Member postings for Howard Lewis

Apart from what has already been suggested.

In the Mill/Drill, I use one of the centering devices, (a 90 degree V, with a small pointer, pivoted on a spindle held in a drill chuck) followed by a Centre Driil.

Also, I have the redundant centre square from a scrap combination set, which has been drilled/reamed and carrying a hardened silver steel centre punch, which is used to dot the centre of the round bar.

If you are dubious about using a centre drill straight away on the round surface, after centering, mill a small flat, and then centre the work piece, as above.

If all else fails MEASURE, either using cigarette papers, held on with oil/grease on each side with a drill/end mill/slot drill ; or use a wobbler or edge finder, or zero a clock on the fixed vice jaw, and move the table half the diameter of the bar.

DON'T forget to take out/allow for, the backlash when noting the scale readings and to allow for the diameter of the cutter/wobbler/edgefinder probe!

Howard

Fake, or not, my experience of supposedly "genuine" Duracells is that they seep and crystallise at the base. Competitive make batteries don't; so Duracell lost my business. Sad

Howard.

Agree that some form of paint is needed to minimise dust problems.

But bare, even painted, concrete will be cold in the winter.

Don't look at the prices in Cromwell Tools, unless you have a strong heart and are sitting down!

Some time ago, Toys R Us were selling 1 Metre square perforated rubber mats, about 25mm thick (intended to catch toddlers coming down slides, presumably) fairly cheaply.

The mat could be cut in half to provide a two Metre strip of matting, 500 mm wide.

Standing on them will be warmer, and more comfortable for your feet.

(I have something similar in hard plastic - donated as nil value scrap from work), warm comfortable, and the swarf drops through, so they only need to be lifted for for cleaning underneath about every six months or so.

Also tends to restrict the movement of dropped 6 BA washers and the like, so making locating and retrieval a bit easier.

AND, you are far less likely to be accused of bringing "that dirty stuff (presumably swarf /oil etc) into the house"

Howard

Do you want hard copy, or just the function?

If just function, Scientific calculators provide logs and antilogs, and are available pretty cheaply now.

If I were a computer buff, I could probably tell you how to use Excel in a similar way!

Howard

A1 Steel are in Saville ROAD, Westwood, not far from the A47, on the western side of the city.

B & M Steel, (Barclay and Mattheison) are on the eastern side of the city, not far from Oxney Road.

Take your choice, Both are quite helpful, although I prefer B & M,despite being on the opposite side of town.

Since you seem to be in the Peterborough locality, have you thought of joining the Peterborough Society of Model Engineers? You would get a lot of help and advice if you need it. Look at their website!

Howard

Jonathon,

If you are in Cambridge, UK, you might like to contact Shoebridges in Stanground, Peterborough. They rewind and repair motors, and so could help, if only with advice. And they are about forty miles away.

They got me out of trouble, saving buying a new motor, when I thought that the motor on my Myford had gone west.

Howard

I am not a loco man, but my understanding is this.

1) A two cylinder engine, whether single or double acting has the cranks set at ninety degrees to ensure self starting.

2) Full scale locos, intended to run at speed had three, or possibly, more often, four cylinders, to improve the balancing. Weights added to provide primary balance, result in a secondary out of balance force, at right angles to the primary.

In a loco, this results in hammer blow, which increases the loads, and therefore, wear on the track.

This does not endear them to the civil engineers, who reduce the maximum allowed axle loads to compensate!

Reputedly, a type of loco built and used on (I think) the LBSC, had greatly reduced primary balance, to minimise hammerblow, but they gave the passengers in the front carriage a very rough ride, shaking them to and fro!

By using more cylinders, the balance weights become smaller and lighter, decreasing the secondary out of balance forces.

As a digression, the Brough Superior motorcycle (Known, with R-R agreement, as the Rolls Royce of Motorcycles) always used two cylinder ninety degree twins. With each cylinder subjected to primary balancing, the secondary out of balance matched the forces from the other cylinder.

