Apprentice Piece – Turning

[JellyParticipant @jelly]

I’ve been asked to help organise the induction of around 40 people for safe use of lathes and milling machines.

There will be a team of 4-6 volunteers delivering this, so we need to standardise our approach somewhat, part of this is developing a standard “Apprentice Piece”, due to various constraints I’m struggling to work out what this could be, as ideally it would be something useful or purposeful; but consulting with the volunteers who did craft apprenticeships, they’re all equally stumped as they started by turning non-functional test-pieces.

The induction is only required to teach safe practice, and normal operation, with precision and advanced techniques being something users are required to develop off their own back.

I’m looking for a standalone piece of which could be completed by a novice under instruction in 1-2 hours. I have been asked to include the following operations: Facing, Plain Turning, Drilling, Boring, Parting/Grooving, Taper Turning (using top slide only).

Has anyone got any suggestions?

(We’ll be using a Myford Super seven for teaching, but may wish to migrate to using a Warco GH1440 in time).

[JellyParticipant @jelly]

[Nick_GParticipant @nick_g]

.

A plumb bob.

Make it as simple :-

Or as fancy as you like :-

Nick

[HopperParticipant @hopper]

Posted by Joshua Kelly on 13/10/2016 00:20:59:

I'm looking for a standalone piece of which could be completed by a novice under instruction in 1-2 hours. I have been asked to include the following operations: Facing, Plain Turning, Drilling, Boring, Parting/Grooving, Taper Turning (using top slide only).

That's a big ask for a beginner to get across in 1-2 hours. The trouble with trying to make one standalone piece encompassing all those is that an error in one step, say halfway through, ruins the whole piece and they have to start all over again. Hence the common use of sample pieces for beginning work. Master one skill, with the usual errors and restarts along the way, move on to a new piece and master another etc.

You may be able to break it down into a few separate useable items, such as the simple plumb bob already posted. Another I remember at high school was making a centre punch, it uses plain turning, taper turning, knurling and parting, then the heat treatment with the oxy torch and a bucket of old engine oil. Drilling and boring could be take a piece of say 3/4" round and part it off into two pieces, drill and bore a hole 7/8ths of the way through each piece, bore a step inside one piece and reduce the OD of the other so the two pieces fit together as a small container in which to store the centre punch, or the plumb bob..

But at trade school as an apprentice, I remember starting on test pieces of 1" bar turned to various diameters at various steps to match a drawing, then grooving, then screwcutting one end. Graduated then to stuff like making a C clamp from solid plate and turning, knurling and screwcutting the clamping screw and the foot to go on it. Then a crankshaft made from 1" bar turned between centres using offset centre holes. Later came a socket ratchet handle turned and milled and finally a 3" machine vice milled and the screw turned.

[not done it yetParticipant @notdoneityet]

Six diferent operations in an hour? They would be quick if there was to be any cutting to size involved! QCTP? Tools already set to centre height? Etc, etc? The simple plumb bob shows all but boring, so doable in an hour or so, for a novice. As long as they don't have to manually hacksaw a piece of hard steel, maybe…..

[Chris Evans 6Participant @chrisevans6]

Unless the pupils have had a day or two basic training on use of the lathe, they will not achieve much in an hour or two.

[MWParticipant @mw27036]

Ideally they should already have experience fitting/measuring and reading drawings before they try the machines, so hacksaws, files, scribes and punches, drills. You get the point. First lesson should be showing them how the lathe works,H&S and what exactly turning is, as well as the speed calculation and then you could try a basic step turning exercise.

I'm afraid you might have to explain to whoever is in charge that this is going to take more than a couple of hours. These kind of skills(turning,boring,facing,knurling,threading, tapers) are normally spread out over a number of projects rather than just one. 

Michael W

 

Edited By Michael Walters on 13/10/2016 08:06:29

[john carruthersParticipant @johncarruthers46255]

A scriber? measure/cut/turn/knurl/drill/part off/bond hard tip?

[MWParticipant @mw27036]

It's a good point john, but there wouldn't be any drilling unless you wanted to make a scriber with replaceable tips, would be a better design i have to admit. You'd even have a bit of threading to do with the grub screw! 

It's probably just too much to take in one session for people who don't know what they are. Leave some decent tolerances on it then you wont make them feel like a complete failure. Although that seemed to be the point of my college course!

