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Member postings for Alistair Robertson 1

Here is a list of all the postings Alistair Robertson 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: What to use for New Worktop?
21/03/2020 18:30:16

A few years ago I got cut-offs of Corian which were perfect for the tops of my benches made from 30mm thick beech boards about 125mm wide. I got them from a local supplier who cut them out of bigger sheets as part of some contract they had which left about 250mm all around with the 1.5 meter x 2 meter dimensions.

I got the off-cuts for about 10% of the price of a virgin bit of material but I was probably in the right place at the right time and the Corian has been my bench surface for about 15 years and is still in very good condition.

Thread: Cheap drill bit sets
09/03/2020 20:37:08

I see John has bought a couple of sets of Cleveland drills, probably made in Brazil and for the money perfectly adequate but Cleveland Drills etc, used to be made in Peterhead, Scotland, 15 miles from me. I still have some smaller sized drills but the biggest I now have is 1 1/32".

I had some up to 2" although hardly ever used and about 10 years ago I put out the word that I was clearing my stores. Well within the week I had four engineers from the oil industry looking over my stock and every drill (about 125) I was selling was gone and at about 6 to 10 times the price I had bought them for! I bought a new car and took the good lady on a holiday to Jersey on the proceeds! One drill went for more than £500 and the guy said that they were the only drills that would work on some of the exotics the were using for their products.

Sadly production ceased in the late 1980's. A lot of financial shenanigans that went on was the principal cause.

Thread: Powder coating
03/03/2020 10:10:17

A company that I worked for about 20 years ago manufactured aluminium cylinder heads etc. for a very well known engine maker. After they were made and tested they were finished with powder coating but it was not a simple process with at least four processes (or maybe more as I wasn't really involved) where they were blasted, dipped, painted, heat-treated and then the whole process was gone through time and again.

They were powder coated as a final process and I remember one of the managers saying that the painting/coating process was more expensive than the machining!

I was never in a position to afford one of these engines but a couple of years ago I came across one of them in the storage area of a motorsport company and when we blew of the accumulated dust the powder coating was as good as the day it left our factory.

So it seems it is not a case of simply applying some powder coating and hoping for the best. Proper preparation is absolutely critical.

Thread: Best Milling Machine Ever????
24/02/2020 14:29:23

Best mill I ever used was a Huron, Like a DSG lathe it was designed by people who understood how a good machine tool was operated. Everything falls to hand and with controls on both sides of the table. We bought it for £4500 used it for 10 years and sold it for £12500 for CNC conversion. I have been in contact with the buyer of the converted machine and it is still in use in a very fancy research company!

A former employer still has a couple of Schaublin 53s which were bought in 1972 with every available extra and accessory. Good machines but not as user friendly as a Huron.

We also had a Swabishi with double inclinable and rotatable powered tables which could be used to produce the most incredible shaped sections and components, though not easy to setup and use and I have never seen or even heard of another one.

Thread: Trolleys at Lidl/Aldi
20/02/2020 19:36:32

Hi, All.

We often seem to be discussing the latest bargain tool at Lidl and Aldi and I must admit that sometimes the goods on offer are not easy to leave on the shelf, although my wife thinks they should be chained down to prevent them jumping in to our trolley!

Ah, Trolleys! A few months ago all the trolleys at our local Lidl were replaced with new although most of the old trolleys had never been used and as we are in a coastal town about 90% of them were totally rusted. I am told that a lot of them had to be lifted out as the wheels were seized!

I counted the new trolleys and found 104. Assuming that it was calculated at 1 person per trolley and a quick check on the size of a trolley and person against the free space in the aisles meant that about 95% of the available floor space would be occupied! I think that is probably how they worked out how many trolleys they should order when they build or re-equip a store.

If they thought about it they could probably just buy 25% of the trolleys and save a bit of money and sell their tools even cheaper although that might not go down too well with the ladies!

Thread: VFD drives
10/02/2020 10:45:56

To use a VFD it is necessary to fit a 3 phase motor to allow the speed to be varied,

A single phase motor cannot be varied in speed, well it can, but it is difficult, unreliable and expensive!

I fitted a 3 phase 240 volt motor and a Siemens VFD to a Warco drill and it really transformed the machine.

Varies from about 75rpm to 1500rpm and so smooth it is difficult to believe it is the same machine that I got from Warco. I am sure there is a market for supplying drills with this sort of specification as an option.

Thread: Metric V Imperial Measurement
08/02/2020 19:35:56

When discussing pipe threads it is good to remember that most of the world uses variations of BSP even though they call them something different. For instance 2" BSP is variously called in.

