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Member postings for Howard Lewis

Here is a list of all the postings Howard Lewis has made in our forums. Click on a thread name to jump to the thread.

Thread: A new member with some questions please
06/06/2022 12:34:30

Welcome!

Definitely, join a club and learn how to prepare, fire and drive the loco.

You do not want to get it wrong and do some expensive damage.

To run near the public, you MUST have a boiler certificate. The Club should have boiler inspectors who can examine the loco, and if it is safe and conforms to regulations, will issue a boiler certificate.

A boiler under pressure can be very dangerous should it fail.

Even at 50 psi, the steam contains enough energy to do you some real harm., so don't take any chances.

Howard

Thread: Cutting threads
05/06/2022 13:33:36

If using Taps or Dies in the lathe, particularly small such as 8 BA, using a Tailstock Sliding Die or Tap holider is necessary

A fine thread is too shallow and too weak to pull a Tailstock along the bed, and will be damaged, if not completely stripped. I found the hard way, some time ago, so bought a Sliding Die Holder, and made up a sliding Tap Holder, using ER Collets.

The holder does not need to be a snug fit on the arbor. Larger than normal clearance allows the tap or mDie to follow the workpiece and cut concentric.

Needless to say, use a lubricant such as Rocol RTD or Trfolex. If any doubt about swarf build up, stop, back out and clean before resuming.

Howard

Thread: Warco WM 250V power feed stuck/crash
05/06/2022 13:25:34

When I had my disaster, the gear/shaft was in stock, so obviously a frequent event and a good seller.

In view of the low strength component, I made a new shaft from 16mm Silver Steel, and cut my own gear to Loctite into it. This required a brass spacer to locate the shaft relative to the Apron, and was how i found errors in the chart for HV6 Rotary Table.

It won't happen again, as I ground off the first four teeth of the racxk, (Two were badly bruised anyway! )

The pinion comes out of mesh just before Saddle / Headstock contact, so occasionally needs to be pulled back into mesh.

Howard

04/06/2022 22:08:19

When I failed to pay proper attention to all that was going on, crashed my Saddle into the Headstock.

During freeing off everything, and repairing found that the Leadscrew and Feed shaft were joined to their drives by ROLLPINS! The replacements are 5 mm brass, drilled through 2.5 mm. to weaken them

Hopefully, the next time that I make a gross error, the pin will shear rather than damage what is downstream of it.

HTH

Howard

Thread: Shed floor
04/06/2022 21:59:53

You MUST have solid support for your ML7. The machine itself is not the most rigid, so whatever it sits on must be rigid so that when you come to take the twist out of the bed, it stays out, and is not repeated by the bench floating about.

I never bolted the bench for my ML7 to a concrete plinth, but the support cannot be too rigid.

O K, you are not working in a Toolroom or Standards Room, but being in any way flexible detracts from accurate and consistent work. Which is, one day, what you will try to achieve.

But seeing your other threads, concentrate on solving one problem at a time! Get the machine sorted before worrying about what you bolt it to for ultimate accuracy. Fix the cover / pulley fouls, then deal with the bench.

Then start looking to "level" and then align the lathe.

Do one job at a time, otherwise you won't know what is affecting what.

Howard

Thread: Headstock problem
03/06/2022 23:11:52

If you say where you are, some kind soul might volunteer to come over and help you.

Not only will you stand a chance of sorting this problem, but they may well mentor you and teach you how to operate a lathe.

(Today, I had a second session with a newbie, letting him get experience of operating a lathe. This morning he made three nuts and faced up the column for a Cehtre Height Gauge. He has now faced, chamfered, drilled, Tapped and parted off for the first time. He was quicker as his experience and confidence grew. )

This is what you should be trying to do.

Howard

Thread: Back gear and tumbler reverse
03/06/2022 23:03:57

Quite right folks

After 20 years the memory fails. My ML7 had a dog, secured by a capscrew, on the chuck side of the pulley to lock the pulley to the spindle. This needed to be disengaged when Back Gear was engaged..

My present lathe has a spring loaded peg, which can be locked out, in the second driven gear to perform the same function.

Howard

Thread: My Faith in Human Kindness is Reinforced
03/06/2022 22:55:38

During Covid, already having a nodding acquaintance with neighbours, relations got even better.

Asian neighbours from a couple of doors away, and their friends from across the road, brought us food from time to time.

In return I have been able to do a little work fixing their children's bikes, or inflating car tyres..

Next door, new tenants moved in. Our first contact was when there was a knock on the door and the young Romanian lady brought us some cake, as it was her 31st birthday.