Michael W

Edited By Michael Walters on 13/10/2016 09:01:24

[mechman48Participant @mechman48]

+1 for Michael & others. Having spent 9 years as Mech.Eng. instructor in a training centre ( covering NVQ L2 / BTEC ) & some months in my local college what your asking is a big ask; the groups were made of up to 12 apprentices who firstly learned the art of filing, inc. types of files & uses, filing square to Eng. squares, learning measuring using engineering rules/verniers/ micrometres /height gauges etc. Reading eng. assembly & parts drawings & safe use of drilling machines & all they encompassed; then producing a test piece…usually after 8 -12 weeks; depending on the capabilities of the apprentice.

On to machining… at least 2 days learning about the machinery / operation / feeds / speeds, H & S, only then on to calculations for RPM / surface speeds for material in use, which tool for which job, reading machining drawings 1st / 3rd angle etc…. & then practicing on the lathe, machining to shoulders, stepped diameters, drilling to depth, using callipers, micrometres, depth gauges, hand tapping / ext.threading etc. Parting off was left until the apprentice had gained more experience. As previous comments the first test piece was the plumb bob which encompasses all the points you are asking for, but to cover all that & produce a test piece in 1 – 2 hrs… highly unlikely, not surprised you / your volunteers ( albeit craftsmen ) are stumped.

George.

[Nick HughesParticipant @nickhughes97026]

A simple thick washer?

I would set the topslide to 45 Deg at the start (to save time later) and use a 45 deg approach tool, then :-

1) Turn O.D.

2) Face

3) Form a small chamfer on the outside edge

(All the above done with the same tool. Hence the 45 Deg approach tool)

4) C.Drill & Drill

5) Bore

6) Generate rather than form a chamfer on the bore using topslide and boring tool

7) Part off (probably best with the rear toolpost if available)

Edited By Nick Hughes on 13/10/2016 10:18:29

[Neil WyattModerator @neilwyatt]

Height gauge

Useful, easy to incorporate all the skills if you have the right design (even hardening and tempering) & relatively small.

[AjohnwParticipant @ajohnw51620]

I'm inclined to agree with George. Also 40 people ? All in one go ? I suspect not.

I think lots of people will be rather cautious the first time they are stood in front of a lathe and told to use it. Seeing some one doing a hands on demonstration with a bit of a chat might help with that and not consume too much of what sounds to be a rather short time. Throw in too much information and some will get a sort of glazed look and what is said will go in one ear and straight out of the other and don't I know it. Best kept casual and simple, sort of look how simple it is approach.

Boring seems to have stumped all suggestions. Maybe a brass or al egg cup ? It wont have a curved interior but could have a tapered internal bottom and eggs generally don't fit egg cups that well anyway.

I'm pretty sure that my first piece of lathe work was a centre punch. No boring and needs some simple heat treatment. There may be H&S worries if the end is polished up in a lathe for tempering but it could be done in a vice. Worth while too really as it wont be made of air hardening steel. Same with low diameter punches. I made a couple having got fed up with what can be bought. One's around 0.110 dia and used to knock out anything larger than that.

A small tap wrench is easy to make. 2 piece with tapered handles one of which screws in. The tap is held in a round hole that has had a V hand filed to one side. Ideally the screw in part needs a hardened insert in the end – say a short length of 3mm silver steel locktited in. In my case the centre part was hand filed flat on both sides but it could be turned or milled, 2 hrs though and it needs some precise turning and the use of taps and dies and a needle file.

A number of things I made in training followed me around on various sections. Part of the work done on one and more done on the next etc. In some cases that meant that they went away for hardening and were waiting for me when I finally got to grinding. Some started with hand work. One item that might suite and include milling is a certain style of tap wrench. I'll try and describe it.

Toolmakers clamps are opened and closed by holding the usually knurled screw heads and twirling the whole thing one way or the other to open or close it. The tap wrench is opened and closed coarsely exactly the same way. The "handles" are easy to make but need to be a decent fit where they pass through the side of the jaws to the one that has the screw thread in it. The jaws are just a square block split down the middle with V's added to grip the tap. The only complication I can think of is milling the V's so that they line up. My father and many others made these during their training and they stood many years of real toolroom use. The handles were a bit fancy, flanged at the end so that the diameter there was a touch less than the thickness of the jaws. Then reduced and came out again tapered to meet the knurled ends. 2 handles in 2 hrs – just about on I would have thought. Milling – easily.

