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Member postings for mgnbuk

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

Thread: Coronavirus
09/04/2020 15:32:37

Was able to replensish dog & cat food, loo roll and milk as well as some fresh food, although their stocks of fresh fruit and veg are very sparse.

I did a shop at the local (West Yorks - not far from Morrisons head office) Morrisons for the MIL last week - fresh fruit and veg, meat & fish and in-store bakery bread products were plentiful, but no loo roll or flour. Can't find any type of flour locally.

Nigel B.

09/04/2020 14:55:34

I agree that our country appeared to be woefully unprepared for a pandemic and I hope those who neglected preparations are taken to task and learn from this situation.

Any preparation (i.e. stockpiling of PPE, purchase of testing & intensive care equipment etc.) would have had to have taken place well before the current situation started in Wuhan. It appears that most (if not all) of the required consumables are not made here, and when the problems started either the items could not be obtained (China - due to lockdown) or would not be supplied (certain European counties - due to export bans).

Preparations and/or an ability to be able to cope in future would seem to me to start with an ability to produce the items we need (or may need) here, without having to rely on others to provide them to us. Perhaps this situation will cause a re-think about "globalisation" - it does not appear to be serving us well at the moment.

Maybe such investment - in stockpiled items or increased medical & testing capability - should be considered part of the Defense budget, as it is obvious that not all threats towards the Country are of a Military nature.

Nigel B.

Thread: Essential and non-essential workers lockdown rules
09/04/2020 14:00:02

My current "furlough" has been ended - I am to return to work on the 15th April.

The letter from the company informing me of my requirement to return will be carried while travelling to & from work, to be shown to anyone who feels they have a right to know.

Nigel B.

Thread: Coronavirus
09/04/2020 12:00:19

So what part of YOU CANNOT TRAVEL does Myrtle Lloyd, the HMPO chief operating office not understand.?

Travel has very little to do with it.

Many Government processing organisations are being re-deployed to do Universal Credit application processing, so just because they are being told to go in to work does not mean that the work they are to be doing is their "normal" work. UC applications are up considerably (I saw up 850% mentioned last week) - DWP staff on their own can't be expected to process these applications as quickly as is needed, so other Government departments whose normal roles are not required (or have a much reduced workload) at present are being seconded to help out.

There is a bigger picture.

Nigel B.

Thread: Which Lathe???
06/04/2020 19:10:31

What's the make that used a big screwed collar onto a short tapered register, with a C-spanner?

L00 ? Used on the Boxford VSL & some Harrisons (the 140 at my last employment had this type, but may have been the bigger L01).

Nigel B.

06/04/2020 16:58:14

Broken teeth are a common problem on Myfords.

Super 7s have a spindle lock that enages at the rear of the spindle pulley to avoid this ? Seems to be more of an issue on earlier Boxfords that didn't have a spindle lock.

A "half way house" solution that offers the security of bolt-on,and almost as easy a change as a cam-lock (but without the expense) is the keyhole plate type - slacken the clamping nuts, then rotate the keyhole plate to release the chuck.

Nigel B

Edited By mgnbuk on 06/04/2020 16:58:40

06/04/2020 11:11:26

I took out my headstock shaft, if that's what it is called

The correct term is "spindle". The threaded section that you wish to try in a backplate is the "spindle nose".

It is not, as some insist on calling it, a "mandrel". A mandrel is a form of workholding device that is mounted on the spindle, in a chuck or between centres.

Nigel B.

06/04/2020 10:01:12

Slightly modified description :

Model A:- Screwcutting with quickchange g/box., power cross feed & long. feed. Back geared headstock.

Model B:- Screwcutting with changewheels, power cross-feed & long. feed. Back geared headstock.

Model C;- Screwcutting with changewheels. Back geared headstock.