Unfortunately, it is not really practicable to build locos with the cylinders, (as opposed to crankpins) disposed at ninety degrees to each other.

Ninety degree V4 and V8 engines are smooth, rotationally, and well balanced, vertically and horizontally, but tend to squirm because the various forces become distanced from those that they are supposed to counteract.

In the model world, hammerblow may be of less consequence, because, although the rails are smaller, lighter, and much less strong . ( Beam strength is related to the cube of the beam depth) The out of balance forces are related to the square of the speed, and the components involved are so much smaller (and since volume is effectively a square law effect) much lighter, so drastically reducing the forces.

The Romney Hythe and Dymchurch Railway, at one third scale, had two locos, designed by Henry Greenly, with three cylinders. But with the additional complication, and the difficulty of the boiler being able to feed three cylinders adequately, they were converted to two cylinders. To this day, they acquit themselves well.

Howard

On the subject of LED lamps, we got a couple of Chinese ones for our ES standard lamp. Brilliant, but after a while one began to flicker quite rapidly, soon after, so did the other. I suspect that the internal bridge rectifier partially failed so that the LEDS were only seeing half wave DC and so only lit on one half of the cycle.

The replacements, from LIDL, have been trouble free, so far. (as have the other Chinese /E bay ones on the machines in the shop. Maybe they don't run long enough to get really hot?)

Germany 1, China via E bay 0

As already said, ultimately "You get what you pay for"

Howard

Edited By Neil Wyatt on 26/09/2014 17:41:21

If it is possible, insulate the walls and ceiling, either with proper insulating board, or polystyrene sheet covered by hardboard, or better, plywood. It will retain whatever heat applied whilst the shop is occupied.

My shop was built without windows, and insulated with 50mm glass fibre behind 12mm ply, with 19mm wood outer cladding on the walls, 12mm ply each side of 50mm glassfibre under mineral felt (now a rubber roof membrane) for the ceiling.

Normally it is unheated, unless occupied. When frosty (in Eastern UK) a 60 watt tubular heater leaves metal benches not cold to the touch within 24 hours of switch on.

When working in there, a thermostatically controlled 2Kw fan heater is used. The shop is 3m x 2m and just over 2m floor to ceiling. The heater runs for less than 10 mins each hour.

Lighting is by one or two 65 watt ceiling mounted fluorescents, plus LED lights on the machines, so no great heat input there.

Ventilation, when needed, is by a weatherproofed 6" fan mounted high up with two or three fixed 50mm dia vents near to floor level. Obviously, it gets ventilated when the door is opened . Whenever possible, I try to work with the door open.

Rust is almost unknown.

My old uninsulated shop, with windows, often left the oil on the machines turning milky with condensation each morning, unless some heat was applied. Hence my love of insulation

60 watts will raise the temperature above the dew point in temperate climes. Colder climes, obviously will require greater heat input. Locating the heater (60watt bulb?) under the sheet or blanket covering the machine (tools need to be in drawers) will go along way to preventing rusty beds or tables.

Howard

It will be surprising if your fellow M.E.S.members are anything less than helpful with advice and even facilities, so do ask questions and chat with them.

Many superb models have been made on small lathes; the ingenuity used is amazing.

With regard to weight, don't forget the bench on which the lathe will sit. It needfs to be sturdy and rigid, which will mean weight. 50mm x 50mm framing will make a strong bench, but be heavy, especially once you have added a ply top (preferably 18mm) to it. You could well make the bench fill all the space available, as you will need room for other work, especially vice work.

This may sound like overkill, but a flimsy bench will lessen accuracy, and in the long run, could eventually twist the lathe bed slightly.

I would urge setting the lathe so that bed is free of twist. For this you either need to adopt the practice given in books like The Amateur's Workshop (Ian Bradley /The Amateur's Lathe (L.H.Sparey)/ Myford Series 7 Manual (Ian Bradley). One or all will be useful reference s for years to come, as will The Model Rngineerrs Handbook by Tubal Cain. And, No, I don't have shares in any of the publishers!

