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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: Interfering with fits?
20/08/2021 21:46:58

To make life easierv on machine, tool ,a nd you.

Make a sacrificial plug to go into the bore, and then drill a hole, centred on the boundary between sacrificial plug and bore.. This will remove a lot of the material that needs not to be there.

Remove plug and cut keyway.

You can either hold the tool in the tailstiock in some way, or in the toolpost, (Obviously equally disposed vertically about the centreline ) and then rack the tool to and fro, using the Saddle or tailstock handwheel..

The toolpost method is better since the Cross Slide can be used to control the depth of cut.

Once, I did cut a square hole, using a tool in the tailstock, but bit was laborious, since I had virtually no control over depth of cut. The method was to cut as deep as possible, about 0.010", withdraw, rotate chuck by 90 degrees, and repeat. Continue repeating until hole was to completed depth. Crude, and slow, but it produced the desired result. Not that I would want to make a habit of it!

With 20/20 hindsight, should have mounted the tool in the Toolpost!being bone idle, the tool was ground on the front face only, so that the swarf had to be cleared on each backstroke. Should have been ground like a small parting tool, with clearance on both sides.

Howard

Thread: Strange stain in caravan
20/08/2021 21:23:58

If gentle methods fail, try bleach (Sodium Hypochlorite ) removes tannin stains from tea pot and mugs very well!

You only need a few drops to roll around and the stain disappears almost before your eyes.

Howard

Thread: Reaming a hole
20/08/2021 21:19:12

One thought about reaming in the lathe, is that is anything is slightly off centre, the resulting hole will be oversize, because of the reamer acting like a boring bar, and predominantly cutting on one side.

My method is always to use a floating reamer holder. Thus the reamer can follow the hole that has already been drilled / bored which should be concentric.

If the hole is blind, machine reamer, having a shorter lead than a hand reamer will produce a greater length of hole to size than a hand reamer. Less of a problem with through holes.

Howard.

Thread: Clinging to the Past
20/08/2021 20:54:32

Someone said that those who ignore history are condemned to repeat the mistakes.

Because basic arithmetic seems to have been omitted from the syllabus, folk now have difficulty working out pulley sizes to give a required speed, from a motor of known speed. Similarly calculating the gear ratio between Mandrel and a Leadscrew of known pitch. Cutting a screw thread of the required pitch seems to be difficult, (Except, perhaps for the geriatrics among us, who had such things drummed into our heads at an early age )..

Remember "Times Tables"? Meccano taught me multiples of 19, as well as calculating simple and compound pulley and sprocket ratios.

So fractions are still necessary to find the gears to reduce a speed to says 5/6 of its value, A 35T gear driving a 42T (if one is available ) is one possibility, or a 75T driving a 90T?. Reversed, any of those should allow a 2.5 mm pitch to be produced on a lathe with a 3 mm pitch Leadscrew.. Compounded with a 3:1 reduction the original reduction would allow a 8 tpi Leadscrew to produce a 20 tpi thread.

Just fractions really.

Ask Brian Wood!

An understanding of the basics makes the complicated more understandable.

Understanding the principles makes anything more comprehensible.

Despite spending lots of time with fuel injection equipment, to me, microns are less easy to visualise than thous.

An average human hair is more easily visualised as being 0.005" than 127 microns.

Again, using whatever system / measurement is most easily applicable. Who wants to measure their car's fuel consumption in dimensions of 1.6 Km per 277 cubic inches?

Again, horses for courses

Howard

Thread: Is there such a thing as an 'external reamer'?
19/08/2021 09:31:52

If the object is to produce the spigot, what is the matter with turning the OD of the spigot and finally facing to length?

Thread: Converting fractions to decimals
18/08/2021 23:11:09

This looks be getting a little bitter and twisted, when we are taking of UNITS.

The same parameter can be dimensioned in whatever unit you like, Angstrom units, Light years, yards; rods, poles or perches; spans, or bricks, if that is what takes your fancy. Just depends on how many decimal points you are prepared to tolerate, even if you prefer duodecimal, or whatever..

Film speeds were measured in Hurter and Driffield, Scheiner, Weston, Gost, and ASA, all for the same material,

Before anyone says it, not all at the same time!

They are only units, you choose the one that suits best. Best to try to use the same units as other people, which is where Whitworth, Sayers, BSI and ANSI, etc came in.

Because my kit is all Imperial, I am an "Ancient Oddity" in all senses, but occasionally use Metric,WHEN IT SUITS.

My shop made Workshop Comparator incorporates 8-32 UNC, 5/16 BSW and half round 4 mm pitch 0.0625"deep threads, because

a ) the UNC and BSF fixings were available, and

b ) I wanted a coarse thread, and the lathe could be set to 4 mm pitch, into which I could match a 1/8" ball bearing..

They happened to be the horses that suited my courses, did the job, and do not need to be interchangeable with anything else....

Howard

Thread: small toothed belts
18/08/2021 21:51:20

Suppliers of "pulleys" for cogged belts, such Davall Gears, Reliance Gears, HPC Gears etc?

