Reverse Sanding

[Bryan Milham]

I'm sure many of us use those 2" sanding discs on one of the many rotating bowl sanders available, but a question.

When held on one point of the wood the sanding head rotates one way (as, say, sands from the rim to the centre), if held slightly differently it rotates the other (sands from the centre towards the rim).

Is this the same as reverse sanding, i.e. rotating the lathe in reverse?

My thought processes say it ought to be but I cannot fully convince myself.

[Doug Barratt]

I know what you mean as I use the Hegner sanding disc & depending on the angle of approach this dictates the direction of spin of the disc. So I suppose as the one direction is opposite to the other then it could be said to be reverse sanding.


Cheers.

[Derwent Woodturning club]

My interpretation of 'reverse' sanding is to have the abrasive pushing the fibres the opposite way to 'normal', thereby not allowing them to bend out of the way. This is usually done by reversing the wood rotation on the lathe, guaranteeing reverse sanding, but if the section of the abrasive that is cutting is moving against that direction, you have, in effect, got reverse sanding. The only criteria for that to be the case is that the abrasive is moving faster downwards than the wood is moving downwards. I am assuming you are sanding in the usual 8 o'clock position. When using my bowl sander I can find positions where it spins hardly at all or very fast, depending on which part of the disc is driving the rotation, so it's not necessarily the direction of rotation of the the sanding disc, more the speed and position where it's cutting.
Hope that makes sense and would be interested to hear other's opinions,

[Paul Disdle]

Just a thought but if you are working between centres and swap your work over from head to tail, would you be reverse sanding then?

[Eric Harvey]

to my mind,you have to reverse the direction the wood is spinning to get reverse sanding,although the disc is spinning the opposite direction when moving from pressure from one side of the disc to the other it is still spinning in a downward direction when the lathe is rotating in the normal (anticlockwise ) direction,to get the disc to spin upwards (clockwise ) you have to reverse the lathe direction to get reverse sanding,regards,

Eric.

[julcle]

I think Paul is probably correct if you are doing spindle work as the wood is turning is the
opposite direction the problem lies with face plate work, if your lathe has no reverse I
guess you have to sand on the back end of the piece rather than the front end if that
makes sence.