Member postings for Graham Meek

Neil Hemingway called by my home one afternoon on his way home from GHT's. On the trailer was George's Senior Mill and a lot of other equipment from his workshop. I seem to recall SMEE showing one of GHT's lathe on one of their stands at Warwick. I assumed that it was donated to them, but I cannot say for sure.

Regards

Gray,

Chuck the Muddle Engineer described a Glow Plug horizontal engine in ME some time back. This used a single cam, but other than a scale drawing no build description was give,

Regards

Gray,

Some years back someone at the Midlands Exhibition had a Quorn or similar with such a variable Helix device set-up for grinding endmills.

Unfortunately I did not take any photographs of this but someone might have done.

From what I can remember it was a very simple and elegant design.

Regards

Gray,

Edited By Graham Meek on 22/01/2023 13:43:17

Hi Mike,

You generally have the Gist of what is going on with your summary.

However the Tempering process is a Refining Process in that it modifies the grain structure of the material. As hardened the structure is coarse and therefore Brittle. Tempering modifies the grain structure by making it finer. More grain boundaries improves the internal bond making it less brittle.

Quenching stops the grain refinement at that particular stage and this is denoted by the colour change.

Allowing the part to cool in air will not stop the grain growth at that particular point as effectively as quenching.

Like you I have nothing more than a Propane torch.

Regards

Gray,

Hi Mike,

With 40 years of Toolmaking under my belt and also a Home Machinist for much of that time.

If a carbon Steel item is hardened then it will need Tempering. This will depend on the application the tool or item is being used for. Leave it dead hard and there is a pretty good chance the item will shatter.

Silver Steel is usually Hardened and Tempered in Water or better still Brine. Gauge Plate or Ground Flat Stock as it is called today is an Oil Hardening Steel. Use water with this material and you run the risk of surface cracks.

Oil can be used for Silver Steel but the hardness will be down when compared to water.

There are many steels that do require Air Hardening and Tempering, but I doubt you will come across these in the home workshop as many of these are done in controlled environment furnaces. Some steels even require to be heat treated in a vacuum.

Regards

Gray,

PS Jason wrote while I was writing,

Edited By Graham Meek on 19/01/2023 11:16:47

The Mounting Board for the Proxxon mill has finally been fitted. The Switch and Knob are for the variable power feed. This now has a dedicated 12v Power Supply feeding a PWM unit. While I have more variation of the feed rate lower down with this set-up. It has been at the expense of a reduced top feed rate. However due to use of the Proxxon plug arrangement on the table feed motor. It is still possible to substitute the Proxxon power supply if needed, so I have the best of both worlds.

Talking to a friend recently I was saying I was making a milling machine vice stop for the Proxxon mill. My listener was not familiar with this term or set-up. These type of stops are used widely in industry and I have used countless hundreds in my career. Up until I had completed this unit I had been managing to do jobs with a stop mounted in the tee-slot off the milling table.

However the manufacture of the Table Protectors to help keep the table clear of swarf made using this type of stop a nuisance. Plus when using the vice as shown above there is no Tee slot to use such a stop.

This view shows the construction of the table protectors and the stowing position for the stop when this is not being used. The spigot positions are such that the protectors will also fit across the table when using the Emco Compact 5 rotary table.

The Acrylic is Yellowish and it is not the camera. This was some off-cuts I had left over from an assembly tool which used UV light and this particular Acrylic blocked the UV.

Regards

Gray,

For sometime I have been wanting to make some Insert toolholders for the C5. Now I have the Proxxon mill where I want it, I decided the time had come to make some.

Each Insert holder has been machine such that it is automatically on Centre Height. The main body of the toolholder completely fills the tool turret so no swarf can enter and become a problem when changing tools. A step in the underside of the tool registers on the edge of the tool turret. This means the tool can be removed and replaced with no loss of index position.

I am currently working/designing a Lever Operated Tailstock Clamping attachment. This attachment will not require any machining to be done to the existing tailstock body. Because of the similarities of the C5 with U3 & 4 this attachment will also fit the Unimat's. Of course it will need to be shortened in length but that will be all.

Regards

Gray

Edited By Graham Meek on 14/01/2023 17:00:24

Everything aircraft usually carries a number. Thin plain washers being an exception. It can be the part number, but more usually it is the production or batch number. Each item being recorded in the build log of the particular item. Be that a fuel system, undercarriage, propeller, etc.

Regards

Gray,

We hand delivered where possible and made arrangements with those farther away that we would send an increased donation to The Salvation Army. Given the economic climate it seemed the SA needs would be more sought after this year.

As regards receiving cards via Royal Mail that is a laugh. We received two piles of cards after Christmas, some we were told were posted on the 10th of December. I don't think there were that many days strikes in this period.

By contrast a package posted in Germany arrived 2 days later.

Regards

Gray,

That brings back memories. My first car, £15.00, it came with a burnt out exhaust valve. The chance of a brand new 100E engine still in the crate Ex-Fords UK for 10/- (50p) scrap weight was too good to miss. Using a 100E Gearbox casting and the gears out of the E93A box made this a good transplant. Plus the change to 12v electrics and electric wipers.

New rod brakes were made out of stainless steel, made following a breakage while going down a hill with a junction at the bottom. Luckily the handbrake was still connected to the unbroken linkage to the rear brakes. That plus the foot brake on the front wheels saved the day.

The chap I sold the car to eventually changed the 100E engine for a Ford Pilot V8 and the usual Jaguar back axle.

