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Member postings for Ian P

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

Thread: VFD off the bay
26/11/2019 22:25:52

I must admit that I missed the word 'on' in the Robert's statement about buying from eBay, Amazon etc which changes the meaning of what he was saying. I had also not seen the link to the cheap VFD on eBay. As far as I am concerned I would never in my wildest moments buy anything from a seller with that sort of feedback (120 negative in one month! and that's only from the buyers that bother to complain).

Having the VFDs original control panel on the end of a cable is of very limited appeal as its nowhere near as ergonomic as having robust switches and knobs on a proper pendant (or on the machines own panels.

For anyone not conversant with electrics I endorse all the previous suggestions regarding buying from the companies specialising in VFDs.

Ian P

Thread: diy power on mill
26/11/2019 15:51:22

The most suitable power supply for that motor would be the same as it used when it was on the golf cart. The motor armature will be quite low resistance and the start up current very high. Low voltage heavy current PSUs are available but one to drive that motor would be quite expensive. Controlling the speed is best done by PWM but finding one (unless off a golf cart or mobility trolley) might also be expensive.

Ian P

Thread: VFD off the bay
26/11/2019 13:58:08
Posted by Robert Atkinson 2 on 26/11/2019 12:09:05:

I would not recommend buying ANY mains powered device from any far eastern supplier on ebay, amazon bangood etc. I would definitely not buy a VFD from one.

You can have little or no confidence that it meets applicable safety requirements (Low Voltage Directive EMC Directive etc) or that it even meets it's specification. Buy a branded unit from a UK (or possibly EU) supplier. If nothing else you will have some one to complain to. If they don't have a proper UK address don't bother.

Robert G8RPI

Not buying 'ANY' mains powered product from other than a UK or EU supplier is bit of a blanket statement. A far as I know eBay and Amazon are not far eastern companies although they do supply equipment manufactured in the far east.

I would not bother trying to buy something like a VFD direct from China or wherever, I would by a Chinese made one from an eBay seller, but only one that has UK stock. Actually its probably not easy to find many VFDs that are not made in China, which is where even all the big name brands get theirs made.

In the last 20 years or so I have used and fitted new and secondhand VFDs both cheap Chinese and expensive well known reputable brands. I cannot say that any have been unreliable, caused interference, or had problems of any sort. Documentation varies considerably but nowadays there is so much information and support online its not a problem.

Ian P

Thread: aluminium troubles
24/11/2019 14:41:30

and the grade of aluminium


Edit, Oops as its already been asked

Edited By Ian P on 24/11/2019 14:42:09

Thread: Rake angle on Cutting Tools.....memory tips???
22/11/2019 11:56:41
Posted by Neil Wyatt on 22/11/2019 11:09:58:

I don't think anyone has answered the original question, which was quite straight forward,


Maybe I am the only one but I found the original question far from straightforward so hard to understand.

Chris seems to be asking for an easy method of remembering the angles, maybe something like a mnemonic.

In one of my replies I did ask Chris to clarify but got now response, later though he did mention some of the replies were polite which I took to mean that mine wasn't.

Ian P

Ian P

21/11/2019 21:50:49
Posted by Mark P. on 21/11/2019 21:48:31:

I tend to grind all mine at about 10°, works for me.

Mark P.

Go on then Mark, is that positive or negative and is that for steel or brass?devil

Ian P

21/11/2019 21:49:40

Posted by Chris TickTock on 20/11/2019 21:36:56:

Has anyone come across some method to easily remember positive, neutral and negative rake angles. I have so far looked in vain.


My bafflement is not the facts about rake angles but more about your last reply where you mention polite polite input and then say some (people here presumably) do not understand rake angle being important.

Your original question was far from clear, initially I took it that you wanted to know how to improve your memory, then I wondered if you were trying to clarify the terminology of the tool geometry.

To answer your last question, yes, rake angle is important

Ian P

21/11/2019 20:59:57

I'm even more baffled now

Thread: DIY magnetic DRO
21/11/2019 15:48:10

I quite like the way Jed proposes to mount the tape and sensor as it really does protect the tape. There is no reason why the tape mounting bracket has to be a one piece component and I would bond the tape to a (say) square or rectangular beam and then have a length of unequal angle fixed to the top surface with the longest face coming down well below the sensor.

As I understood it, whilst the tape has a magnetic pattern in it, the amount of magnetic force is so low its unlikely any swarf or chips would stick to it, maybe ferrous dust might accumulate but with the protective stainless foil over, it would be easy to wipe off once every few years.

Ian P

Thread: Rake angle on Cutting Tools.....memory tips???
20/11/2019 23:02:55

Do you mean the actual numerical values, or the relationship of the angled faces with the workpiece?

This was meant as a straight question.

Ian P

Thread: The Workshop Progress Thread 2019
20/11/2019 21:39:37
Posted by Ian McVickers on 17/11/2019 17:14:44:

Finally managed to get back into the shop and get the dro install finished on the Omnimill. I went down the pc based dro route seeing as I had a small pc and spare touch screen lying around. I had planned on using rotary encoders and rack I have as well but that idea didn't work out so I went for scales.

