool Post Grinding

**Anorak Bob** · 17th August 2011, 12:04 AM

In my copy of Care and Operation of Portable Precision Lathe Grinders ( the Dumore Company - Fourth Edition 25 cents!) under the heading of "Dressing the Wheel..." the following is stated -

"Care should be taken to see that the height of the horizontal centerline of the grinding wheel is at exactly the same height as the horizontal centerline of the spindle of the lathe. It is also important to have the diamond set at the horizontal centerline of the grinding wheel. This is necessary to ensure accurate truing of the face of the wheel".

I have made a dedicated tool "post" that locates the grinding spindle correctly. After reading about exploding wheels, I have positioned the diamond a whisker below the wheel centerline.

Further perusal of the handbook revealed this - an unbalanced wheel is a great hindrance to precision grinding. Because of the high speeds, an unbalanced condition will not only prove detrimental to the bearings, but will leave long regularly spaced chatter marks on the work. For this reason, the Dumore Company recommends the use of Dumore wheels which are carefully balanced...."

Well, the Norton wheel I've been using is anything but balanced and could well be the cause of my grief.

Dumore have been using oil mist lubricated ball bearings in their grinders for at least seventy years. The larger No. 5 grinder can run at 42,500 rpm, my little 44, 38,000 rpm.

Given my complete lack of knowledge regarding the intricacies of grinding, I am extremely grateful for the advice given to me by you blokes.

Thank you.

Bob.

**Stustoys** · 17th August 2011, 12:29 AM

Hi Bob,
One guy was suggesting dressing the sides of the wheel if you had axial run out. I'm not sure how I feel about that.

Stuart

**Anorak Bob** · 17th August 2011, 01:20 AM

I'd have nothing to loose by doing it Stu. I don't know if reversing the wheel after dressing the first side will throw things out though.

Bob.

**azzrock** · 17th August 2011, 02:27 AM

hi stuart. do you think its dangerous?i think it would be ok

**Stustoys** · 17th August 2011, 10:43 AM

Originally Posted by azzrock

hi stuart. do you think its dangerous?i think it would be ok

Now there is(was) a tricky question.

Would I do it? Yes I'm pretty sure I would.

Being that wheels this wide arent meant to take side load I would say it wasnt the best idea out there. But hands up if you have never used the side the wheel on a bench grinder?

Then I found this.
From Norton.

"Avoid excessive side pressure when truing or grinding with straight wheels"

"3. True the wheel face and sides to eliminate any wheel runout for the tightest corner holding control."

I must say I was expecting "don't do it"
Go for it, but go easy seems to be the answer.

Stuart

p.s. a wheel section chart, might be of interest. http://www.nortonindustrial.com/uplo...art%207505.pdf

**Abratool** · 17th August 2011, 11:43 AM

Thanks Stuart for the chart.
I noticed Norton recommend an H bond for surface grinding High Speed steels
After having a lot of difficulty surface grinding Hardened Tool steel called SC23 & a greater difficulty grinding High Speed steel with a K bonded wheel, I tried the softer H bond recommended for these steels & found an enormous improvement.
The softer bonded wheel cut cooler & faster, & was much more efficient.
All of this came about from trial & error, so it is good to have a chart to get the best out of grinding wheels.
Also it known that slower wheel speeds will make a grinding wheel act softer. A higher work or traverse speed in surface grinding will also make the wheel act softer & facilitate the grinding performance on these harder steels.
regards
Bruce
ABRATOOL

**azzrock** · 17th August 2011, 11:58 AM

Being that wheels this wide arent meant to take side load I would say it wasnt the best idea out there. But hands up if you have never used the side the wheel on a bench grinder?

df[/QUOTE]

hi stuyou know i always thought that "the don't grind the side of the grinmging wheel"
stuff was to do with undermining the grinding face. so its side load dangers as well.
interesting

Thread: Tool Post Grinding - Another Go.

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