Howard

Thread: Looking for solution to incorrigibly jumpy needle roller bearings
18/08/2021 21:48:45

If you can find ball races that will fit the shaft and the housing, you could always replace a long , unreliable needle bearing by two, or more, ball races with suitable spacers. To take the loads, it would be worth fitting as many ball races as possible, to carry the loads.

The end product might be more durable than the original equipment!

HTH

Howard

Thread: 4 jaw Independent for a 7x12
18/08/2021 21:43:52

Of the nbregister on the CL300 does differ from the other Sieg mini lathes, (Chester etc ) since you have a lathe with a 3 jaw chuck, you have machinery to turn a suitable register on a backplate to match the flange.

Once fitted to the flange,the OD can be turned to be the register for the new 4 jaw chuck.

Then it needs to be drilled, possibly tapped, for the fixings for the chuck.

If the chuck body is tapped, you will need to make some pointed studs to screw into the chuck, with which to mark the backplate for the holes.

Since the holes will be clearance, location being by the register of the backplate to the flange, and OD to the chuck, the holes can be a little oversize to take care of any small inaccuracies..

HTH

Howard

Thread: Hello from Winnipeg, Canada
17/08/2021 18:21:49

I think that the Me 109 was faster than the Hurricane, and being fuel injected the engine did not cut out during violent manoeuvers. The Merlin was prone to this, in Hurricane and Spitfire, until "Miss Schilling's orifice" was fitted to the carburettors.

The Hurricane and Spitfire's advantage was that tey were more agile, and could turn more tightly than the Me, making it vulnerable.

Thread: hi new here from ely
17/08/2021 17:11:06

P S M E held their first meeting, last night, for goodness knows how many months About 11 attended.

If you can't find anything closer, the next meeting is Monday September 6th (See the website for the location in Eye so a little closer your way on the A47 than coming into Peterborough.

Howard

Thread: Hello from Winnipeg, Canada
17/08/2021 17:02:47

The Hurricane could take a lot more punishment, and was easier to repair than the Spitfire. As long as the missile missed the framework, it passed through the fabric with minimum effect.

The Spitfire was a stressed monocoque so a hole was more serious, and heavy damage less easily repaired, but was faster because it was sleeker.

It easier to believe that the Spitfire won the Battle of Britain, but there were a lot more Hurricanes involved, so they bore the brunt of the battle.

Both aircraft and their pilots did a splendid job for our country and the world in general.

The Defiant seemed a good idea at the time, but the heavy turret made it slower and less manouverable, so was soon withdrawn.

Howard

Thread: Hello from Leeds
17/08/2021 16:49:18

Welcome, and good advice already forthcoming.

Lots of the questions in your mind have been asked, and answered many times before, so look back through previous threads.

You can shorten the search time by narrowing the field of search. So search for one subject at a time.

Howard

Thread: Interfering with fits?
17/08/2021 16:45:27

Not Aluminium into steel, but when I wanted to shrink fit a steel shaftv into a cast iron base, I chose 0.001" (0.0254 mm ) interference.

cast Iron base was reamed to 1", and measured.

Steel shaft was turned own to measured diameter+0.001"

The shaft spent the night in the freezer, and the 6" diameter x 1.25" thick cast iron was cleaned and with permission heated in the oven at gas mark 6.

The shaft was removed from the freezer and wrapped in a towel, while thge base was moved from the oven onto a piece of 10 mm ply on the kitchen floor.

Shaft unwrapped and was a nice fit into the base. The frost on the shaft gradually disappered upwards.

When cool; a tight fit.

Based on industrial experience, Loctite usually needs a clearance of 0..002 - 0.003", You are relying on the shear strength of the anaerobic. So choose the correct grade, such as a retaining compound, not one intended to provide a relatively easy disassembly in the future.

Howard

 

Edited By Howard Lewis on 17/08/2021 16:45:45

Thread: choices of material to turn
15/08/2021 18:03:00

If you are newbie to machining, make your mistakes on free cutting steel, such as leaded.

Stainless, can come later, when you have more experience.

Scrapping some 12 mm free cutting steel, if you get something wrong, will be cheaper than stainless, and less likely..

You learn to walk, before trying to sprint. Channel swimming comes after you have learned swim.

You are at the bottom of a learning curve.

Very few of us ever reach the peak! It's a LONG way off for me!

Get some books and read up on using a lathe, it will save you frustration and puzzlement.

You can gain experience by making simple accessories for the lathe, which will be useful after you have made them.

When you are familiar with the machine and using it, then you can try different materials. Then you will start to learn about feeds and speeds, depth of cut and tool shapes for best effect..

Howard

Thread: Which is better Thompson or er collets
15/08/2021 17:49:35

Clarkson collets will be only for the stated size.

ER collets can accommodate a small range of sizes, usually 1 mm, so that Metric or Imperal sizes can be accommodate. And are widely available.

Your choice, depending on budget and space consideration..

