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Member postings for Roger B

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

Thread: New member in Switzerland
04/05/2020 08:16:29

Welcome from near Zürich

Thread: New design of mains plug?
01/04/2020 14:24:05

You need to check that none of these are being used:

fuses.jpg

In my university days it was not unkown to replace the fuse with the barrel of a 1/4" jack plug (~160A) so you could run a lighting rack from a 13A outlet for a short period. We soon discovered that you got less overheating problems if you installed two neutral pins

01/04/2020 11:47:50

Robert, All modern safety standards have to allow for foreseeable abuse. It is very likely that a four way extension lead will be loaded above 13A so that must be tested for.

Bill, The various fuse values are virtually irrelevant. An appliance that meets European standards and is correctly CE marked will have been designed to be safe when protected by a 16A fuse/circuit breaker (as on the mainland) and so will have a minimum 0.75mm2 lead. There may still be a few old UK appliances around with smaller leads which should have a lower rated fuse.

The harmonised colour coding, Brown, Blue, Green/Yellow, was bought in to deal with a number of safety issues on the biggest being the German use of Red for the earth conductor as they thought it was the most important. As others have said the colours were chosen with colour blindness in mind, especially the bi-colour earth.

01/04/2020 07:38:52

Here is example of a melted 13A plug taken from this report by the Electrical Safety Council:

**LINK**

13a plug failure.jpg

31/03/2020 15:30:42

Lots of things being written on domestic power distribution, not all of which are accurate.

In the beginning properties were wired with a few sockets on radial circuits. Most countries developed their own plug and socket systems. The UK had the round pin 2A, 5A and 15A plugs in two and 3 pin versions. The Germanic countries and a few others had a 16A two round pins to which they later added the side earth connections (Schutzkontakt – hence the name Schuko). The French speaking lands went for two pins and later added an inverted earth pin. You can plug a French plug into a Schuko but you don’t have an earth. The Italians put the earth in the middle and have 10A and 16A versions. The Swiss have a 10A version with an offset earth. The Europeans tended to be a radial circuit per room feeding the lights and sockets. The UK tended to keep sockets and lighting different. In all these cases the fuse for the radial circuit protected the flexible cable against short circuits as long as it was above a specified minimum size. The appliance itself had to protect against overloads, either by making them unlikely or by having an internal fuse.

Then the UK decided to change the system and I will cynically say that this was to make the installation as cheap as possible for the builders and push the costs onto the occupants. Rather than a radial circuit per room (or group of small rooms) they decided on a power circuit and a lighting circuit, one of each in a small property and being duplicated as required in larger ones. To minimise the cost of cable the lighting circuits were 6A with 1mm2 cable and they came up with the ring final circuit for the power circuits. The 2.5mm2 cable with a reduced size uninsulated earth conductor with 30/32A protection was chosen together with fused plugs of a completely new design with rectangular rather than round pins. This left the occupants to buy large heavy 3 pin plugs with an inbuilt fuse to protect the flexible cable rather than a much smaller lighter often 2 pin plug as used elsewhere. The similarities between the mainland systems allowed the development of the 2 pin Europlug which can be used all over Europe except the UK and is ideal for small electronic devices.

The UK carries the legacy of a wiring system which might have been ok when perhaps a couple of electric fires, a vacuum cleaner, a hairdryer, a kettle and the telly were all that were plugged in. Now in the UK the plethora of small electronic devices require a plug larger than themselves and consumes far more materials than necessary. The UK 13A plug is also hazardous due to it’s design. The right angle design means it won’t easily come out if you trip on the wire rather than straight designs. It is heavy and has caused many injuries where people lifted appliances off the top of cupboard or high shelve and were hit by the following plug. Standing on the upturned pins is worse than standing on Lego bricks without shoes. A Europlug is much less unpleasant. Finally the connections to the fuse tend to overheat if the plug is run near it’s 13A rating which can result in the plug softening and the live pin remaining in the socket, still live, when the plug is removed.

Roger

Thread: Complicated post
06/03/2020 10:43:05

If you want to look at new European Wabeco are an option:

**LINK**

As are TECO:

**LINK**

I have the TECO milling head on my lathe and have had no problems with the round column. The guiding key and keyway appear to be very well made. I have read reports of problems with the control electronics on some Wabeco machines but have no details.

Thread: Hobbymat MD65 - help figuring out accessories (photos)
25/02/2020 19:50:34

Mod's please replace Hymem with Hymek ;-(

25/02/2020 19:49:32

I knew I had seen that report when you first posted but couldn't remember where. I was looking through some stuff related to carburetors and it was at the end of a downloaded ME article on a 120cc V8 built to power a 5" gauge model Hymem locomotive.

25/02/2020 09:32:39

Hereis a brief report on the Quick Change Tool Post from Model Engineer. £150 in 1991.

hobbymat qctp.jpg

Thread: VFD conversion for a Hobbymat MD65 lathe
14/02/2020 09:05:52

His wiring is somewhat strange but it appears that he wanted to retain the original controls. The reversing switch between the VFD and motor is also dubious. As the original reversing switch only affected the starting winding operating it while the lathe was running did nothing. Operating his reversing switch while the lathe is running will probably break something.

