Practice material for a newbie

Good morning gents.

I'm soon to be the proud owner of a new mini lathe and I'm wanting to order some material to practice on. I'm thinking probably brass, aluminum and delrin are good starter materials before I progress to steel.

I'm just wondering where id a good source for material, I don't want to spend a fortune at this stage on material that will probably end up in the bin.

Cheers,

B

Why not steel?. Get yourself some EN1A leaded and some brass/ Ali 6082 T6. You will find Delrin/Acetal quite expensive but nice to work with. Macc Models are a good supplier

Free cutting mild steel is the best, in my opinion. With brass you will have needle sharp bits of swarf showering over you and aluminium has a tendency to weld itself to the tip of the cutter.

Many thanks for the replies.

As a newbie I assumed steel would be harder to practice on, but what has been said make sense. Cheers.

I've just had a look at Macc's website. Do I want bright steel or silver steel??

Edited to add, ignore that, I see the mild steel is EN1A as mentioned above, and cheap too.

Edited By Robert Bowen-Cattry on 24/05/2021 11:25:00

If you do try aluminium, then a tiny bit of WD40 spray to keep it damp will avoid it sticking to the tools. As mentioned, brass is messy, mild steel is a better bet. Get a book on turning and milling, it will get you off to a better start.

For your first attempts at metal mangling, I would suggest using leaded mild steel. It will be easy to machine, and relatively inexpensive.

The harder alloys can come later when you have a specific need for such materials.

Brass will spray tiny chips everywhere.

Cast iron machines easily, once you get through the very hard outer skin (Caused by the metal cooling rapidly and chilling) The dust gets everywhere, and is VERY dirty. It can also be abrasive if the machine is not cleaned meticulously afterwards.

If I have machine Cast Iron, I try to place a powerful magnet where I think the swarf will fall, and cover it with newspaper. The magnet attracts a lot (sadly, not all ) of the dust, and once taken away from the magnet allows the dust to be poured into whatever receptacle you use for disposal.

Aluminium machines easily, but can weld itself to the cutting edge of the tool. Paraffin as a lubricant is helpful.

Howard

Steel is going to be the cheapest material, by that I mean EN1A, 230M07 or EN3B, 0070M20, both in bright not black. Keep diameter down to below 25mm, this will make parting off a little less stressful. Brass is an easier material to cut with either high speed steel or carbide tools so is worth a try but the cost is greater. I would avoid aluminium unless you intend to use it in your work, it appears a lot on YouTube videos as most are from the USA and it is more prevalent there than in the UK, i don't know what the cost is in the USA but in the UK it is more than steel. By practicing on the material you intend to produce items from you are learning about the cutting tools as well as the material as there is a geometry difference at the cutting edges. Also avoid silver steel at the beginning, it is tougher than simple steels so more difficult to get a good finish.

Howards suggestions are spot on. Just to clarify the string of No's he mentions, these are the specification codes.

EN1A is the now obsolete code for free cutting mild steel but is still widely used because it is easier to remember than the 'new' code of 230M07 but they both refer to the same type of steel.EN3B (0070M20) is very slightly more difficult to work with.

Brian

When you do try brass, make sure it's CZ120. A lot of brasses don't machine very well at all.

I like aluminium actually and don't find the sticking so much of a problem as long as you have sharp tools, run fast, and use a machinable alloy - 6082 or T6 as recommended are good. Lot's of things are just as good made in aluminium and easier to machine.

You could do a lot worse than obtaining a copy of George Thomas' book The Model Engineers Workshop Manual.

TEE Publishing may still have copies

**LINK**

It's full of very usefull information and help and contains a large number of projects some quite simple to help you get going.

Hemmingway have kits of materials for quite a few of George's designs.

regards Martin

Many thanks for the replies gents, lots to think about.

Be aware that CZ120 is also known as engraving brass. Not surprisingly it is normally only available in sheet and flat strip form. It machines very well:

But not so easy on a lathe. What you need for turning is CZ121, which is widely available in many forms including round, square and hexagon bar. It also machines very well.

Personally I'd avoid EN3B at the beginning. It's a bit "gooey" and has a propensity to tear unless speeds and feeds are correct.

