Poor cutting

[David Standing 1Participant @davidstanding1]

Curtis, where are you located?

[Curtis RutterParticipant @curtisrutter61973]

Posted by David Standing 1 on 21/03/2017 21:37:59:

So here's an even more off the wall suggestion – is the tool holder contacting the brass?!

It's definitely not I'm paranoid about that! I'm located in Ware, Hertfordshire, UK

[David Standing 1Participant @davidstanding1]

Posted by Curtis Rutter on 21/03/2017 22:41:40:

Posted by David Standing 1 on 21/03/2017 21:37:59:

So here's an even more off the wall suggestion – is the tool holder contacting the brass?!

It's definitely not I'm paranoid about that! I'm located in Ware, Hertfordshire, UK

Ok!

I'm regularly in Stansted Abbots, would be happy to cast another pair of eyes over it, it's often much easier to diagnose these things when you can see them before your eyes?

[Curtis RutterParticipant @curtisrutter61973]

Have pm'd you David

[David Standing 1Participant @davidstanding1]

Curtis

Got your PM, thanks.

Will call you in the next evening or two.

In the meantime, what I would suggest is that rather than replace the brass with a piece of mild steel and trying the tangential tool on that as has been suggested; I would keep the piece of brass in the chuck, but replace the tangential tool with a conventional tool and holder, and try facing the brass off with that – and, as has been suggested, preferably with a round nosed tool.

The reason for this is because it will then show up whether or not there is a problem with the tangential tool/holder, or an issue with the lathe, such as spindle or slide/gib wear.

I am also assuming that the tool tip was centred on the brass?

[MWParticipant @mw27036]

Posted by David Standing 1 on 22/03/2017 15:08:33:

and, as has been suggested, preferably with a round nosed tool.

Precisely, there is too much tearing on the face, i'm sure this could be significantly eliminated with a round nosed HSS tool.

Michael W

[Curtis RutterParticipant @curtisrutter61973]

Sooooooooo…… Problem solved

After trying a few different things, ordered a normal hss tool piece, tried other metals, mild steel, aluminium, and another piece of brass was still getting the same results so decided to change belt speeds. After changing the speed to the slower end it then dawned on me….. the competent electrician that wired up my lathe has wired the switch the wrong way round, I didn't notice at higher speed but I'd been using it in reverse, thankfully I was only taking light cuts. Flipped the switch and started again and voila! It's a pleasure to use, the tangential tool cuts the brass like a hot knife through butter as does the HSS tool bit I bought.

We all were beginners at some point

This is the same piece of brass

Edited By Curtis Rutter on 31/03/2017 12:04:35

Edited By Curtis Rutter on 31/03/2017 12:05:28

Edited By Curtis Rutter on 31/03/2017 12:06:26

[SillyOldDufferModerator @sillyoldduffer]

Well spotted Curtis!

I often run my flange spindled lathe in reverse for parting off, and occasionally leave it that way when I've finished. Next session taking a normal cut, I can immediately tell something's wrong. My blood-pressure goes through the roof until I eventually remember that pesky reverse switch…

I've always been a beginner and am likely to stay that way.

Dave

[old AlParticipant @oldal]

Thanks for coming back and sharing the solution. Bit tough to admit it, but even us experienced engineers make simple mistakes occasionally.

[MWParticipant @mw27036]

I think it serves as a testament to the durability of HSS that it will actually cut in the wrong direction

Michael W

[Ian S CParticipant @iansc]

Reminds me of someone who borrowed an electric drill to drill a hole in the dashboard of his car, he seemed to be away for a long time, but eventually he came in complaining that the drill was blunt, went out to have a look, put the drill in forward, gave it back to him, and he just about fell over as the drill popped through in about half a dozen turns.

Ian S C

[mechman48Participant @mechman48]

…but even us experienced engineers make simple mistakes occasionally…

​Occasionally!… you mean we're not s'posed to make them all the time… wow! you learn some thing new every day…

George.

[Neil WyattModerator @neilwyatt]

Posted by Andrew Johnston on 21/03/2017 22:23:22:

Posted by Neil Wyatt on 21/03/2017 16:30:44:

Are you seriously suggesting that a model engineer, the most impecunious of all archetypes, bins a 40mm brass bar?

Yes, precisely because we don't know it is brass, and even if it is, it is almost certainly not CZ108. I suppose it depends if one wants to waste time trying to machine mysterium, or move on and make something useful from known material.

My point is not that it's poor advice, but that such advice is wasted on 99.8% of model engineers!

Neil

[Curtis RutterParticipant @curtisrutter61973]

I will most certainly be keeping it, at the moment I'm just creating swarf and practising techniques anyhow

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