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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: Small bandsaw needed
20/09/2021 17:53:41

Years ago, I bought a small bandsaw from Warco. The idea was that it could be stored undewr the bench. It would break a blade almost before it had cut through a piece of 1 1/2" angle iron. Cost me a fortune in blades, no matter how it was adjusted.

The replacement arrived, with paint in a crack in the casting!

I suspect that the problem was that the pulley centres being so close, the blade was twisted too much for it to be durable.

It was replaced by the 4 1/2" version, which once set up has worked very well.

With the blade tension set with a Jacques Maurel tension gauge it cuts well, accurately, and the blades wear out rather than breaking.

Howard

Thread: 5 Rotary Table/Tailstock/Chuck Kit Info/Questions
20/09/2021 17:29:17

When you come to use the R T in the Vertical mode (Table face vertical, axis horizontal )) you will need yto align the R T and the Tailstock.

My Tailstock has tappings for a key or dowels. Because my T slots differed in width from the keyway on the Tailstock, I made up two stepped dowels. One end is tight fit in the Tailstock keyway, and the other in the T slot of the Mill table.

So that is the Tailstock aligned to the Mill Table. It now needs to be be aligned vertically, with the R T.

The RT also needs to be aligned with the axis of the Tailstock, along and across the Mill table..

These can both be done at the same time.

With an arbor (In my case 2MT ) bore the blank end to a really snug fit around the OD of the Tailstock centre.

Position the R T, loosely, on the Mill table so that it roughly aligns with the Tailstock, in the place where you wish to use it, with the 2MT alignment arbor in place...

Slacken the clamps for the vertical position of the Tailstock centre

Enter the Tailstock Centre into the bore of the 2MT alignment arbor., and clamp the Tailstock to the Mill table.

The dowels will have aligned the Tailstock.

The Centre barrel, being snugly located in the 2MT arbor will have aligned the Tailstock barrel vertically; and the R T along and across the Mill table, so both can be clamped.

Once the Tailstock centre barrel has been aligned, it is set up and should not need to be reset. It can be used, with the 2MT arbor to align the R T on the Mill table in the future.

HTH

Howard  (Anyone know a good typist? )

Edited By Howard Lewis on 20/09/2021 17:36:13

Thread: Screw cutting
20/09/2021 15:15:50

You really need to know the pitch of the Leadscrew on your lathe. You may well need this information at some time in the future.

What follows may be teaching granyy to suck eggs, but is intended to be helpful, by explaining the basics..

In essence, to cut any thread, you need to set up a gear ratio which rotates the Leadescrew at such a rate, relative to the Chuck, so that the tool travels the correct distance for each revolution of the Chuck.

If you are trying to cut a Metric thread on a lathe with an Imperial Leadscrew, or an Imperial thread on a lathe with a Metric Leadscrew, , the gear ratio will need to allow for the fact that there are 25.4 mm to an inch. (Hence you will see references to 127T gears. 127 = 25.4 x 5 ).

Putting simply, if the lathe has a Leadscrew with a 3mm pitch thread, to cut a 3 mm pitch Right hand thread, the Leadscrew needs to rotate at the same speed as the Chuck.

If you wanted to cut a 1.5 mm pitch thread, the leadscrew would need to rotate at half the speed of the chuck, to move the tool towards the chuck..

Chuck makes one turn, Tool moves 1.5 mm. So using changewheels rather than a norton gearbox, the mandrel would carry a gear with, say, 30T, with a 60T gear on the Leadscrew, with an Idler gear to fill the gap, The Idler will not affect the ratio, so the tooth count will not matter, as long as the gear mesh is correct, so could be a 55T if it transfers the drive correctly..

If you wanted to cut a Left hand thread, the gear train would need an additional Idler, to reverse the direction of rotation of the Leadscrew, relative to the chuck, to move the tool AWAY from the chuck

The tool has to be ground to the correct angle for the thread being cut, 60 degrees for metric or Unified threads, 55 degrees for Whitworth or BSF threads, and to have the correct clearance angles ground into the flank,

If everything else is correct, are you trying to take too deep a cut? You will need to take several mpasses, with the depth of cut decreasing as you go in deeper. A M20 x 2.5 mm thread is 1.5336 mm deep,tol so may need a lot of shallow passes, and should have a 0.3125 mm flat on the crest of the thread.

As an example, the Cri Dan industrial screw cutting machines, took at least 20 dry passes to cut a 1 inch BSW thread. The thread depth is 0.080" (so a little over 2 mm ) with the swarf coming off blue at each pass..

You might start with a 0.1 mm DOC but as the width of the cut increases, the depth needs to decrease.

HTH

Howard.

Thread: Absolute beginner, just bought a cheap lathe
20/09/2021 14:42:15

If you contact, and preferably join, your local Model Engineering Club, someone there will probably be able to help you.

It may either be possible to machine away the damaged ares and insert new material, or even to make a complete new Top Slide.

Find out where and when they meet and go and visit.

You will like minds there who will be willing to help and advise you, not just on this problem, but others that you will encounter non journey into Model Engineering.

