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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: Lathe tool angles
14/08/2018 14:10:03

Mostly, chipped CCMT0604 bits are used with the unused 100 degree corners for roughing. (Andrew would like the blue stuff coming off). Hundred thou cuts can make it chatter.

The original tips are used in a Boring bar. So the angles are already chosen. For most of the other straightforward turning, the Diamond (Tangential ) tool is used. Freshly sharpened, (Boasting!) it will take a cut of 0.0005 inch, or much greater. With a 1/4 toolbit have never exceeded a 0.050" cut.

The HSS parting tool, ( Secondhand when I got it, at least thirty years ago, and still nowhere near worn out)   is inverted in the rear toolpost has zero top rake, and gives few problems.

On the RF25 Mill/Drill with HSS cutters, rarely exceed 0.050" depth of cut.

So am looking for fresh types of cheese.

Howard

Edited By Howard Lewis on 14/08/2018 14:16:14

Thread: Lathe turning out of round parts
14/08/2018 13:57:10

If the bearings are ball or roller, and the lathe has been stored with bthe spindle vertical, and even worse, subjected to vibration, it is possible that the outer raceways have become "Brinelled".

The likely result of this would be that the out of round becomes regular, a bit like a very small serration, mimicing the depressions in the raceway of the bearing.

Replacing the bearings (and seals) should rectify the problem.

If the bearings are plain, (parallel or tapered) then one wonders if there is some wear (unlikely in a little used machine) or a lack of adjustment (slack?) allowing the spindle and the workpiece to try to climb around the cutting tool.

H T H

Howard

Thread: drilling files
14/08/2018 12:30:51

Have never had much success with these "hard" drills, have several which have failed. If you are lucky, they will drill HSS, but note the word LUCKY!

Howard

Thread: Are Model Engineering Exhibitions The Same
14/08/2018 12:27:36

In many cases, the problem is made worse by the venue having narrow aisles, (Such as The Fosse. Which, one day, will stop me going there).

Howard

Thread: machine mart CL oil level sight glass
14/08/2018 12:24:36

The original part is shown as No. 74 in the Parts List, Part No: 30000474, if you want to order one.

Howard

Thread: Squealing motor
12/08/2018 11:29:43

The squeal is because the lip has been worn down on the original seal.

So fit new seals, DON'T forget to lubricate the shaft before fitting. You don't want to rip the lip on initial start up.

The grease should be pushed back into the new bearings, which won't do them any harm. They are ZZ, so only shielded, therefore a seal is needed for each one.

Howard

Thread: UNEF to BSP adaptor - a question.
12/08/2018 11:10:27

Yes, I recall seeing a spherical face to the connection for my blowlamp to the regulator on the Propane cylinder.

Even if the faces are not an exact match (producing a long leakage path) the line contact from an inexact match would produce such pressure that the two metals deform slightly to produce a seal. And Brass is relatively soft.

(Which is what the valve/seat machining seeks to do for internal combustion engine valves)

Howard

Thread: Identify/parts for a Swiss Metal Lathe
11/08/2018 22:20:40

Barry,

Where are you? In UK? Whereabouts?

Possibly someone near would be prepared to assist you.

Howard

Thread: M.E.S RT3 - rotary table kit
11/08/2018 22:11:53

F W I W,

The 2 MT taper can be used to centre the Rotary Table, in horizontal mode, under the spindle of the vertical Mill.

I bought a 2MT arbor with a MYford nose. It has been invaluable carrying work in a 4 jaw Myford type chuck, for turning work in my larger lathe, before transfer to the Mill/Drill with the HV6 with the table vertical, for cutting gears.

Howard

Thread: Adept and Super Adept Register
11/08/2018 22:00:44

Mine has been passed on to a friend, and a couple of years ago, there were two at the Spalding Model Engineering Show.

One was owned by an ex working colleague, living in Spalding, and the other was working on the Wolverhampton Club stand. They were described , briefly in M E W under the heading of Assorted Adepts.

Howard

Thread: Identify/parts for a Swiss Metal Lathe
10/08/2018 19:22:04

9.5mm calculates as 0.374 inch, so I would vote for 3/8". Since the lathe is of mature years, the thread form will probably be Whitworth form. The pitch will decide whether it is BSW or BSF.

Hope that what follows is not "Teaching Granny to suck eggs"

With regard to the Tailstock Centre, a thread will not provide a repeatable centre, unless there is a register onto which it will locate. A taper, such as a 1MT would be far better) You can make a centre by taking a suitable piece of steel, putting in the Headstock (Firmly and accurately located0, setting the Toolpost over by 30 degrees, and turning up a centre. Whilst you are about it, make another for the Headstock, against the time when you need one.

