Angles to grind for 303 stainless

This topic has 9 replies, 9 voices, and was last updated 29 August 2026 at 14:09 by Journeyman.

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29 August 2026 at 09:47 #862628
paul1956
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@paul1956
I’m quite confident with the mechanical process of grinding HSS tools. What’s baffling me is the lack of consistency of naming the various facets of the tool faces, so knowing exactly what angles to grind starts to become a bit of a puzzle. I’ve several books, have looked on other web sites, and none of them use exactly the same terms for the faces.
In an attempt to get a decent answer for angles for 303 stainless steel I asked ChatGPT. A long text answer and when I asked it to clarify with an illustration of which face was which I got the image below. To my novice eye that looks wrong, anyone care to offer an opinion.
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29 August 2026 at 09:57 #862633
JasonB
Moderator
@jasonb
I never bother to grind anything specificaly, generally the same tool does me for all metals so don’t get too hung up an grinding a tool for every material you come across.
29 August 2026 at 09:58 #862634
Bazyle
Participant
@bazyle
Some of these ‘guides’ can get a bit precious and are really directed at production. Just do everything at 10 degrees.
29 August 2026 at 10:02 #862635
paul1956
Participant
@paul1956
I was more interested in what people thought of the illustration.
The bottom right layout looks wrong and the tool ‘back rake’ seems to go the wrong way ?

More AI slop or am I reading it wrong ?
29 August 2026 at 10:18 #862636
Nicholas Farr
Participant
@nicholasfarr14254
Hi Paul, I agree with what JasonB and Bazyle has said, the angles are not really critical for most work we do, and if mine look OK and are sharp, they will do the job.

Regards Nick.
29 August 2026 at 10:44 #862638
Pete Rimmer
Participant
@peterimmer30576
I would not trust anything in that illustration that shows the direction of rotation as being away from the cutting edge. Go on archive.org and download some old text books and take your info from those.

303 is wonderful to machine and doesn’t readily tear up the surface like some mild steels but you don’t easily get a nice shiny finish on it.
29 August 2026 at 11:40 #862652
Howard Lewis
Participant
@howardlewis46836
In my limited experience, as long as there are clearance angles, the exact value is less important.

As Jason says, 10 degrees will suffice for most purposes.

Whilst the optimumn clearance angle might be 8 degrees, disaster is unlkely to strike if it is actually 5 or 10 degrees. The essential thing is that the tool is on centre height, and there is clearance so that the tool does not rub.

FWIW, being me, Top rake is often zero, seemingly without problems.

Howard
29 August 2026 at 12:23 #862674
Roderick Jenkins
Participant
@roderickjenkins93242
On 29 August 2026 at 10:02 paul1956 Said:

I was more interested in what people thought of the illustration.
The bottom right layout looks wrong and the tool ‘back rake’ seems to go the wrong way ?

More AI slop or am I reading it wrong ?

AI seems to have tied itself into a knot, it clearly hasn’t read Harold Hall’s “Tool and Cutter Grinding” as part of its Large Language Model.

Rod
29 August 2026 at 14:00 #862707
duncan webster 1
Participant
@duncanwebster1
I find my eccentric engineering tangent tool works well on SS. Most important is keeping tool sharp and keeping it cutting. If it rubs the SS can work harden.
29 August 2026 at 14:09 #862708
Journeyman
Participant
@journeyman
Steve’s Workshop has some useful info on this topic. Including the poster below.
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