Yesterday, a friend invited us to a Queen's Jubilee party in their cul de sac. There were Sikhs, Moslems, and Brits all sharing food and talking to each other.

Today, we have been given a tomato plant and a hanging basket by our neighbours.

Nice to think that out of seven houses, six all talk to each other and are friends.

Howard

Thread: Headstock problem
03/06/2022 22:34:22

O K, you have rushed in where angels fear to tread.

Experience lallows you to spot the mistake the next time that you make it.

One thing that you have learned is not to exceed your knowledge and capabilities.

They enlarge as you learn.

If possible, try to reset everything to where it was before you adjusted everything.

As already said, first ensure that the correct belt is fitted. Unless it is you don't stand much chance of putting things right.

Make one adjustment at a time. If it doesn't solve the problem, reverse the adjustment and then try something else.

Above ALL, think and work logically. Failure to do this will produce an expensive doorstop, and a bargain for someone who does know what to do.

You CAN fix it, if you go about in in a sensible way. It is a matter of making the correct adjustment, but only do one thing at a time, and make small incremental adjustments, rather than a few large ones.

Once upon a time, the machine was right. Your task is to work steadily to find out what someone else did wrong, and whet you did to compound that error. Armed with that knowledge, you CAN put things right.

As you do that. you will be learning. But don't imagine that you are going to become sub contractor to NASA this month! A skilled turner takes years to really learn his trade.

Find and join a local model engineering club.

Someone there can probably mentor and advise you, face to face, and save you a lot of time and possibly money.

Howard

Thread: Back plate
03/06/2022 22:17:08

Ideally, the backplate should start by being machined to fit onto the spindle of the lathe.

If a flange fitting, first machine a register that is a tight fit on the flange. (If it can't be fitted into a chuck, mount on the faceplate, and centre as well as possible ).

Having fitted it to the spindle flange via the new register, you can then machine a register to take the collet chuck backplate.

It will be worth boring the middle of the backplate to at least the same maximum bore of the spindle, so that you can pass long work through the spindle bore..

Hopefully, when you clock the internal taper to check concentyricity, there will be almost no fluctuatioinnofnmthe needle.

Howard

Thread: A New Member
03/06/2022 22:07:45

Welcome!

Can imagine that you have a lot in common with horologists in the techniques used, so you won't be alone

Howard.

Thread: Advice on Belt Tensioners
02/06/2022 13:20:11

Reading what Tim says, automotive V belts are usually tensioned by moving the dynamo or alternator outward. This has two advantages; it tensions the belt and increases the angle of wrap around the pulley of the generator.

For just a two pulley set up, an outside idler increases the wrap around the pulleys decreasing the risk of slip.

(One way of holding a pulley to slacken the retaining nut, is to wrap a belt around the pulley, as closely as possible, to maximise wrap. )

If a V belt is incapable of flexing, it is not much use Very often, because of torsional vibrations, they flap, and survive for long periods..(I have seen such violent torsionals, that the belts actually turn over! )

Polyvee belts,often in serpentine runs in automotive use. are often tensioned by an idler running on the back of the belt.

Howard

Thread: Back gear and tumbler reverse
02/06/2022 12:21:56

Chris,

It is good that yoiu are asking questions about the lathe.

Some, probably many, will be answered if you buy and read Ian Bradley's "Myford Series 7 Manual"

You must become familiar with the machine before using it, otherwise you might well damage it.

At this stage, I would not worry about setting up the changewheels for screwcutting or fine feeds. Wait until you have gained more experience.

If you engage Back Gear, you MUST slacken, or remove m(To prevent loss ) the grubscrew located in the bottom of the groove in the driven pulley.

If you do not do this, everything will lock up, since you are trying to drive the lathe with two different gear ratios engaged at the same time.

Maybe I should PM you.

Howard

Thread: Advice on Belt Tensioners
31/05/2022 13:12:56

In many cases, the weight of the motor, pivoting about a shaft provides sufficient tension.

Faced with a choice between a ratchet or a screw tensioner, the screw gives the better chance of getting the right tension..

Excess tension should be avoided, (usually about 10 mm flex , half way between the pulleys should be adequate ).

Excessive tension merely puts extra load on both sets of pulley bearings, which will shorten their life.

Wherever possible, run the tensioner on the back of the belt, to increase the angle of wrap around the pulleys.

Howard

Thread: Riser blocks
31/05/2022 12:23:30

Something along the lines of Tubal Cain's method (Does not have to be absolutely identical ) will do the job.

