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View Full Version : Rake angle ?



Tiger
25th August 2005, 06:54 PM
Hi everyone,

I keep seeing references rake angle and negative rake etc. I have seen some definitions that are contradictory to each other. Anyone out there able to describe what it is in simple terms?

ozwinner
25th August 2005, 06:59 PM
Try here. (http://www.google.com.au/search?hl=en&q=rake+angle+and+negative+rake+&btnG=Google+Search&meta=)


Al :)

Studley 2436
25th August 2005, 10:16 PM
This takes me all the way back to my days as a fitter and turner.

Basically a tool cutting must have two main angles the clearance and the rake.

Draw a circle and put a cross through the centre. This is your job viewed from the end. The tool should be at the same height as the centre. If it is angled back, so the back of the tool is below centre that is positive rake. If the back of the tool is above centre and the point is on centre then you have negative rake. We used to grind tools for turning brass with negative rake. The reason being that the tool could bite and dig in to brass because of it's softness. Negative rake used to cut steel would mean that the tool would skip or bounce away from the job. The same sort of thing goes on I imagine with timber.

Studley

echnidna
25th August 2005, 10:51 PM
Negative rake saws are used in radial arm saws and should be in SCMS as well to minimise the possibility of climb cutting.