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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: Suitable metal / enclosure for project
11/11/2019 13:30:19

Was that the link you meant to send Michael?

The product description and the video is all about grinding. Lapping as far as I know is a different process. True both use abrasives but my original point was not to be a pedant but to avoid misleading forum readers.

Ian P

11/11/2019 12:24:40

This might sound like silly question but on a forum such as this the level of knowledge and skill of the members varies over a very wide range. One of the many benefits of even just reading the various posts is how much information gets picked up that then becomes part of one's knowledge. Like most things on the internet there is also a lot of misinformation and it is one tiny bit of this that prompted me to write this.

Why are the grinding wheels that ChrisTT is going to use now being called 'Laps'?

Ian P

Thread: How does someone gauge the power of a DC or AC motor?
09/11/2019 15:14:59

I left it too late to edit but I wanted to add that one should not take the sellers description too seriously.

The motor you showed purports to have a 'governor', which I assume refers to the speed potentiometer and I doubt there is much in the way of actual speed regulation.

The ER16 spindle Bill linked to is described as 'High precision', that too is in the eye of the beholder. No details of what bearings are used and whether it is capable of accepting axial loads.

Ian P

09/11/2019 14:59:38

For a motor, mount, power supply, speed control pot, 13 ER collets and an adapter to hold them in I am sure its very good value. (they seem to be less then £50), however....

Whether its will do the job you want it to do is another matter. I would not expect any great accuracy from the collets and even less from the collet holder clamped to the motor shaft with grub screw. For the size of diamond wheels you showed earlier an ER11 collet adapter would not be an idea way of mounting them, the total overhang from the front motor bearings is far more than ideal.

You now mention that you want to use the diamond wheels for lapping, that is quite different from using them for grinding, what is your intended use of these wheels and with what materials?

Ian P

Thread: Source of Stainless Strip
06/11/2019 17:11:40

I've not heard of SS being specified as Half-Hard but from the description I presume you are looking for springiness as a characteristic feature.

Nowhere near the size you mention but I have a more than ample supply of 'flat' SS spring wire. It is 2.5mm wide and 0.7mm thick with rounded edges, I have lost the Certificate of Conformity that gave its metalurgical content but you are welcome to have some if you could use it, it might mean changing your design but several strips could be fixed side by side etc.

Ian P

Thread: Cutter Advice for silver steel Micro machining
03/11/2019 21:58:56
Posted by roy entwistle on 03/11/2019 21:13:40:

These have been made by watchmakers using hand held gravers for more years than I care to think about. Many driven by a bow.


Very true.

However mass produced watches had turned parts with just as fine, if not even finer, than could be made by hand, with not a graver in sight.

If the OP is wanting to make more than a few of these balance staffs then as good as Sherline is I cannot help feeling that there may be a high reject rate. The hand graver method has a lot going for it.

Ian P

Thread: Polishing Acetal/Delrin and other plastics
01/11/2019 20:50:15

Acetal is quite a low friction slippery material a bit like PTFE, filing or abrading with even the finest wet and dry just leave a matt, white-ish surface. I'm not sure what temperature it melts at but I have never heard of it being flame polished.

Most, maybe its all, commercially manufactured Acetal components have visible signs of the machining so I have just assumed its not economic or possible to polish.

Ian P

01/11/2019 20:03:55

A lot of plastics like, acrylics (Perspex) and hard PVC are easy to polish, some like Acetal (Delrin) are more of a challenge and probably near impossible. I machine a lot of parts out of black Acetal and have not found any practical way of making even a very fine machining marks disappear.

Jason, the ER collet in your pictures look a tad unusual in that the gaps between the tines look unequal, is it just an optical illusion?

Ian P

Thread: Jacobs model 6414 chuck - removal
28/10/2019 13:53:03

That (video) brings back memories!

I bought a Wolf Cub drill sometime in the late 50's and I think the cost was £4-19-6

John Reese is right about the chuck, its accuracy was limited by the fact that the conical outer sleeve parts (which centres the jaws) had a square thread that had no self centering action, and plenty of clearance.

Ian P

27/10/2019 14:14:35

That sounds like the same chuck fitted to the early Wolf 'Cub' pistol drills. The cam mechanism you mention is operated with an Allen key inserted radially into the conical screw hex recess.

Put the key in the recess and give it a tap with a hammer in the undo direction. There is no need to lock the spindle as there is enough mass to resist the inertia.