In the past I have used studding and nuts to provide a means of adjusting to level and remove twist.

My present lathe, larger than the ML7, sits on 1/2 UNF setscrews and nuts.

The idea of using the door from a steel cupboard is a good one. It saves a lot of sheet metal cutting and bending.

(That is what sits under my Mill/Drill )

Howard

Thread: More beginner questions
31/05/2022 12:17:43

Agree with what has already been said.

In your picture, the tool is well below centre height. That tool, or any other, will, not cut properly.

It MUST be on centre height. Don't go above. The tool will not cut, just rub.

If the tool is off centre height, when you face across the end of the bar, it will, leave a pip in the middle.

As I said earlier, make yourself a Centre Height Gauge (But fit some more clamping screws into that 4 way toolpost.) Rigidity is important, so clamp the tool securely, and keep tool, overhang as short as possible.

If you want to know how, PM me with an E mail address, and I'll send a picture of one or two that I have made, with a few notes.

Until then, as said, trap a piece of thin steel between tool and work. If the steel is vertical, the tool tip is on centre height. Ifv it not it will not be vertical If it leans away from you, the tool is too high, towards you it is too low.,.

Don't worry about all the different tools, at this stage.

Just learn how to grind a plain knife tool and start learning with that. The fewer variations that you have, the better you will learn the effect of any change that you make.

One of the first techniques that you need to learn is how to hand feed at a steady and consistent rate.

For roughing, you can feed REASONABLY quickly, but. for finishing cuts, tghe feed rate needs to be small, of the order of 0.004" - 0.002" per rev.

No longer have a ML7, but the thread will, or should, be 1/4 BSF, (Probably., unless a previous owner has departed from the original specification )

My preference is for a 4 way toolpost, as opposed to the standard Myford clamp, or the Quick Change Toolposts advocated by others.

(Purely my opinions, but in my view, most of the the time, you can change tools as quickly with a 4 way as with a QCTP, and the 4 way is slightly or rigid, since there is less overhang and fewer mating faces. This is based upon the tool heights having been set previously. You will need to be ingenious to fit more than 3 tools into a 4 way post, though )

The books that I recommended will show the angles at which to grind the tool.

As a personal note, I use a Tangential Turning Tool for a lot of my work. You can buy from Eccentric Engineering (There is an agent in UK ) Probably too soon to suggest that you make your own.

There is only one face to grind, and the "Diamond" tool should come with a grinding jig.

Don't worry about what coolant, if any, to use, for the moment.

Just learn the basics first of all..As you learn, you will be able to try new things and learn more.

Where are you located? In addition to reading up on how to set up and operate a lathe, you can do with some face to face guidance.. Possibly, there is someone near to you who would be prepared to visit and advise you.

Howard

Thread: Which stand for Myford ml7
30/05/2022 19:00:18

Ah! A typical engineer.

To the practical, many things can be repaired or improved.

Look at how many Drummond lathes are still in use, ditto Myford ML7s dating from 1947.

Some Austin 7s are still on the road and running although over 80 years old. But I fear that my 67 plate car won't be running in 80 years time, even if petrol is still available!

For those without practical skills and knowledge, if it doesn't work as intended, "It can't be fixed, so throw it away and buy a new one",,aided by designed in obsolescence.

A good quality lawnmower, bought cheaply, secondhand, served us well for many years, until the casting finally rotted through; ONCE I'd fitted the blade the right way round!

Howard

Edited By Howard Lewis on 30/05/2022 19:01:14

Thread: Ml7 just bought, need help to set up
30/05/2022 18:40:29

Welcome to the Forum.

Whereabouts are you?

If you don't recognise a Catchplate, you probably need help with other things, as well. So person to person will be the quickest way to learn the trade.

Try to find a local Model Engineering Club, and join.

In this way, you can probably get some face to face help in setting up your lathe.

Watching someone more skilled will be a help, with a demonstration being followed by guidance while working hands on.

A good starting point would be to buy and study some books.

A good one for you would be Ian Bradley's "Myford 7 Series Manual".

Another good one, on general workshop practice, would be his "The Amateurs Workshop"

These will give advice on the bench for the lathe and how to set it up to turn accurately.

You will need a set of Zeus Charts. The charts give a LOT of information on threads and the sizes needed to cut them. I still regularly use the ones that I bought in 1958,

For sizes below 1/2", mostly you can use Taps and Dies It is usual to start a drilled hole by using a centre drill to make a starting point for the pilot drill, before using the final size drill..

If you do not have any measuring equipment, you will need to buy some.

