How to drill hardened and ground steel

[Ramon WilsonParticipant @ramonwilson3]

Hi again,

 

Without wanting to appear to be going over the same ground……..

 

Terry’s comment that Chronos state this to be hardened and ground sheds a little more light on this John.

If this block is through hardened then as said before this is going to be difficult if nigh on impossible to bore or drill out to the diameter you need given the kit you have at your disposal  – indeed that would not have been attempted on anything I have used over my working experience. Outside of erosion techniques it would either have to have been ground out or tempered first then machined and then re-hardened and re-ground given that it were dimensionally possible. I’m definitely not suggesting that that is an option just pointing out how a hardened component that had to be re-machined with limited kit would have been looked at. It would to put it politely certainly have caused some puttering! Nowadays its all to so easy with the advance of wire/edm erosion techniques where hardness of material is immaterial! I have to say that if you can find someone as Jeff suggests then despite Chris’s reservations this would be the easiest way to increase this bore without stressing anything except perhaps your pocket a bit. The actual time for this to be wire cut for instance would be no more than a few minutes as it could be done at max speed without need for high dimensional accuracy or surface finish that these machines can give and even the fastest speed will leave a finish far better than would be required for the job in hand.

If on the other hand it is only case hardened then, providing you can get under the skin you should be able to machine this slowly as you describe.

 

I say this again only because what you are wanting to do would be challenging in a workshop environment (if its hardened that is) and it would be so easy to mess up your tooling or stress your equipment and/or spoil the component trying not something I would wish to see.

 

I understand your reservations John but personally I would agree with Terry and reiterate my original thought – examine carefully the possibilty of changing the stud – that is your easiest option providing of course you are able to remove the original one without damage. It is certainly worth another look and if you do the job carefully you certainly won’t be bodging up your lathe – merely modifying it to suit your needs.

 

Terry, most of the turning I did at work over the years was on Triumph 2000’s three of them had QC the fourth a 4W. All the QC’s had a centralising spigot and whenever I did need to remove the body I would always think I must do this at home – but…. you know how it is. Perhaps one day

 

Regards – Ramon

 

 

[TerrydParticipant @terryd72465]

Hi Ramon,

 

I know exactly what you mean …..some day!! but time is so short when you get to have some free after all those years of chasing a living .

 

I recently came across a great quote by a famous industrialist to the effect that:

 

“these days people spend too much time making a living and not enough making a life.“

 

No, it wasn’t a trade union leader or Alan Sugar or Richard Branson, it was another self made millionaire, Frank Hornby (of the Meccano, Hornby and Dinky world empire)  writing in 1935.

 

Nothing much changes then ,

 

Best regards,

 

Terry

[John CoatesParticipant @johncoates48577]

OK guys I will look closer at the toolpost stud

The reason I said it appears to be pressed home is because there is no apparent way of rotating it to remove it i.e. A slot in the base. Unless the nut is put on, rotated until it locks against the shank of the stud and then this loosens the stud – a left hand thread

I’ll take some photos tonight after work

Terry – its a 1947 5″ x 24″ roundbed. I’m just doing the two tests (parallel turning and turning between centres)in Harold Halls book “Lathework – a complete course” to check it is concentric

Luckily I am in no hurry. I bought the lathe last September but didn’t get it set up until four weeks ago. It has been a slow pace since then due to an operation with complications and having a young family. So far I have turned a drawbar for the Chester (not pretty but it works! So I had better do a better one someday in the future when skills are better developed) and have been practising by turning down some rusty bars I was given by my mechanic.

So far progress is steady, gaps in practical ability are being rapidly identified, but I am thoroughly enjoying both the lathework and milling and the forums on here.

You are a great bunch of guys so thanks for your help and apologies for my never ending flow of questions

John

[John CoatesParticipant @johncoates48577]

Sorry about the lack of paragraphs or formatting in my post above – it was sent from my Blackberry

[John CoatesParticipant @johncoates48577]

Terry – it is a 1947 Barker 5″ x 24″ round bed lathe.

 

I have 3 and 4 jaw chucks and a tailstock drilling chuck. The current toolpost is basic (for 1/2″ tools with one side square slotted and the other round for bars) hence the exhuberant purchase of a QCTP (perhaps, from today’s perspective,  in haste). The tailstock is a 3MT so can take the collect chuck and boring head I have since bought. The headstock is 4MT and I have a 3-4MT adapter

 

[TerrydParticipant @terryd72465]

Hi John,

 

Is it like this example?

 

http://www.lathes.co.uk/barker/index.html

 

I must admit I’m not familiar with these lathes, even though we had an eclectic mix of older lathes (going back to 1904 in one case) in the m/c shop of he company I served my time with.

 

Terry

[John CoatesParticipant @johncoates48577]

Hi Terry

 

Yep. Mine is the one shown in picture 6 with the title “An original, unmodified Barker on the maker’s cabinet stand”

Going by the serial number of 2470/128 mine would appear to be the 27th machine built in 1947

John

[Richard ParsonsParticipant @richardparsons61721]

A few years ago I came across a most useful formula to determine the speed to drill mill or turn. 