Model T : Plain lathe - no screwcutting facility, no back gear. May only have been available as underdrive (TUD)

Unlike the Models A & B, the Model C does not have the power longitudinal feed provided by the bed rack & pinion. The leadscrew on the A & B has a longitudinal groove that drives the power feed apron, with the thread on the leadscrew just being used for screwcutting. The C does not have the groove & just has half nuts - longitudinal feeds use the leadscrew thread. which causes more leadscrew wear & could (in theory) cause screwcutting errors.

TUDs seem an inexpensive way to buy an unworn bed to refurbish a more capable machine.

I have always considered Home & Workshop Machinery pricing to be "optimistic".

Nigel B.

Thread: How can I use this motor economically?
05/04/2020 10:57:58

Unlikely to have hall sensors

I would have expected that as well, but reference to the manual does show Hall A,B & C outputs in the encoder connector at the motor, as well as the usuall A. /A, B, /B. I, /I of an incremental encoder, 5V & ground (two connections for each) and a thermal switch. There is also a asingle output called "ABS" which is described as being an absolute encoder - though how that is achieved through a single pin I don't know.

Strangely the Hall signals do not appear to be used by the BRU amplifier, as they do not appear on the amplifier encoder input port pinout. The copy of the manual I found is here

"Universal" drives are available - one that springs to mind is the Control Techniques Unidrive, which can be connected to pretty well any type of AC motor, with or without feedback. CT also used to do a Vector drive that used a standard squirrel cage 3 phase motor with an encoder fitted & an independant axial blower. I used one of these many years ago as a spindle drive on a Cincinatti NC drilling machine retrofit, but can't recall anything specific about it. I seem to recall that Siemens Simodrive 611 use the same output modules to drive synchronous or asynchronous motors, but they may use different interface cards to suit the type of motor - I try to avoid anything Siemens unless I absolutely have to & have not had to specify or commision one of these systems from scratch.

Nigel B.

Thread: Boxford Lathe résurrection
04/04/2020 14:45:11

It's likely to be a Universal Motor intended for use with a speed controller.

Not necessarily Dave. Early washing machines (single tub & maybe twin tub) used normal capacitor start motors. I have such a Hoover motor runnng my 6x4 bandsaw, which was bought motorless.

Nigel B

Thread: How can I use this motor economically?
04/04/2020 12:47:29

Looks like there is a repair service in the UK here

I (or, more accurately, my employer ) typically pay around £600 + Vat to repair Fanuc AC servo drives of similar vintage & I would expect it would be a similar amount to repair your unit.

Looking at a BRU series drive manual available online, it says that the setup parameters are stored in non volatile Ram or Eprom & makes no mention of a backup battery. The manual gives full motor specs & the motors seem to use a standard 5V encoder for feedback, so it may be possible to find a modern drive that will work with the motor - Kinco drives from Zapp Automation use encoders for feedback, so if your motor specs are similar to Kincos that might be an option though not cheap either (£550ish + Vat upwards ) - industrial stuff generally isn't hobbyist wallet friendly !

From the date on the manual I found, your Electro Craft kit is around 25 years old, so maybe time to retire it ? Might be cheaper overall to stick the motors on Ebay & put any proceeds towards buying a replacement 3 phase motor & VFD for a simple linisher application.

Nigel B.

Thread: Box-Ford travelling steady
31/03/2020 13:35:08

although the company was Boxford, the lathes were marketed as Box-Ford

It was just Boxford when I started working there September(ish) 1980. The logo was the same bold blue font as the current version. Standard lathe colours at the time were the two tone beige/brown & I have a suspicion that the threads may have been all metric at that time, but can't find anything to back that up.

Nigel B.

Thread: Mill drill Y axis power feed
31/03/2020 11:10:00

Yes Lainchy, same company (as you have just posted, you found that !).

Link to the Align company power feed website (with videos) below.

Align power feed

Nigel B.

31/03/2020 10:34:57

The OP asked about a power feed for the Y axis & both replies show solutions for the X axis ?