The simplicity of these engines is a far cry from today's engines, but even though I still prefer the comfort and reliability on my present car.

Regards

Gray,

Hello Dick,

I forgot to mention Proxxon have started using Loctite Thread Locking compound in more recent times.

Regards

Gray,

Hello Dick,

My apologies for not responding sooner. The Pulley unscrews once you have removed the M3 grubscrew. You will need a Peg spanner to go in the two holes in the pulley. I made mine from a short piece of aluminium bar and two short lengths of silver steel.

When replacing the pulley do not over tighten the grubscrew or the pulley will wobble. Also bear in mind that this pulley also adjusts bearing pre-load which does not want to be excessive. Just enough to eliminate any endwise play.

When I made the new ER 20 spindle for my Proxxon I altered this design. I introduced a separate circular nut. This nut adjusts the bearings while the Pulley locks the adjustment and the assembly. I hope in due course to publish details on this mod, as well as the spindle mod.

Regards

Gray,

To all my fellow Home machinists everywhere, Seasonal Greetings from the Forest of Dean.

Gray,

PS Your reply above came in while I was typing,

The Quill was always supplied as an assembly, if my memory serves me correctly.

Regards

Gray,

Hello Julius,

I regret to say I have to agree with Andy_G. Those bushes are Sintered BRONZE, Brass is softer than Bronze so making the bushes out of brass would be a retrograde step. Plus they would need to be constantly oiled to give anything of a service life.

You also run the risk of permanent damage to the spindle bearing surface. I don't consider this to be an option. You should always replace like with like.

I have just done a Google search for the above bearing and had several results. As you are having difficulty getting SKF you will need to settle for some other make. You have already considered a compromise with substituting the bushes with brass. I have seen these bushes listed at £1.86 on a well known auction site.

Also the glue would not be something I would be willing to try.

Regards

Gray,

Hello Julius,

Using the above link I found this bush that will do the job, PSMF 152015 A51. You will have to turn the flange down, but that is far easier than boring Sintered Bronze I can assure you. You will need to turn this off a mandrel, don't be tempted to hold it in the chuck. The mandrel does not have to be that good a fit, and the bush can be held with a suitably sized capscrew and washer in the end.

Regards

Gray,

Hello Julius,

Be sure you get Flanged bearings, 20 x 26 x 15 is the code you want.

The length is not a problem, any additional length will not be used due the reduced portion in the middle of the shaft. The extra length might act as a small oil reservoir which is no bad thing.

Regards

Gray,

Hello Julius,

The Quill housing bore is as I suspected down on the Nominal 20.00 mm bore size. This will tend to close in the bore of the Oilite bush and give you a closer running fit. I don't think you will get a very precise reading with a vernier on this bore size. I would anticipate the actual size to be in the region of 19.95 to 19.97 mm.

The Oilite Bush I would expect to be around 20.03 mm diameter before insertion. It is best to press these bushes in or use a large washer and some studding to draw them into position.

As supplied an Oilite bush is impregnated with oil, and just for good measure they should be soaked overnight in oil before insertion. They should go for many, many hours before the need to replenish this oil.

Grease will tend to clog the bearing and stop the release of the impregnated oil in the bearing. Plus grease in a cold workshop will provide a huge source of drag on the spindle with such a small motor. As I said earlier I would oil using an ISO 32. If you oil in the recess at the top of the quill and leave it to stand, the oil will find its way into the quill. Failing that if you really want to be sure, immerse the whole quill for 24 hours in a container filled up to the flange with oil. Then allow the excess to drain out afterwards before use.

I cannot see why you are going for 14 mm bore bushes. When 20 x 26 x 15 bushes are widely available, or was this a Typo error?

Regards

Gray,

Hello Julius,

I cannot say what age the heat treated spindle I have is. It is something that was given to me so the origins are unknown.

It is easily distinguishable by the dark, nearly black band where the Tommy Bar hole is. The other spindle which is in my 2/3 rds full size Quorn, is from the 1980's and is distinguished by a bright band where the Tommy bar hole is. The earlier black one is probably hard or toughened and this is why there is negligible wear. I say earlier as it would make sense to machine the part straight to size and reduce the cost of the part. By not having to heat treat and grind afterwards.

The softer one will off course wear quicker. This may have been off-set somewhat by using an already heat treated raw material.

The size of your spindle is about right, and I would say based on the Shaft Based system of measurement used on the Continent that you have about 0.009 mm of wear. (Based on the 14.98 mm figure)

The Oilite bush when inserted will probably give up to 0.05 mm total clearance on your shaft. It could well be better than this if Emco made the Quill Housing bearing register deliberately undersize to crush the Oilite bushes more than usual. I have known them to play about with bush bores in the past.

Without the parts at my disposal I cannot say any further than this. I would certainly replace the bushes with SKF sourced originals. The far eastern Oilite bushes I have purchased leave a lot to be desired.

Just remember to reduce wear you need have a film of oil for the shaft to rotate on. Get the clearance too small and there is no room for the film of oil and the parts will wear prematurely.

Some of the spindles are wasted in the central bearing portion so will not benefit from a full length bearing. A full length bearing also increases the amount of power required to drive the spindle before any work takes place.

Regards

Gray,

I have two Unimat 3 Milling Spindles. One has been heat treated from new and the other is soft. The former is an early version and despite its age shows no sign of run-out or wear. I would only recommend using a good quality ISO 32 machine oil to lubricate the Oilite bearings. Especially for those working in an outdoor workshop.

Regards

Gray,