France = Gas conique.

Czech Republic = G Kon.

Belgium = G conique.

Switzerland = Gc.

Norway = Gj.

Denmark = Krg.

Plus about 20 countries who use the G designation but specify them in metric dimensions!

I have a copy of the "Robertson Guide To World Threads" which is a superb source of the obscure threads but even it is stumped sometimes!

Thread: renew driving licence
07/02/2020 11:50:09

Many years ago, probably in the late 50's my aunt sent away for a provisional license after filling in the form she got at the local Post Office. About a week later she received in the post a license enabling her to drive "All Groups" including a Steam Roller and lorry of any size!

She returned the license with a covering note that she was applying for a provisional license but the license came back with a note that said as she had "All Groups" there was no other test she could take therefore a provisional license could not be issued!!

After many letters backwards and forwards she eventually had to take the train to Aberdeen to explain her situation at the government offices where she was told to just accept she had a full license as the paperwork to correct the error did not exist.

The irony is she never did take up driving so the license was never used.

Thread: Stepper motor and driver supplier recomendations
22/01/2020 17:28:36

Hi, Andrew.

I bought the CW8060 60 volt drivers and the 60 volt power supply from CNC4You.uk.

The Ethernet Smooth Stepper I got from from Amadeal.

The Break-out Board I got from Machdrives in Australia. This is a very good board with a very stable 0 - 10 volt output to control a Siemens Micromaster 6SE Variable Frequency Drive which drives the original GEC 3 phase motor. The spindle pulses come from the original Orac and if the Mach3 settings are correct it is excellent.

I have cut a 30mm diameter x 5mm pitch (not 6mm as I said before) trapezoidal thread at 200 rpm and though it is scary to look at everything worked fine for the 150mm long shaft.

20/01/2020 11:17:54

Hi,

I have a Denford Orac which I converted to Mach 3 using the existing steppers but used a couple of generic type drivers. I found they were powerful enough to do anything that could be mounted in the lathe. I fitted a Smoothstepper Board and found that the Orac runs a lot smoother since then. I control the spindle with a Seimens VFD and I find that the programmed speed is correct within a couple of revs, in fact as good as the spindle on the Haas TL1 at work! I used the original index pulse and I can thread beautifully and have thread from 1/8" BSP to 30 mm x 6 trapazoidal successfully. I also have a Denford Novamill converted to Mach3 and the original steppers and drives have never run out of power or accuracy but she settings in Mach3 must be spot-on.

Thread: Carbide insert holders
16/01/2020 17:50:07

Suitable holders are available from Arc Eurotrade **LINK**

Not too costly and very good quality as well.

Thread: Great experience buying a dehumidifier
09/01/2020 17:00:33

I too have an Ecoair dehumidifier and I am very impressed with the machine and the excellent service.

About 10 months after I got mine it stopped shutting off when the tank was full. I worked out that the level switch was faulty and contacted Ecoair, they arranged to get a courier to pick it up next day, it was back in four days with a new switch and float and an emailed apology for the problem about 5 minutes after the delivery.

A great working machine and excellent service.

P.S. The Ecoair has a clothes drying mode and my good lady loves it if the weather is inclement. ( She hangs the clothes in the garage/workshop which means I am banned from working in there for the duration!)

Thread: Abracs Quick-lock abrasive tool
30/12/2019 20:10:00

Hi, All.

The colour was a wee bit lighter than Makita Industrial Green with almost a blue tinge to it.

The tool had a speed scale on the variable speed knob with 5000, 10000, 15000, 20000 and 25000 markings and from the noise generated I am sure that these speeds were close. There was a power supply/transformer on the floor, not very big about 100 x 150 x 65mm so it could have been DC voltage, The head looked as if it could swivel from in-line with the axis to 90 degrees like a 41/2" grinder. It must have been a bevel gear but the diameter of the housing was no bigger than about 30mm. The system may not have been Quick-lock but very similar. (I have some Quick-lock stuff so that is what came to my mind!)

When the festivities are past I will try and contact the press company and see if they can help but I don't think the contractor was employed by them directly.

29/12/2019 18:10:17

Hi,

A few weeks ago we had a guy who was re-sealing a press that is used to crush small rocks for research.

i was not really involved but I was intrigued that the guy had a tool like an angle grinder (but a bit smaller) that used Abracs Quick-Lock discs about 50mm in diameter to polish up various surfaces before proceeding with the re-seal.

