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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: Md-30 Milling Machine Pulley Cover
24/05/2020 12:33:47

Jeremy,

I have created a public album in my profile "RF30 mill drill" with various pictures of the pulley guard arrangement from a number of angles, inside and out.

A worthwhile excercise, as I found that I had not been as effective at keeping the metal worm at bay as I thought - the top part of the column had some light surface rust, now cleaned off and oiled. An unheated garage does cause problems with condensation on machinery with temperature changes.

Not so happy to find that the supposedly flexible plastic column cutout cover had gone brittle with age & snapped at the hinge when I opened it. - always something ! Still usable, though, just doesn't hinge any more.

I'll put some dimensioned sketches in the same album when I get them done.

Nigel B.

Thread: Source for wiper felt
24/05/2020 10:41:04

When we neeed some at my last employment it was supplied by Brammer (BSL as was) in pieces about 6" square IIRC. May be worth trying other bearing suppliers if you don't have a Brammer branch nearby.

Nigel B.

Thread: Grease gun thread
22/05/2020 13:14:59

1/8" BSP is 28 tpi & 9.5mm OD - Google "BSP threads" for a choice of thread charts.

The odd grease gun I have had to change nozzles on have had 1/8" BSP threads.

Nigel B.

Thread: Md-30 Milling Machine Pulley Cover
22/05/2020 10:24:18

The Chester version was called the Eagle 30 see here.

It does not seem to be present on the Chester website now (though it was until fairly recently) - could just be that they are awaiting stock.

Chester's contact details are at the bottom of this page.

Nigel B.

(edits for spelling  - fingers getting ahead of brain ! )

Edited By mgnbuk on 22/05/2020 10:25:47

Edited By mgnbuk on 22/05/2020 10:25:57

Edited By mgnbuk on 22/05/2020 10:27:01

Thread: Stepper motor driver help
21/05/2020 19:52:13

The general suggestion when there is an option seems to be to use bipolar parallel operation for best overall performance. As the drive will handle the bipolar parallel current, why go for series operation ?

When I bought the motors & drives for my Triac from Arc Eurotrade many moons ago, I went for 3A drives as i could not run to the larger versions at the time. The motor data sheet showed similar current values to the Op's motor (4.2 bipolar / 2.1 series) but these are rated 2.2Nm. The motors did work after a fashion using these drives in series connection on a 24v supply, but performace was "pedestrian". Note that this was on the bench, not driving the machine,. The same motor in bipolar mode driven from a Stepper Online digital drive at 36V is night and day different under the same testing conditions. I have yet to try this drive a with the 48V supply I recently received.

Nigel B.

Thread: Md-30 Milling Machine Pulley Cover
21/05/2020 19:41:01

OK - should be able to get to do that over the weekend.

My machine is the earlier type with the belt cover comprising two steel pressings - all smooth edges & radii. I would guess that a one-off would be folded from sheet & welded / rivited - maybe not as "smooth" looking, but just as good for keeping your bits from getting entangled with the whirly bits !

Nigel B.

Thread: Stepper motor driver help
21/05/2020 19:35:39

Hi Brian,

The data sheet shows 4.2A phase current for that motor when parallel connected. The motor wires need to be connected in the "bipolar parallel" arrangement shown at the bottom of the data sheet.

The drive you mentioned shows a 4.2 amp setting for the current switches - set SW1 to ON, with SW2 & SW3 set to OFF to get this.

HTH

Nigel B.

Thread: Which Digital Compact Camera?
21/05/2020 19:26:37

Mrs B has used a Lumix LX3 for several years, to the point of having worn out some of the controls. Its performance was almost indistinguishable form my Pentax K20D + Sigma 17-70 lense, and in certain conditions (museums, for eaxmple) it produced better pictures with sone of the modes.

We had a look for a replacement & the current version of the LX3 - the LX15 - didn't seem as robust, with a fold-out rear screen. So she went for an LX100 instead. This is not as "automated" as the LX3, with fewer modes, but has a lwider range lense, an EVF & a much bigger sensor. While a bit bigger than the LX3, it is still compact enough for motorcycle use, carried in a Lowepro case on a belt for easy access.

If I can't be bothered to lug the DSLR about I have a Lumix DMC-XS1 - not a patch on the LX100 quality-wise, but compact and light enough to drop into a shirt pocket. And as the old adage has it, the best camera is the one you have with you to be able to take the shot & the XS1 works admirably in that regard.

Nigel B.

Thread: Stepper motor driver help
21/05/2020 19:10:36

I am driving a Nema 23 motor

Nema 23 is the frame size of the motor - to set up the drive you will need to know the electrical characteristics of your particular motor and in particular the phase current. This varies according to the motor output & windings & is independant of the frame size, though they seem typically to be between 3 and 4.5 amps for Nema 23 motors. Can you post a link to your specific motor ? It is the phase current of the motor that tells you what the switches on the drive need to be set to. If you set the current to less than the rated value the motor will not develope it's rated torque - set it too high and you risk overheating the motor.

The full/half current setting is for the standstill current - when the drive has not received step pulses for a while, this setting detremines if the current is maintained at the full value while the motor is stationary, or reduces the current by half. This can reduce heat build up in the motor at standstill, but does so at the expense of holding torque which reduces with the current reduction. This may be important if the axis could be moved out of position with a lower standstill torque.

Nigel B.

Thread: Md-30 Milling Machine Pulley Cover
21/05/2020 10:53:04

Warco, Chester, Axminster all do versions of the "30" size mill/drill (frequently called RF30, as I understand the originator of the type was a Taiwanese company Rong Fu), so would be worth contacting for spares.

I would try Chester first, as I have visited their Broughton site on open days & they seemed to have a lot of parts stored from machines that arrived damaged & retained for parts.

