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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 backplate chuck help
06/12/2016 18:08:24

Personally, am not enamoured of swopping chucks between backplates. But, at the moment, this will get you going, and then you can search for a suitable backplate for the 4 jaw in a more leisurely way. By then you will have gained enough skill and confidence to undertake machining the register between backplate and the 4 Jaw chuck.

There's been a first time for everything, for every one of us!

Agree with the advice to buy screw thread gauges, (for Whit, Unified, and Metric threads). In the future, you will find them invaluable.

As a newcomer, DO try to find a Model Engineering Club near to you, and join. You will get a lot of help and advice, and companionship, (or you should if the club is any good). One day you may need, for a once in a lifetime job, an oddball Tap or Die, and someone will be prepared to lend it to you; or to give practical help (their shop or theirs) with a particularly difficult problem.

I can vouch for being made welcome when visiting other Clubs. Next season, (I think that you are near Gloucester?) Visit Hereford S M E at Broomy Hill. You will be welcomed (Living 140 miles away, I am not a member, and The WaterWorks Museum is next door, and worth a visit. Very occasionally, I volunteer there).

Hope this all helps


Thread: Compressed air system
06/12/2016 17:51:59

Perhaps a counsel of perfection, but try to have the take offs pointing vertically upwards, to reduce picking up the moisture that will be in the compressed air.

Ideally, you will have installed a water separator, (which you drain regularly, if it has no auto drain function), between the compressor and the ring main.

The standard advice, given by the professionals is that when the compressor is shut down and left for any time, leave the reservoir drain tap open. Again, ideally, the ring main should also have a drain at the lowest and furthest points.

Hope that this helps


Thread: Article: A Simple Tailstock Depth Readout
29/11/2016 17:40:21

Like Chris evans, I tried drilling a cheap 6" Calliper for use as a tailstock readout. Took three sharpenings of a HSS drill for one hole. So bought a linear DRO, 'cos fitting that was so much easier. Right nuisance, tho' when changing the battery and the new one falls onto the floor!


Thread: Cataracts [ocular, not Hardinge]
29/11/2016 17:13:53

Some time ago, my optician told me that I was just starting to develop a cataract. Since then, I have worn glasses to correct other optical faults, such as astigmatism. My experience is that when bending forwards, they tend to shift, and impair my vision. (Try looking down the back of something like a transverse car engine!)

Given the choice, I would choose to have good near sight and use glasses for long distance vision, such as driving.



Thread: Shaver blade refills
27/11/2016 21:51:24

Sharpening, or stropping the Rolls Razor acted as an alarm clock for everyone else in the house.

Still got mine, (given by my late father) but now depend on the local power station to shave me each morning.

Prevents me getting in a lather!


Thread: Suction Cup Adhesive
27/11/2016 21:45:15

To prevent any telltale rings where the sat nav had been mounted, I formed an Aluminium sheet to the shape of the dashboard, and clamped the sat nav to it, along with a lump of steel to add some ballast.

To the underside of the Aluminium sheet was glued some "nonslip" rubber sheet. It takes quite a big bump to shift it even slightly.

After use, it can be locked in the boot, (trunk) or taken with me, leaving no trace that there might be a sat nav somewhere in the car waiting to be stolen.


Thread: Heinz Beanz advert banned for health and safety reasons
27/11/2016 21:22:06

THEY should do something about this!

My usual comment about H&S pundits is that they should not have doors on their offices, for fear of trapping their fingers.

I am told that near here is a factory where the H&S office has a door leading into the main office, but the inner office for the "supremo"', has no door. At least someone seems to practice what he preaches.

Has Common Sense, just like telling the truth, been made illegal, or is it just extinct? Seems to be very little about these days.


Thread: how does this ball turner work ?
27/11/2016 20:58:34

My understanding of all Radius Turning Tools is:

That the cutting tool is on the centre line of the workpiece, and is rotated about a centre point, which is located somewhere within the workpiece.

As the job rotates, the cutting tool is fed towards it, in small increments, whilst the Cutting Tool Holder is rotated about the centrepoint within the workpiece, until the required radius or ball is produced.

Have I got that correct?.