The tool was a really nice bit of kit that had variable speed up to 25000 rpm. and the head could be adjusted from 0 degrees to 90 degrees. There was no makers name that I could see and the guy was not very communicative but he said he thought it was Australian.

Can anyone cast some light on what this tool is and where it could be bought, I can find nothing on-line.

Thread: Warco WM18 lead screws upgrade
27/12/2019 16:00:35

A few years ago a friend of mine acquired a scrapped Bridgeport CNC mill. He was busy removing the ball-screws to fit his manual machine to eliminate the back-lash.

I said I didn't think it was a good idea as there would be no self locking of the table. He didn't believe me and could see no problem.

A few weeks later I visited him and lo and lo and behold he is removing the ball-screws and re-instating the original acme screws. He sheepishly agreed that I was right and later confessed he had been machining a cylinder head for a customer when the cutter grabbed and with nothing to prevent the table moving under the cutter power the head was destroyed. He had to buy a new head for the customer at more than £1000!

Lesson learned the hard way!

Thread: Keyway Broaching
16/12/2019 09:49:40

A push broach will work fine but care is really needed. When we had long bore to keyway we usually made up a sacrificial bush (of the same material!) then drill a hole of the right size through the assembly. This removed most of the material leaving the broach to square things up.

The length of the broach will be the problem and need an extension so what we did was grind the top end of the broach to a diameter then machine the extension piece to fit on to it. This meant everything was in line and we didn't have to juggle and hold bits with a hand under the press ram!

I once broached a steam engine pulley that was about 9 inches long with a 1/2" keyway through an 2 1/8" bore with no problems.

Thread: Long bed lathes affected by the tide
05/12/2019 17:42:00

A factory where I worked had an internal rail siding (Long gone when I was there) it was only about 100 yards from the beach and built on basically sand.

During the war, parts were made for aviation engines and some machines could only be used when the loaded wagons were either in or out of the works as the whole building sunk with the weight. I never heard them mention the tide but in a heavy storm the dust used to come off the rafters so that could have been a factor as well!

Thread: Cast iron welding electrodes
29/10/2019 12:07:21

Back when I was doing repairs off all types we often got broken castings to repair.

we always discussed the job with the client to make sure that welding was the best (or only!) option.

If a weld repair was all that could be done then we would usually use a high nickel content rod as it was easier to machine after the welding. What we always did is use a welder with a high voltage which made it easier to strike and maintain an arc. A really old Murex/BOC welder was the favorite tool with up to 120 volt AC or DC. Probably illegal now!

A modern inverter welder works really well when set at a high frequency and with the proper rods.

If you do it right it will be as good as the original casting.

Thread: High Paint Costs
15/10/2019 15:44:12

I work as a volunteer at a local railway museum where we recently repainted a wagon used for transporting prisoners. The wood primer was £130 for 5 ltrs. The undercoat was £155 per 5 ltrs. and the top coat was £178 for 5 liters. This was bought from a specialist paint supplier and was of quite outstanding quality and those were "Trade" prices as we are a charity. The "retail" price was 30% higher!

I suppose you get what you pay for.

I remember many years ago we made a system to dip wooden windows in some sort of preservative. We were supplied with the paint which came in two, one gallon tins, one completely full and one half full.

The instructions said that no more than 60 minutes before use we had to pour the full tin into the half full can and quickly stir with an old wooden spoon or stick. This didn't look right but with everyone standing around to see what was going to happen, the foreman started and to gasps of surprise the full tin poured in to the other can without any spillage. So it was given a stir and with all hands on deck the painting was completed in about 45 minutes. 30 minutes later the small amount of paint left in the tin was solid like plastic, hence the reason for the strict time instructions.

I have never seen anything like that stuff since but the dipping plant is still in the workshop where it was installed although no longer used, The dipping agent is probably banned from use nowadays!

Thread: Help and advice on a drill bit for hardened steel
14/10/2019 12:25:25

I don't know what your broken stud is screwed in to, aluminium,steel or cast iron.

Personally I wouldn't attempt to drill a hardened steel stud unless it was with a drill press or mill and with the component clamped in place.

A far better way is to build up a pillar of weld on the exposed end of the stud using a mig welder, then when the pillar is high enough to then weld a suitable nut on top of the whole lot. The heat of the weld is almost always enough to free off the stud and is a simple twist-out job. Use an aluminium bush to prevent the weld and spatter sticking to the surrounding metal.

I have never failed to extract a broken stud in this manner in forty years since I got a mig welder!

We had one welder who was so good he could build up a pillar on a 3mm stud and successfully get the offending stud out.

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