I have a Taiwan built RF30 branded "Trutool" - happy to supply pictures & dimensioned sketches of the sheet metal belt guards if you decide to go the DIY route.

Nigel B.

Thread: Milling spindle motor
19/05/2020 09:31:17

In addition to the PSU you would need a stepper motor controller to generate the step pulses.

The drive description shows that speed control can be either by an internal potentiometer, 0-5V signal or PWM input, so a stepper motor drive pulse generator would not be required ?

There appear to be other power outputs available - the same seller has 330W motor/drive packages for around £10 more. Obviously would require a larger power supply as well.

Nigel B.

Thread: 3D CAD software - what do you use?
18/05/2020 15:39:13

I'm another FreeCad user.

I can't use Fusion 360 without buying a new PC & FreeCad has a 32 bit version that is running fine on my 32 bit Win 7 machine. A series of useful YouTube tutorials "Learn FreeCad" by Invent Box Tutorials helped me a lot on the steep learning curve :

A warning! Learning a new 3D CAD package when you already know another, including 2D CAD, or have preconceived ideas about how it should work can be agonisingly difficult. Unlearning is really hard work and it may be essential!

is very true ! But I have been able to design simple parts that have 3D printed fine after a couple of days of trying & re-trying and it is making more sense now - being furloughed before Easter gave me the time to play around with it.

Nigel B.

Thread: 3 phase cable for a VFD
18/05/2020 08:11:30

What does the manual for your particular drive recommend ?

Generic "advice" about connecting just one end of the screen, or not using the screen as a PE is not always helpful or correct where inverter drives are concerned - the ABB ACS 150 drive that is today's job at work is quite specific about the cable requirements for the motor and how to connect it. Both ends of the motor cable screen are to be connected & the screen can be used as PE if the total CSA of the screen is equal or greater than the conductor CSA, otherwise use an extra core or a separate external earth cable of appropriate size.

When all else fails - RTFM !

Nigel B.

Thread: Readly and MTM
17/05/2020 13:19:58

I have been subscribing to Readly (digital magazine reading platform) for a couple of years now - a large & varied selection of magazines (with a couple of years of back issues) available to download to my tablet to read off line. No option to print them off as far as I can see, but I use it along the lines of "The WH Smith Reading Room" to catch up with quite a few magazines that I used to subsribe to & would probably not buy but like to browse.

The number of available publications is constantly increasing & I noticed yesterday the "Engineering in Miniature" has now appeared on the list (didn't realise that EIM was now a Warner's publication). What are the chances that My Time Media witth get involved to bring their magazines to a wider audience ? MTM already have a presence on Magzter Gold - a similar service at similar cost - but many of the publishers who appear on Magzter also appear on Readly, so the platforms do not appear to be mutually exclusive.

Maybe something that Neil could raise with MTM ? I'm not sure of the commercial arangements, but understand that the pubilsher gets some payment for the magazines when they are downloaded / read + more exposure for the advertisers.

Nigel B.

Thread: G code sender for grbl
12/05/2020 14:32:59

Grblgru

I have installed this & had it communicating with the latest Grbl version (v1.1) on an Arduino, though have not yet tried driving a machine with it (machine still not ready).

Also had Universal G Code Sender doing the same UGS website

Nigel B.

Thread: Oil
12/05/2020 10:41:54

Hydraulic oil is intended to be pumped around a lot like water but without the corrosion effect of plain water - hence thin, the clue is in the name.

Hydraulic oil is so much more than that, plus it comes in a range of viscosities like most oils - my supplier at work lists ISO viscosities from 5 to 220 !

Hydraulic oil also has to maintain it's viscosity through a range of operating tempetaures, includes anti-frothing additives, corrosion inhibiters & extreme pressure additives to lubricate pumps, motors & actuators which often operate at extreme pressures. As well as being used in hydraulic systems it is also regularly specified as a gearbox lubricant in machine tools (typically 32 or 46 viscosity) and sometimes for slideway lubrication.

If you wanted to splash out on just one bottle of "special" oil for a hobby sized machine, a bottle of ISO 46 hydraulic oil would do a pretty good job for all applications.

Nigel B.

Thread: Help 11NR14NPT insert
11/05/2020 20:28:16

Both 14 NTPF and 14 NTP are listed - use the Pitch/TPI tab at the top of the list to show all the available options.

Part number of the 11 IR 14 NPT is 021-50346

Nigel B.

11/05/2020 20:14:42

Cutwel appear to do these - see here.

In stock at £18.84 each inc. Vat + delivery.

Nigel B.

Thread: Crime rate
10/05/2020 17:03:07

so no speed camera fines

Mobile speed cameras still operating in North Yorkshire & there are reports indicating that the number of prosecutions for speeding offences has increased despite lower traffic levels. This confirms what I have seen since returning to work after my "furlough" was lifted after Easter - far less traffic on the M63/M1/A1M, but a lot of that is travelling regularly at elevated speeds. Stopping for red traffic lights also appears to have become optional. Can't say I have seen a marked change in Traffic Police activity - there was very little before the lockdown & there is very little during it.

Domestic violence offences also reported to have increased.

Nigel B.

Thread: Stepper Motor Flexible Coupling.
10/05/2020 16:37:07

Apologies to you or anyone who has different coupler use/preference, if you feel that I am giving that impression.

No apology required on my part, Ketan. There are frequently many routes to the same end & our experiences tend to guide us - mine are just different to yours. Both of the coupling solutions we highlighted between us will do a better job for the OP than the spiral cut type initially requested IMO - but doubtless someone else's experience will say that type is best !

It would have been nice if my Triac had been a hardly used ex-school machine, but in that case it would doubtless have cost me more than the £100 I paid for the carcass of my industrial version - yet another alternative route !

Nigel B.

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