It might be that you are using the cheap carbide tipped tools. These don't cut well. Don't worry about the noise. As long as the tube isn't moving in the chuck it's ok.

Move in with the compound slide so it's more controlled or take short, tiny cuts along the diameter

Don't use a parting tool on an intermittent cut as the blade is likely to push off.

You'll soon work out what works best.

Edited By Capstan Speaking on 02/06/2015 12:45:56

Hi Peter

I know you know I am a beginner like you – so take my comments in that context!

I'm a bit of a mother hen when it comes to my equipment and I like to minimise wear and tear as much as I can. If there is 5mm difference, then I say hacksaw, file and then a light cut in the lathe – probably quicker on a little lathe as well – and its only a tube to cut through..

Banging is not good best to reduce that kind of use to a minimum on your new kit…

Cheers

Garry

Interrupt cuts should not be a problem, same occurs when you have a casting or some other shaped part in the lathe.

I tend to use auto feeds where ever possible as my lathe has auto feed on the saddle and cross slide this has the advantage of always taking the same amount per rev even fresh air, if you do not have auto feed then remember air is very easy to machine so don't be tempted to speed up a nice constant feed is what is required.

Bob

Steel tube,particularly tube rolled and seam welded,is the worst of the common materials to machine,its tough and stringy, On a small lathe I would use a hss tool with small tip rad and 20 degree top rake, and feed the cross slide by hand, when feeding by hand you can feel how the tool is cutting and if it is about to dig in the feed can rapidly slowed or if necessary stopped or reversed,if using power feed by the time the the stop lever has been operated the tool will have dug in, with jobs like this its patience not speed thats required.Now if you had a heavy lathe like a colchester triumph with 40 mm tube held in a big 10 inch chuck the method would be ,use big carbide or hss tool and feed the saddle towards the chuck cutting the entire 6mm width,it would knock a bit but that does not matter, when close to the finished length,lock the saddle and take a finish cut by facing with the cross slide to ensure face is square to the axis of the tube. I recently squared off 30 lengths of scaffold tube like this on my triumph,horrible material but thats what the customer required.

I think your being a tad over-cautions Gary. Even the bearings on my mini-lathe are bigger than those on most cars, and while the latter aren't used for high precision metalworking, they do have an expected life of over 200,000 miles of continual battering.

A well-adjusted lathe should be quite happy with interrupted cuts, the issue is when slides or bearings are loose – then things flap about and can get damaged.

Neil

I would sugest putting the CT tooling in a draw, and learn to use HSS, this will be adequate for 90% of the work, and you can easily shape and sharpen your tools to suit the job. Steel pipe such as the bit you are having a go at is horrible stuff, but can be usefull, the cylinder of one of my oldest Stirling Engines is made of it, it's run a bit over a 1000 hrs, and shows no sign of wear, so it's worth learning how to get a good finish on even this sort of C**p.

Here it is, built not long after I got my lathe.

Peter, bear in mind that Tipped tooling always needs to run about 150% faster than HSS! HSS has a sharp edge and a good degree of clearance whereas Tipped tooling has very little clearance and its cutting action is more like shearing the metal, it also requires more power which may not be available in a small lathe. There is also a degree of rigidity required to absorb all this deflection.

Definitely go on to HSS and learn to grind the correct clearances for the cutting edges, do that and your reward will be good finishes and less problems.

Keep the tipped tools for hard metals etc.

Clive