Ian P

Thread: Boxford metric lead screw fitted to imperial lathe?
26/10/2019 21:07:18

The leadscrew I have came off a lathe that had no gearbox and I dont know what the between centre distance was, do you know what the overall leadscrew length should be if a gearbox is fitted?

Ian P

26/10/2019 20:01:27

I'm not sure what bed length the lathe was but whilst I no longer have the lathe I do still have the leadscrew which I am sure is imperial. Whereabouts are you located.

I no longer have a Boxford lathe but the 5" metric AUD with gearbox I am sure was able to cut metric and imperial threads without swapping any changewheels (or maybe my memory is playing tricks)

Ian P

Thread: Turning a recess in the end of a bar
22/10/2019 13:03:41
Posted by larry phelan 1 on 22/10/2019 12:00:54:

I need to turn a recess in the end of a bar of 40mm dia. The recess needs to be 30mm x6mm deep.

What type of tool bit or cutter do I need and how should I go about it ?

I will have to produce a number of these. I think they are intended to with some form of supports

I need to turn a recess 30mm x 6mm deep in the ends of a bar 40mm dia and I have a number of these to do.

What kind of toolbit or cutter do I need and how do I begin ?

All ideas welcome

As others have said, start with a drilled hole (about 6mm to the correct depth) I would then switch to an endmill held in the toolpost that is used in the same manner as a boring bar. The endmill can have 2 or more flutes so just line up one flute on the centerline. Even if the endmill is not a centre cutting one, up to about 10 or 12mm diameter it will plunge into the drilled hole and then just wind out the crosslide to the bore needed.

Without knowing the intended purpose of the recess all you can do is make the part to the specification given, but it may be that it would not matter if there was a pip or the remnants of the drilled hole still present at the bottom of the recess.

Ian P

Thread: Boring bar
21/10/2019 19:30:34

I have the identical Komet bar (8mm OD) which I bought with ten inserts in 1980something. The original Komet inserts have long since gone and whilst I have fitted other makes none have ever performed as well as the originals and the bar now just sits in a drawer.

I cannot remember the part number for the tiny triangular tips I found, Jenny at JB tooling gave me one as a sample to try so it might be worth contacting her.

Ian P

Thread: Unimat 3 dividing head
21/10/2019 19:22:39

None of the sellers pictures showed that the disks had holes (other than at the zero position?) and I'm always wary of sellers not fully describing items so I thought this Emco product relied on the users eysight. In reality having anodised labels is a good feature.

Ian P

21/10/2019 17:16:30
Posted by Michael Gilligan on 21/10/2019 16:46:43:

Further to Emgee’s post ...

This has some useful pictures of the internals [of the SL version] **LINK**



Edit: It is disappointing to see how different the Unimat 3 version is:


Edited By Michael Gilligan on 21/10/2019 16:52:11

I suppose that if there are no holes or other detents in the plates shown then one would have to describe this amazing Emco product as an 'Optical dividing head'.

The seller seems averse to showing what the body looks like but it looks to have a very short spindle

Ian P

Thread: What Did You Do Today 2019
20/10/2019 15:08:23

Document was created in 2014 by 'Woody', could that be Alan Wood?

Ian P

Thread: Limiting pressure to a gauge
16/10/2019 22:03:31
Posted by Pete Rimmer on 16/10/2019 21:55:02:

Put a 30psi pressure relief valve before the gauge.

Where does the 'relieved' oil or pressure go?

Ian P

16/10/2019 22:02:17

If originality is not important an easy solution it to fit a higher pressure gauge. True, it will not allow accurate interpretation of low pressure values but mostly with engines its not the actual pressure of the oil that is important, its the presence of pressure that matters.

There are probably pressure limiting valves (some vehicle rear brakes were so equipped to stop wheels locking up) but whether anything ready made exists for your application I have no idea.

If the high pressure is only present for a very short period then a restrictor close to the source of the pressure would act as a snubber and the pressure 'event' would be over before the gauge had time to respond and suffer damage.

Ian P

Thread: Toolpost drill mill attachment
16/10/2019 21:27:06
Posted by Emgee on 16/10/2019 21:18:13:

John, at 10,000 revs perhaps the toothed belt drive system is contributing to the vibration issue.


Since this is a low powered tool (motor power is the limiting factor) I was going to suggest using flat pulleys and using the back of the existing belt as a flat belt. Possibly though the teeth on the outer face might still impart some vibration effects that would effect grinding.

However rather than reverse a toothed belt, better would be a reversed polyvee because the full power transmission capabilities of the multi 'V's not really be required for this tool.

Ian P

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