If there is an obvious taper (chamfer) at the entrance to the tailstock bore, you could use that as the location, screwing the centre hard against it for a location, (But you need to have turned the centre with a similar chamfer at the headstock.  To ensure that the taper/chamfer at the Headstock end is truly on centre, you can either lightly trim it (if there is one) or make a "collet" for the Headstock. Drill and tap a piece of steel in the Headstock, and turn a taper / chamfer without moving the workiece.  You now have a location which is on the centreline of your lathe, that you can now use to turn the centre for the Tailstock.

For a Tailstock Drill Chuck, make up another arbor for the Tailstock, but with the correct thread, or taper, for the drill chuck. Chucks for Pistol Drills used to use 3/8 - 24 UNF thread, whilst the later ones (usually reversible drills) use 1/2 - 20 UNF thread. Chucks intended for use in lathes or Milling Machines usually have a Jacobs taper, (which one will depend on the chuck, and its size), which you will need to turn yourself, so you will need to experiment a little and test with a felt tip marking pen, or Micrometer brand blue. When you have produced a taper which is a good match for the female taper in the chuck, you clean everything, and fit the chuck onto the taper with a little endwise force, and you should then be ready to go!

Howard

Edited By Howard Lewis on 10/08/2018 19:30:16

Thread: How would you fix this?
10/08/2018 18:52:41

A thought that may help the O P.

When my wife lost the screw on cap to a stainless steel Thermos flask, I made a new bung from Nylon, and incorporated a groove for an O ring. It seals, perfectly, which the original screw in one did not.

So you seal on the inside of the spout, rather than the outside or top? So what! The objective is to seal the container, to prevent the salt from contaminating the rest of the machine.

Howard

Thread: Let's hear it for British manufacturing!
10/08/2018 18:46:34

A very good point that we need to save, not only the Heritage artifacts, but the skills that made them, and to maintain and operate them, for future generations.

We have already lost a lot of the skills of the handle twirlers, fitters, blacksmiths, boilermakers and foundrymen who produced the originals.

Howard

Thread: Cleaning Lathe after use
10/08/2018 17:58:44

If you are taking a first cut on an iron casting, make it deep, so as to remove the outer skin. This may well be hard, having been chilled, so needs to be removed in one hit.

(A whole set of inserted tooth milling cutters on a transfer line were wrecked when a batch of castings, that had been inadvertently chilled, were loaded in). Imagine the frustration of knowing that every pair of cutters, on every stage, is going to be smashed, and there is no means of stopping or unloading!

Inserting chills into moulds is a way of hardening cast iron locally; often used for cast camshafts.

Howard

Thread: Sign up to boxes
10/08/2018 14:34:31

Predictive (mis)spelling?

Apart from surgery, is there a cure for fat fingers?

Howard

Thread: Hello from St Ives Cambs
10/08/2018 14:27:29

Welcome aboard Simon!

If you are thinking of joining a M E Club, there are ones in Cambridge and in Peterborough. Am sure that you would be made welcome at either if you feel inclined to travel a little way.

You are likely to find yourself making "gadgets" very soon, as you start on one task, you realise that "I need a widget to...." A bit like " Greater fleas have lesser fleas upon their backs to bite 'em, and so on ad infinitum!"

Whether in a Club, or on here, there will be great deal of exchange of information and experience.

Howard

Thread: Which books
10/08/2018 14:08:10

+ 1 for Tubal Cain's book.

Although written when the Myford ML7 was the most populous lathe, Sparey's "The Amateur's Lathe" is a good starting point, followed by Bradley's "The Amateur's Workshop". "The Myford Series 7 Manual" is specific, but contains information that is useful elsewhere. After that you are into books from the "Workshop Practice Series", for more specific activities, such as Soldering and Brazing, Taps and Dies, Workshop Hints and Tips, Making Small Workshop Tools, Screwcuttiing in the Lathe, and when you are more experienced and confident; Milling, or Gearcutting.

The books by Neil Wyatt and Dave Fenner deal with the mini lathe, but the techniques and principles, if not the specifics, can be read across onto other machines.

If you want to get into screwcutting, Brian Wood's "Gearing of Lathes for Screwcutting" can be a good source of information, so that you grasp the principles involved.

Plus, you will always have a crowd of folk on here who will be happy to give advice, and even practical help.

Howard

Thread: Latest issue - thread indicators
10/08/2018 13:47:06

Lots know the theoretically correct way to mesh the gear with the Leadscrew.

But bear in mind that the gear on a T D I is only required to transmit enough torque to overcome the friction in the bearings of its shaft.

So, I would imagine that a theoretically incorrect spur gear, probably only making point contact, would be quite adequate for the task, as long as the tooth form conformed fairly closely to that of the thread on the Leadscrew..

"C'est brusque, mais ca marche"; as someone said of the "crash" gearbox.

Howard

Thread: Suspected stuck piston rings
08/08/2018 19:48:10

Bryan,

You have a couple of PMs

Howard

Thread: using the Worden
08/08/2018 19:07:15

Whereabouts are you?

Perhaps someone nearby would lend you their Instructions.

(if you choose to copy them for your personal use/study, you may not run foul of the copyright law)

Howard

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