Thread: Metric Mini Lathe Leadscrew
27/11/2016 20:39:17

The screwcutting chart in the handbook for my Chester Conquest Super quotes 40 - 60 - 40 to cut a 1.5mm pitch Metric thread, which implies a 1.5mm pitch Leadscrew. I think that that was what I found when I checked, when I bought secondhand, a year or so ago, but memory is not infallible.

In the R H bottom corner of the front sheet of the handbook, it says "C3" so I take it to be a Seig C3.

For anyone wanting to cut Imperial on a machine with a Metric leadscrew, or vice versa, there should really be a 127T gear in the changewheel train.

However, for the C3, Arc Eurotrade offer a 63T gear, and apparently the error is small enough to be ignored for most purposes, something like the fourth decimal place? (but possibly not if you are manufacturing allthread!)

Must  get round to installing a graduated Handwheel on the Leadscrew, with 60 divisions, (0.025mm/div'n) which I calculated to equate to something of the order of 0.00098 inches per division

Being a Super, the Cross and Top slides have DRO, but these Leadscrews were definitely 20 tpi when I checked!


Edited By Howard Lewis on 27/11/2016 20:42:53

Edited By Howard Lewis on 27/11/2016 20:45:30

Thread: Motor pulley
27/11/2016 20:13:50

Surely, thread cutting relies on the ratio between the Mandrel and the Leadscrew, which is determined by the change gears.

The problem that you may have is not having such low speeds available, as previously; IF the ratio between the motor pulley and the Input Pulley is different..

To overcome this, you could add further complication, (and pulleys and belt) by driving via a countershaft so that the speeds seen by the lathe are the same as the original motor set up.

As usual one job creates at least three more than you first expected! (You would not believe how many typos came as I tried to correct the first ones!)

Good luck.


Edited By Howard Lewis on 27/11/2016 20:15:33

Thread: Benches
27/11/2016 19:50:45

Personally, am wary of timber, because it can move according to temperature and humidity.

Fortunately, before retiring, was able to buy some redundant steel benches (60" x 24" , with 1/8" steel top) from my workplace, 2 inch angle or box section framing, . The lathe, all 300Kg of it sits on some ex Supermarket warehouse staging. I was amazed at how strong and stiff it is,(3" x 2" galvanised box section beams, mounted on diagonally braced channel section end frames. Shelves, above and below, using the same beams, add extra bracing. The machine benches sit on 2.5" x 2.5" angle iron bearers to spread the load on the floor.

The bench under the RF25 is reinforced with 2.5 x 2.5 angle to form runners for drawers.

The tops are high by most peoples standards, but as already said, minimise bending and the resultant backache.

Probably overengineered, but stable and pretty immovable, and excellent value for money, as all bought as scrap!

The chap who bopught my ML7 mounted it on a frame of angle iron, with all joints welded. Again, a rigid construction, which is the objective.


Thread: Apprentice Piece - Turning
19/11/2016 20:53:35

In the late 50s, early 60s, every grade of Apprentice, at Rolls Royce, Oil Engine Division, from Craft through to Graduate, spent a year in the Training School. As the year progressed, the higher grades moved on to projects where machining was a means to the end. But everyone had an insight into Turning, Milling, Grinding, Fitting and Inspection. Some of us, myself included, had never seen a lathe before, let alone used one!

For the folk, apparently, envisaged by the OP, the first 20 or 30 minutes are going to be spent on H & S, and showing how to stop and start the machine, then its other controls. Only then should they be allowed to run the machine, whilst closely supervised. (1:1) Very likely, the first thing that they will learn is that the cut will reduce the diameter by twice that amount! Then , again, under supervision the student could start making the plumb bob. Starting with planning the sequence of operations, leading to plain turning, drilling, taper turning. Boring will be too slow to cover in a session lasting only two hours. Even completing a small two part piece like the plumb bob will be very tight on time.

Cannot see that there will be time available for thread cutting, by any means. So, if the two parts of a Plumb Bob are made, securing the two parts has to be by "sticking", two part epoxy/anaerobics etc.

At the end, the student ought to have a very basic understanding of what a lathe can do, but little else, other than (hopefully) a respect for power driven equipment.

These students will not have the experience and skills of many of the readers of this forum, so their work rate will be SLOW. And the safer for that, for them.