With regard to noise, you could try standing the bench legs on rubber pads, to reduce the risk of noise "telephoning" through to the rest of the house. (You don't want the ground floor complaining every time that you drill a hole!) 6 mm minimum would be my suggestion to try to isolate the lathe and bench from the floor.

But don't use rubber so soft, or so thick that the whole thing wobbles like a jelly on a plate.

On the subject of flooring and swarf removal, how about something along the lines of a cushionfloor material? You may be able to pick up a remnant fairly cheaply from a carpet/flooring shop. Sweeping swarf off it with a dustpan and brush will be easy as there is nothing for the swarf to hang onto, and oil or coolant can easily be wiped up. And there are no cracks/crevices where a dropped small nut/washer/drill or tap can hide.

It will make standing a little more comfortable and cleaning easier If possible make it bigger then the workshop floor area by about 50 or 60 mm all round, so that the excess curls up the walls to avoid corners where swarf can hide. It would be nice if the top edges could be attached, or sealed to the walls, so that the swarf can't get behind it, (It matches Houdini or Heineken for reaching places that you can't!)

You will already be aware of the need for measuring equipment. An inexpensive starting point is a digital calliper, (Lidl or Aldi have them as draw lines from time to time, for about £9. Assuming that you are UK based)

Don't forget the old faithful of a good 6" rule for rough measurements. (One of my Instructors warned me, as an Apprentice, that it was possible to correct to within a thou, but be an inch out - a good point! Another could use his and measure to within a few thou- EXPERIENCE!)

The next stop en route to bankruptcy, should be via a Dial Test Indicator (aka a "clock", ideally on a Magnetic Base, but a Scribing Block will be just as good, for a lot of work. A nice extra would be a "finger clock" (Verdict type) graduated in 0.005" (in old money) or 0.01mm for EU members.

You may well be able to acquire some or all of these, and Micrometers, secondhand, from fellow Club members, if a Club "junk sale" is ever held, or at one of the Model Engineering Exhibitions. Only caveat is if it looks battered, DON'T.

An inaccurate measuring device is a waste of time, money, and ultimately material. Once I bought a Vernier Calliper, new, from the local branch of major "high street" tooling supplier. After finding that the Inside and outside jaw readings differed by a couple of thou, it was returned, and exchanged for an accurate one. To my horror, "mine" was replaced in the display cabinet, with the comment "Well, it's only for hobby use"!!!!!!

Hope that all of this is of some help to you starting out on a most useful and absorbing hobby.

Howard

Yes, do be wary of making assumptions about fasteners. (It is easy to mistake 0BA for M6; same OD but the thread angles are different).

And as already said, manufacturers do mix threads. Remember some Morris cars used Hotchkiss engines, many years ago.

A little more recently, the Bristol RE bus used Gardner engines, with BSW and BSF threads. On manual transmission models, the clutch was bolted on to the flywheel, using 5/8 A.F head bolts with 5/16 BSF threads! AND the Bell Housing was retained by three 3/8 BSF studs and nine 3/8 UNF studs.

The Leyland Leopard, of the same vintage was to Unified standards, but used the Leyland 0600 and 0680 engines with BSF and BSW threads. The later ones could use the metric standard 500 Series engines.

So with fittings being read across from earlier versions, you can imagine the care that needed to be taken when in for repair.

The BMC A Series engine was to Unified standard, BUT the valve clearance adjusters were 1/8 BSP because of the fine thread.

And occasionally, you come across a fine thread variant of a thread form, such as UNEF (used on the Transfer Pump Rotor of the CAV DPA Injection Pump)

Someone once said that ASSUME makes an ASS out of U and ME.

Just look at the posts about the threads used on Myford 7 Series lathes, to realise the need to consider all possibilities.

Wherever possible try to check with thread gauges and a Micrometer or Calliper (Vernier or Digital), or a known thread, and even then be careful.

The Mandrel on my lathe puzzled me for a time, 8tpi Whit form, but no obvious Imperial or Metric size.  Eventually, seeing an ad for backplates with 2 1/4" Whit  x 8tpi thread, the penny dropped!

