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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: What’s the tolerance??
04/07/2020 08:20:12

At one time, if the dimension was given as a fraction of an inch, it was assumed that the tolerance was 1/64

In high volume manufacturing industry, often an untoleranced dimension would be taken to be +/- o.005".

Almost always there was a note on the drawing template, stating this..

The parts made had to be interchangeable with others to the same drawing.

The manner in which dimensions were shown could cause problems. A series of holes dimensioned from centre to centre could result in a tolerance build up meaning that the distance between first and last holes could vary greatly, although all hole centres were within tolerance. Imagine ten holes all to +/- 0.005 centres,, for the studs to secure a sump to an engine block The first and last holes could differ by as much as 0.100" and yet be to drawing!

The better way was to dimension each hole from the same datum point, so that no tolerance build up could prevent a matching part from fitting.

Tolerances will be important if you are working on a Club project, where parts that you make have to fit to parts made by someone else, But where you are making the matching parts they are not important, as long as the bore does not break through when it should be blind or have a minimum wall thickness.

Howard

Thread: Warco WM280V-F Gearbox
03/07/2020 19:08:25

So soon, you will be up and running again, and better than when the machine left then factory.

Good work!

Howard

Thread: Colchester Chipmaster
03/07/2020 19:03:07

If the Saddle lock is 7/16" square, would not a 7/16" A/F spanner operate it?

Thread: Pulley removal help needed please!
03/07/2020 17:57:10

The pictures show that the Alpine is different from the RF 25, having more speeds, and a different nut (C spanner type as opposed to hexagon ) so not a clone of each other.

If the pulley is steel, you can be more confident in using a pulley,possibly aided by a tap if it fails mto come off with the puller alone. Very often, the shock breaks mth taper more readily than a steady pull.

Howard

03/07/2020 14:36:29

The thing to remember is that the nut retaining the pulley to the spindle is a Left Hand thread!

On the RF25 (Warco Economy ) the pulley is Aluminium, so some gentle heat ought to help removal.

Howard

Thread: How does one scale a worm gear?
01/07/2020 10:37:10

A really good effort! Well done

Howard

Thread: Thread identification
01/07/2020 10:34:55

For a long time, French cars, certainly Renaults, used a TACL screw head, a sort of enclosed diametral slot, with a small central female spigot. At least a narrowed thick conventional screwdriver would deal with those.

Then the continental motor industry started using Torx heads on cylinder head bolts..

To retain aftermarket exclusivity some manufacturers used really odd fixings. The governor shaft on the Bosch EPVE was retained by three sided fixings (Guess what was the only place you could buy a socket to fit? )

I came out of a meeting with a potential fastener supplier, having just said "Nothing special, we don't want five sided heads" to find a Japanese cartridge type injection pump with five sided heads!

Presumably all in the name of tamperproofing; or exclusivity?

Howard

Thread: TOOL BOXES
01/07/2020 10:23:27

The good quality and specialist Automotive tools are stored in Cromwell Tools (Kennedy ) Roller Cabinet, Step up box, and Top Box.

The less valuable spanners and tools live in a battered five tier cantilever tool box on the floor, near the lathe.

The toolbox that came with the lathe, containing spare changewheels, is by the lathe and also contains small sets of Allen keys.

Most of my measuring equipment is stored in a three +1 drawer Kennedy steel cabinet, (now almost too heavy to lift ) and the rest are kept in their boxes on a shelf.

Good kit is worth protecting from dust or damage.

Howard

Thread: Coronavirus, advice from ME
30/06/2020 19:10:14

If teaching while wearing a mask, it is going to be really difficult eating at a restaurant while wearing a mask!

The social distance bit is easy

Howard

Thread: Thread identification
30/06/2020 19:04:19

manufacturers make odd sizes / pitches as a means of holding onto the spares aftermarket.

Fords need a 7 mm Allen key for the brake callipers at one time.

European vehicle manufacturers seemed to like the "odd" A/F sizes for nuts, where Far Eastern seemed to prefer the "even" sizes.

A friend had the bearings fail on the roller of his lawnmower. Guess what, they were a special for that machine, and no longer available!

Four standard 12 x 28 x 8 2RS bearings, a length of silver steel, and opening up the 27 mm bore in the rollers, and bit of drilling and tapping, solved his problem at fairly minimal cost, preventing an otherwise useable machine from being scrapped.

Model engineers, the scourge of the unique aftermarket vendors!

