Shopsmith Forums

jsburger wrote:

dusty wrote:My guess is that with the old chart the numbers are gross estimates that are intended to put you in the general range for the operation being charted.

The new chart, however, is a bit more scientific (exacting, if you will).

In both cases, remember that the craftsman has some responsibility in this matter too.

I see the number differences but I don't see any glaring errors.

You don't see the fact that the speeds are upside down between the two charts?

The old chart has lower speeds for the corser grits and the newer chart has the higher speeds with the courser grits. That is a total reverse.

NO. I am sorry but I see the following - ON BOTH CHARTS. As the Grit being used gets Coarser the recommended Speed get Slower

I have to assume the PP belt sanding speeds do not match the new chart and that the new chart is in error.

I also assume course/medium/fine mean 60/100/150 grit.

The speed numbers agree between the two charts, but are reversed.

Anyone yet verified the pp settings?

I would be surprised if the pp is 'reversed'.

dusty wrote:

jsburger wrote:

dusty wrote:My guess is that with the old chart the numbers are gross estimates that are intended to put you in the general range for the operation being charted.

The new chart, however, is a bit more scientific (exacting, if you will).

In both cases, remember that the craftsman has some responsibility in this matter too.

I see the number differences but I don't see any glaring errors.

You don't see the fact that the speeds are upside down between the two charts?

The old chart has lower speeds for the corser grits and the newer chart has the higher speeds with the courser grits. That is a total reverse.

NO. I am sorry but I see the following - ON BOTH CHARTS. As the Grit being used gets Coarser the recommended Speed get Slower

???????

JPG wrote:I have to assume the PP belt sanding speeds do not match the new chart and that the new chart is in error.

I also assume course/medium/fine mean 60/100/150 grit.

The speed numbers agree between the two charts, but are reversed.

Anyone yet verified the pp settings?

I would be surprised if the pp is 'reversed'.

If you mean that they are not charted the same way, I agree. One reads top to bottom coarse to fine while the other reads top to bottom fine to coarse but that does not make they in error. That makes they difficult to read and compare.

The PowerPro and recent speed chart based are based on updated testing.

We now show slower speeds for finer grits on sanding.

The simplified explanation, as I understand it, is that with finer grits you have more "grit" particles per inch and need a slower speed to achieve the optimum grit-particles speed to avoid burning.

I stepped through every speed setting in the Power Pro database, and it is an exact match to the printed chart, except that one Scroll Saw speed setting was missing from the printed chart. Inadvertently, I assume.

Mike

dusty wrote:

JPG wrote:I have to assume the PP belt sanding speeds do not match the new chart and that the new chart is in error.

I also assume course/medium/fine mean 60/100/150 grit.

The speed numbers agree between the two charts, but are reversed.

Anyone yet verified the pp settings?

I would be surprised if the pp is 'reversed'.

If you mean that they are not charted the same way, I agree. One reads top to bottom coarse to fine while the other reads top to bottom fine to coarse but that does not make they in error. That makes they difficult to read and compare.

Positioning is not the issue. One must read the contents of each line.

Grit vs speed. Nothing else matters(not top, not bottom, not left nor right).

I find it interesting that the numbers are the same(assuming c/m/f = 60/100/150).

I am unconvinced re the 'explanation'.

What new factors were included in the 'updated testing'? It is (as already pointed out)the complete reverse of over 60 years of 'experience'.