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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: 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

Thread: How does someone gauge the power of a DC or AC motor?
16/11/2019 16:48:43


Is there some danger to life or limb that warrants an all capital beware warning?devil

I doubt it myself, and dont see the connection with where an imperfect surface (less than a quarter of a micron) causes loss of oil pressure. I think there was more wrong with the design of the 'broach grinder' than the plummer blocks.

Ian P

Thread: Mechanical Edge Finder, should it be lubricated?
14/11/2019 20:20:48

I bought one of the Arc Eurotrade edge finders a couple of years ago and apart from a quick test when it first arrived I have never really used it. Today I experimented again but am not convinced it is any more repeatable than my goto method (short length of 4mm precision ground rod and observing light between it and the edge).

I then started to think about what the physics/principles of its operation were. I know the basic idea but how much does friction between the job and the (moving surface) compared with friction between the two faces of the finder affect its operation?

Other factors that might come into play are, the outer diameter of the two abutting faces and the diameter of the operating tip (on this Arc one there is a 4mm tip which is about 40mm lower than the split diameter bit). There is sticky grease between the moving faces but I dont know if that is meant to be removed or not.

Edge Finders

I know lots of people use these without problems (presumably) so maybe I am missing something.

Ian P

Thread: Metric micrometer what t buy?
14/11/2019 16:24:43

Putting a DRO on a mill is a transformation which I would rate higher than fitting a VFD, neither of which I would not be without now. however I have enough difficulty using a digital caliper on the mill (on the occasions something on the job needs measuring) and for the work I do I cannot think of any places or opportunities where a micrometer would either be better suited to taking a measurement off a mounted work in progress.

Access for a conventional mic or a caliper is very restricted unless the head is raised or the work traversed away from the cutter.

Ian P

Thread: Record 25 vice handle
14/11/2019 14:03:41

Ndiy, there is more than one model I think and the larger one is about £5k

Ian P

14/11/2019 13:14:12

This is one vice you wouldn't want to bend the handle on, maybe it a vice that you wouldnt even dare to uselaugh

Bugatti Vice


Ian P

PS in the region of £5K!!!

Edited By Ian P on 14/11/2019 13:15:15

Thread: Metric micrometer what t buy?
14/11/2019 11:40:59


What or which is the Baty instrument you are referring to?

Ian P

Thread: Boring bar with inserts shape choice??
14/11/2019 10:52:44


With respect, and going back to your post asking whether this should be a RH or LH thread I think it was a pointless thing to ask. The direction of the thread is determined solely by what it has to screw into. Since you have or will have the chuck no one on this forum can answer the question.

A Jason said a chuck, collet or whatever is not going to help making the wheel run true and both will extend the distance from the bearings to the working surface so unless interchangeability is essential it would be best to mount the wheel on the shortest simplest adapter you can make.

As regards threaded drill chucks, they are not generally precision devices unless you pay a lot of money, 99% will have female RH threads but to the mount to make them run true the thread has have a spigot of the correct diameter and a dead square face for the chuck to tighten against.

Lastly, your last paragraph you say that the answer would be obvious to 'some', Are you not one of those?

Ian P

13/11/2019 12:41:29

John are you saying that slot drills are wider at the end than near the shank (so slightly tapered)?

That would make my suggestion to slightly angle the cutter superfluous but I had always assumed that end and slot mills were parallel.

Ian P

13/11/2019 11:21:30

Boring bars are not really separately defined into blind and through hole types, mostly the same tool can be used for any type of hole unless there is some special requirement.

There is no right (or text book) way to bore a hole, my suggestion would be to get some hands on experience and see what works for you.

Ian P

12/11/2019 21:25:40
Posted by Chris TickTock on 12/11/2019 15:31:08:


I will in all probability have to machine up a spindle adapter for a DC motor. The spindle is 10mm (yet to arrive). Having never done any boring I have some advice from Jason in as much drill a pilot hole say 8mm and mild steel will be OK..


As (far from old and far from being a duffer) SOD remarked that ChrisTT was good at asking questions that inspire long answers, or something to that effect. It made me re-read the original question and I think the most significant thing is that Chris says he has never done any boring. I would suggest that this adapter he is planning to make should not be his first attempt. He could learn a lot just by getting some bits of offcuts and have a play, experiment and practice just to get a feel. I dont think one can chose which boring bar, type of tool, or many other of the factors involves without first getting some experience.

I'm sure a lot of Chris's questions would answer themselves, or at least be better focussed once he has spent more time cutting metal.

If I were making the said adapter, my first thoughts would be how to keep the external (wheel fitting) section truly concentric with a bore on the opposite end. Machining the bore to the correct diameter is only one small part of the job but to make the part, the whole machining sequence needs to be thought through in advance. (not that I always practice what I preach!)

Ian P

Thread: EN3 bowing after machining
12/11/2019 21:02:51

If you have not drilled the holes through it then getting it straight (enough) whilst it in a long length should not be too difficult. Worst case you could re-machine the two faces that sit under the slot ears.

Ian P

Thread: Boring bar with inserts shape choice??
12/11/2019 16:36:40

+1 for John Haine's suggestion. TBH if the slot drill (or end mill) is mounted close to centre height it can be used to open the pilot hole (say 5mm for a 6mm cutter) to a tad over 6mm. The tool can then be used to finish bore the hole from a size only slightly more than the cutter diameter to a size many times more diameter.

Whilst a milling cutter will never be a rigid as a boring bar, for light cuts it will produce quite deep holes especially long series type. Bear in mind that the cutting end of an end mill will not produce a dead flat bottom face, also the end mill needs to be very slightly askew relative to the lathe axis so that there is clearance for the flutes relative to the corner that does the cutting.

Ian P

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