Howard.

Edited By Howard Lewis on 19/09/2014 14:59:46

If a woodruff key is no longer available, you can always make one, with minimal "hand crafting".

With a piece of round bar (silver steel?) of the correct diameter, part off to the correct width (thickness), and hacksaw/file a flat until the key is the correct depth.

(Alternatively, if you know what the correct depth is, make the flat before parting off.

Deburr, and voila!

At least, that's how my son in law's circular saw was repaired when he sheared the key on the spindle.

Howard

With regard to ventilation, damp air is heavier than dry. Since you are in a cellar, you will need a fan to extract the damp air, and a fixed vent of adequate cross sectional area, to allow fresh air to enter.

My suggestion would be to run a duct almost down to floor level, from the intake side of an extractor fan.

A bathroom ventilation fan, mounted at floor level, might be suitable as ducting will be available for the outlet side. Not too near the lathe to avoid the swarf that will fall onto it

(Possibly wire the fan to run when ever the lights are on?)

If the fresh air inlet is outside the building, do shield it to prevent ingress of rain or any other sort of weather.

Some fairly fine gauze across it may exclude flies/moths /beetles/spiders etc.

If you have damp, you WILL have problems with rust, on the lathe, other machines, and corrosion of raw materials and completed items.

Since you don't want to recirculate the damp air, the fan exit duct needs to kept away from the fresh air inlet.

Once the lathe is in position, you ought to set it level, to ensure that there is no twist in the bed, to avoid inadvertent taper turning!

You can either adopt the method advocated in the Myford 7 Series handbooks, or use a sensitive level across the bedways at headstock and tailstock ends. (You may need to use parallels or some form of consistent packing if you have a VEE bed).

You just keep reiterating the adjustments until any twist is eleiminated. My preference is for screw adjusters, rather than shimming the feet, to maximise accuracy. (My lathe sits on six 1/2 UNF setscrews and nuts, and the 20 tpi thread gives a fine adjustment).

I found when levelling my old Myford, that the torque applied to the mounting hardware would affect the level!

If you are planning to use pumped coolant, there is the additional complication of setting up so that there is a slight "run" towards the drain hole in the chip tray, whilst keeping the bed twist free.

Since you are imposing a heavy load on a few points of the flagstones, they may settle. So it will be worth rechecking the levels after a month or two, and from time to time afterwards.

Good luck!

Howard

Another source of data on O rings and the grooves for them should be Simrit, who manufacture O rings of all types and sizes. Have a look at their website to see where it leads you.

Howard

Reply to Bill Hancox re the rubber roof.

Wouldn't think that the rubber came from recycled tyres.

EPDM is a material often used for coolant hoses on engines, so would expect it to have a completely different composition. No need to have different Shore hardness, or coefficients of friction, just resistance to oils, glycol, high temperatures etc.

The roof on the garage and utility room has survived well for about twenty years, (in U.K.) so the workshop roof will definitely outlast me!

And it was surprisingly easy to put into place, although a second person to help with the unwieldy bits (Helping to hold the Trims, even on this small size roof) of the job is very useful.

Re comments about smell of plasticiser; NO problems like that with the previous EPDM roof.

Neighbours had glassfibre to replace felt, that did smell for a while, and someone got the levels wrong; so some big puddles!

Howard

Edited By Howard Lewis on 12/09/2014 12:06:24

And now for something completely different!

Replaced the mineral felt on the workshop roof with EPDM rubber.

The felt was the original, just on eleven years old and beginning to show signs of imminent failure

With a guaranteed life of 20 years, and an expected life of 50 (Just like the garage and utility room roof) I should never have to worry about keeping out the weather again!

My experience was of placing the order at 1545 on 2nd September 2014, and receiving the materials, and fitting kit at 0835 on 4th September 2014, so prompt service.

There were more than sufficient materials to apply the EPDM rubber and the trims, (even the nails) using the leaflet supplied as a follow up to the video on the website.