The VFD can also bring an advantage for screw cutting. The quick stop function can be connected to a limit switch to allow threading up to a shoulder. A similar conversion on a minilathe would stop in 1/3 of a revolution. As it is not a screw on chuck the stop speed is only limited by the motor torque of the drive belts slipping.

If you use the slow speed attachment for threading it takes a long time to stop due to the motor inertia.

13/02/2020 14:40:19

This chap has carried out a similar conversion:

**LINK**

He has used a 63 frame size 0.25kW 2800rpm motor.

If you have a VFD you shouldn't need the slow speed attachment. I have only used mine when screwcutting or turning a 125mm diameter CI flywheel.

If you can manage German there is some more stuff on here:

**LINK**

Thread: Too ambitious or achievable?
21/01/2020 07:29:33

This is the vertical slide setup I used on my minilathe. I think that the vertical slide was a Machine Mart one and I drilled and tapped the cross slide to fit it. The first picture is milling a cavity in an oil reservoir. The second one is the set up I used for milling camshafts. The depth for each cut is set using the DTI and the G cramp keeps everything a bit more rigid.

52 milling out the oil reservoir.jpg

70 slides locked for added rigidity.jpg

Thread: Hobbymat MD65 fixed steady
17/01/2020 20:12:26

Both the fixed steadies seem to be Cast Iron. I think that the Minilathe one could be modified but for my purposes a bore of less than 50mm would not work.

As you can tell by the discolouration I make quite a lot of use of the fixed steady very little of the travelling steady.

Thread: Lathes as bling!
17/01/2020 19:50:36

Unfortunately the same applies to music reproduction systems (gramophones). Some people listen to the music, others listen to the equipment. Both are valid hobbies.

Thread: Too ambitious or achievable?
17/01/2020 19:27:04

You probably have as much equipment as the designer had. Give it a go, there will be plenty of help available on here if you are not sure of some operations.

The possible issue with castings is that replacements can be expensive if you make a bad mistake. With a bar stock engine you just cut off another piece and start again. Most of the loss is just your time.

Thread: Hobbymat MD65 fixed steady
17/01/2020 18:10:06

I have found the box with the lathe accessories in so here are a couple of pictures of the Hobbymat fixed steady compared to a Minilathe fixed steady.

hobbymat and minilathe steadies 2.jpg

hobbymat and minilathe steadies 1.jpg

The Minilathe steady won't accept a 50mm bar whereas 60mm fits easily in the Hobbymat one.

Finally a picture of the Hobbymat fixed and travelling steadies. There are tapped holes in the carriage for the travelling steady.

hobbymat and minilathe steadies 3.jpg

15/01/2020 15:07:48

Teco were somewhat slow to respond but delivered what I expected to receive. I bought directly from Teco as it didn't make sense to ship the milling head to England and then back to Switzerland. They were also as expected cheaper.

The Teco head is ike the later Prazi ones with belt drive and MT2. The earlier ones had a geared drive and MT1.

Teco don't offer the option of a combined lathe and mill only the two separate machines so they don't have the adaptor block that bolts to the back of the lathe.

15/01/2020 14:17:04

The T slotted table is only fitted for milling. I the picture above it is just resting on the cross slide (the picture was taken to explain to Teco what I had and what parts of the milling head I needed to order).

Milling table in use

Thread: Hobbymat MD65 - help figuring out accessories (photos)
15/01/2020 13:21:37

As far as I can see my toolpost is identical. I works without any problems and allows easy adjustment of centre height. I tend to use it when boring or screw cutting with HSS tools. The tool holders are rigid when clamped but do not always go back in exactly the same place when removed (the larger more expensive versions are more reproducable).

The benefit of indexable tools is that by design the tool tip is the stated dimension above the bottom of the tool. If I put a 10mm tool holder in the standard toolpost it will be on centre. The tips are not cheap and when they get blunt or chipped you just throw them away. I have a selection of 6mm, 8mm and 10mm tools. The smaller ones are set to height with 2mm thick packing pieces. I started out with a Proxxon set

**LINK**

I have additional holders from Glanze (Chronos) and CTC.

The additional hole in the top slide is to allow the yellow vice to be fitted in milling mode.

15/01/2020 08:39:39

The quick change toolholder was comercial item. I also have one and find it useful for setting the tool to centre height for non indexable tip tools.

I have not had to dismantle mine so I can't help there. I don't have a tommy bar, I just use a convenient sized allen key.

Most of the time I use the original tool post with indexable tip tools so the certre height is automatically correct. I believe that the cutaway parts of the fixing bolts are to limit the forca that can be applied to the rather thin top slide.

I think that this key should fit your lathe chucks:

**LINK**

I guess you already know of RC.

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