Howard

 

Edited By Howard Lewis on 30/06/2020 19:04:45

Thread: Lollipop maybe?
30/06/2020 18:42:45

You could make a round bar with finely faced ends, using a known accurate Micrometer or Vernier to measure the length. Silver steel?

(My Shardlow Height gauge has just such a Calibration block in the box ).

A 1.5 inch diameter Ball Race / Roller Bearing would be a bit large to store in the box, as a standard?

Howard

Thread: West Yorkshire Police
30/06/2020 18:36:15

Nothing beats looking where you are going!

The first time that I drove M25 westbound, cars catching up with me were tail ending the ones in front!

Fortunately, the traffic cleared and I was able to move away before they came sideways and got me involved.

Maybe modern cars are so easy to drive that you no longer need to think what you are doing?

Howard

Thread: Hello from deepest Somerset
30/06/2020 18:28:48

Welcome!

Lots of folks on here with similar interests to you, so you are in good company.

If you can think of an interest or skill, there will someone (several) on here of like mind.

Howard

Thread: Hiyas
30/06/2020 18:25:25

Welcome!

LOTS of experience on here, on all manner of subjects. Just ask!

+1 for HSS tools. An easier way of learning how to set up tools.

With a lathe, you can make all sorts of accessories, some quite specific for the task that you wish to perform.

If you can find your local M.E Club, you will probably find fellow ,horologists there.

Howard

Thread: Exploding Grinding Wheel
30/06/2020 07:48:55

Industrial grinding wheels are particularly dangerous at start up. Whilst standing, the coolant tends to drain to the bottom throwing the wheel out of balance. Once up and running either the wheel has thrown off the coolant or become uniformly loaded.

But until then!

Am always a little wary of my 6" bench grindeer, but have never had any hairy moments, so far, Thank Heaven!

Howard

Thread: WM250 Sticky Carriage
29/06/2020 09:04:38

If it is a new machine, having oiled the bedways, and checked that the Saddle lock is free, I would talk to Warco, rather than do anything that would void the warranty.

If the pinion is off centre on its shaft, or the shaft is bent, that is for the supplier to correct, if only as an absolute minimum, by supplying a new shaft, for you to fit.

If it is like my older larger Chinese lathe, the pinion is integral, with teeth being cut into the shaft.

Howard .

Edited By Howard Lewis on 29/06/2020 09:05:22

Thread: Hi everyone
29/06/2020 08:57:37

Welcome!

Where are you located?

When things approach normal, do find and join your local M E Society, to meet others face to face, to compare notes

Howard.

Thread: ER32 frustration
29/06/2020 08:55:35

Occasionally, I have the same problem with a 3MT ER25 chuck, but not with an ER25 2 MT one, (from different suppliers, separated by several years ). So I assume that the problem, if there is one, results from the fit of the nut to the body, maybe the chamfer on the start of the thread in the body.

I just live with it, Can't afford to lose any more hair over such a thing!

Howard

Thread: Inherited Lathes and Milling Machines
28/06/2020 18:06:22

Hi Shaun,

Yes, you have a sad task.

But, as Peter says, accessories can be very valuable.

A complete set of changewheels will enhance the value of the lathe , so try to find them and keep them with the machine.

A Taper Turning Attachment, being fairly rare could be worth almost as much as the lathe.

Steadies may generate more as separate items that if sold with the machine.

A collet chuck and its collets can be a valuable item

Ditto for extra lathe chucks, especially if they have the internal and external jaws and the chuck key

Milling cutters may not add too much to the machine, but may be worth more as a separate lot..

Hope that this may be of some help

Howard

Thread: Motor reduction speed
28/06/2020 17:57:29

You are not really at the best starting point.

The most compact way of getting a 30:1 reduction would be a worm and wheel. But this would mean your motor sticking out at right angles to the machine. (Unless you fancy having two worm boxes, say 6:1 feeding a 5:1 to bring the drive lines back parallel again )

For 30:1 with belts you would need at least a two stage drive, again a 6:1 and then a 5:1. With a minimum pulley diameter of 1.5 inches,the driven pulleys are still going to be pretty large,, 7.5" and 9 " diameter.

Assuming that you are using a standard 12" hacksaw blade, a Z section belt would probably cope with such small pulleys.

Polyvee belts might be better, for small diameter driving pulleys..

With small driving pulleys, to increase the wrap around the pulley, you will need fairly long pulley centres.

A four pole motor with a nominal 1475 rpm would halve the ratios needed, allowing driving pulleys of 2" minimum, and smaller driven pulleys..

If the motor can be mounted under the machine, it could drive to the countershaft at the rear, to make things compact.

Howard

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