As well as the RF30 specific unit shown on Martin's picture, Align also make units to suit the X, Y & knee axes of Bridgeport type knee mills

apf-00025.jpg

The picture is of a Y axis unit (according to the MSC Industrial catalogue entry). Not an inexpensive option at £500 inc Vat from them though.

Chester have Y axis units on sale at the moment at £277 (but maybe + Vat)

All that said, it may be that the OP has his Xs & Ys crossed & is looking for an X axis (table left-right) feed unit. like this one.

Note that these units are 110V & require a fairly hefty transformer to operate.

Nigel B.

Thread: Minilathe/Mill motors
29/03/2020 19:31:34

this is an SCR controlled bridge. These are old technology now. The switching rate is limited to 2 x the line frequency (100 or 120Hz often causing audible noise) and as (most) SCRs can't be turned off they stay on until the next zero crossing of the mains supply. They have been made obsolete in most applications by the development of high voltage and current power transistors.

By no means obsolete - still standard technology for industrial DC drives. Currently available from Sprint Electric, Parker, Control Techniques, Baumueller & others.

Nigel B.

Thread: Myford super 7 Drive
28/03/2020 10:58:11

Toothed timing belts run the risk of a cogging effect resulting in finish issues on your parts

Modern timing belts run smoothly. If that were not the case, many (if not most) of the worlds CNC machines would have surface finish issues from the axis drives, as timing belts are the most popular way of connecting servo motors to ballscrews.

A bigger issue with high speed timing belt drives is noise, generated by air getting trapped between the belt teeth & the pulley grooves. This is more of an issue with wider belts & one recommendation is to use multiple narrow belts on a wide pulley to allow the air to escape more easily. One of my former colleagues used a wide timing belt on a milling machine spindle drive. The motor was around 15Kw, so the belt was quite wide & large pitch. The noise was horrendous - like being stood next to an air raid siren & ear defenders were a must while operating it. The customer was not happy but, fortunately, the drive had been designed around standard Taper lock pulleys & replacing the timing belt solution with 3 groove B section vee belts transmitted the required power in near silence.

I have not had good experiences with Poly vee drives. Higher power than model engineer size machines admittedly, & only chosen due to the theoretical ability to transmit the required power at short centre distances, but the belts wore out in short order. Moulded cog raw edge wedge belts would be my choice here.

Could be fun trying to unscrew a Super 7 chuck after putting a 1.1Kw load though it.

Nigel B.

Edited By mgnbuk on 28/03/2020 10:58:42

Thread: Lathe Milling Machine BLDC control board
25/03/2020 19:09:53

There is a Youtube video by Blondihacks covering sorting a failed system similar to that (Precision Mathews mill - maybe be Weiss ?) here.The encapsulated drive board with plug in connectors looked very similar.

She ended up having to change the motor . Her symptoms were a flash & a bang & it stopped IIRC.

Nigel B.

Thread: Coronavirus
25/03/2020 16:06:31

The goverment have said they are extending MOT certs by 6 months from the 30th March therefore MOT's will be valid

But only for MoTs which expire after the 30th March - guidance for expiries between now an the 30th here

Nigel B

25/03/2020 11:57:09

6 month MoT extension

For Mots that expire after 30th March

Nigel B.

(currently "furloughed" )

edit to remove unwarranted "smiley"

Edited By mgnbuk on 25/03/2020 11:58:01

Thread: vfd question
23/03/2020 20:14:34

That is clearly a "component" meant to be incoroporated into a final "product" by a competent entity that ensures it's safeand compliant. Most VFDs fall in the same category it's just not so obvious from looking at them that you need to put them in a box with an isolator, fuse, filter etc.

Which is the point I was labouring to try & make, Robert.

In some ways, the type of terminal cover NDIY prefers seems to me to be less safe overall, as it leads untrained users to make the wrong decisions about mounting these (at best) IP20 components - screwing them to walls behind the machine being the all too regular dubious choice. More visible terminals might make some reconsider this approach, though I accept that some might just go ahead anyway regardless of the consequences.

Nigel B.

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