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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: 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.

Thread: Is this chuck mounted on a 5C collet?
11/10/2019 16:13:52

When I was working we had a few Hardinge lathes with 5c built in to the spindle.

We could fit 3, 4 and 6 jaw chucks but it meant removing the draw tube etc. every time.

We bought a chuck like that and it was very popular with the guys, in fact we had to buy one for each machine to keep everybody happy!

The quality was very good for the price.

Thread: Murad Antarctic
09/10/2019 10:32:14

Just for interest I see that there is a Murad lathe for sale in the October edition of "Classic Tractor" magazine on page 146.

Not sure of the type but does look as if it is is on an original stand. It is single phase and apparently has lots of accessories. There can't be many of these around and at £560 it could be an interesting bargain!

Thread: Universal Joint Alignment
03/10/2019 10:49:58

A few years ago a friend who was helping a group with a tractor pulling sledge who could not get the traveling weight box to run smoothly asked for my help. I spotted that the universals on the driveshaft were not aligned and asked them to slide it out and realign on the splines. Problem solved!

I know that was the problem as a member of the group did not believe that was the problem and pulled the shaft off and put it back the way it was and "hey how" the problem came back!

Even a few degrees of input and output shaft misalignment can cause bothers and aligning the universals correctly can halve the included angle.

Thread: What the he**
24/09/2019 09:31:06

A couple of years ago our next door neighbors car, which he parks in the space outside my front window was sitting peacefully when there was the most almighty bang, the car took a lurch and a cloud of dust appeared from under the car, then almost immediately the car took a second lurch and dropped about another couple of inches!

The spring had broken after sitting without moving for a couple of days then the force of the car dropping had broken the remainder of the spring. Quite spectacular to witness and I wish I had had a security camera set up at the time. I might have made £250 from a TV show!

The car had to be transported to the local garage to get the remains of the coil spring removed.

Thread: 0.300" & 0.400" 28TPI Tap
28/08/2019 12:46:32

Threads! Don't get me started!

When I was working at a research establishment we had equipment from all over the world and the headaches of connecting bits together was unbelievable.

We had a Robertson Guide to Screw Threads book and although it covered everything from 3, an Israeli copy of BSP. to Zs a Hungarian thread of 40mm x 6 tpi.? we still got some connections and fittings that defied logic.

I still have a copy of "The Robertson Guide to World Screw Thread Series Symbols" produced by W. H. A. Robertson and Co. Ltd. Lynton Works. Bedford. England. who made dies and chasers.

A truly wonderful publication with some REALLY strange threads, such as.

Artillerie (French)

British Standard Insulator (Cordeaux)

Sewing Machine 100 (German)

Round 30 degree. (Switzerland)

Bearing Form B (German "Klammergewinde" truly amazing and I don't know how you could make it!

or how about American Aero Thread or Dardelet.

Humans really know how to complicate things.

Thread: My digital calipersseems to give varying readings
15/08/2019 12:41:08

I bought a couple of digital verniers from Aldi a couple of years ago. One works perfectly but the other gains 0.200" when I move it in and out, Eventually it goes up to a reading of 9.999" if I persevere.

I took it back to the store but they were sold out and the manager was not prepared to send them back as she said they were working as they should!! I contacted Aldi at the number on the paperwork but they weren't helpful at all and said I had to return them to the store. I tried again but with no luck at getting them to understand the problem and they said they were a special buy and they wouldn't be getting any more. At this point I gave up and as they only cost about £8 it really wasn't worth he hassle. They are still somewhere in my workshop.

Thread: Looking for a locking stay for machine canopy.
13/08/2019 09:36:23

Hi, All.

Thanks for all the valuable information. I have bought a pair of the type suggested by Brian G from RS. Why I didn't look there before i don't know. I ordered some bits and pieces from them last week!

I didn't want to use a gas strut as when they have to be compressed to "go overcentre" they put a big strain on the perspex cover which weighs about 25 Kgs. as I well know when I knocked out the plastic tube I was holding it up with and had to visit the hospital for a neck X-Ray. It was sore for more than a week.

The pair I bought a few years ago were not the same as the Camloc I have bought from RS they were more like a drawer slide that locked when extended.

12/08/2019 19:25:01

I have a Denford Novamill and to gain a bit more room in the workshop I altered the central pivoting of the Perspex "bubble" top cover to a rear hinge. This allowed me to place the machine against the wall saving about 200mm space.

I was going to fit a couple of struts that lock when they are extended then release when you push them up again to allow the guard to lower. I measured up the length I would need and went to my local hardware store to be met with stony silence when I explained what I was after. I had fitted the same sort of strut to a previous machine for a customer a few years ago. "You can't get anything like that" I was told, But I had bought them previously so I went home and looked up my old paperwork as to where I had bought them. I had bought them from a different shop so a few days later I went to town and strode confidently in to the counter to be told "Never seen anything like that!" I showed them my old invoice which said "Self Locking Strut" but no part number and they also said "Never seen them!!"

I have looked on the Internet but I am not sure what the correct description should be! They are like a drawer slide but with no balls (I think) and when they fully extend a bit of metal pops out of a square hole locking the strut in place. Push the strut further up and it releases.

Can anyone give me a correct description as I can't remember what I asked for about 10 years ago!

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