For mild steel

• If you are using Inches the formula is 288/D where ‘D’ is the diameter in Inches of the stock you are turning or the diameter of the cutter/drill for milling or drilling.
• If you are using metric the formula is 7315/D where ‘D’ is the diameter in Millimetres of the stock you are turning or the diameter of the cutter/drill for milling or drilling

It is useful guide and should be thought of as a base line.  If you are like me and do not have electronic speed control I pick the nearest speed available.  For harder materials I slow the old Myford/mill/drill down a one or available two speeds (pulleys)!

Re drilling and boring is a little trickier than straight external turning.  No problem with measuring etc.  For myself I would have made a new stud for the tool post.  OK 7/16” is only 1/32” off each side of 1/2″ so I would have a good look at the existing thread.  If it is say ½” BSF I would probably use 7/16” UNF.  You would have to get a new nut, but these can be bought.
 As Chris quite correct says There are there are many different ways of doing a job andevery blooming one is right.  However some are better that others.  

[TerrydParticipant @terryd72465]

As Orwell said:

 

“all are equal, but some are more equal than others.” 

 

 

Terry

Edited By Terryd on 20/05/2010 12:24:10

[John CoatesParticipant @johncoates48577]

SUCCESS !!

 

Using the boring head with the QCTP fixed in the 4 jaw chuck at 74rpm it has successfully bored out the hole to 1/2″ 

 

All I need to do now is machine a nut with a 1/2″ BSW thread to secure the QCTP as the nut that fixes my current tool post is very large, too big for the QCTP, so I need a smaller diameter nut to fit. My plan is to use one of my practice pieces that has sufficient clearance to miss the QCTP adjusters, bore it out then tap a 1/2″ BSW thread. The top will have a hex that matches the spanner that came with the QCTP which I will weld on permanently later

 

Thanks everyone. I am many steps closer to my end goal

 

John

 

[Ramon WilsonParticipant @ramonwilson3]

Well done John.

Nothing better than a successful outcome to bring a big grin on. 

 

Good luck in your future endeavours

[chris stephensParticipant @chrisstephens63393]

Hi John,

Well done, somehow I just knew the metal would not be too hard. If it had been too hard to drill/bore Guinness World Records should have been informed, it would have been the first recorded case. 

chriStephens 

[TerrydParticipant @terryd72465]

Hi John,

 

Let me add my congrats as well.  As you know I was sceptical, mainly because of the Chronos claim that the qctp was made from ‘hardened and ground steel’. (perhaps time for a little humble pie) .At least we now know that they mean ‘case hardened and ground steel’ –  should we inform them and ask them to change their listing!

 

But, again well done.  Let us know how you get on with that lovely old lathe and let us have some pictures of progress and anything you make with it. 

Regards,

 

Terry

[TerrydParticipant @terryd72465]

Hi Chris,

 

I suspect now that the Chronos (and other) Chinese qctp is case hardened.  After all John was able to find a soft spot on the base corner with a file (no carbide there then).  Obviously once under the skin when boring it is an easy job.  No Guiness record there.

 

I was concerned that the toolpost is advertised as ‘hardened and ground’ and after quite  a bit of experience in a toolroom making press tools I wouldn’t have liked to try to bore something of unknown provenance with a hardness of up to 1900HB at home, even with carbide tooling (which I prefer not to use for all sorts of reasons).

 

Perhaps Chronos aught to ensure their descriptions are more accurate.

 

T

[John CoatesParticipant @johncoates48577]

First of all apologies if this is poorly formatted as it is from my Blackberry (early morning downstairs looking after the little ones)

Once again a big thanks to everyone on here for the help. Having reflected upon my endeavours I think the main thing you are teaching me which the books miss is to have a plan before I attempt something and the basis for that plan will be the material I am working with as this will determine the best tool(s) and speeds to use. Most of my errors thus far fall broadly into too fast or wrong speed or tool.

Obviously getting into this hobby later in life (45) with no engineering background is a challenge but it is one I am thoroughly enjoying

John

[TerrydParticipant @terryd72465]

Hi John,

 

Enjoyment and fulfilment when things eventually go right are what it’s all about.  There is no greater buzz than creating something, whether it is a new life (as in your little ones) or a working steam engine.  It is just a matter of degree.

 

We are all learning, see the thread on anodising that Ramon started, many of us learned a lot from each other’s experiences there.  That’s what this forum is all about and long may it continue.

 

Welcome to the ‘club’.

 

Terry

[John CoatesParticipant @johncoates48577]

Here are two photos of the finished QCTP. The securing nut is like most of my learning efforts, functional but not pretty. I intend to make one that matches the L shaped wrench that came with the QCTP but for that I will need some way of accurately measuring angles on the mill to make a hexagonal stud. So I guess my next purchase will be some sort of vice with a dividing potential

 

[Ramon WilsonParticipant @ramonwilson3]

Hi John, Terry has summed it up so well.