Mill dro.jpg

The monitor is 21" wide screen so I don't have an excuse for miss-reading the dro now. So far it works well and I plan on fitting further scales on the vertical axis and quill.

Edited By JasonB on 17/11/2019 17:17:24

I assume there is a PC with box of tricks driving the monitor, I have looked on the Machine DRO website and cannot see anything that resembles the equipment in the picture. Please could you post a link.

Ian P

Thread: Cutting plastic on Sherline lathe
20/11/2019 21:34:21

It would help greatly if we knew what type of 'plastic' the material is. Since you are calling it 'tube' and have sort of confirmed its soft material (by positively acknowledging Howard's stiffening thoughts) then possible contenders for 6mm (OD or ID?) tube might be Nylon, PTFE, PFA, PVC or something harder like Polycarbonate.

I presume that whatever you are making needs to have a large length to diameter ratio and that the tube has to pass through the headstock spindle? I can think if no other reason for not using solid material and drilling a hole through.

Am I correct in assuming that you are wanting to make a large quantity of whatever the item? Why otherwise would you need to a number of tests to find the optimum cutter?

Obviously the replies, or some of them may have helped you but by providing more detail with your initial question the help offered will be much more focussed.

Ian P

Thread: New Pratt chuck without mounting holes
18/11/2019 13:09:10

I would have thought that the mounting details would be shown in the PB catalogue but what is wrong with the three mounting holes seen in your picture?

Whilst self centering this is a lever operated rather than a key operated chuck.

Ian P

The eBay pictures, not yours I mean

Edited By Ian P on 18/11/2019 13:10:12

Thread: Mitutoyo DRO Fault
17/11/2019 19:37:58
Posted by Brian H on 17/11/2019 19:04:15:

Ah well, all this swapping of plugs and amplifiers has resulted in the one that WAS working, now isn't!


That really clarifies things.

The 'one' what?

Ian P

Thread: My new lathe a Warco 918
17/11/2019 16:54:26
Posted by JasonB on 17/11/2019 16:42:45:

If it's anything like mine then the last digit jump in 0.0005" steps

Oh, that's disappointing then. I hoped it might have the full compliment of digits, not that I would have expected to have that much more accuracy, but it helps to interpret the readings better.

I know there are calipers available that display to 0.0001mm but they are not cheap. I bought a Starrett caliper in the 90's that had a miniature bargraph (with 9 segments) after the usual 0.00mm, unfortunately it was addicted to batteries and later became intermittent.

Ian P

17/11/2019 16:31:48

Ron, which model of Mitutoyo caliper is the one in your (third) picture?

It appears to have a display resolution of 1/10 of a thou

Ian P

Thread: Mitutoyo DRO Fault
16/11/2019 22:46:10

All the Mitutoyo resolution measurements are shown in the form of 0.0(and whatever) with the suffix um. (I dont know the ascii code for the micro symbol).

Is the suffix irrelevant, or should it just be 'm'?

I find it hard to believe that the resolution of some models is a 1000th of a micron

Ian P

Thread: How does someone gauge the power of a DC or AC motor?
16/11/2019 22:05:10
Posted by Chris TickTock on 16/11/2019 12:40:45:

Adapter now made not 100% happy with as blind hole face could be better but on whole acceptable and should do the jobadaptermk1.jpg

Thanks for all help and posts which are appreciated.


I would not be in the slightest concerned with the state of the face at the bottom of a blind holes, its not like anyone will ever see it and its serves no functional purpose whatsoever. As long as the shaft enters far enough its done its job.

One observation I would make is to say that ideally the grubscrew should make contact with the shaft about half way along their engagement length. It helps to increase the chance that the axis of the two parts are parallel with each other.

Out of interest, how did you ensure the concentricity of the bore relative to the threaded shank?

Ian P

Thread: Mitutoyo DRO Fault
16/11/2019 20:50:28

I am not familiar with Mitutoyo DROs but I understand now that one channel of your display unit is not working (it lights up but does not change readings with a good scale connected to it. If I understand you also said you can switch units on that channel but it just remains at zero. Most likely then the fault is (electrically) near the input connector and the counting and display part of the signal chain is OK.

From an electronic engineers point of view having a fault on one channel of a two channel system helps significantly in diagnosing the fault, It could be as simple as a dodgy connector pin, or that the voltage supply that powers the scale is not present. It might be worth measuring and comparing the voltage on the same pins of both connector. I would expect one pin on each connector to have 5 volts as that is commonly used for optical scales.

Ian P

16/11/2019 19:41:17

'Amplifier' is not a term that is normally used to denote part of a DRO system so interpreting your fault description is all the more confusing.

To clarify, There are two scales with their reader heads they are usually electronically identical to each other and only become X and Y when fastened to slides etc. The same applies to the readout/display unit which again usually has identical electronic channels but just labeled X and Y on the panel.

If you connect the lead from ONE scale and try it in both the display inputs do both displays work correctly?

Let us know and we can move on.

Ian P

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