If you give your location, there may be someone on the Forum who would be able and willing to help you.

Howard

Thread: Myford m series
17/09/2021 07:47:42

Firstly, Welcome to the Forum.

Don't be afraid to ask about anything. VAST amounts of experience on here, should you need it. And you can help mothers if they have a problem, to whichr you know the answer.

If the M is like the early MLs, (1,2,3 and 4 ) the gears are driven from the mandrel, and on to the Leadscew by Driving Collars.

This just a collar with a grubscrew to secure it to the mandrel, or Leadscrew, with a 3/32" hole part way through to take the pin that drives the gear.

From memory, the grubscrew is 1/4 BSF

If you have to use a compound gear, the two are coupled by a 3/32" pin in the same way

So, IF this is the same arrangement as the ML4, you should have two Driving bCollars, and ideally four pins.

Four because two will be needed for the Driving Collars and the other two in case you need to have two compound gears in the train.

If you have not got the two Driving Collars, you can easily make them. They are only a simple turning job, the same thickness as a gear, probably 5/8" bore with the 1/4 BSF tapping and the 3/32 hole, drilled half way through..

HTH

How\ard.

Thread: cutting spur gears on a mill
16/09/2021 07:47:41

As a spectator, a long and interesting debate, from which i have learned a few things.

1 IF this method is to be used, a spiral tap is probably the better way to go.

2 There are some quite short fuses about.

3 To maintain an accurate NUMBER of teeth (Not necessarily Form ) pre gashing is required.

Since this is required, will this be a lot quicker than using a gear cutter, considering the need then to reset from some means of Dividing to allowing the blank to rotate?

This ignores the fact that most of us will have a slitting saw, and the likely absence of the required gear cutter, and the cost of buying one.

A while ago, I did consider using a tap for gear cutting, but since a definite ratio, and an accurate gear was required, I took the coward's way out and bout a spur gear and a worm of the same Module..

Horror since the two will not be an exact match. But for unloaded very low speed operation, this is considered to be a small problem.

For other spur gears, I shall continue to use gear cutters. So far, cutting a gear has never taken as long as reading this thread. .

Howard

Thread: Myford ML7 accuracy
16/09/2021 06:49:34

If it will cheer anyone, I know a jewelry maker who uses an OLD Myford ML4 for his work (Helped him get it up and running )

It may not command the price of a 7 Series, but does the job as far as he is concerned. He does not envisage doing any screwcutting, although having a complete set of chanewheels.

It just depends upon what level of accuracy is requited.

If a pair of ear rings differ in diameter by 0.005" it probably won't matter.

Possibly a Drumond, Myford M, ML1, 2, 3 or 4, a Loughborough Training lathe or a Boxford T might be adequate for the OP's purposes. Air tight fits, or screwcutting would probably require a more sophisticated machine,

Many a good tune played on an old fiddle!

Howard

Thread: in a mount fitting the Leica and with thread M 39x1
16/09/2021 06:28:55

0.75 mm seemed to be the standard pitch for screw in filters.

Once I bought a wide angle lens with a damaged (dented ) filter thread. A fellow member of the photographic club,(an instructor inn the C A V Training School ) made up a partial male thread so that I could do some "panel beating" and restore the thread thread to be useable.

After all these years, I don't know what happened to the "repair" kit!

Howard

Thread: Hello forum
16/09/2021 06:11:02

If it is the 250-550 it looks to be a pretty good package.

Shall be interested to know how you get on.

Enjoy!

Howard,

Edited By Howard Lewis on 16/09/2021 06:11:37

Thread: Auto-Oiler replacement for Myford and other drip oilers.
15/09/2021 07:28:59

A nice project, well explained.

You should submit it to Neil as an article for MEW..

Howard

Thread: New Member, Hi From Northern Ireland.
15/09/2021 07:11:39

Hi Scott.

Welcome to the Forum.

Don't know the Harrison, but am sure that others on here will offer help and advice for your questions about the machine, and how to overcome any problems.

There will always be advice available for any problems with tooling and operating methods

(Beware of getting me on my hobby horses! ).

Howard

Thread: Hello forum
15/09/2021 07:06:17

Welcome to the Forum!

Chester Tools

I bought a Conquest Super, secondhand, but little used, to keep as a second lathe.

I don't use it much, but was not impressed by the service, or the pricing, from Chester, when inquiring about converting back from DRO to plain dials.

The machine has only had one problem, but it could have been quite serious. The locknut on the Mandrel Bearing preload came loose.

Ketan at Arc Euro was very helpful with advice on resetting b the bearing preload.

(The Conquest is made by Sieg, which are the machines that Arc Euro sell ) They carry a range of spares for the machines, should you ever need any, and some spares for earlier machines. I have bought a few extra changewheels for my SC3..

The conversion kit was out of stock, but they advised when when it arrived. And the price was half that quoted by Chester!

I have had far better relations with everyone at Arc Euro, over all my purchases.