 

FWI My interest in model engineering began in 1972 and from then until 1981 I struggled to get to grips with machining. I had no real concept of machine speeds and feeds of materials. I remember so clearly watching in disbelief as the tool glowed red hot as the cylinder block for the Stuart engine whirred round on the faceplate! Despite that and many other similar disillusioning incidences I was truly hooked and so, in ’81 retrained and came ashore to work in an engineering environment. For me being taught the basics of cutting speeds of the various metals was the single biggest factor in increasing my enjoyment and subsquently the results I was achieving.  I still believe that today for it really was like a light going on.

 

I can well appreciate your situation as a newcomer to the hobby so may I respectfully suggest that you take a short time to take on board the requirements in cutting speeds of various metals relative to the material of the cutting tools. I’m sure your enjoyment of the hobby will definitely benefit for the better.

 

I wish you well in your future ‘adventures’ – I wish time was on my side to start over again.

 

Good luck – Ramon

Edited By Ramon Wilson on 22/05/2010 21:32:49

[TerrydParticipant @terryd72465]

Hi John,

 

A relatively cheap and effective way of dividing for a hexagon is to drill and tap your locking nut, then lock a hex head machine screw into place in the drilled and tapped blind hole (using a thin lock nut under the head perhaps or loctite which can be broken later with gentle heat).  Set up in the vice horizontally using normal set up techniques

 

Then using a parallel under a flat of the screw’s hex head, mill your first flat, then without altering the height settings rotate the nut one flat at a time on the parallel, milling each as you go.  Hey presto a milled hex head without complex dividing facilities.

 

In the past I have used a short length of hex bar. drilled a suitable hole in the lathe through the centre, made my component a little longer than need be and fitted a cross screw to lock it in place then used the hex bar in the vice with to make simple indexable settings, rotating for each flat.  I then trim the component to length to remove any marks the lock screw may have made.  It is almost quicker to do than to describe.

 

There are a lot of simple ways of producing a hex with this sort of method.

 

Let us know how you get on

 

Terry

Edited By Terryd on 23/05/2010 06:59:13

[Ian S CParticipant @iansc]

I find it useful to make hexagons(and squares/triangles) with a file rest in the lathe using either the three or four jaw chuck(I know John’s yet to get a lathe), often this method is good enough, and is often quicker than setting up the mill and rotary table.Ian S C

[TerrydParticipant @terryd72465]

I agree Ian,

 

It’s just that one doesn’t often need expensive equipment and there are many ways to skin that cat.  It is very enlightening and interesting John, to read the exploits of the pioneer engineers and find out how they used everyday methods to solve what seem to us to be intractable problems. Those guys really were geniuses. 

 

By the way, the words ‘genius’, ‘ingenuity’ and ‘engineer’ come from the same root.  Pity modern (British at least) society doesn’t give the engineer his/her rightful accolades.  Nowadays, those are reserved for bankers and accountants, or perhaps the latest recession will help change that.  I don’t really think so though in a society that worships at the altar of money and greed.

 

Terry

[Ian S CParticipant @iansc]

Wot munny

[TerrydParticipant @terryd72465]

Not mine that’s for sure

 

Terry

[John CoatesParticipant @johncoates48577]

Posted by Ian S C on 23/05/2010 10:00:47:
(I know John’s yet to get a lathe)

 

Oh, I’ve got one. About half a ton of 1947 Barker ! Hence the pictures of the QCTP above

 

First impressions of the QCTP are good. Being able to adjust the height of the cutting point of the tool without shimming makes lining it up with the centre of the lathe a doddle. Only problem is that my 12mm carbide tipped tools appear to be too large to get lined up with the lathe centre line. Need to investigate further or else mill off a little of the underside of each tool to enjoy the full range of adjustment.

 

[TerrydParticipant @terryd72465]

Hi John,

 

Just a small point, but from the pictures your tools appear to have a rather large overhang from the toolpost.   You should aim to get the minimum possible sticking out i.e. unsupported, as excess can lead to vibration and chatter and hence poor surface finish.

 

Sometimes it is necessary to reach difficult cuts but generally try to keep it to a minimum.

 

I never really had a problem with shimming.  With a good stock of precut shims (sheet steel, tin-plate from old cigar tins, shim stock, even old credit card plastic etc.) it’s quite quick and easy.  I learnt from the Late G H Thomas (you should read his books, most libraries have them, his style is a bit long winded but his information and advice is priceless)  that once a tool is correctly shimmed you just need to keep the shims with that tool until you need to grind it.  With insert carbide tools that’s even easier as the tool height never changes,, nor does the height of the work, and there are less screws and knobs to scar your knuckles – don’t ask how I know.

 

Great stuff though.

 

Terry

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