Andrew

I'm going to state the obvious here, but as a newbie you might not have considered safety too much.

I'm not a H&S nut, and often despair with some of the ridiculous rules and regs that defy common sense, but beginners really need to consider the possibilities of injury even when using relatively small low-powered machinery. I'm sure there will be postings on this site relating to sensible do's and dont's so have a search, or / and get a good book.

Machining brass for example - someone mentioned earlier about being showered with tiny chips - yes it often does, and they can be very sharp, if they get in an eye they can be a nightmare to get rid of at hospital. Safety glasses may not always be adequate - a full face visor may be prudent. (3 guesses who's speaking from experience!)

Don't want to put people off, but a timely reminder is sometimes sensible.

Thanks for your thoughts Mike.

Safety is always paramount to me. Although new to lathes I have been using varIous power tools for many years (angle grinder, bandsaw, chop saw, etc) and having minced the tip of a finger on a table router many years ago I am super cautious.

As others say, buy a copy of a book like Geo. Thomas'. Note the title above, not his Model Engineers' Handbook which is a valuable reference on the more theoretical side.

You'll want one that covers the basics and if it has some simple projects for making tools and machine accessories, it's a bonus. If that's now out of print there are equivalents - look on the TEE Publishing site, and I see by the side-bar ads that two of this forum's denizens have become technical authors too!

It's not just the material you need consider. Different metals and plastics need different tool geometries for best results - the reference-books will give the details.

The silver-steel you mention is tough stuff. It is not a general-purpose material but can be hardened and has a precision-ground finish, for making cutting-tools, small shafts, bearing pins and the like.

You'll also need a reasonable bench-grinder - though many use both High-Speed Steel and carbide insert tools, or inserts only, I would advise HSS at least for now. As well as cheaper (carbide tips are single-use), you can buy them already made to the main shapes, and they are relatively easy to re-sharpen to appropriate geometry for a good, accurate finish. Ordinary lathe tools don't need fine sub-degree accuracy except for precision thread-cutting, can be ground free-hand, and it's not too hard to make simple rests to guide them against the grinding-wheel. Authors such as Harold Hall have published designs for these.

Edited By Nigel Graham 2 on 25/05/2021 13:03:22

Whatever material you settle on, don't try copper yet, unless you have experience of machining cheddar cheese!

Not sure the difference is worth worrying about - for similar sizes they cost about the same. Just checked on the web and 3m x ⌀25mm Black mild steel is £51.16 compared with Aluminium at £55.56 today in the UK. (Both ex-VAT) Didn't check carriage cost, but Aluminium might be cheaper because it's lighter.

I probably use more Aluminium than any other metal because it cuts faster than steel, resists corrosion, and is strong enough for my experimental purposes. Important to get a machinable alloy - pure Aluminium and many of it's alloys are nasty squishy stuff. Steel for strength, weight, and wear resistance.

Brass is my favourite metal - machines well without fuss. The sharp needle-like swarf is a menace though.

Apparently the easiest metal to machine is Magnesium but it's rarely useful for home projects.

Generalising wildly, the preferred metal in a workshop depends on the type of work:

• Clock makers use lots of Brass
• Loco makers are into steel and cast-iron
• Experimenters get good results from Aluminium

However, all common metals get used sooner or later, and plenty of other materials are useful too. I've turned Silver steel, Bronze, Copper, Graphite, Cupro-nickel, plastics, cardboard, MDF, rubber and wood more-or-less successfully. Even attempted glass, didn't go well.

I learned a lot by building Stewart Hart's PottyMill Engine; steel, aluminium and brass, artfully combined to get a working machine by exploiting their individual virtues.

Dave

Thanks for the advice gents, I've ordered a selection of mild steel, ali and brass to practice on.

Perhaps one important facet has not been considered: What cutters do you intend using?

I am like SOD - I like aluminium. Easy to machine, doesn’t need exceedingly specialised/exotic cutters to get a reasonable finish and doesn’t blunt/chip cutting edges quite so quickly. Brass is expensive. Aluminium welding on the tip usually means it is too hot at the cutting point. Insufficient cooling/lube or a blunt cutter are the usual causes.

I’ve never particularly bothered with free-cutting steel for most things I make.