Common tool angles

[wayne ollerenshawParticipant @wayneollerenshaw89933]

I am seeing if i can adapt a tool to a tool grinder, first off for the lathe then milling tool and drill bits.

What if any are the most common angles to grind the tool to ?

 

Thanks Faffer 🙂

[noel shelleyParticipant @noelshelley55608]

There is a book in the workshop series that covers this subject, it  would be a good starting point. Noel.

[BazyleParticipant @bazyle]

Apart from screwcutting tool tips the only angles you need  for amateur metal working are 5 and 10 degrees. Books will show all sorts of angles , like 6 and 8 aswell  but that is just something the author perhaps remembered from production work or the whim of his tutor.
For mass production at maximum removal / tool life a more specific angle might be used depending also on the exact spec of the material but amateurs really don’t need to be so fussy.

[DiogenesParticipant @diogenes]

What Bazyle says – but I wonder whether if you can easily arrange to allow the table to accommodate angles up to 15-20 degrees it would be worth doing – there are always ‘odd’ jobs that crop up (boring and trepanning tools, etc.) where a little more range might be useful..

Some materials do cut better with a bit of rake on the top, although it seems to be less commonly discussed these days ?

If you are limited in the range you can achieve, it’s always possible to make holders to present ‘special’ tools at the correct angles..

[Thor 🇳🇴Participant @thor]

There is a downloadble guide from LMS that gives angles for grinding lathe toolbits, may be that can give you some ideas.

Thor

[JourneymanParticipant @journeyman]

[Rod RenshawParticipant @rodrenshaw28584]

Nice clear explanation of the “naming of parts” and useful Chart.

[BazyleParticipant @bazyle]

I think the table is interesting and really emphasises what I was warning about in published data. There is absolutely no point for amateurs to have one set of tools with a 12 degree angle and another with 10 degrees. It will make sod all discernible difference.
For beginners, when you can afford extra tool steel (ie several years before you buy a QCTP as the solution to all your problems) it is worth having tools specific to brass and aluminium.

[noel shelleyParticipant @noelshelley55608]

I grind them by eye, if they cut metal then it’s ok ! If it  dosn’t then I re grind it, paying more attention to the cutting edge. Angles, I havn’t the faintest idea, but it’s worked for 50 odd years ! Is it theoretcally correct, Does it work ?    Noel

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Morning all.

Thanks for all the replies, very helpfull.

@journeyman cracking tat. brings it all back for being and apprentice, many ,moons ago. seem  to remember something like that in the fitters bay. By eck i would love a surface grinder and shaper to play with.  good old days they were.

I am halfway through designing the tool grinder, well the modifications to the key cutter. I used to to grind by eye as with all my drill bits.But then i got a mill. So this tool will be hopefully of i can sort it, will be to grind the Milling cutters aswell as the Lathe tool. And then maybe the drill bits.

I am using what i have fitted if i can and at the minute as its only a couple of angles it is perfect.

Il put a post up later on the project as some of you mite be able to offer some ideas for a better set up.

 

yes maybe best to sat a new thread on this itself.

 

All best chaps

[noel shelleyParticipant @noelshelley55608]

Hi Wayne, If you get as far as doing milling cutters come back to me and I will copy the tables that Clarkson published for you. Keep us posted and good Luck.

PS, check out bedroom-workshop.com     There are a huge number of pictures, admittedly all Clarkson but it might give you some ideas.   By interesting coincidence there are dimensions to make a tapping guide. Noel.

[Howard LewisParticipant @howardlewis46836]

As otghers say, don’t get too woumd up over exact tool angles.

Yes, what optises machining EN32 may be less than for EN16, but you are not trying to manufacture as many as possible, in as short a time as possible with maximum tool life.

You are, presumably a hobyist, so a few seconds more on the time for a particular operation is not going to be the difference between bankruptcy or not. The object is probably to make a maximum of six, not ten thousand.

Clearance is needed, to prevent the tool rubbing, but absolute precision in the angle is not vital.

For the sort of work that most of us do, the difference between five and ten degrees clearance will hardly be noticeable.  AND, excessive angles weakens the tooling, ans shortens its life, since there is a smaller area to withstand cutting forces, and to conduct away the heat.

By all means, stone a SMALL radius on the edge of a tool for finishing. En excessive radius will encourage chatter, which is not what you need for the final cut.

HTH

Howard

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