John

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[Nick HughesParticipant @nickhughes97026]

John, re-read my post about a thick washer. It covers all the original posters requirements, also introduces the difference between Forming and Generating as a bonus and the big plus is it's all possible within the time frame.

My interpretation of the original posting is that this is a "one off" hour or two and so anything other than very basic or simple would not be possible.

Nick

[Steve PaveyParticipant @stevepavey65865]

There are several problems with what you're proposing. Firstly, and as others have said, 1-2 hours is not long enough to make anything useful.

Secondly you say "a Myford". Do you really mean just one lathe, or did you mean one lathe per person? If just the one lathe per group, that could mean 12 minutes per person actual lathe time (actually much less in practice).

Thirdly, given your numbers, that is 7 to 10 students per instructor – that is definitely too many if you're talking about complete novices who have never been in a workshop before, and especially so if they each have a lathe to themselves.

Fourthly, what are you actually trying to achieve, and what will these students do with this knowledge? You have to decide whether it's a safety training course or a practical lesson. If these students will be going on to do some proper machinery training then they should have more time in the future for a practical project. If it's safety training they don't need to make anything.

I would strongly recommend a re-think on the time allowed, and probably on the numbers (of both students and lathes). 1 to 2 days is a bit more realistic for just the basic safety training, double that if you actually want them to produce something.

Sorry to sound so negative, but it really annoys me when I see these sorts of courses proposed (and I saw lots in my past life) – there is no way you can teach a complete novice anything useful on machining in an hour or two and then expect him/her to have any real fundamental understanding of anything.

Edited By Steve Pavey on 13/10/2016 11:31:31

[mechman48Participant @mechman48]

In my experience, college/classroom training would take up no more than 40 min; after that any student/ apprentice would be off into lala land … closely followed by the instructor/lecturer ( I have on more than one occasion ) much better to have them out on the shop floor 'doing stuff '. Going back to my previous post; a group of 12 was pushing it, & that was one lathe ea. … H & S factors where machinery is concerned, there was usually my self & another instructor covering a group of 12, much more manageable & practical.

G.

[Ed DuffnerParticipant @edduffner79357]

I can't remember how it long it took but in metalwork class at school we made a Toolmaker's clamp, involving:

– Marking out with ref' to a drawing.
– Cutting / Filing
– Drilling through and blind holes.
– Turning / threading / knurling / parting off.
– Heating to cherry red with oxy/acetylene and "blackedising"? in oil. I think the teacher did this part.

I still have the clamp somewhere in the shed.

Ed.

[RICHARD GREEN 2Participant @richardgreen2]

when I was at school ( early 1970's ), one of the first things we made in the metalwork class was a very useful screwdriver,

Handle was turned from a piece of 3/4" dia, aluminium about 5" long, knurled for the grip, tapered slightly towards the blade end, & drilled for the blade,

The blade was forged to form the screw end, then hardened and tempered, then pressed or loctited into the handle,

The handle could be as ornate as you like, grooves , knurling etc.

Richard.

[AjohnwParticipant @ajohnw51620]

The clamps could also include milling again I think that is achievable and a useful end product. The screws would be easier to make than handles for a tap wrench. Mild steel should be fine too – free cutting so relatively easy to get a decent finish.

Like the tap wrench this can take care of the milling aspect as well. Every time I use some of my bought tap wrenches I think about making one.

There is another simple type as well. It starts with say 2 150mm lengths of square bar. Turn a short handle on the end of each. The remaining square parts overlap and are fastened with opposing socket screws suitably spaced apart. V's cut central to locate the tap. The knurl on the sockets screw is fine for tightening. I do use one of these for what might be called model engineering sizes apart from the small stuff. Definitely apprentice made. It came with one of my lathes. The screws are spaced some way apart – to gain a bit more leverage from them I suspect.

My Dad's rusted past redemption but would be using those if they could be resurrected. I used them as kid.

John

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[AjohnwParticipant @ajohnw51620]

Curious. Thought there might be. Here is a video describing making all 3 types I mentioned.

On the last one I mentioned I would personally space the screw further apart. It also makes it easier to set the jaws parallel.

May need to edit this to correct the video link. Free pre tuition.

John

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[AjohnwParticipant @ajohnw51620]

Looking at the video on the last type there is no need to centre that accurately or turn the handles that long – it just weakens them. He looks to centre drill too deep to me as well.