Howard

Thread: Hello from Winnipeg, Canada
15/08/2021 17:44:17

Welcome!

You are abouit to engage in a very satisfying hobby.

Lots of help and advice onn here, (some of it conflicting, according to which hobby horse is being ridden )

May I suggest some reading matter?

Assumes that such things will be obtainable in Canada

Zeus charts - Invaluable as a quick reference.

Ian Bradley "The Amateur's Workshop". Contains info that the usual "textbook" does not contain.

L H Sparey "The Amateur's Lathe" very much illustraed with Myford ML7, but good on general principles.

Both these above date from the 60s and 70s, but good none the less.

Harold Hall, and Neil Wyatt have both written books, more recently, dealing with more recent machines.

Tubal Cain "The Model Engineer's Handbook" is a very useful reference book, and useful to have, in my view.

Most of the current 12 x 24 lathes are gear head. The Chester Craftsman is belt driven. (my lathe is like the Crafts man a Taiwanese machine, similar to it, as is the Warco BH600.

If it needs to be said, you will need to budget for tooling, most probably a Bench Grinder, for a start. This will allow you to learn to grind High Speed Steel tools. They are more forgiving than Carbide, of knocks.

(My HSS parting tool was secondhand when it was given to me, and some 30 years on is still not yet worn out 

You will need some measuring instruments, a set of Feeler Gauges and a Digital Calliper for starters.

The digital calliper can measure 0-6" or 0-150 mm at the touch of a button. Prices (and probably quality ) vary from supermarket instruments, upto near industrial quality, with a price differential in UK of about 7:1.

(I use a supermarket one for most work, with a mid range for a second opinion, when it is needed Keep spare batteries! )

Before launching into an expensive kit for a model, my advice would be to learn, and make mistakes, making small tools / accessories for the lathe, such as (On my hobby horse! ) a Centre Height Gauge,, and a Mandrel Handle, even a sliding Tailstock Die Holder set. You will need to buy a stub arbor to make this, probably a 3 MT...

All useful learning process and money saving into the bargain..

Taps and Dies, and Tap Wrench and Die Holder, you can buy as and when you need them

Buying complete sets will make you ready for almost anything, but a capital investment cost. (Don't ask! how I know! )

In this day and age, probably Meric and Model Engineer nwill be nthe most useful, unless you get into vehicle restoration, in which case Unified m may be useful. I do find 1/2 UNF (1/2 x 20 ) useful for forcing screws.

BSF nand Whitworth only if the vehicles mare British and OLD.

If your lathe is like mine, making a Rear Toolpost will be a useful addition. It makes parting off easier, for a lot of the time, and if you stick with the four way front Toolpost, it leaves room for an extra tool in it.

My front post carries, Rougher, Finisher, and a boring tool, with then rear post, being a shop made four way, carries front and back chamfer tools as well the parting tool.

With a 4 jaw independent chuck, you will find a need for DTIs and a Magnetic Base. You may find that a Plunger clock will read twice as coarsely (0.001" ) as a Finger Clock, (0.0005" ) but both have their uses. This assumes that Canada is like US tending still be Imperial, although your new machine may well be Metric., so your clock is likely to resolve in 0.01 mm increments.

Eventually, you will want to mill, but that is another field to, learn!

I've rambled on for far too long, but hope that this may be some help.

Howard

Thread: Consequences of Machining Cast Iron
14/08/2021 12:42:12

Oh Yes,

Black or dark grey towels are a MUST after the workshop. You MIGHT get away with a heavily patterned dark one

That way you won't be accused of "Making my towel dirty", until it goes for washing!

Some towels and clothes are not allowed in the washing machine. Only handwashed, in the utility room sink!

Such is life

Howard

What I forgot say is that when machining cast iron, I try to site a powerful magnet under where the swarf is likely to fall, covered with newspaper. In this was most of the swarf is attracted and caught and can be tipped away more easily once the newspaper has been taken away from the magnet.

If the magnet starts to grow "whiskers", Blu Tack is a good way of removing them and cleaning the magnet.

Edited By Howard Lewis on 14/08/2021 12:45:27

Thread: Dore-Westbury Mill
13/08/2021 20:25:05

The thought of that 3 jaw coming loose is frightening!

For holding cutters use ER collets,m 25 or 32, will give youupto 16 mm for 25 and to 20 mm shanks for the 32.

I use ER25, since the largest shank that I have i 16 mm.5 Anything larger, and I am into the realms of Face Mills.

HTH

Howard

Thread: Making Tapered Castellations in Aluminium
13/08/2021 15:52:38

If using a 1.5 mm End mill, I'd buy several (lots? )

The thought did came of suggesting mounting the bar horizontally in the vice, and using a 1.5 mm slitting saw. In my hands the saw will last longer than small end mills.

With regard to Rotary Tables, I have a Vertex HV6, and apart fro the original divisions chart containing errors (Spent over a day setting up a spreadsheet to check / correct the chart, after producing three scrap gears - thought I couldn't count ) have been quite satisfied.

HTH

Howard

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