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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: Boring bar with inserts shape choice??
12/11/2019 21:25:40
Posted by Chris TickTock on 12/11/2019 15:31:08:

Hi,

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..

Chris

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

Thread: How does someone gauge the power of a DC or AC motor?
12/11/2019 11:46:28

Thats one of the better produced YouTube videos and I learnt two useful things from it, one that he describes it use as lapping as well as grinding, secondly, I want one!

The diamond disks that he uses are much cheaper than I thought they would be and two from different sellers are on their way to me now.

Ian P

Thread: Suitable metal / enclosure for project
11/11/2019 21:11:34

Happy with agreeing to disagree

Ian Psmile

11/11/2019 20:25:49
Whilst I can see the similarity between a charged lap and abrasive material bonded into a rigid substrate, I doubt anybody would consider the lap as a grinder. Equally I cannot see the wheels that ChrisTT has being used in the manner of a charged lap.
Ian P
This is what Google comes up with for the two processes.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
Grinding is an abrasive machining process that uses a grinding wheel or grinder as the cutting tool. ... Grinding is used to finish workpieces that must show high surface quality and high accuracy of shape and dimension. It has some roughing applications in which grinding removes high volumes of metal very rapidly.
Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or using a machine. ... The other form of lapping involves a softer material such as pitch or a ceramic for the lap, which is "charged" with the abrasive.
Thread: Inverters and stop switches
11/11/2019 19:21:35
Posted by Brian H on 11/11/2019 17:57:54:

XD 351

Many thanks for all your trouble, I have carefully filed away your suggestion for use at a later date and yes, those instructions are identical to the ones that came with the unit.

I have been running the motor and mill at low speeds to bed in the new bearings and also to distribute the grease in the re-packed bearings. The mill is quieter that the VFD unit!

Brian

Is it fan noise you can hear from the VFD?

Ian P

Thread: Suitable metal / enclosure for project
11/11/2019 15:07:18

Grinding and lapping are both material removal processes but they are distinctly different techniques as far as I know.

Eze-Lap is just the name the manufacturer chose for the product, I've seen them referred to a diamond 'files' too.

Ian P

11/11/2019 14:34:40
Posted by Howard Lewis on 11/11/2019 14:26:48:

Removing metal with a carborundum wheel would be Grinding in my book.

Using a diamond wheel for the final polish, to remove very small amounts of metal would be Lapping to me.

Howard

Removing metal with a (driven) diamond wheel would be grinding in my book too, however fine the grade.

Ian P

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.

Roy

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

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