Dad;s type should have a square centre too – imho. Looks like he doesn't know about twirling to open and close them keeping the jaws square. Some don't know that can be done with tool makers clamps either,

Knurling is pointless too really. I find it often turns out too sharp. I was taught and do knurl in one go and don't worry too much about how square the knurl is to the work. In fact with a heavy knurl I'm pretty sure I have angled it slightly to cut it gradually.

Tut Tut oh dear, he doesn't reverse his taps to break the chips.

John

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Edited By Ajohnw on 13/10/2016 13:24:15

[JasonBModerator @jasonb]

Seem to remember a key ring fob was the first thing I did at school – marking out filing, sawing and a hole for the ring. Next was an ash tray can't imagine that on the corriculum now

I'm surprised no one has asked whether the Myford meets all the current safety requirements as you should be teaching safe practice from the start.

J

[JellyParticipant @jelly]

So a couple of things I’ve failed to adequately explain.

The purpose it to allow them to use the lathe safely and independently without damaging it through inappropriate use; it’s being organised on behalf of a community run workshop facility which offers members the chance to develop skills and use machines it’s wholly impractical for them to otherwise access.

All the inductees will be adults, usually with a hands on practical background, but usually in art, “design/craft” or electronics rather than engineering.

Up to now we’ve struggled greatly with inducting people who had no engineering background, as we tried to teach everything in one hit, resulting in long sessions, poor retention of knowledge and an inability to effectively deal with the volume of people.

It’s very much our ethos to provide info and mentoring on safe use, but to expect functional learning (that is developing the skills to make a thing) to be wholly self directed.

We will be running a group classroom session or e-learning module to familiarise people with basic engineering concepts (drawings, conventions, names), the theoritical bit of machining (Speeds & Feeds, Chip theory, relative hardness of materials etc.) And safety aspects.

The practical teaching will be 1:1, with each inductee having as much time as required within reason, but we’d like to get it to within 2 hours just for everyone’s sanity, and to allow us to get through whole group in good time (I’m reasonably expecting to manage a maximum of 10-15 a month between all 5 volunteers).

We’re debating whether to have a group practical session making hand fitted parts first before the mill and lathe practicals, but it’s additional volunteer time which is like gold dust.

It’s quite likely we’ll also use the production of the “Apprentice Piece” as a truncated induction process for new members with prior experience, as if they can take a piece of material and a drawing, then appropriately produce the finished product under loose supervision, we have no need to worry.

[Nick_GParticipant @nick_g]

Posted by JasonB on 13/10/2016 13:17:50:

I'm surprised no one has asked whether the Myford meets all the current safety requirements as you should be teaching safe practice from the start.

J

.

Project could be to cut up the Myford and use the bits to make 8 Super Adepts. – Neil would like that.

Nick

[MWParticipant @mw27036]

Posted by Joshua Kelly on 13/10/2016 13:34:06:
So a couple of things I've failed to adequately explain.

The purpose it to allow them to use the lathe safely and independently without damaging it through inappropriate use; it's being organised on behalf of a community run workshop facility which offers members the chance to develop skills and use machines it's wholly impractical for them to otherwise access.

All the inductees will be adults, usually with a hands on practical background, but usually in art, "design/craft" or electronics rather than engineering.

Up to now we've struggled greatly with inducting people who had no engineering background, as we tried to teach everything in one hit, resulting in long sessions, poor retention of knowledge and an inability to effectively deal with the volume of people.

It's very much our ethos to provide info and mentoring on safe use, but to expect functional learning (that is developing the skills to make a thing) to be wholly self directed.

Hi Joshua,

I think regardless of whether they are a child or a fully grown adult will be beside the point. They must be all taught to embrace the principles of metalworking in the same way, as you cannot assume one mans knowledge to be equal of the next. And as much respect i have for arts as a prior student myself, i would be lying if i told you this adequately prepared you for the basis of metalworking.

You cannot have self directed study without expecting a few knocks and chips on your tools, and maybe even a disaster if a workpiece or key is thrown out at high speed.

You've already said how disastrous it was taking on too many people, it could be the same result with even 40, you need classes of 12 people maximum.

I can't see how this setup would work without expecting them to be already competent in lathe work, as a kind of members commune, whilst i have admiration for your endeavor, it might be wise to scale down the size of this ambition to manageable numbers of people.

Michael W

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