And i am not a big spender, Never bought a machine from them, only bits and pieces. Usually things like the odd drill or stub arbors, sleeves etc.usually under £50, with only one purchase over £100.

As you may gather, they tend to be my supplier of choice, even if my orders are of low value. Goods usually arrive within a couple of days of being placed.

On the two occasions when I have visited (To exchange items where I have ordered incorrectly, I have been made welcome. )

I have made a few small accessories for the SC3, the most complicated being a Graduated Handwheel for the Leadscrew, based on the the Alistair Sinclair design.. Another was an extension for the mandrel, so that any swarf falls outside the gear cover..

HTH

Howard

Thread: electronic cylinder indication
14/09/2021 17:37:27

Good Work, Werner!

Very pleasing that your work enabled Jurgen's Garret to be so improved. Electronic sensors allow measurements to be taken and shown at higher engine speeds.

Your work is pioneering! And others will, also benefit from it.

I like the "Driver" on your Merryweather!

On high speed (2100 rpm ) diesels, in 1959, we measured cylinder pressures by balancing a floating diaphragm with Nitrogen from a gas cylinder until it balanced cylinder pressure, and there was no movement of the diaphragm.

On the flywheel was a Tufnol disc with magnets in slots (one the opposite way round to show tdc ) to give angular position, and speed, relative to a pick up coil)

Diaphragm movement changed capacitance and the frequency of a VHF amplifier, so that when the frequency became constant, we knew that the diaphragm was balanced and the pressure could be read off the gas cylinder. Slow by modern standards, but this was cutting edge technology at the time. (The amplifier was a valve one, 300V DC on the anodes! The Mullard OC71 transistor was new! )

Progress has made life easier!

Howard

Thread: Garador door closer
14/09/2021 16:27:32

Not an electronics man, but maybe, the capacitor is the cause of your problems, by leakage current causing the overload, and the heating?

Might be worth replacing it, for what it costs, possibly under a tenner.

Howard

Thread: SIEG Mini-Lathe DRCD to Manual Conversion Kit
14/09/2021 16:24:36

My second hand Chester Conquest Super came with DRO on Cross and Top Slides.

My only problem on a little used machine was that when it was needed, the batteries always seemed to be flat!

The screws retaining the battery covers are small (and so easily lost), and I had problems obtaining batteries..

A pity, since the DRO gave the choice between Metric and Imperial readout (On mine, the Leadscrews appear to be 20 tpi, if the DRO is to be believed, although the main Leadscrew is 1.5 mm pitch

Chester quoted £100+ to convert to analogue Metric, involving Dials, Leadscrews and Cross Slide..

Eventually, Arc supplied a kit for half that price. STILL not fitted, having obtained a supply of batteries..

Maybe conversion would be the ideal opportunity to modify the new Cross Slide to take a Rear Toolpost, (and to make one? )

The restriction is likely to be the Cross Slide hitting the Splash Back, but that is a bridge yet to crossed.

Howard

Thread: in a mount fitting the Leica and with thread M 39x1
14/09/2021 16:08:46

At the risk of adding confusion, 26 tpi has a pitch of 0.97623 mm, differing from 1 mm by 0.023. (23 microns ), or just less than 0.001"

Maybe if the 39 x 1 thread was produced slightly undersize, for the very short thread engagement involved, the difference in pitch and form MIGHT not be too noticeable, as long as the register distance was maintained .

But am surprised that, PRE WW2 Zeiss should produce 39 x 1 rather than physically checking a Leica thread.

Post WW2, one could possibly understand Jena following the lead (edict? ) of Russia in using 39 x 1 like the Fed, but prewar seems unusual.

Even more intriguing is that so many other makers of lenses and accessories (LDB, Corfield and Kopil to my knowledge ) did not check and accurately copy the Leica. Maybe, they all assumed that because the OD was 39 mm the pitch would be 1 mm, because it looked like it, without checking pitch or form?

Those who would have known are no longer with us to tell.

Howard

Edited By Howard Lewis on 14/09/2021 16:09:48

Thread: Extension to Digital Version
14/09/2021 15:42:10

So far, all my MEW subscriber copies have arrived, more or less on time, In UK. m No E mail was received.

Was the E mail perhaps, primarily intended for overseas subscribers, who may be more affected?

Howard

Thread: Workholding Problem
14/09/2021 15:20:19

The end result is probably more accurate and durable than the original!

When completed your son may have a potential race winner there!

Howard

Thread: Milling Slide for my CL250M
14/09/2021 15:00:31

Good that the V S and the lathe are being put to good use in pursuit of other hobbies.

Since the lathe was probably made by Sieg, Arc Euro may well be able to provide many of the bits that you need, as they sell Sieg machines..

Howard

Thread: Help identifying some tools
14/09/2021 14:52:53

If the worst comes to the worst, and you only have one weight, it can be used to calculate the diameter of the plunger.

Once that is known, it should be possible to calculate the weight for each increment of pressure, and then to make new ones..

Alternatively, the easier calculations may be; knowing the weight that gives a known pressure, others can be calculated by multiplying or dividing and making weights to match the required pressures.

Howard,

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