The work was quite straightforward, taking less than a day, (unhurried with a long lunchbreak) to apply the rubber and trims to a 3.2 x 2.2 metre roof; and the end result is quite pleasing.

Have never dealt with Rubber4Roofs, here in UK, but am pleased with the experience.

The time taker was removing the old felt and the bitumen holding it place. It took two of us with heat guns and scrapers nearly four hours to remove it. And half as long to clean up everything afterwards.

With hindsight, it would have been much quicker, having removed the felt, to remove the 12mm ply boards, invert , and screw them back into place. We would have aligned the edges better, and so not had to plane the edges to bring them level with the 50mm framing. Hope that I shall not need to remember that for a next time.

Experience is what enables you to recognise the mistake the next time that you make it!

If I could get a picture to paste, you would be able to see the result, although it is really pretty boring!

Howard

Just a comment re BUBBLE's oil pump gears.

Hopefully, the gears are not too tight a mesh.

Many years ago, at Rolls Royce, we found that some long, external ERW lub. oil pipes were "ringing" and and eventually splitting!

Instrumenting the oil pump delivery showed transient spikes of 600 psi, although the gauge was only indicating 60 psi. The problem was caused by the gears being such a close fit. The solution was to increase the tooth clearance very slightly, allowing a little leakage, which the pump could easily tolerate because of its over capacity.

At the same time, the pressure relief valve was changed from a poppet type to a plunger, using the plunger/bore clearance as a damping orifice.

Reference improving oil pressure by lapping the end cover flat, to reduce leakage.

The Skoda 100 Series engine gear type oil pump had shims between the baseplate and the body. Removing one of these shims, and sealing with Hylomar restored the oil pressure to within the quoted limits.

Howard

My experience of lighting in my workshop, (approx 3 m x 2m and 2 m to the sloping ceiling). The walls, not that you see much of them for shelves, and ceiling were painted gloss white eleven years ago.

On the ceiling, above the central narrow aisle are two 5 foot fluorescent tubes, the second is switched from the first when required.

The Mill/Drill has progressed from 2 x 60W filament worklights, positioned on each side, through CFLs to LEDs.

Above the vice is a similar worklight, with similar history, with a 3 or 9 watt LED.

These give a good white light , no detectable heat, and consume minimal current.

The lathe came witha 24V 50W Quartz halogen lamp which gave a warm light and plenty of heat, but the lamps failed often. After filing two diametrically opposed slots, about 8mm wide on the outer edge of the reflector, to improve ventilation, lamp life has increased dramatically. (just as well as the lamps are not obtainable locally in East Anglia!

About 600mm above the lathe, I recently installed a short mains fed LED strip (£9.99 from Aldi or Lidl - can't remember which) giving a bright white light which makes the Q H lamp look orange. It has certainly improved visibility on the lathe.

The ceiling mounted fluorescents are feeling their age, so I am interested to know what would be the best / cheapest form of replacement; LED tubes or LEDs strips.

Howard

To set the gears with about the right backlash, (None or negative WILL cause noise, and wear of gears and bearings) as you set the gears, roll a sheet of paper through the meshing point.

Ordinary writing paper is about 0.003" thick, and will give the right sort of backlash to work.

Excessive backlash will make the gear tooth contact points incorrect, and may result in extra noise.

Gears are usually designed to work with a small amount of backlash when located on the correct centre distance.

When the gears are loaded the backlash will be eliminated on the area of contact.

Howard

Edited By JasonB on 19/08/2014 15:35:47

The advice given to me was always to cut the tooth to full depth in one pass. Multiple passes risks errors in indexing the blank.

As Neil says, to reduce the risk of chipping or delamination, use a sacrificial blank (aluminium?) behind the workpiece.

If you are cutting gears in a laminated material, use the material so that the laminations of the gear teeth are not in shear.

i.e use sheet for the blank, rather than rod. This may seem obvious, but many years ago, a motor manufacturer did not, and a lot of Idler Gears lost their teeth, because of this.

Howard