A digital calliper will be a good starting point. Since you have a four jaw chuck, you will soon need a Magnetic base and a D T I. Without such equipment, it will be impossible to set work to run truly concentric..

Another help with such work will be second centre. Once you have mastered centering work in the 4 jaw, you can make one, It would be a good training exercise for you.

And remember that a 3 jaw chuck, whilst it may be self centering, will not hold work absolutely central. A good one will hold work so that it is only 0.003" eccentric. And the concentricity may well vary, depending on the diameter being held..

The hardware on the ML7 will be Imperial threads and sizes, not Metric

You can become familiar with the lathe and its use by using it to make a few tools. Start with simple ones, and become more adventourous as you gain experience.

Making a Centre Height Gauge will give some experience in simple turning, and in drilling an tapping.holes,

Then you can make a couple of Tap Wrenches,.one for small taps, and one for larger.ones.

You will need to lubricate Taps and Dies, and learn the technique for their muse, so that you do not break them, and ruin the workpiece.

As you gain experience, and confidence, you can move on to make more complicated tools. O K, you could buy some of them, but you won't learn as much from a credit card!

Making tooling can become a hobby in itself.

You will make mistakes, but you will learn from them and your successes.

By making simple small tools, you will learn (Better to scrap a bit of mild steel bar than an expensive casting in a kit! ) The tools will be useable for many years to come.

I still have a Tap Wrench made when I was an Apprentice, a LONG time ago

If you do not have one, you will soon need a Bench Grinder so that you can grind tools for the lathe. Since the ML7 is a design from 1947, you would do well to use High Speed Steel, rather than carbide tips. (These were developed for heavy, rigid, industrial machines to remove a lot of metal FAST. As hobbyists, we are not on piecework so do not really need them. They have their uses, but for a lot of work, you can manage with HSS )

HTH

Howard

Thread: Which stand for Myford ml7
30/05/2022 15:48:47

LOTS of ML7 users on here to help you.

You don't have to have the Myford stand.

What is needed is a sturdy, stable, support for the lathe.

Riser blocks are a good idea, they will make "levelling" the lathe a lot easier. The main object is not to set the lathe absolutely level, as such, but to eliminate twist from the bed so that it cuts parallel.

It might be an idea to make the bench top from some thick kitchen worktop. Within reason, the thicker the better, for stiffness. A lathe mounted on a flexible surface will never give consistent results.

Having got a stiff surface, the riser blocks are useful to adjust the mounting feet of the lathe to eliminate twist from the bed.

HOW?

Ian Bradley's "The Amateurs Workshop" and his "Myford Series 7 Manual" both quote the method advocated by Myford. Sometimes known as "Rollie's Dad's Method"

Ian Bradley relates the procedure, and says which mounting to adjust and in which direction, to minimise twist..

Basically, you set a length of steel, at least 1" diameter, (the thicker the better, so aim for 1.5" or even 2" ) set to protrude 4 - 6" from the chuck.

Skim the OD to just clean up, before turning a thinner sectiojn in the middle, to leave a collar standing proud at each end. (A bit like a long cotton reel ) A light cut , without any any further adjustment over both collars should tell you if the lathe is cutting parallel. Different diameters at each end will indicate that it isn't, and the need to adjust the mounting feet under the Tailstock.

Follow the instructions to correct the fault, and take another very light skim, (0.003" or so The minimum to just clean up the collar ).

Repeat this procedure until both diameters are the same. Make small adjustments each time.

There is a certain amount of trial and error to begin, but having fixed the Headstock end, sensible adjustments under the Tailstock end should bring things to where they need to be.

Ideally, both collars will finish up being the same diameter.

It can be also done with an alignment bar held only in the chuck using a sensitive spirit level

Once the bed is free from twist, then the Alignment bar, between centres, can be clocked to align the Tailstock.

It would only be moved from this setting if it is desired to turn a taper, longer than can be achieved with the Top Slide.

Howard

Edited By Howard Lewis on 30/05/2022 16:26:27

Thread: MES Kennet Tool and Cutter Grinder
30/05/2022 14:10:16

Adding a shop made ER20 collet holder (A la Giles Parkes ) to the Hemingway Inclined jig, enables almost any straight shank drill, upto 13 mm to be held for grinding, and with the holder being square, repositioning it to grind the other face or lip at the same setting is easy. (I marked the rear face on the one that I made, making it easier to keep track of where we were.)

Having four faces, in the conventional Worden Tool Slide, it can be used to grind Slot Drills, or four flute End Mills, as well.

Howard

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