Thread: Hoover motor died I think
19/11/2016 18:05:02

Am NOT an electrician, but it may be, as already suggested, a failed capacitor.

The one on my small air compressor failed quite suddenly; a loud bang followed by fluid leaking out. Replacement cost £6.00, a few years ago, from the local motor rewinders.

If, the centrifugal switch contacts have welded, then the Start windings will have been in circuit continuously, which they are not supposed to be. Another possible source of heat and smoke.

The motor on my Myford once gave a good show of flashes and smoke. Fortunately, the local rewinders diagnosed it as swarf across the centrifugal switch and managed to clean it up enough to continue working until after I had sold it

If in any doubt, have your local motor repairers check it out. Hopefully it will be capable of further service, after a bit of rectification.


Thread: dividing head /indexing
19/11/2016 17:51:04

Coming in late, as usual, if you lack welding facilities, you could fabricate and bolt parts together. (for belt and braces dowel as well to guard against any movement in the future).

You only need to ensure that the faces and bore are square to each other, (first face machined to clean up will act as datum) and machining using as few set ups as possible should do that. The end result may not be concours d'elegance contender, but the test is: Will it do the job?

How you drive it, manual, stepper motor or water wheel; is your choice, depending upon skill/materials available.

College Engineering Supplies used to do a kit for a Rotary table, and sold the Worm and Wheel as a separate item. Presumably, the new owners still do?

FWIW, my Vertex HV6 Rotary table is 90:1 ratio, which would be my choice.

Good Luck with the project.


Thread: C0 self centraling 3 jaw chuck.
08/11/2016 20:34:21

Having got the jaws into the "correct" position, dare I suggest trying to engrave (probably too hard to stamp) both Chuck and Jaws, (say A, B, C; or may be A-C, B-B, C-A ) so that you know which slot to put them in next time?

Four hours of frustration each time is not what the hobby is about, AND the stress is not good for you or those around you!

Simon's tip about using a cleaned redundant tooth brush for cleaning is an excellent one. They are good for cleaning taps before you put them away.


Thread: Stiffness for an indicator mount
08/11/2016 20:13:25

Are there two tapped holes in the back?

If so, why not make up a plate with dowel holes to match the two dowels, and fix to to the form of adaptor, (1/4" dia?) to fit into the monkey block on your mag base?

Yes, keep it as light as possible, but not so thin that it flexes, (1/4"/6mm gauge plate springs to mind) with the adaptor bar screwed into the edge.

If it measures in microns, everything needs to be secure, but don't spend too long breathing on the set up or thermal expansion will become noticeable.


Thread: Float reamer holder
08/11/2016 20:01:01

Surely, the reason for using a floating reamer holder is to eliminate the effect of the reamer and hole not being accurately aligned?

A reamer solidly mounted in a Tailstock which is is not in perfect horizontal and vertical alignment with the hole to be reamed, will cause it to act as a boring bar, and produce an oversize hole, by cutting on one side of the hole.

If the reamer flexes, the hole may well be tapered as well as oversize!


Thread: Bore Reducer
08/11/2016 19:54:30

Totally agree with the advice to turn one's own, close fitting sleeve. You can measure the shaft and pulley bore and so turn the sleeve to be really snug fit to both. Once slit, the grub screw will ensure a good grip, and then you are in business. It is likely that the cast iron pulleys will last longer than contemporary light alloy ones., and will maintain the "original" appearance, as well as behaviour. (Current pulleys may well be metric, and will still need boring or sleeving to fit the motor shaft, so you will have spent money to be doing what you need to do with what you have at present)


Thread: Air casters
07/11/2016 12:06:00

Trev T you are not alone. Just cannot bring myself to dump all the SLRs, Enlargers, Colour and B & W processing kit, and studio lighting. Too many happy hours spent with them.

Wife has suggested that i do and move the mini lathe in to the darkroom. It would avoid a few steps in the dark and rain to workshop.

In some respects, the march of progress isn't as much fun.


Thread: Its a what?
07/11/2016 11:57:41

The clamp shown by Silly Old Duffer was called a crab clamp when I bought it. Mine was cheap imitation, or I exceeded the design limits by stripping the female thread in the mazak/alloy "nut" part. The steel BSF threaded replacement is still intact tho'


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