Whats the best tool planform for turning 22mm Nylon bar?

[Steve WithnellParticipant @stevewithnell34426]

I've been using a classic knife tool ground for steel, which works but leaves significant, partially melted burrs, so not sure if there is a better shape of tool or if Nylon just does that.

I'm using a highish spindle speed c2500rpm taking a 1.5mm cut to take me straight to size and being gentle with the feed.

Steve

PS: Yes I have returned to the workshop…

[Steve WithnellParticipant @stevewithnell34426]

[Sub MandrelParticipant @submandrel]

Steve –

If you find a way that works, let me know! I have to make a plastic nut and bolt sometime to fix a metal; detector.

Neil

[NJHParticipant @njh]

Steve

Sharp tool, about half the speed you are using, and coolant would be my approach – I suspect you are melting the material.

N

Edited By NJH on 20/04/2013 19:02:15

[Cyril BonnettParticipant @cyrilbonnett24790]

**LINK** any help?

[KWILParticipant @kwil]

I use a CCGT insert, the polished one intended for aluminium, cuts a treat and leaves a very good finish.

[Anonymous]

I use inserts intended for aluminium too. The key to machining plastics is low surface speed and high feedrate, otherwise all you end up doing is melting the plastic. For 22mm nylon I'd be down below 1000rpm and a feedrate of up to 10 thou/rev. I've never used coolant when machining plastics. For turning I let it get on with it, and for CNC milling I hover with the vacuum cleaner going.

Regards,

Andrew

[Chris TriceParticipant @christrice43267]

What Ken and Andrew said. Polished inserts for aluminium and not too fast a speed. Because Nylon is soft, a blunt tool will still cut it but generates a lot of heat from the fact it rubs a little. Don't know what the job is or what spec you need but you might want to consider acetal and its kin as they turn a little crisper.

[Gordon WParticipant @gordonw]

I had some success with a carbon steel tool (old file ground up ) made for cutting wood, ie. about 60 deg. angles and honed sharp. slow revs. and high feed.

[Kevin FParticipant @kevinf]

I use tool steel with a negative rake ground on the top of the tool, this tends to 'shoot' swarf upwards ,this stops the swarf from wrapping around the job ,also a high feed rate helps too and I also give the nose of the tool a small flat edge as I found it gives a better finish ,too sharp a point gives a poor finish .

[Steve WithnellParticipant @stevewithnell34426]

Using an HSS knife tool very sharp at low rpm about a 100, and a decent cut (1mm) solved the problem. Taking light cuts works but not well. Anyway job done, thanks all.

Steve

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